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Sample records for heteropoly acid catalysts

  1. Biomass Conversion over Heteropoly Acid Catalysts

    KAUST Repository

    Zhang, Jizhe

    2015-04-01

    Biomass is a natural resource that is both abundant and sustainable. Its efficient utilization has long been the focus of research and development efforts with the aim to substitute it for fossil-based feedstock. In addition to the production of biofuels (e.g., ethanol) from biomass, which has been to some degree successful, its conversion to high value-added chemicals is equally important. Among various biomass conversion pathways, catalytic conversion is usually preferred, as it provides a cost-effective and eco-benign route to the desired products with high selectivities. The research of this thesis is focused on the conversion of biomass to various chemicals of commercial interest by selective catalytic oxidation. Molecular oxygen is chosen as the oxidant considering its low cost and environment friendly features in comparison with commonly used hydrogen peroxide. However, the activation of molecular oxygen usually requires high reaction temperatures, leading to over oxidation and thus lower selectivities. Therefore, it is highly desirable to develop effective catalysts for such conversion systems. We use kegging-type heteropoly acids (HPAs) as a platform for catalysts design because of their high catalytic activities and ease of medication. Using HPA catalysts allows the conversion taking place at relatively low temperature, which is beneficial to saving production cost as well as to improving the reaction selectivity. The strong acidity of HPA promotes the hydrolysis of biomass of giant molecules (e.g. cellulose), which is the first as well as the most difficult step in the conversion process. Under certain circumstances, a HPA combines the merits of homogeneous and heterogeneous catalysts, acting as an efficient homogeneous catalyst during the reaction while being easily separated as a heterogeneous catalyst after the reaction. We have successfully applied HPAs in several biomass conversion systems. Specially, we prepared a HPA-based bi-functional catalyst

  2. Heteropoly acid promoted catalyst for SCR of NOx with ammonia

    DEFF Research Database (Denmark)

    2012-01-01

    comprising alkali or earth alkali metals. Such gases comprise for example flue gases arising from the burning of biomass, combined biomass and fossil fuel, and from waste incineration units. The process comprises the selective catalytic reduction (SCR) of NOx, such as nitrogen dioxide (NO2) and nitrogen......The present invention concerns the selective removal of nitrogen oxides (NOx) from gases. In particular, the invention concerns a process, a highly alkali metal resistant heteropoly acid promoted catalyst and the use of said catalyst for removal of NOx from exhaust or flue gases, said gases...... oxide (NO) with ammonia (NH3) or a nitrogen containing compound selected from ammonium salts, urea or a urea derivative or a solution thereof as reductant....

  3. Heteropoly acid promoted Cu and Fe catalysts for the selective catalytic reduction of NO with ammonia

    DEFF Research Database (Denmark)

    Putluru, Siva Sankar Reddy; Mossin, Susanne L.; Riisager, Anders

    2011-01-01

    Cu/TiO2, Fe/TiO2 and heteropoly acid promoted Cu/TiO2, Fe/TiO2 catalysts were prepared and characterized by N2 physisorption, XRPD, NH3-TPD, H2-TPR and EPR. The catalysts exhibited only crystalline TiO2 phases with the active metals and promoters in highly dispersed state. The acidic properties...... activity and acidity was lower for promoted catalysts than for unpromoted catalysts. In the heteropoly acid promoted catalysts the SCR active Cu and Fe metals were protected from potassium poisons by bonding of the potassium to the Brønsted acid centres. Thus heteropoly acid promoted catalysts might...

  4. Cu-exchanged heteropoly acids as efficient and reusable catalysts ...

    Indian Academy of Sciences (India)

    Administrator

    Amidoalkyl naphthol; heteropoly acid; Cu-exchanged salts; ionic liquid; tetrabutylammo- nium bromide. 1. Introduction. Compounds bearing 1,3-amino oxygenated func- tional groups are ubiquitous to a variety of biologi- cally important natural products and potent drugs including a number of nucleoside antibiotics and. HIV ...

  5. Valorization of Lignin by Partial Wet Oxidation Using Sustainable Heteropoly Acid Catalysts

    Directory of Open Access Journals (Sweden)

    Abayneh Getachew Demesa

    2017-09-01

    Full Text Available The production of carboxylic acids by partial wet oxidation of alkali lignin at elevated temperatures and pressures was studied experimentally. Two different heteropoly acids, phosphotungstic acid (H3PW12O40 and phosphomolybdic acid (H3PMo12O40, were used to catalyze the oxidation of lignin under hydrothermal conditions. Factors influencing the total yield of carboxylic acids formed during the partial oxidation of lignin were investigated. Formic, acetic and succinic acids were the major products identified. Of the two catalysts used, phosphomolybdic acid gave the most promising results, with carboxylic acid yields and lignin conversions of up to 45% and 95%, respectively.

  6. Esterification of camphene over heterogeneous heteropoly acid catalysts: synthesis of isobornyl carboxylates.

    OpenAIRE

    Meireles, Augusto Luís Pereira de; Rocha, Kelly Alessandra da Silva; Kozhevnikov, Ivan V.; Goussevskaia, Elena Vitalievna

    2011-01-01

    Silica supported H3PW12O40 (PW), the strongest heteropoly acid in the Keggin series, is an active and environmentally friendly solid acid catalyst for liquid-phase esterification of camphene, a renewable biomass-based substrate, with C2, C4 and C6 short-chain fatty acids. The reaction provides isobornyl carboxylates, useful as fragrances, in virtually 100% selectivity and 80–90% yield. The reaction is equilibrium-controlled and occurs under mild conditions with a catalyst turnover number of u...

  7. SELECTIVE SYNTHESIS OF PEG-MONOESTER USING CESIUM HETEROPOLY ACID AS HETEROGENEOUS CATALYST

    Directory of Open Access Journals (Sweden)

    Fatimah Zahara Abdullah

    Full Text Available Esterification of oleic acid with polyethylene glycol 600 (PEG-600 to produce polyethylene glycol monooleate (PEG-monooleate and polyethylene glycol dioleate (PEG-dioleate as by-product has been studied in the presence of heterogeneous acid catalysts, i.e. cesium heteropoly acid (Cs HPA. The results are compared with those obtained from a classical homogeneous acid catalyst; p-toluene sulphonic acid (p-TSA. The reaction was conducted under nitrogen flow with vigorous stirring at 130 ºC and 150 ºC. The catalyst loading kept at 4% and the reaction was monitored at 1, 3, 7 and 24 hours. Reaction samples were analyzed using high performance liquid chromatography (HPLC equipped with evaporative light scattering detector (ELSD. The results obtained showed that Cs HPAs exhibit 100% selectivity of PEG-monooleate from the first hour until 24 hours. However, this does not happen with homogeneous p-TSA, where formation of by-product; PEG-dioleate is observed in the initial stage. It is also showed that the mole ratio is the most important parameter not only to produce high yield of monoester but also to maintain it along the reaction. Chemical and physical properties of catalysts were characterized using Thermal Gravimetric Analysis (TGA, Differential Scanning Calorimetry (DSC, Fourier Tranmittance Infra-Red (FTIR, ammonia temperature programmed desorption (NH3-TPD and X-ray Diffraction (XRD.

  8. Heteropoly acid promoted V2O5/TiO2 catalysts for NO abatement with ammonia in alkali containing flue gases

    DEFF Research Database (Denmark)

    Putluru, Siva Sankar Reddy; Jensen, Anker Degn; Riisager, Anders

    2011-01-01

    V2O5/TiO2 and heteropoly acid promoted V2O5/TiO2 catalysts were prepared and characterized by N2 physisorption, XRPD and NH3-TPD. The influence of the calcination temperature from 400 to 700 1C on crystallinity and acidic properties was studied and compared with the activity for the selective cat...... and acidity with increase in calcination temperatures. Furthermore, the heteropoly acid promoted V2O5/TiO2 catalysts showed excellent alkali deactivation resistance and might therefore be alternative deNOx catalysts in biomass fired power plants....

  9. Hydrophobic Lurylamine Modified Heteropoly Acid as an Efficient and Recyclable Catalyst for the Hydrolysis Reaction in Aqueous Solution under Microwave

    Directory of Open Access Journals (Sweden)

    Wu Lin

    2017-01-01

    Full Text Available A new modified phosphotungstic acid (HPW catalyst (HPW-catal was synthesized b y a simple mixing method under ambient atmosphere and evaluated for the hydrolysis of sucrose and ethyl acetate under microwave irradiation. The as-synthesized catalyst was characterized by X-ray diffraction (XRD, Fourier transform infrared spectroscopy(FTIR, and NH3-TPD, which proved that HPW was sucessfully modified with lurylamine and the catalyst still remains the Keggin structure. Significantly, the HPW-catal showed excellent catalytic hydrolysis perforance for the sucrose and ethyl acetate under microwave irradiation. Both of the reactions were studied over other solid acid catalysts, such as AM-15 and ZSM-5. At mild tempretures, the sucrose and ethyl acetate could be hydrolyzed into corresponding products. The maximum glucose yield and alcohol could reach 100% and 95%, respectively. The HPW-catal can be recycled and reused. The HPW-catal will provides new ideas for the modifying of heteropoly acids.

  10. Catalyst of a metal heteropoly acid salt that is insoluble in a polar solvent on a non-metallic porous support and method of making

    Science.gov (United States)

    Wang, Yong [Richland, WA; Peden, Charles H. F. [West Richland, WA; Choi, Saemin [Richland, WA

    2002-10-29

    The present invention includes a catalyst having (a) a non-metallic support having a plurality of pores; (b) a metal heteropoly acid salt that is insoluble in a polar solvent on the non-metallic support; wherein at least a portion of the metal heteropoly acid salt is dispersed within said plurality of pores. The present invention also includes a method of depositing a metal heteropoly acid salt that is insoluble in a polar solvent onto a non-metallic support having a plurality of pores. The method has the steps of: (a) obtaining a first solution containing a first precursor of a metal salt cation; (b) obtaining a second solution containing a second precursor of a heteropoly acid anion in a solvent having a limited dissolution potential for said first precursor; (c) impregnating the non-metallic support with the first precursor forming a first precursor deposit within the plurality of pores, forming a first precursor impregnated support; (d) heating said first precursor impregnated support forming a bonded first precursor impregnated support; (e) impregnating the second precursor that reacts with the precursor deposit and forms the metal heteropoly acid salt.

  11. Heteropoly acid encapsulated into zeolite imidazolate framework (ZIF-67) cage as an efficient heterogeneous catalyst for Friedel–Crafts acylation

    Energy Technology Data Exchange (ETDEWEB)

    Ammar, Muhammad; Jiang, Sai; Ji, Shengfu, E-mail: jisf@mail.buct.edu.cn

    2016-01-15

    A new strategy has been developed for the encapsulation of the phosphotungstic heteropoly acid (H{sub 3}PW{sub 12}O{sub 40} denoted as PTA) into zeolite imidazolate framework (ZIF-67) cage and the PTA@ZIF-67(ec) catalysts with different PTA content were prepared. The structure of the catalysts was characterized by XRD, BET, SEM, FT-IR, ICP-AES and TG. The catalytic activity and recovery properties of the catalysts for the Friedel-Crafts acylation of anisole with benzoyl chloride were evaluated. The results showed that 14.6–31.7 wt% PTA were encapsulated in the ZIF-67 cage. The PTA@ZIF-67(ec) catalysts had good catalytic activity for Friedel-Crafts acylation. The conversion of anisole can reach ~100% and the selectivity of the production can reach ~94% over 26.5 wt% PTA@ZIF-67(ec) catalyst under the reaction condition of 120 °C and 6 h. After reaction, the catalyst can be easily separated from the reaction mixture by the centrifugation. The recovered catalyst can be reused five times and the selectivity can be kept over 90%. - Graphical abstract: The PTA@ZIF-67 catalysts with different PTA content were prepared by encapsulating the PTA into ZIF-67 cage and the as-synthesized catalysts exhibited good catalytic activity for the Friedel–Craft acylation of anisole with benzoyl chloride.

  12. Study on solar chemical heat pump system. Basic experiment on dehydrogenation of 2-propanol using heteropoly-acid photo catalyst; Solar chemical heat pump no kenkyu. Heteropoly sankei hikari shokubai wo mochiita 2-propanol no dassuiso hanno

    Energy Technology Data Exchange (ETDEWEB)

    Doi, T. [Electrochemical Laboratory, Tsukuba (Japan); T-Raissi, A.; Muradov, N. [Florida Solar Energy Center, FL (United States)

    1996-10-27

    With the purpose of converting solar heat energy to an industrial heat energy, an examination was carried out empirically on the case of using a heteropoly-acid photo catalyst for the decomposition reaction process of 2-propanol. The experiment was performed in Florida Solar Energy Center, in the U.S.A.. The device for the experiment was constituted of a reaction part, distribution manifold for feeding from the lower part of the reaction part a 2-propanol solution for which a photo catalyst was suspended, storage tank served also as a gas-liquid separating container, and circulating pump. Silica-tangstic acid was used as the photo catalyst. In an outdoor experiment using solar radiation, the quantity of inclined global solar radiation was 530-950W/m{sup 2} in clear days and 100-600W/m{sup 2} in cloudy days, with temperatures between 17 and 26{degree}C throughout the experiment period. In addition, an indoor experiment was also conducted using an artificial light source (UV light). As a result of the experiment, the energy conversion efficiency was at most about 1% of incident UV light, a low figure compared to a heat utilization ratio of approximately 15% with a thermal catalyst. 6 refs., 8 figs.

  13. KSF-supported heteropoly acids catalyzed one-pot synthesis of α ...

    African Journals Online (AJOL)

    In the presence of KSF-supported heteropoly acid as a heterogeneous, reusable and inexpensive catalyst, three-component reactions between aldehydes or ketones, amines, and trimethylsilyl cyanide preceded to afford α-aminonitriles in excellent yields, very short reaction times, and low loading of catalyst. This catalyst ...

  14. Nano scale magnetically recoverable supported heteropoly acid as an efficient catalyst for the synthesis of benzimidazole derivatives in water.

    Science.gov (United States)

    Rafiee, Ezzat; Rahpeima, Nasibeh; Eavani, Sara

    2014-01-01

    12-Tungstophosphoric acid supported on silica-coated magnetic nano particles was prepared and characterized by transmission electron microscopy, scanning electron microscopy, powder X-ray diffraction and inductively coupled plasma atomic emission spectroscopy. Acidity of the catalysts was measured by potentiometric titration with n-butylamine. Catalytic activity of the prepared sample was evaluated in the model synthesis of 1,2-disubstituted benzimidazole derivatives in water. The catalyst showed excellent catalytic activity and the corresponding products were obtained in good to excellent yields under mild reaction conditions. Furthermore, the catalyst could be easily recovered using an external magnet and reused several times. The leaching and surface acidity of the recovered catalyst were also investigated.

  15. KSF-supported heteropoly acids catalyzed one-pot synthesis of α-aminonitriles

    Directory of Open Access Journals (Sweden)

    Ezzat Rafiee

    2010-08-01

    Full Text Available In the presence of KSF-supported heteropoly acid as a heterogeneous, reusable and inexpensive catalyst, three-component reactions between aldehydes or ketones, amines, and trimethylsilyl cyanide preceded to afford α-aminonitriles in excellent yields, very short reaction times, and low loading of catalyst. This catalyst was highly selective and other functional groups including carbon-carbon double bond, and heterocyclic moieties did not affect the reaction.

  16. Conversion of industrial (ligno)cellulose feeds to isosorbide with heteropoly acids and Ru on carbon

    Energy Technology Data Exchange (ETDEWEB)

    Op de Beeck, B.; Van Lishout, J.; Jacobs, P.A.; Sels, B.F. [Centre for Surface Chemistry and Catalysis, Katholieke Universiteit Leuven, Kasteelpark Arenberg 23, 3001 Heverlee (Belgium); Geboers, J. [Max-Planck-Institut fuer Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Muelheim an der Ruhr (Germany); Van de Vyver, S. [Massachusetts Institute of Technology MIT, Massachusetts Avenue 77, Cambridge, MA 02139-4307 (United States); Snelders, J.; Courtin, C.M. [Centre for Food and Microbial Technology, Katholieke Universiteit Leuven, Kasteelpark Arenberg 22, 3001 Heverlee (Belgium); Huijgen, W.J.J. [Biomass and Energy Efficiency BEE, Energy research Centre of the Netherlands ECN, Westerduinweg 3, 1755 LE Petten (Netherlands)

    2013-01-11

    The catalytic valorization of cellulose is currently subject of intense research. Isosorbide is among the most interesting products that can be formed from cellulose as it is a potential platform molecule and can be used for the synthesis of a wide range of pharmaceuticals, chemicals, and polymers. A promising direct route from cellulose to isosorbide is presented in this work. The strategy relies on a one-pot bifunctional catalytic concept, combining heteropoly acids, viz. H4SiW12O40, and redox catalysts, viz. commercial Ru on carbon, under H2 pressure. Starting from pure microcrystalline cellulose, a rapid conversion was observed, resulting in over 50% isosorbide yield. The robustness of the developed system is evidenced by the conversion of a range of impure cellulose pulps obtained by organosolv fractionation, with isosorbide yields up to 63%. Results were compared with other (ligno)cellulose feedstocks, highlighting the importance of fractionation and purification to increase reactivity and convertibility of the cellulose feedstock.

  17. Fractal analysis of bentonite modified with heteropoly acid using nitrogen sorption and mercury intrusion porosimetry

    Directory of Open Access Journals (Sweden)

    Rožić Ljiljana S.

    2011-01-01

    Full Text Available Experimental adsorption isotherms were used to evaluate the specific surface area and the surface fractal dimensions of acid-activated bentonite samples modified with a heteropoly acid (HPW. The aim of the investigations was to search for correlations between the specific surface area and the geometric heterogeneity, as characterized by the surface fractal dimension and the content of added acid. In addition, mercury intrusion was employed to evaluate the porous microstructures of these materials. The results from the Frankel-Halsey-Hill method showed that, in the p/p0 region from 0.75 to 0.96, surface fractal dimension increased with increasing content of heteropoly acid. The results from mercury intrusion porosimetry (MIP data showed the generation of mesoporous structures with important topographical modifications, indicating an increase in the roughness (fractal geometry of the surface of the solids as a consequence of the modification with the heteropoly acid. By comparison, MIP is preferable for the characterization because of its wide effective probing range.

  18. Comparison of Catalysts Preyssler and Silica-Supported Nano Preyssler in the Synthesis of Acetyl Salicylic Acid

    OpenAIRE

    Nazari, H.; Ahmadpour, A.; Bamoharram, F. F.; Heravi, M. M.; Eslami, N.

    2012-01-01

    The extensive demand for cleaner environment is forcing chemical industry to use less hazardous materials. In this regard, heteropolyacids attracted considerable amount of interest due to the less toxic behavior in addition of possessing higher acidity. Heteropoly acids have been used as catalysts for the reaction of salicylic acid with acetic anhydride. The performance of different forms of heteropoly acids in the presence of acetic anhydride as acetylating agent for acetylation of salicylic...

  19. Comparison of Catalysts Preyssler and Silica-Supported Nano Preyssler in the Synthesis of Acetyl Salicylic Acid

    Directory of Open Access Journals (Sweden)

    H. Nazari

    2012-01-01

    Full Text Available The extensive demand for cleaner environment is forcing chemical industry to use less hazardous materials. In this regard, heteropolyacids attracted considerable amount of interest due to the less toxic behavior in addition of possessing higher acidity. Heteropoly acids have been used as catalysts for the reaction of salicylic acid with acetic anhydride. The performance of different forms of heteropoly acids in the presence of acetic anhydride as acetylating agent for acetylation of salicylic acid was compared. The best conditions were observed using Preyssler and Silica-supported Preyssler Nanoparticles as catalysts. The catalyst is recyclable and reusable.

  20. Molybdenum-containing acidic catalysts to convert cellulosic biomass to glycolic acid

    KAUST Repository

    Han, Yu

    2014-09-30

    Embodiments of the present invention include methods and compositions related to catabolic conversion of cellulosic biomass to glycolic acid using molybdenum-containing acidic catalysts. The invention includes the use of heteropoly and isopoly acids and salts as the molybdenum-containing multi-functional catalysts for biomass conversion. In embodiments of the invention, the reactions employ successive hydrolysis, retro-aldol fragmentation, and selective oxidation in a noble metal-free system.

  1. Characterization and catalytic performance of heteropoly acid H4SiW12O40 supported on nanoporous materials.

    Science.gov (United States)

    Chen, Fengxi; Ma, Jiping; Dong, Zhibing; Liu, Rong

    2014-09-01

    Heteropoly acid H4SiW12O40 (SiW) has been supported on different nanoporous materials and characterized by powder X-ray diffraction (XRD), FTIR, HRTEM, N2 physisorption, and thermal analysis. No SiW diffraction peaks are observed after loading 33-50 wt% of SiW on various mesoporous materials (pore size: -30 Å) except for siliceous MCM-48. In contrast, the SiW diffraction peaks appear at 14 wt% loading on zeolite EMT with micropore size of ca. 7.4 x 6.5 Å. Supported SiW retains the Keggin structure on mesopore surface. The cubic mesostructure of MCM-48 is stable while MCM-41 loses its regular hexagonal mesostructure upon loading SiW. Several factors account for different behaviours of various supports, including pore size, curvature of mesopore interface and interaction between SiW and aluminium sites in the framework. The resulting 33-50 wt% SiW/MCM-48 solid acid catalysts have large surface area (- 550 m2/g), regular pore arrangement with uniform pore size (- 25 Å), finely dispersed SiW and good thermal stability. They exhibit significantly improved activity in acid-catalyzed cracking of long-chain hydrocarbons in comparison with bulk SiW and SiW/MCM-41.

  2. Cu-exchanged heteropoly acids as efficient and reusable catalysts ...

    Indian Academy of Sciences (India)

    A series of amidoalkyl naphthols were prepared in high yields using various aldehydes and urea or amides. The reaction was catalysed by Cu1.5PMo12O40 (CuPMo) and Cu1.5PW12O40 (CuPW) and conducted in molten tetrabutylammonium bromide as an ionic liquid.

  3. Oxidative Desulfurization of Dibenzothiophene Using Dawson Type Heteropoly Compounds/Tantalum as Catalyst

    Directory of Open Access Journals (Sweden)

    Risfidian Mohadi

    2016-03-01

    Full Text Available Catalyst (NH46[b-P2W18O62]/Ta has been synthesized by simple wet impregnation at 30-40 °C under atmospheric conditions using Dawson type polyoxometalate (NH46[b-P2W18O62] and tantalum. The catalyst was characterized by FTIR spectrophotometer, XRD, SEM, and N2 adsorption desorption methods. FTIR spectrum of (NH46[b-P2W18O62]/Ta showed that Dawson type polyoxometalate (NH46[b-P2W18O62] and Ta was successfully impregnated which was indicated by vibration spectrum at wavenumber of 900-1100 cm-1 for polyoxometalate and 550 cm-1 for Ta. The surface area of the (NH46[b-P2W18O62]/Ta after impregnation was higher than (NH46[b-P2W18O62]•nH2O and its morphology was found to be uniform. The catalytic activity of (NH46[b-P2W18O62]/Ta toward desulfurization of dibenzothiophene was three times higher than the original catalyst of (NH46[b-P2W18O62]•nH2O without impregnation. The catalytic regeneration test of catalyst (NH46[b-P2W18O62]/Ta showed that the catalytic activity for first regeneration of catalyst has similar catalytic activity with the fresh catalyst without loss of catalytic activity indicated by almost similar percent conversion.

  4. Conductivity Measurements of Synthesized Heteropoly Acid Membranes for Proton Exchange Membrane Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Record, K.A.; Haley, B.T.; Turner, J.

    2006-01-01

    Fuel cell technology is receiving attention due to its potential to be a pollution free method of electricity production when using renewably produced hydrogen as fuel. In a Proton Exchange Membrane (PEM) fuel cell H2 and O2 react at separate electrodes, producing electricity, thermal energy, and water. A key component of the PEM fuel cell is the membrane that separates the electrodes. DuPont’s Nafion® is the most commonly used membrane in PEM fuel cells; however, fuel cell dehydration at temperatures near 100°C, resulting in poor conductivity, is a major hindrance to fuel cell performance. Recent studies incorporating heteropoly acids (HPAs) into membranes have shown an increase in conductivity and thus improvement in performance. HPAs are inorganic materials with known high proton conductivities. The primary objective of this work is to measure the conductivity of Nafion, X-Ionomer membranes, and National Renewable Energy Laboratory (NREL) Developed Membranes that are doped with different HPAs at different concentrations. Four-point conductivity measurements using a third generation BekkTech conductivity test cell are used to determine membrane conductivity. The effect of multiple temperature and humidification levels is also examined. While the classic commercial membrane, Nafion, has a conductivity of approximately 0.10 S/cm, measurements for membranes in this study range from 0.0030 – 0.58 S/cm, depending on membrane type, structure of the HPA, and the relative humidity. In general, the X-ionomer with H6P2W21O71 HPA gave the highest conductivity and the Nafion with the 12-phosphotungstic (PW12) HPA gave the lowest. The NREL composite membranes had conductivities on the order of 0.0013 – 0.025 S/cm.

  5. Investigation of the thermal stability of phosphotungstic Wells-Dawson heteropoly-acid through in situ Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Matkovic, Silvana Raquel, E-mail: matkovic@quimica.unlp.edu.ar [Centro de Investigacion y Desarrollo en Ciencias Aplicadas-Dr. Jorge J. Ronco. U.N.L.P., CONICET, CCT La Plata. Calle 47 N 257, B1900AJK La Plata, Buenos Aires (Argentina); Briand, Laura Estefania [Centro de Investigacion y Desarrollo en Ciencias Aplicadas-Dr. Jorge J. Ronco. U.N.L.P., CONICET, CCT La Plata. Calle 47 N 257, B1900AJK La Plata, Buenos Aires (Argentina); Banares, Miguel Angel [Laboratorio de Espectroscopia Catalitica, Instituto de Catalisis y Petroleoquimica, CSIC. Marie Curie 2, Cantoblanco, E-28049 Madrid (Spain)

    2011-11-15

    Highlights: {yields} Insitu Raman is used to monitor the thermal stability of Wells Dawson heteropolyacid. {yields} TP-Raman follows the gradual dehydration and the effect on the secondary structure. {yields} Wells-Dawson heteropolyacid does not decompose into Keggin and WO{sub 3} units below 600{sup o}C -- Abstract: The present investigation applies laser Raman spectroscopy under in situ conditions to obtain insights on the effect of the temperature on the molecular structure of the bulk phosphotungstic Wells-Dawson heteropoly-acid H{sub 6}P{sub 2}W{sub 18}O{sub 62}.xH{sub 2}O (HPA). The in situ temperature-programmed studies followed the evolution of phosphotungstic Wells-Dawson and Keggin heteropoly-acids along with tungsten trioxide under controlled atmosphere and temperature. The spectroscopic investigation of the Wells-Dawson HPA demonstrated that in situ Raman spectroscopy is a suitable technique to follow the effect of a gradual dehydration on the secondary structure of such a complex structure. Moreover, the absence of the signals belonging either to the Keggin or WO{sub 3} phases provides further evidence that the phosphotungstic heteropolyanion does not decomposes towards those materials at temperatures below 600 {sup o}C.

  6. Direct conversion of cellulose to glycolic acid with a phosphomolybdic acid catalyst in a water medium

    KAUST Repository

    Zhang, Jizhe

    2012-08-03

    Direct conversion of cellulose to fine chemicals has rarely been achieved. We describe here an eco-benign route for directly converting various cellulose-based biomasses to glycolic acid in a water medium and oxygen atmosphere in which heteromolybdic acids act as multifunctional catalysts to catalyze the hydrolysis of cellulose, the fragmentation of monosaccharides, and the selective oxidation of fragmentation products. With commercial α-cellulose powder as the substrate, the yield of glycolic acid reaches 49.3%. This catalytic system is also effective with raw cellulosic biomass, such as bagasse or hay, as the starting materials, giving rise to remarkable glycolic acid yields of ∼30%. Our heteropoly acid-based catalyst can be recovered in solid form after reaction by distilling out the products and solvent for reuse, and it exhibits consistently high performance in multiple reaction runs. © 2012 American Chemical Society.

  7. The use of the heteropoly acids, H{sub 3}PMo{sub 12}O{sub 40} and H{sub 3}PW{sub 12}O{sub 40}, for the enhanced electrochemical oxidation of methanol for direct methanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Ferrell, Jack R. III. [Department of Chemical Engineering, Colorado School of Mines, Golden, CO 80401 (United States); Hydrogen and Electricity, Systems and Infrastructure Group, National Renewable Energy Laboratory, Golden, CO 80401 (United States); Kuo, Mei-Chen; Herring, Andrew M. [Department of Chemical Engineering, Colorado School of Mines, Golden, CO 80401 (United States); Turner, John A. [Hydrogen and Electricity, Systems and Infrastructure Group, National Renewable Energy Laboratory, Golden, CO 80401 (United States)

    2008-05-30

    Polarization and electrochemical impedance spectroscopy experiments were performed on a direct methanol fuel cell (DMFC) incorporating the heteropoly acids (HPAs) phosphomolybdic acid, H{sub 3}PMo{sub 12}O{sub 40}, (HPMo) or phosphotungstic acid, H{sub 3}PW{sub 12}O{sub 40}, (HPW) in the anode Pt/C catalyst layer. Both HPW-Pt and HPMo-Pt showed higher performance than the Pt control at 30 psig of backpressure and at ambient pressure. Anodic polarizations were also performed, and Tafel slopes were extracted from the data between 0.25 V and 0.5 V. At 30 psig, Tafel slopes of 133 mV/dec, 146 mV/dec, and 161 mV/dec were found for HPW-Pt, HPMo-Pt and the Pt control, respectively. At 0 psig, the Tafel slopes were 172 mV/dec, 178 mV/dec, and 188 mV/dec for HPW-Pt, HPMo-Pt and the Pt control. An equivalent circuit model, which incorporated constant phase elements (CPEs), was used to model the impedance data. From the impedance model it was found that the incorporation of HPAs into the catalyst layer resulted in a reduction in the resistances to charge transfer. This shows that these two heteropoly acids do act as co-catalysts with platinum for methanol electrooxidation. (author)

  8. Catalytic oxidation of light alkanes (C1-C4) by heteropoly compounds

    KAUST Repository

    Sun, Miao

    2014-01-22

    Heteropoly compounds (HPC) have revealed their potential to generate catalyst for selectively converting light alkanes to oxygenated products. There are various structures in which they are active the primary structure being that of the heteropolyanion itself, the secondary structure is the three-dimensional arrangements of polyanions, and the tertiary structure representing the manner in which the secondary structure assembles into solid particles. There are also a huge variety of elements inside the HPA. The heteropoly acids can have acidity, which varies dramatically depending on composition. This complexity of situation makes it very difficult to really have a predictive vision of their ability to activate and functionalize alkanes. However, a large amount of data reported suggests that the initial formula of the precatalyst is pivotal to direct the selectivity of the reaction toward different oxygenates. Inclusion of alternative transition metal atoms as addenda is highly influential with iron, vanadium, and antimony being particularly outstanding.

  9. Silica-titania xerogel doped with Mo,P-heteropoly compounds for solid phase spectrophotometric determination of ascorbic acid in fruit juices, pharmaceuticals, and synthetic urine.

    Science.gov (United States)

    Morosanova, Maria A; Morosanova, Elena I

    2017-01-01

    Ascorbic acid is one of the most important vitamins to monitor in dietary sources (juices and vitamins) and biological liquids. Silica and silica-titania xerogels doped with Mo,P-heteropoly compounds (HPC) have been synthesized varying titanium(IV) and HPC content in sol. Their surface area and porosity have been studied with nitrogen adsorption and scanning electron microscopy, their elemental composition has been studied with energy-dispersive X-ray analysis. The redox properties of the sensor material with sufficient porosity and maximal HPC content have been studied with potentiometry and solid phase spectrophotometry and it has been used for solid phase spectrophotometric determination of ascorbic acid. The proposed method is characterized by good selectivity, simple probe pretreatment and broad analytical range (2-200 mg/L, LOD 0.7 mg/L) and has been applied to the analysis of fruit juices, vitamin tablets, and synthetic urine. New sensor material has been used for simple and selective solid phase spectrophotometric procedure of ascorbic acid determination in fruit juices, vitamin tablets, and synthetic urine.Graphical abstractWe synthesized several silica-titania xerogels doped with Mo,P-heteropoly compounds, studied their properties, and designed the sensor material for solid phase spectrophotometric determination of ascorbic acid in fruit juices, pharmaceuticals, and synthetic urine.

  10. Activities of Heterogeneous Acid-Base Catalysts for Fragrances Synthesis: A Review

    Directory of Open Access Journals (Sweden)

    Hartati Hartati

    2013-06-01

    Full Text Available This paper reviews various types of heterogeneous acid-base catalysts for fragrances preparation. Catalytic activities of various types of heterogeneous acid and base catalysts in fragrances preparation, i.e. non-zeolitic, zeolitic, and mesoporous molecular sieves have been reported. Generally, heterogeneous acid catalysts are commonly used in fragrance synthesis as compared to heterogeneous base catalysts. Heteropoly acids and hydrotalcites type catalysts are widely used as heterogeneous acid and base catalysts, respectively. © 2013 BCREC UNDIP. All rights reservedReceived: 20th January 2013; Revised: 31st March 2013; Accepted: 1st April 2013[How to Cite: Hartati, H., Santoso, M., Triwahyono, S., Prasetyoko, D. (2013. Activities of Heterogeneous Acid-Base Catalysts for Fragrances Synthesis: A Review. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (1: 14-33. (doi:10.9767/bcrec.8.1.4394.14-33][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.1.4394.14-33] | View in  |

  11. Role of vanadium in Keggin heteropoly molybdate supported on ...

    Indian Academy of Sciences (India)

    ated for oxidation of 1,2-benzenedimethanol using H2O2 and O2 as oxidants. .... C on oil bath. In the case of O2 as oxidant, reaction was conducted under O2 atmosphere. Progress of the reaction was monitored by using thin-layer chro- ... The role of vanadium in heteropoly molybdate catalysts for oxidation reactions. 469.

  12. Iodination of Alcohols over Keggin-type Heteropoly Compounds: A ...

    African Journals Online (AJOL)

    ... several competitive reactions were studied between structurally diverse alcohols. This protocol provides a mild and expedient way for the conversion of various alcohols to their corresponding alkyl iodides with high selectivity. Keywords: Keggin-type Heteropoly Compounds, Supported Catalyst, Alcohols, Alkyl Iodides, ...

  13. Heteropoly acid catalytic treatment for reactivity enhancement and viscosity control of dissolving pulp.

    Science.gov (United States)

    Wang, Xinqi; Duan, Chao; Zhao, Chengxin; Meng, Jingru; Qin, Xiaoyu; Xu, Yongjian; Ni, Yonghao

    2018-04-01

    The reactivity enhancement and viscosity control are of practical importance during the manufacture of high-quality cellulose (also known as dissolving pulp). In the study, the concept of using phosphotungstic acid (HPW) for this purpose was demonstrated. The Fock reactivity of resultant pulp increased from 49.1% to 74.1% after the HPW catalytic treatment at a dosage of 86.4 mg HPW/g odp. The improved results can be attributed to the increased fiber accessibility, thanks to the favorable fiber morphologic changes, such as increased pore volume/size, water retention value and specific surface area. HPW can be readily recycled/reused by evaporating method, where maintaining 87.1% catalytic activity after six recycle times. The HPW catalytic treatment concept may provide a green alternative for the manufacture of high-quality dissolving pulp. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Alternative alkali resistant deNOx catalysts

    DEFF Research Database (Denmark)

    Putluru, Siva Sankar Reddy; Kristensen, Steffen Buus; Due-Hansen, Johannes

    2012-01-01

    potassium doping (250 and 280 µmol of K/g, respectively). The increased poisoning resistance was due to high substrate acidity (sulphated, heteropoly acid promoted and zeolite supports), substituting the active species of the catalyst (other than vanadium species, i.e. Cu, Fe) and new catalyst synthesis...... by onepot sol–gel method. All catalysts were characterized by BET, XRPD and NH3-TPD. Initial SCR activities of 8 out of 9 catalysts showed higher NO conversion at least at one temperature in the temperature range 300–500 ◦C compared to the conventional V2O5-WO3/TiO2 catalyst. After potassium poisoning (100...

  15. Biodiesel fuel production from waste cooking oil by the inclusion complex of heteropoly acid with bridged bis-cyclodextrin.

    Science.gov (United States)

    Zou, Changjun; Zhao, Pinwen; Shi, Lihong; Huang, Shaobing; Luo, Pingya

    2013-10-01

    The inclusion complex of Cs2.5H0.5PW12O40 with bridged bis-cyclodextrin (CsPW/B) is prepared as a highly efficient catalyst for the direct production of biodiesel via the transesterification of waste cooking oil. CsPW/B is characterized by X-ray diffraction, and the biodiesel is analyzed by Gas Chromatography-Mass Spectrometer. The conversion rate of waste cooking oil is up to 94.2% under the optimum experimental conditions that are methanol/oil molar ratio of 9:1, catalyst dosage of 3 wt%, temperature of 65 °C and reaction time of 180 min. The physical properties of biodiesel sample satisfy the requirement of ASTM D6751 standards. The novel CsPW/B catalyst used for the transesterification can lead to 96.9% fatty acid methyl esters and 86.5% of the biodiesel product can serve as the ideal substitute for diesel fuel, indicating its excellent potential application in biodiesel production. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Preparation and characterization of magnetic Wells-Dawson heteropoly acid nanoparticles for magnetic solid-phase extraction of aromatic amines in water samples.

    Science.gov (United States)

    Amiri, Amirhassan; Saadati-Moshtaghin, Hamid Reza; Zonoz, Farokhzad Mohammadi; Targhoo, Azadeh

    2017-02-03

    In this work, aminopropyl modified silica-coated magnetite nanoparticles with Wells-Dawson heteropoly acid (P2W17Fe@APSCMNPs) was first synthesized and underwent highly efficient magnetic solid-phase extraction (MSPE) of aromatic amines from aqueous samples. The resulted nanomaterials were characterized with different physicochemical techniques such as Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM). Aniline, N,N-dimethylaniline, o-toluidine and 3-chloroaniline were selected as target compounds. The sample quantification was carried out using gas chromatography-flame ionization detector (GC-FID). Under optimal working conditions, the developed method showed good linearity (R>0.9912) in the range of 0.01-100ngmL(-1). The method displays detection limits (at an S/N ration of 3) in the range from 0.003 to 0.01ngmL(-1), and the limits of quantification (at an S/N ratio of 10) are between 0.01 and 0.04ngmL(-1). The enrichment factors (EFs) were in the range of 75-113. Relative standard deviations (RSDs) are 4.8-8.3%. The applicability of the developed method was examined by analyzing different water samples (river water, tap water, well water and wastewater) and the relative recovery values for the spiked water samples were found to be in the range of 90.7-99.8%. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Heteropoly acid as a novel nitrene transfer agent: a facile and practical aziridination of olefins with Chloramine-T.

    Science.gov (United States)

    Kumar, G D Kishore; Baskaran, Sundarababu

    2004-04-21

    Environmentally benign HPA is found to be an efficient catalyst for aziridination of olefins in the presence of inexpensive Chloramine-T as a nitrogen source: instantaneous at room temperature, requires only stoichiometric amount of olefin and no allyl amine side product.

  18. Novel Approaches to Immobilized Heteropoly Acid Systems for High Temperature, Low Relative Humidity Polymer-Type Membranes - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Herring, Andrew M; Horan, James L; Aieta, Niccolo V; Sachdeva, Sonny; Kuo, Mei-Chen; Ren, Hui; Lingutla, Anitha; Emery, Michael; Haugen, Gregory M; Yandrasits, Michael A; Sharma, Neeraj; Coggio, William D; Hamrock, Steven J; Frey, Matthew H

    2012-05-20

    Original research was carried out at the CSM and the 3M Company from March 2007 through September 2011. The research was aimed at developing new to the world proton electrolyte materials for use in hydrogen fuel cells, in particular with high proton conductivity under hot and dry conditions (>100mS/cm at 120°C and 50%RH). Broadly stated, the research at 3M and between 3M and CSM that led to new materials took place in two phases: In the first phase, hydrocarbon membranes that could be formed by photopolymerization of monomer mixtures were developed for the purpose of determining the technical feasibility of achieving the program's Go/No-Go decision conductivity target of >100mS/cm at 120°C and 50%RH. In the second phase, attempts were made to extend the achieved conductivity level to fluorinated material systems with the expectation that durability and stability would be improved (over the hydrocarbon material). Highlights included: Multiple lots of an HPA-immobilized photocurable terpolymer derived from di-vinyl-silicotungstic acid (85%), n-butyl acrylate, and hexanediol diacrylate were prepared at 3M and characterized at 3M to exhibit an initial conductivity of 107mS/cm at 120°C and 47%RH (PolyPOM85v) using a Bekktech LLC sample fixture and TestEquity oven. Later independent testing by Bekktech LLC, using a different preheating protocol, on the same material, yielded a conductivity value of approximately 20mS/cm at 120°C and 50%RH. The difference in measured values is likely to have been the result of an instability of properties for the material or a difference in the measurement method. A dispersed catalyst fuel cell was fabricated and tested using a 150¼m thick HPA-based photocurable membrane (above, PolyPOM75v), exhibiting a current density of greater than 300mA/cm2 at 0.5V (H2/Air 800/1800sccm 70°C/75%RH ambient outlet pressure). Multiple lots of a co-polymer based on poly-trifluorovinylether (TFVE) derived HPA were synthesized and fabricated into

  19. Structural and transport effects of doping perfluorosulfonic acid polymers with the heteropoly acids, H{sub 3}PW{sub 12}O{sub 40} or H{sub 4}SiW{sub 12}O{sub 40}

    Energy Technology Data Exchange (ETDEWEB)

    Meng Fanqin [Department of Chemical Engineering, Colorado School of Mines, Golden, CO 80401 (United States); Aieta, Niccolo V. [Department of Chemical Engineering, Colorado School of Mines, Golden, CO 80401 (United States); Hydrogen and Electricity, Systems and Infrastructure Group, National Renewable Energy Laboratory, Golden, CO 80401 (United States); Dec, Steven F. [Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401 (United States); Horan, James L. [Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401 (United States); Hydrogen and Electricity, Systems and Infrastructure Group, National Renewable Energy Laboratory, Golden, CO 80401 (United States); Williamson, Don [Department of Physics, Colorado School of Mines, Golden, CO 80401 (United States); Frey, Matthew H. [3M Corporate Research Materials Laboratory, 3M Company, St. Paul, MN 55144 (United States); Pham, Phat [3M Fuel Cell Components Program, 3M Company, St. Paul, MN 55144 (United States); Turner, John A. [Hydrogen and Electricity, Systems and Infrastructure Group, National Renewable Energy Laboratory, Golden, CO 80401 (United States); Yandrasits, Michael A.; Hamrock, Steven J. [3M Fuel Cell Components Program, 3M Company, St. Paul, MN 55144 (United States); Herring, Andrew M. [Department of Chemical Engineering, Colorado School of Mines, Golden, CO 80401 (United States)], E-mail: aherring@mines.edu

    2007-12-20

    A perfluorosulfonic acid (PFSA) polymer with pendant side chain -O(CF{sub 2}){sub 4}SO{sub 3}H was doped with the heteropoly acids (HPAs), H{sub 3}PW{sub 12}O{sub 40} and H{sub 4}SiW{sub 12}O{sub 40}. Infrared spectroscopy revealed a strong interaction between the HPA and the PFSA ionomer. Modes associated with the peripheral bonds of the HPA were shifted to lower wave numbers when doped into PFSA membranes. Small-angle X-ray scattering (SAXS) measurements showed the presence of large crystallites of HPA in the membrane with d spacings of ca. 10 A, close to the lattice spacing observed in bulk HPA crystals. Under wet conditions the HPA was more dispersed and constrained the size of the sulfonic acid clusters to 20 A at a 5 wt% HPA doping level, the same as in the vacuum treated ionomer samples. Under conditions of minimum hydration the HPA decreased the E{sub a} for the self-diffusion of water from 27 to 15 kJ mol{sup -1}. The reverse trend was seen under 100% RH conditions. Proton conductivity measurements showed improved proton conductivity of the HPA doped PFSAs at a constant dew point of 80 deg. C for all temperatures up to 120 deg. C and at all relative hummidities up to 80%. The activation energy for proton conduction generally was lower than for the undoped materials at RH {<=}80%. Significantly the E{sub a} was 1/2 that of the undoped material at RHs of 40 and 60%. A practical proton conductivity of 113 mS cm{sup -1} was observed at 100 deg. C and 80% RH.

  20. Solid Acid Catalysts in Green Chemistry

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 10. Solid Acid Catalysts in Green Chemistry - Some Practical Examples. Leena Rao. General Article Volume 12 Issue 10 October 2007 pp 30-36. Fulltext. Click here to view fulltext PDF. Permanent link:

  1. Solid Acid Catalysts in Green Chemistry

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 8. Solid Acid Catalysts in Green Chemistry - Emerging Eco-Friendly Practices in Chemical Industry. Leena Rao. General Article Volume 12 Issue 8 August 2007 pp 65-75 ...

  2. Promoted V2O5/TiO2 catalysts for selective catalytic reduction of NO with NH3 at low temperatures

    DEFF Research Database (Denmark)

    Putluru, Siva Sankar Reddy; Schill, Leonhard; Godiksen, Anita

    2016-01-01

    The influence of varying the V2O5 content (3–6 wt.%) was studied for the selective catalytic reduction (SCR) of nitrogen oxides by ammonia on heteropoly acid (HPA)- and tungsten oxide (WO3)-promoted V2O5/TiO2 catalysts. The SCR activity and alkali deactivation resistance of HPA-promoted V2O5/TiO2...

  3. Promoted V2O5/TiO2 catalysts for selective catalytic reduction of NO with NH3 at low temperatures

    DEFF Research Database (Denmark)

    Putluru, Siva Sankar Reddy; Schill, Leonhard; Godiksen, Anita

    2016-01-01

    The influence of varying the V2O5 content (3–6 wt.%) was studied for the selective catalytic reduction (SCR) of nitrogen oxides by ammonia on heteropoly acid (HPA)- and tungsten oxide (WO3)-promoted V2O5/TiO2 catalysts. The SCR activity and alkali deactivation resistance of HPA-promoted V2O5/TiO2...

  4. Catalyst and electrode research for phosphoric acid fuel cells

    Science.gov (United States)

    Antoine, A. C.; King, R. B.

    1987-01-01

    An account is given of the development status of phosphoric acid fuel cells' high performance catalyst and electrode materials. Binary alloys have been identified which outperform the baseline platinum catalyst; it has also become apparent that pressurized operation is required to reach the desired efficiencies, calling in turn for the use of graphitized carbon blacks in the role of catalyst supports. Efforts to improve cell performance and reduce catalyst costs have led to the investigation of a class of organometallic cathode catalysts represented by the tetraazaannulenes, and a mixed catalyst which is a mixture of carbons catalyzed with an organometallic and a noble metal.

  5. Pre-treatment of biomasses using magnetised sulfonic acid catalysts

    Directory of Open Access Journals (Sweden)

    Yane Ansanay

    2017-06-01

    Full Text Available There is a significant interest in employing solid acid catalysts for pre-treatment of biomasses for subsequent hydrolysis into sugars, because solid acid catalysts facilitate reusability, high activity, and easier separation. Hence the present research investigated pretreatment of four lignocellulosic biomasses, namely Switchgrass (Panicum virgatum L ‘Alamo’, Gamagrass (Tripsacum dactyloides, Miscanthus (Miscanthus × giganteus and Triticale hay (Triticale hexaploide Lart. at 90°C for 2 h using three carbon-supported sulfonic acid catalysts. The catalysts were synthesized via impregnating p-Toluenesulfonic acid on carbon (regular and further impregnated with iron nitrate via two methods to obtain magnetic A and magnetic B catalysts. When tested as pre-treatment agents, a maximum total lignin reduction of 17.73±0.63% was observed for Triticale hay treated with magnetic A catalyst. Furthermore, maximum glucose yield after enzymatic hydrolysis was observed to be 203.47±5.09 mg g–1 (conversion of 65.07±1.63% from Switchgrass treated with magnetic A catalyst. When reusability of magnetised catalysts were tested, it was observed that magnetic A catalyst was consistent for Gamagrass, Miscanthus × Giganteus and Triticale hay, while magnetic B catalyst was found to maintain consistent yield for switchgrass feedstock. Our results suggested that magnetised solid acid catalyst could pre-treat various biomass stocks and also can potentially reduce the use of harsh chemicals and make bioenergy processes environment friendly.

  6. Solid acid catalysts in heterogeneous n-alkanes hydroisomerisation ...

    African Journals Online (AJOL)

    Both solid and gaseous acid modifiers could similarly modify their textural characteristics. The activities of all catalysts could under uncontrolled conditions lead to side reactions such as cracking, aromatisation and dehydrogenation. Keywords; Solid acids, n-alkanes, hydroisomerisation catalysts, gasoline, octane number.

  7. Catalytic oxidative conversion of cellulosic biomass to formic acid and acetic acid with exceptionally high yields

    KAUST Repository

    Zhang, Jizhe

    2014-09-01

    Direct conversion of raw biomass materials to fine chemicals is of great significance from both economic and ecological perspectives. In this paper, we report that a Keggin-type vanadium-substituted phosphomolybdic acid catalyst, namely H4PVMo11O40, is capable of converting various biomass-derived substrates to formic acid and acetic acid with high selectivity in a water medium and oxygen atmosphere. Under optimized reaction conditions, H4PVMo11O40 gave an exceptionally high yield of formic acid (67.8%) from cellulose, far exceeding the values achieved in previous catalytic systems. Our study demonstrates that heteropoly acids are generally effective catalysts for biomass conversion due to their strong acidities, whereas the composition of metal addenda atoms in the catalysts has crucial influence on the reaction pathway and the product selectivity. © 2013 Elsevier B.V.

  8. Solid acid catalysts: Stain and shine

    Science.gov (United States)

    Chen, Peng

    2011-11-01

    Catalyst particles for fluid catalytic cracking are vital for the oil-refinery industry, but their activity is hard to diagnose because of their inter- and intra-particle structural inhomogeneity. With fluorescence confocal microscopy and selective staining, one can now pinpoint the catalytic activity within single catalyst particles from an industrial reactor.

  9. Method for producing iron-based acid catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Farcasiu, M.; Kathrein, H.; Kaufman, P.B.; Diehl, J.R.

    1998-04-01

    A method for preparing an acid catalyst with a long shelf-life is described. Crystalline iron oxides are doped with lattice compatible metals which are heated with halogen compounds at elevated temperatures.

  10. Highly Selective Deoxydehydration of Tartaric Acid over Supported and Unsupported Rhenium Catalysts with Modified Acidities.

    Science.gov (United States)

    Li, Xiukai; Zhang, Yugen

    2016-10-06

    The deoxydehydration (DODH) of sugar acids to industrially important carboxylic acids is a very attractive topic. Oxorhenium complexes are the most-often employed DODH catalysts. Because of the acidity of the rhenium catalysts, the DODH products of sugar acids were usually in the form of mixture of free carboxylic acids and esters. Herein, we demonstrate strategies for the selective DODH of sugar acids to free carboxylic acids by tuning the Lewis acidity or the Brønsted acidity of the rhenium-based catalysts. Starting from tartaric acid, up to 97 % yield of free maleic acid was achieved. Based on our strategies, functional polymer immobilized heterogeneous rhenium catalysts were also developed for the selective DODH conversion of sugar acids. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Enantioselective Iodolactonization of Disubstituted Olefinic Acids Using a Bifunctional Catalyst

    Science.gov (United States)

    Fang, Chao; Paull, Daniel H.; Hethcox, J. Caleb; Shugrue, Christopher R.; Martin, Stephen F.

    2012-01-01

    The enantioselective iodolactonizations of a series of diversely-substituted olefinic carboxylic acids are promoted by a BINOL-derived, bifunctional catalyst. Reactions involving 5-alkyl- and 5-aryl-4(Z)-pentenoic acids and 6-alkyl- and 6-aryl-5(Z)-hexenoic acids provide the corresponding γ- and δ-lactones having stereogenic C–I bonds in excellent yields and >97:3 er. Significantly, this represents the first organocatalyst that promotes both bromo- and iodolactonization with high enantioselectivities. The potential of this catalyst to induce kinetic resolutions of racemic unsaturated acids is also demonstrated. PMID:23199100

  12. Structural and transport effects of doping perfluorosulfonic acid polymers with the heteropoly acids, H3PW12O40 or H4SiW12O40

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Fanqin; Aieta, Niccolo V.; Dec, Steven F.; Horan, James L.; Williamson, Don; Frey, Matthew H.; Pham, Phat; Turner, John A.; Yandrasits, Michael A.; Hamrock, Steven J.; Herring, Andrew M.

    2007-12-01

    A perfluorosulfonic acid (PFSA) polymer with pendant side chain –O(CF2)4SO3H was doped with the heteropoly acids (HPAs), H3PW12O40 and H4SiW12O40. Infrared spectroscopy revealed a strong interaction between the HPA and the PFSA ionomer. Modes associated with the peripheral bonds of the HPA were shifted to lower wave numbers when doped into PFSA membranes. Small-angle X-ray scattering (SAXS) measurements showed the presence of large crystallites of HPA in the membrane with d spacings of ca. 10 Å, close to the lattice spacing observed in bulk HPA crystals. Under wet conditions the HPA was more dispersed and constrained the size of the sulfonic acid clusters to 20 Å at a 5 wt% HPA doping level, the same as in the vacuum treated ionomer samples. Under conditions of minimum hydration the HPA decreased the Ea for the self-diffusion of water from 27 to 15 kJ mol-1. The reverse trend was seen under 100% RH conditions. Proton conductivity measurements showed improved proton conductivity of the HPA doped PFSAs at a constant dew point of 80 °C for all temperatures up to 120 °C and at all relative hummidities up to 80%. The activation energy for proton conduction generally was lower than for the undoped materials at RH ≤80%. Significantly the Ea was 1/2 that of the undoped material at RHs of 40 and 60%. A practical proton conductivity of 113 mS cm-1 was observed at 100 °C and 80% RH.

  13. A prolific catalyst for dehydrogenation of neat formic acid.

    Science.gov (United States)

    Celaje, Jeff Joseph A; Lu, Zhiyao; Kedzie, Elyse A; Terrile, Nicholas J; Lo, Jonathan N; Williams, Travis J

    2016-04-14

    Formic acid is a promising energy carrier for on-demand hydrogen generation. Because the reverse reaction is also feasible, formic acid is a form of stored hydrogen. Here we present a robust, reusable iridium catalyst that enables hydrogen gas release from neat formic acid. This catalysis works under mild conditions in the presence of air, is highly selective and affords millions of turnovers. While many catalysts exist for both formic acid dehydrogenation and carbon dioxide reduction, solutions to date on hydrogen gas release rely on volatile components that reduce the weight content of stored hydrogen and/or introduce fuel cell poisons. These are avoided here. The catalyst utilizes an interesting chemical mechanism, which is described on the basis of kinetic and synthetic experiments.

  14. Environmentally Benign Bifunctional Solid Acid and Base Catalysts

    NARCIS (Netherlands)

    Elmekawy, A.; Shiju, N.R.; Rothenberg, G.; Brown, D.R.

    2014-01-01

    Solid bifunctional acid-​base catalysts were prepd. in two ways on an amorphous silica support: (1) by grafting mercaptopropyl units (followed by oxidn. to propylsulfonic acid) and aminopropyl groups to the silica surface (NH2-​SiO2-​SO3H)​, and (2) by grafting only aminopropyl groups and then

  15. Formic acid oxidation at platinum-bismuth catalysts

    Directory of Open Access Journals (Sweden)

    Popović Ksenija Đ.

    2015-01-01

    Full Text Available The field of heterogeneous catalysis, specifically catalysis on bimetallic surfaces, has seen many advances over the past few decades. Bimetallic catalysts, which often show electronic and chemical properties that are distinct from those of their parent metals, offer the opportunity to obtain new catalysts with enhanced selectivity, activity, and stability. The oxidation of formic acid is of permanent interest as a model reaction for the mechanistic understanding of the electrooxidation of small organic molecules and because of its technical relevance for fuel cell applications. Platinum is one of the most commonly used catalysts for this reaction, despite the fact that it shows a few significant disadvantages: high cost and extreme susceptibility to poisoning by CO. To solve this problem, several approaches have been used, but generally, they all consist in the modification of platinum with a second element. Especially, bismuth has received significant attention as Pt modifier. According to the results presented in this survey dealing with the effects influencing the formic acid oxidation it was found that two types of Pt-Bi bimetallic catalysts (bulk and low loading deposits on GC showed superior catalytic activity in terms of the lower onset potential and oxidation current density, as well as exceptional stability compared to Pt. The findings in this report are important for the understanding of mechanism of formic acid electrooxidation on a bulk alloy and decorated surface, for the development of advanced anode catalysts for direct formic acid fuel cells, as well as for the synthesis of novel low-loading bimetallic catalysts. The use of bimetallic compounds as the anode catalysts is an effective solution to overcoming the problems of the formic acid oxidation current stability for long term applications. In the future, the tolerance of both CO poisoning and electrochemical leaching should be considered as the key factors in the development

  16. Hydrolysis of isocyanic acid on SCR catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Elsener, M.; Kleemann, M.; Koebel, M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    Standard SCR catalysts possess high activity for the hydrolysis of HNCO and thus explain the suitability of urea as a selective reducing agent for NO{sub x}. At high space velocities HNCO-slip can get perceptible over the entire temperature range. This can be attributed to the fact that the temperature dependence is strong for the SCR reaction, but weak for the hydrolysis reaction. (author) 3 figs., 5 refs.

  17. Organometallic catalysts for primary phosphoric acid fuel cells

    Science.gov (United States)

    Walsh, Fraser

    1987-01-01

    A continuing effort by the U.S. Department of Energy to improve the competitiveness of the phosphoric acid fuel cell by improving cell performance and/or reducing cell cost is discussed. Cathode improvement, both in performance and cost, available through the use of a class of organometallic cathode catalysts, the tetraazaannulenes (TAAs), was investigated. A new mixed catalyst was identified which provides improved cathode performance without the need for the use of a noble metal. This mixed catalyst was tested under load for 1000 hr. in full cell at 160 to 200 C in phosphoric acid H3PO4, and was shown to provide stable performance. The mixed catalyst contains an organometallic to catalyze electroreduction of oxygen to hydrogen peroxide and a metal to catalyze further electroreduction of the hydrogen peroxide to water. Cathodes containing an exemplar mixed catalyst (e.g., Co bisphenyl TAA/Mn) operate at approximately 650 mV vs DHE in 160 C, 85% H3PO4 with oxygen as reactant. In developing this mixed catalyst, a broad spectrum of TAAs were prepared, tested in half-cell and in a rotating ring-disk electrode system. TAAs found to facilitate the production of hydrogen peroxide in electroreduction were shown to be preferred TAAs for use in the mixed catalyst. Manganese (Mn) was identified as a preferred metal because it is capable of catalyzing hydrogen peroxide electroreduction, is lower in cost and is of less strategic importance than platinum, the cathode catalyst normally used in the fuel cell.

  18. Dissolution of Metal Supported Spent Auto Catalysts in Acids

    Directory of Open Access Journals (Sweden)

    Fornalczyk A.

    2016-03-01

    Full Text Available Metal supported auto catalysts, have been used in sports and racing cars initially, but nowadays their application systematically increases. In Metal Substrate (supported Converters (MSC, catalytic functions are performed by the Platinum Group Metals (PGM: Pt, Pd, Rh, similarly to the catalysts on ceramic carriers. The contents of these metals make that spent catalytic converters are valuable source of precious metals. All over the world there are many methods for the metals recovery from the ceramic carriers, however, the issue of platinum recovery from metal supported catalysts has not been studied sufficiently yet. The paper presents preliminary results of dissolution of spent automotive catalyst on a metal carrier by means of acids: H2SO4, HCl, HNO3, H3PO4. The main assumption of the research was the dissolution of base metals (Fe, Cr, Al from metallic carrier of catalyst, avoiding dissolution of PGMs. Dissolution was the most effective when concentrated hydrochloric acid, and 2M sulfuric acid (VI was used. It was observed that the dust, remaining after leaching, contained platinum in the level of 0.8% and 0.7%, respectively.

  19. Polyvinylpolypyrrolidone Supported Brønsted Acidic Catalyst for Esterification

    Directory of Open Access Journals (Sweden)

    Song Wang

    2016-01-01

    Full Text Available A polyvinylpolypyrrolidone (PVPP supported Brønsted acidic catalyst ([PVPP-BS]HSO4 was prepared by coupling SO3H-functionalized polyvinylpolypyrrolidone with H2SO4 in this work. After the characterization through FT-IR, FESEM, TG, BET, and elemental analysis, it was found that 1,4-butane sultone (BS and sulfuric acid reacted with PVPP and were immobilized on PVPP surface. The prepared [PVPP-BS]HSO4 catalyst shows high catalytic activity for a series of esterification reactions and could be separated from the reacted mixture easily. Moreover, this catalyst could be recycled and reused for six times without significant loss of catalytic performance.

  20. Cellulose sulphuric acid as a biodegradable catalyst for conversion ...

    Indian Academy of Sciences (India)

    ... reaction times are advantages of this methodology. The selected catalyst is found to be highly efficient and recyclable. Keywords. Cellulose sulphuric acid; aryl azides; diazotization; biodegradable. 1. Introduction. Aromatic azides are useful intermediates with various applications in organic and bioorganic chemistry.1 Two.

  1. Simultaneous determination of two active components of pharmaceutical preparations by sequential injection method using heteropoly complexes

    Directory of Open Access Journals (Sweden)

    Mohammed Khair E. A. Al-Shwaiyat

    2014-12-01

    Full Text Available New approach has been proposed for the simultaneous determination of two reducing agents based on the dependence of their reaction rate with 18-molybdo-2-phosphate heteropoly complex on pH. The method was automated using the manifold typical for the sequential analysis method. Ascorbic acid and rutin were determined by successive injection of two samples acidified to different pH. The linear range for rutin determination was 0.6-20 mg/L and the detection limit was 0.2 mg/L (l = 1 cm. The determination of rutin was possible in the presence of up to a 20-fold excess of ascorbic acid. The method was successfully applied to the determination of ascorbic acid and rutin in ascorutin tablets. The applicability of the proposed method for the determination of total polyphenol content in natural plant samples was shown.

  2. Heterogeneous acid catalysts for acetylation in glycerol

    OpenAIRE

    Dosuna Rodríguez, Inmaculada

    2012-01-01

    Glycerol is a low value molecule obtained as a sub-product from the manufacture of first generation biodiesel. The surplus of glycerol can be revaluated by its acetylation, forming high value molecules (monoacetin, diacetin and triacetin) which can be used in the polymer industry and as a biodiesel among other possibilities. This work provides a comparative study of the catalytic performances of a large scope of acid solids in the esterification of acetic acid with an excess of glycerol. ...

  3. Naphthenic acid removal from HVGO by alkaline earth metal catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ding, L.; Rahimi, P.; Hawkins, R.; Bhatt, S.; Shi, Y. [National Centre for Upgrading Technology, Devon, AB (Canada); Natural Resources Canada, Devon, AB (Canada). CanmetENERGY

    2009-07-01

    This poster highlighted a study that investigated naphthenic acid removal from bitumen-derived heavy vacuum gas oil (HVGO) by thermal cracking and catalytic decarboxylation over alkaline earth-metal oxides and ZnO catalysts in a batch reactor and a continuous fixed-bed reactor. X-ray diffraction (XRD), thermogravimetric-differential thermal analysis (TG-DTA) temperature-programmed desorption (TPD) of carbon dioxide (CO{sub 2}-TPD), and scanning electron microscopy were used to characterize the fresh and spent catalysts. With MgO and ZnO, naphthenic acid removal proceeded via catalytic decarboxylation. No crystalline phase changes were observed after reaction. With CaO, multiple pathways such as catalytic decarboxylation, neutralization, and thermal cracking were responsible for naphthenic acid conversion. The spent catalysts contained Ca(OH){sub 2} and CaCO{sub 3}. With BaO, naphthenic acid conversion occurred through neutralization. All BaO was converted to Ba(OH){sub 2} during the reaction. tabs., figs.

  4. Production Hydrogen And Nanocarbon Via Methane Decomposition Using Ni-Based Catalysts. Effect Of Acidity And Catalyst Diameter

    Directory of Open Access Journals (Sweden)

    Widodo Purwanto

    2010-10-01

    Full Text Available Objectives of this research are mainly to study impacts of acidity strength (by varying amount of precipitant and loading Al-Si and the effect of nickel particle size (by varying calcinations temperature on decomposition reaction performances. In this research, high-nickel-loaded catalyst is prepared with two methods. Ni-Cu/Al catalysts were prepared with co-precipitation method. While the Ni-Cu/Al-Si catalyst were prepared by combined co-precipitation and sol-gel method. The direct cracking of methane was performed in 8mm quartz fixed bed reactor at atmospheric pressure and 500-700°C. The main  results showed that the Al content of catalyst increases with the increasing amount of precipitant. The activity of catalyst increases with the increasing of catalyst's acidity to the best possible point, and then increasing of acidity will reduce the activity of catalyst. Ni-Cu/4Al and Ni-Cu/11Al deactivated in a  very short time hence produced fewer amount of nanocarbon, while Ni-Cu/15Al was active in a very  long period. The most effective catalyst is Ni-Cu/22Al, which produced the biggest amount of nanocarbon (4.15 g C/g catalyst. Ni catalyst diameter has significant effect on reaction performances mainly  methane conversion and product yield. A small Ni crystal size gave a high methane conversion, a fast deactivation and a low carbon yield. Large Ni particle  diameter yielded a slow decomposition and low methane conversion. The highest methane  conversion was produced by catalyst diameter of 4 nm and maximum yield of carbon of 4.08 g C/ g catalyst was achieved by 15.5 nm diameter of Ni catalyst.

  5. Production Hydrogen and Nanocarbon Via Methane Decomposition Using Ni-based Catalysts. Effect of Acidity and Catalyst Diameter

    OpenAIRE

    Widodo W. Purwanto; M Nasikin; E Saputra; Song, L.

    2005-01-01

    Objectives of this research are mainly to study impacts of acidity strength (by varying amount of precipitant and loadingAl-Si) and the effect of nickel particle size (by varying calcinations temperature) on decomposition reactionperformances. In this research, high-nickel-loaded catalyst is prepared with two methods. Ni-Cu/Al catalysts wereprepared with co-precipitation method. While the Ni-Cu/Al-Si catalyst were prepared by combined co-precipitation andsol-gel method. The direct cracking of...

  6. Selective production of aromatics from alkylfurans over solid acid catalysts

    DEFF Research Database (Denmark)

    Wang, Dong; Dumesic, James A.; Osmundsen, Christian Mårup

    2013-01-01

    to deactivation by carbon deposition than do microporous materials. Results from Raman spectroscopy and the trend of turnover frequency with varying tungsten surface densities for a series of WOx-ZrO2 catalysts are consistent with previous investigations of other acid-catalyzed reactions; this suggests...... that the high reactivity of WOx-ZrO2 is mainly associated with the presence of subnanometer WOx clusters mixed with zirconium, which reach a maximum surface concentration at intermediate tungsten coverage....

  7. High-efficiency palladium catalysts supported on ppy-modified C60 for formic acid oxidation.

    Science.gov (United States)

    Bai, Zhengyu; Yang, Lin; Guo, Yuming; Zheng, Zhi; Hu, Chuangang; Xu, Pengle

    2011-02-14

    A facile preparation of polypyrrole-modified fullerene supported Pd nanoparticles catalyst is introduced; electrochemical measurements demonstrate that the obtained Pd/ppy-C(60) catalyst shows a good electrocatalytic activity and stability for the oxidation of formic acid.

  8. Temperature regulated Brønsted acidic ionic liquid-catalyze esterification of oleic acid for biodiesel application

    Science.gov (United States)

    Rafiee, Ezzat; Mirnezami, Fakhrosadat

    2017-02-01

    By combining phosphotungstic acid (PW) and SO3H- functioned zwitterion, heteropoly anion-based Brønsted acidic ionic liquids (HPA-ILs) were successfully obtained. Scanning electron microscopy and energy dispersive X-ray spectroscopy were provided the morphology and composition of the prepared material. Catalytic performance and reusability of the catalysts were evaluated through an esterification reaction between oleic acid and methanol for production of biodiesel. Relationship between catalytic activities and acidity of the catalysts have been discussed by potentiometric titration. The results showed that HPA-ILs had good activity and reusability. HPA-ILs dissolved in the reaction mixture during the reaction process and could be precipitated and separated from products at lower temperature.

  9. Glucose reactions with acid and base catalysts in hot compressed water at 473 K.

    Science.gov (United States)

    Watanabe, Masaru; Aizawa, Yuichi; Iida, Toru; Aida, Taku M; Levy, Caroline; Sue, Kiwamu; Inomata, Hiroshi

    2005-09-05

    The effects of the homogeneous catalysts (H(2)SO(4) and NaOH) and heterogeneous catalysts (TiO(2) and ZrO(2)) on glucose reactions were examined in hot compressed water (473 K) by a batch-type reactor. From the homogeneous catalyst studies, we confirmed that the acid catalyst promoted dehydration, while isomerization of glucose to fructose was catalyzed by alkali. Anatase TiO(2) was found to act as an acid catalyst to promote formation of 5-hydroxymethylfuraldehyde (HMF). Zirconia (ZrO(2)) was a base catalyst to promote the isomerization of glucose. The effects of the additives were also confirmed through fructose reactions.

  10. Acid activated montmorillonite as catalysts in methyl esterification reactions of lauric acid.

    Science.gov (United States)

    Zatta, Leandro; Ramos, Luiz Pereira; Wypych, Fernando

    2012-01-01

    The catalytic activity of acid activated montmorillonite in the esterification of free fatty acids (FFA) is reported. Standard Montmorillonite (MMT) type STx-1 provided by the Clay Mineral Society repository was activated using phosphoric, nitric and sulphuric acids under different conditions and the resulting materials were characterized and evaluated as catalysts in the methyl esterification of lauric acid. Blank reactions carried out in the absence of any added catalyst presented conversions of 32.64, 69.79 and 79.23%, for alcohol:lauric acid molar ratios of 60:1, 12:1 and 6:1, respectively. In the presence of the untreated clay and using molar ratios of 12:1 and 6:1 with 12% of catalyst, conversions of 70.92 and 82.30% were obtained, respectively. For the acid activated clays, conversions up to 93.08% of lauric acid to methyl laurate were obtained, much higher than those observed for the thermal conversion or using untreated montmorillonite. Relative good correlations were observed between the catalytic activity and the development of acid sites and textural properties of the resulting materials. Therefore, a simple acid activation was able to improve the catalytic activity and produce clay catalysts that are environmental friendly, cost effective, noncorrosive and reusable.

  11. Periodic Mesoporous Organosilica Functionalized with Sulfonic Acid Groups as Acid Catalyst for Glycerol Acetylation

    Directory of Open Access Journals (Sweden)

    Pascal Van Der Voort

    2013-08-01

    Full Text Available A Periodic Mesoporous Organosilica (PMO functionalized with sulfonic acid groups has been successfully synthesized via a sequence of post-synthetic modification steps of a trans-ethenylene bridged PMO material. The double bond is functionalized via a bromination and subsequent substitution obtaining a thiol functionality. This is followed by an oxidation towards a sulfonic acid group. After full characterization, the solid acid catalyst is used in the acetylation of glycerol. The catalytic reactivity and reusability of the sulfonic acid modified PMO material is investigated. The catalyst showed a catalytic activity and kinetics that are comparable with the commercially available resin, Amberlyst-15, and furthermore our catalyst can be recycled for several subsequent catalytic runs and retains its catalytic activity.

  12. Butyric acid esterification kinetics over Amberlyst solid acid catalysts: the effect of alcohol carbon chain length.

    Science.gov (United States)

    Pappu, Venkata K S; Kanyi, Victor; Santhanakrishnan, Arati; Lira, Carl T; Miller, Dennis J

    2013-02-01

    The liquid phase esterification of butyric acid with a series of linear and branched alcohols is examined. Four strong cation exchange resins, Amberlyst™ 15, Amberlyst™ 36, Amberlyst™ BD 20, and Amberlyst™ 70, were used along with para-toluenesulfonic acid as a homogeneous catalyst. The effect of increasing alcohol carbon chain length and branching on esterification rate at 60°C is presented. For all catalysts, the decrease in turnover frequency (TOF) with increasing carbon chain length of the alcohol is described in terms of steric hindrance, alcohol polarity, and hydroxyl group concentration. The kinetics of butyric acid esterification with 2-ethylhexanol using Amberlyst™ 70 catalyst is described with an activity-based, pseudo-homogeneous kinetic model that includes autocatalysis by butyric acid. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Non-noble catalysts and catalyst supports for phosphoric acid fuel cells

    Science.gov (United States)

    Mcalister, A. J.

    1981-01-01

    Tungsten carbide, which is active for hydrogen oxidation, is CO tolerant and has a hexagonal structure is discussed. Titanium carbide is inactive and has a cubic structure. Four different samples of the cubic alloys W sub x-1Ti sub XC sub 1-y were found to be active and CO tolerant. When the activities of these cubic alloys are weighted by the reciprocal of the square to those of highly forms of WC. They offer important insight into the nature of the active sites on W-C anode catalysts for use in phosphoric acid fuel cells.

  14. Meso- and macroporous sulfonated starch solid acid catalyst for esterification of palm fatty acid

    Directory of Open Access Journals (Sweden)

    Ibrahim M. Lokman

    2016-03-01

    Full Text Available In the present work, a heterogeneous solid acid catalyst was successfully developed from starch. The catalyst was prepared by a significant two-step process; the initial step was incomplete carbonization of starch (ICS at 400 °C for 12 h and consequently followed by sulfonation process using concentrated H2SO4 to produce sulfonated-incomplete carbonized starch (ICS-SO3H. The characterization of the ICS-SO3H catalyst was done for chemical and physical properties such as X-ray diffraction (XRD, ammonia-temperature programmed desorption (NH3-TPD, surface area analysis, thermal gravimetric analysis (TGA, elemental analysis and morphology analysis by scanning electron microscope (SEM. BET results showed the structure of ICS-SO3H consists of meso- and macro-porous properties, which allowed high density of the SO3H group attached on its carbon networks. The catalytic activity of ICS-SO3H catalyst was determined by analyzing the catalyst performance to esterify palm fatty acid distillate (PFAD and sequentially produced methyl ester. The maximum free fatty acid (FFA conversion and FAME yield were as high as 94.6% and 90.4%, respectively, at 75 °C using 10:1 methanol-to-PFAD molar ratio and 2 wt.% of catalyst within 3 h. The catalyst has sufficient potential to recycle up to 6 reactions without reactivation step and any remarkable loss of catalytic activity. It revealed that the heterogeneous ICS-SO3H catalyst exhibits high stability, reusability and catalytic activity.

  15. Effects of water on the esterification of free fatty acids by acid catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ji-Yeon; Kim, Deog-Keun; Lee, Jin-Suk [Korea Institute of Energy Research, 71-2, Jang-dong, Yuseong-gu, Daejeon 305-343 (Korea); Wang, Zhong-Ming [Guangzhou Institute of Energy Conversion, No. 2 Nengyuan Rd, Wushan, Tianhe, Guangzhou 510-640 (China)

    2010-03-15

    To maximize the production of biodiesel from soybean soapstock, the effects of water on the esterification of high-FFA (free fatty acid) oils were investigated. Oleic acid and high acid acid oil (HAAO) were esterified by reaction with methanol in the presence of Amberlyst-15 as a heterogeneous catalyst or sulfuric acid as a homogeneous catalyst. The yield of fatty acid methyl ester (FAME) was studied at oil to methanol molar ratios of 1:3 and 1:6 and reaction temperatures of 60 and 80 C. The rate of esterification of oleic acid significantly decreased as the initial water content increased to 20% of the oil. The activity of Amberlyst-15 decreased more rapidly than that of sulfuric acid, due to the direct poisoning of acid sites by water. Esterification using sulfuric acid was not affected by water until there was a 5% water addition at a 1:6 molar ratio of oil to methanol. FAME content of HAAO prepared from soapstock rapidly increased for the first 30 min of esterification. Following the 30-min mark, the rate of FAME production decreased significantly due to the accumulation of water. When methanol and Amberlyst-15 were removed from the HAAO after 30 min of esterification and fresh methanol and a catalyst were added, the time required to reach 85% FAME content was reduced from 6 h to 1.8 h. (author)

  16. Highly active iridium catalyst for hydrogen production from formic acid

    Institute of Scientific and Technical Information of China (English)

    Ying Du; Yang-Bin Shen; Yu-Lu Zhan; Fan-Di Ning; Liu-Ming Yan; Xiao-Chun Zhou

    2017-01-01

    Formic acid (FA) dehydrogenation has attracted a lot of attentions since it is a convenient method for H2 production.In this work,we designed a self-supporting fuel cell system,in which H2 from FA is supplied into the fuel cell,and the exhaust heat from the fuel cell supported the FA dehydrogenation.In order to realize the system,we synthesized a highly active and selective homogeneous catalyst IrCp*Cl2bpym for FA dehydrogenation.The turnover frequency (TOF) of the catalyst for FA dehydrogenation is as high as 7150 h-1 at 50 ℃,and is up to 144,000 h-1 at 90 ℃.The catalyst also shows excellent catalytic stability for FA dehydrogenation after several cycles of test.The conversion ratio of FA can achieve 93.2%,and no carbon monoxide is detected in the evolved gas.Therefore,the evolved gas could be applied in the proton exchange membrane fuel cell (PEMFC) directly.This is a potential technology for hydrogen storage and generation.The power density of the PEMFC driven by the evolved gas could approximate to that using pure hydrogen.

  17. Cathode catalysts for primary phosphoric acid fuel cells

    Science.gov (United States)

    1981-01-01

    Alkylation or carbon Vulcan XC-72, the support carbon, was shown to provide the most stable bond type for linking cobalt dehydrodibenzo tetraazannulene (CoTAA) to the surface of the carbon; this result is based on data obtained by cyclic voltammetry, pulse voltammetry and by release of 14C from bonded CoTAA. Half-cell tests at 100 C in 85% phosphoric acid showed that CoTAA bonded to the surface of carbon (Vulcan XC-72) via an alkylation procedure is a more active catalyst than is platinum based on a factor of two improvement in Tafel slope; dimeric CoTAA had catalytic activity equal to platinum. Half-cell tests also showed that bonded CoTAA catalysts do not suffer a loss in potential when air is used as a fuel rather than oxygen. Commercially available polytetrafluroethylene (PTFE) was shown to be unstable in the fuel cell environment with degradation occurring in 2000 hours or less. The PTFE was stressed at 200 C in concentrated phosphoric acid as well as electrochemically stressed in 150 C concentrated phosphoric acid; the surface chemistry of PTFE was observed to change significantly. Radiolabeled PTFE was prepared and used to verify that such chemical changes also occur in the primary fuel cell environment.

  18. Palladium catalyst system comprising zwitterion and/or acid-​functionalized ionic liquid

    DEFF Research Database (Denmark)

    2011-01-01

    The present invention concerns a catalyst system in particular a catalyst system comprising Palladium (Pd), a zwitterion and/or an acid-functionalized ionic liquid, and one or more phosphine ligands, wherein the Pd catalyst can be provided by a complex precursor, such as Pd(CH3COO)2, PdCI2, Pd(CH3...... methyl methacrylate and/or methacrylic acid. Catalyst systems according to the invention are suitable for reactions forming separable product and catalyst phases and supported ionic liquid phase SILP applications....

  19. Esterification of free fatty acids using sulfuric acid as catalyst in the presence of triglycerides

    Energy Technology Data Exchange (ETDEWEB)

    Marchetti, J.M.; Errazu, A.F. [Planta Piloto de Ingenieria Quimica (UNS-CONICET), Camino La Carrindanga Km. 7, 8000 Bahia Blanca (Argentina)

    2008-09-15

    Biodiesel is one of the new possible substitutes of regular fuel for engines and is produced from different vegetable oils or animal fats. The main reaction involved is the transesterification of triglycerides into esters. When an acid oil, such as spent or waste oil, is used, the amount of free fatty acids range from 3% to 40%, and another reaction takes place simultaneously with the transesterification, the direct esterification of the free fatty acid. In this work, the direct esterification reaction of triglycerides to biodiesel was studied and the effects of the main variables involved in the process, reaction temperature, amount of catalyst, initial amount of free fatty acid and the molar ratio alcohol/oil, were analyzed. For this investigation, we employed a model acid oil produced by mixing pure oleic acid with refined sunflower oil. Ethanol was used in the experiments instead of methanol since it is less toxic and safer to handle. Sulfuric acid was employed as catalyst because of its advantages compared with conventional homogeneous catalysts (NaOH). It was found that ethanol and sulfuric acid were suitable to perform not only the transesterification reaction but also the direct esterification reaction to increase biodiesel production of the process. (author)

  20. Staining of fluid-catalytic cracking catalysts: Localising Brønsted acidity within a single catalyst particle

    NARCIS (Netherlands)

    Buurmans, I.L.C.|info:eu-repo/dai/nl/31406592X; Ruiz Martinez, J.|info:eu-repo/dai/nl/341386405; van Leeuwen, S.L.; van der Beek, D.; Bergwerff, J.A.; Knowles, W.V.; Vogt, Eelco|info:eu-repo/dai/nl/073717398; Weckhuysen, B.M.|info:eu-repo/dai/nl/285484397

    2012-01-01

    A time-resolved in situ micro-spectroscopic approach has been used to investigate the Brønsted acidic properties of fluid-catalytic-cracking (FCC) catalysts at the single particle level by applying the acid-catalysed styrene oligomerisation probe reaction. The reactivity of individual FCC components

  1. Esterification free fatty acid in palm fatty acid distillate using sulfonated rice husk ash catalyst

    Science.gov (United States)

    Hidayat, Arif; Sutrisno, Bachrun

    2017-01-01

    Indonesia, as one of the biggest palm oil producers and exporters in the world, is producing large amounts of low-grade oil such as Palm Fatty Acid Distillate (PFAD) from palm oil industries. The use of PFAD can reduce the cost of biodiesel production significantly, which makes PFAD a highly potential alternative feedstock for biodiesel production. In this paper, the esterification of free fatty acid (FFA) on PFAD was studied using rice husk ash (RHA) as heterogeneous catalyst. The rice husk ash catalyst was synthesized by sulfonation using concentrated sulfuric acid. The RHA catalyst were characterized by using different techniques, such as porosity analysis, Fourier transform infrared (FT-IR) spectroscopy, total number of acid sites and elemental analysis. The effects of the molar ratio of methanol to PFAD (1-10%), the molar ratio of methanol to PFAD (4:1-10:1), and the reaction temperature (40-60°C) were studied for the conversion of FFA to optimize the reaction conditions. The results showed that the optimal conditions were an methanol to PFAD molar ratio of 10:1, the catalyst amount of 10 wt% of PFAD, and reaction temperature of 60°C.

  2. Production of alpha-hydroxy carboxylic acids and esters from higher sugars using tandem catalyst systems

    Energy Technology Data Exchange (ETDEWEB)

    Orazov, Marat; Davis, Mark E.

    2017-11-07

    The present disclosure is directed to methods and composition used in the preparation of alpha-hydroxy carboxylic acids and esters from higher sugars using a tandem catalyst system comprising retro-aldol catalysts and Lewis acid catalysts. In some embodiments, these alpha-hydroxy carboxylic acids may be prepared from pentoses and hexoses. The retro-aldol and Lewis catalysts may be characterized by their respective ability to catalyze a 1,2-carbon shift reaction and a 1,2-hydride shift reaction on an aldose or ketose substrate.

  3. Preparation and characterization of biomass carbon-based solid acid catalyst for the esterification of oleic acid with methanol.

    Science.gov (United States)

    Liu, Tiantian; Li, Zhilong; Li, Wei; Shi, Congjiao; Wang, Yun

    2013-04-01

    A solid acid catalyst, prepared by sulfonating carbonized corn straw, was proved to be an efficient and environmental benign catalyst for the esterification of oleic acid and methanol. Various synthetic parameters, such as carbonization temperature and time were systematically examined. It was found that the catalyst exhibited the highest acid density of 2.64 mmol/g by NaOH titration. A quantitative yield (98%) of ester was achieved, using the most active sulfonated catalyst at 333 K with a 7 wt.% catalyst/oleic acid ratio for 4h, at a 7:1 M ratio of methanol/oleic acid, while the commercial available Amberlyst-15 only gave 85% yield under the same reaction condition. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Reaction catalyst for the elimination of oxyhydrogen gas in lead--acid storage batteries

    Energy Technology Data Exchange (ETDEWEB)

    Lahme, N.; Sassmannshausen, G.

    1978-12-12

    A reaction catalyst for the recombination of the oxyhydrogen gas produced by lead--acid storage batteries into water in a controlled, exothermic reaction is described. The catalyst element is a solid rod element with a central heat-conducting core. The catalyst rod is positioned inside a gas-tight housing in communication with the battery gas space. This rod element is produced by a fabricating method in which granular catalyst carrier material is worked into a paste which is then shaped and dried, the metallic catalyst being deposited on the surface of the carrier grains. 4 figures, 1 table.

  5. Catalyst evaluation for oxygen reduction reaction in concentrated phosphoric acid at elevated temperatures

    DEFF Research Database (Denmark)

    Hu, Yang; Jiang, Yiliang; Jensen, Jens Oluf

    2018-01-01

    temperatures and hence is not suitable for catalyst evaluation for HT-PEMFCs. In this study, we have designed and constructed a half-cell setup to measure the intrinsic activities of catalysts towards the oxygen reduction reaction (ORR) in conditions close to HT-PEMFC cathodes. By optimization...... of the hydrophobic characteristics of electrodes and the catalyst layer thickness, ORR activities of typical Pt/C catalysts are successfully measured in concentrated phosphoric acid at temperatures above 100 °C. In terms of mass-specific activities, the catalyst exhibits about two times higher activity in the half...

  6. Palladium catalyst system comprising zwitterion and/or acid-functionalized ionic liquid

    DEFF Research Database (Denmark)

    2011-01-01

    The present invention concerns a catalyst system in particular a catalyst system comprising Palladium (Pd), a zwitterion and/or an acid-functionalized ionic liquid, and one or more phosphine ligands, wherein the Pd catalyst can be provided by a complex precursor, such as Pd(CH3COO)2, PdCI2, Pd(CH3......COCHCOCH3), Pd (CF3COO)2, Pd(PPh3)4 or Pd2(dibenzylideneacetone)3. Such catalyst systems can be used for e.g. alkoxycarbonylation reactions, carboxylation reactions, and/or in a co-polymerization reaction, e.g. in the production of methyl propionate and/or propanoic acid, optionally in processes forming...... methyl methacrylate and/or methacrylic acid. Catalyst systems according to the invention are suitable for reactions forming separable product and catalyst phases and supported ionic liquid phase SILP applications....

  7. Oscillatory behaviour of isomers of hydroxybenzoic acid with and without catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Nath, Masood A.; Rastogi, R.P.; Peerzada, G.M. [University of Kashmir, Srinagar (India). Dept. of Chemistry]. E-mail: nath_masood@yahoo.co.in

    2009-07-01

    The present work establishes and compares the oscillatory behaviour of mono-, di- and trihydroxybenzoic acids as organic substrates in acidic bromate (1.0 mol L{sup -1} H{sub 2}SO{sub 4}) without catalyst and in the presence of Mn{sup 2+} ion as the main catalyst. The oscillations are also affected by other catalyst such as Fe{sup 2+} ion. Further, the oscillations start diminishing in mixed catalyst systems. The experimental parameters were obtained potentiometrically and the results have been interpreted on the basis of FKN mechanism. (author)

  8. Removal of free fatty acid in Palm Fatty Acid Distillate using sulfonated carbon catalyst derived from biomass wastefor biodiesel production

    Science.gov (United States)

    Hidayat, Arif; Rochmadi; Wijaya, Karna; Budiman, Arief

    2016-01-01

    In this research, the esterification of PFAD using the sulfonatedcoconut shell biochar catalyst was studied. Carbon solid catalysts were prepared by a sulfonation of carbonized coconut shells. The performances of the catalysts were evaluated in terms of the reaction temperatures, the molar ratios of methanol to PFAD, the catalyst loading and the reaction times. The reusability of the solid acid carbon catalysts was also studied in this work. The results indicated that the FFA conversion was significantly increased with increasing catalyst loading and reaction times. It can be concluded that the optimal conditions were an PFAD to methanol molar ratio of 1:12, the amount of catalyst of 10%w, and reaction temperature of 60oC.At this optimum condition, the conversion to biodieselreached 88%.

  9. Boehmite-An Efficient and Recyclable Acid-Base Bifunctional Catalyst for Aldol Condensation Reaction.

    Science.gov (United States)

    Reshma, P C Rajan; Vikneshvaran, Sekar; Velmathi, Sivan

    2018-06-01

    In this work boehmite was used as an acid-base bifunctional catalyst for aldol condensation reactions of aromatic aldehydes and ketones. The catalyst was prepared by simple sol-gel method using Al(NO3)3·9H2O and NH4OH as precursors. The catalyst has been characterized by X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM), UV-visible spectroscopy (DRS), BET surface area analyses. Boehmite is successfully applied as catalyst for the condensation reaction between 4-nitrobenzaldehyde and acetone as a model substrate giving α, β-unsaturated ketones without any side product. The scope of the reaction is extended for various substituted aldehydes. A probable mechanism has been suggested to explain the cooperative behavior of the acidic and basic sites. The catalyst is environmentally friendly and easily recovered from the reaction mixture. Also the catalyst is reusable up to 3 catalytic cycles.

  10. Leaching of vanadium from sulphuric acid manufacture spent catalysts

    Directory of Open Access Journals (Sweden)

    García, Diego Juan

    2001-02-01

    Full Text Available Recovery of vanadium contained in spent catalysts from the manufacture of sulphuric acid has been studied in this work, resulting in an industrial multistage process for the treatment of them avoiding direct deposition or dumping. Characterization of supplied spent catalysts samples, confirmed vanadium levels showed in the literature. The study of variables influencing leaching process: type of leaching agent, leaching agent concentration, S/L ratio, stirring speed and temperature, allows to fix the most advantageous conditions using industrial application criterion and verifying that the process is difusión controlled. The work is completed by developing an industrial leaching cycle simulation with the aim of reproducing real performance of spent catalyst, proposing operating conditions, and verifying the non-toxic character of the final residue obtained.

    En el presente trabajo se ha estudiado la recuperación del vanadio contenido en los catalizadores agotados procedentes de la fabricación del ácido sulfúrico, planteando un proceso industrial multietapa para el tratamiento de estos residuos, evitando su deposición o vertido directos. La caracterización de las muestras de catalizadores agotados disponibles confirmó los valores encontrados en la bibliografía. Se estudiaron las variables que influyen en el proceso de lixiviación (tipo de agente de lixiviación y concentración del mismo, relación S/L, velocidad de agitación y temperatura definiendo las condiciones más adecuadas desde el punto de vista industrial y verificando que el proceso está controlado por mecanismos difusionales. El trabajo se completa con la simulación de un ciclo industrial de lavado del catalizador y la verificación de la nula toxicidad de los lixiviados obtenidos por degradación del residuo final. 24 Aplicación de la resistencia de ruido al estudio de pinturas ricas en zinc Noise resistance applied to the study of zinc rich paints

  11. Highly active carbon supported Pd cathode catalysts for direct formic acid fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Mikolajczuk-Zychora, A., E-mail: amikolajczuk@ichf.edu.pl [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland); Borodzinski, A.; Kedzierzawski, P.; Mierzwa, B. [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland); Mazurkiewicz-Pawlicka, M. [Faculty of Materials Science and Engineering, Warsaw University of Technology, Wołoska 141, 02-507 Warsaw (Poland); Faculty of Chemical and Process Engineering, Warsaw University of Technology, Warynskiego 1, Warsaw (Poland); Stobinski, L. [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland); Faculty of Chemical and Process Engineering, Warsaw University of Technology, Warynskiego 1, Warsaw (Poland); Ciecierska, E. [Faculty of Materials Science and Engineering, Warsaw University of Technology, Wołoska 141, 02-507 Warsaw (Poland); Zimoch, A.; Opałło, M. [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland)

    2016-12-01

    Highlights: • Palladium catalyst used on the cathode DFAFC is comparable to commercial platinum catalyst. • The treatment of carbon supports in nitric acid(V) increases the electrochemically available metal surface area and the catalytic activity in oxygen reduction reaction of catalysts. - Abstract: One of the drawbacks of low-temperature fuel cells is high price of platinum-based catalysts used for the electroreduction of oxygen at the cathode of the fuel cell. The aim of this work is to develop the palladium catalyst that will replace commonly used platinum cathode catalysts. A series of palladium catalysts for oxygen reduction reaction (ORR) were prepared and tested on the cathode of Direct Formic Acid Fuel Cell (DFAFC). Palladium nanoparticles were deposited on the carbon black (Vulcan) and on multiwall carbon nanotubes (MWCNTs) surface by reduction of palladium(II) acetate dissolved in ethanol. Hydrazine was used as a reducing agent. The effect of functionalization of the carbon supports on the catalysts physicochemical properties and the ORR catalytic activity on the cathode of DFAFC was studied. The supports were functionalized by treatment in nitric acid for 4 h at 80 °C. The structure of the prepared catalysts has been characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscope (TEM) and cyclic voltammetry (CV). Hydrophilicity of the catalytic layers was determined by measuring contact angles of water droplets. The performance of the prepared catalysts has been compared with that of the commercial 20 wt.% Pt/C (Premetek) catalyst. The maximum power density obtained for the best palladium catalyst, deposited on the surface of functionalized carbon black, is the same as that for the commercial Pt/C (Premetek). Palladium is cheaper than platinum, therefore the developed cathode catalyst is promising for future applications.

  12. Highly active carbon supported Pd cathode catalysts for direct formic acid fuel cells

    Science.gov (United States)

    Mikolajczuk-Zychora, A.; Borodzinski, A.; Kedzierzawski, P.; Mierzwa, B.; Mazurkiewicz-Pawlicka, M.; Stobinski, L.; Ciecierska, E.; Zimoch, A.; Opałło, M.

    2016-12-01

    One of the drawbacks of low-temperature fuel cells is high price of platinum-based catalysts used for the electroreduction of oxygen at the cathode of the fuel cell. The aim of this work is to develop the palladium catalyst that will replace commonly used platinum cathode catalysts. A series of palladium catalysts for oxygen reduction reaction (ORR) were prepared and tested on the cathode of Direct Formic Acid Fuel Cell (DFAFC). Palladium nanoparticles were deposited on the carbon black (Vulcan) and on multiwall carbon nanotubes (MWCNTs) surface by reduction of palladium(II) acetate dissolved in ethanol. Hydrazine was used as a reducing agent. The effect of functionalization of the carbon supports on the catalysts physicochemical properties and the ORR catalytic activity on the cathode of DFAFC was studied. The supports were functionalized by treatment in nitric acid for 4 h at 80 °C. The structure of the prepared catalysts has been characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscope (TEM) and cyclic voltammetry (CV). Hydrophilicity of the catalytic layers was determined by measuring contact angles of water droplets. The performance of the prepared catalysts has been compared with that of the commercial 20 wt.% Pt/C (Premetek) catalyst. The maximum power density obtained for the best palladium catalyst, deposited on the surface of functionalized carbon black, is the same as that for the commercial Pt/C (Premetek). Palladium is cheaper than platinum, therefore the developed cathode catalyst is promising for future applications.

  13. Steam Reforming of Acetic Acid over Co-Supported Catalysts: Coupling Ketonization for Greater Stability

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, Stephen D. [Energy and Environmental; Spies, Kurt A. [Energy and Environmental; Mei, Donghai [Energy and Environmental; Kovarik, Libor [Energy and Environmental; Kutnyakov, Igor [Energy and Environmental; Li, Xiaohong S. [Energy and Environmental; Lebarbier Dagle, Vanessa [Energy and Environmental; Albrecht, Karl O. [Energy and Environmental; Dagle, Robert A. [Energy and Environmental

    2017-09-11

    We report on the markedly improved stability of a novel 2-bed catalytic system, as compared to a conventional 1-bed steam reforming catalyst, for the production of H2 from acetic acid. The 2-bed catalytic system comprises of i) a basic oxide ketonization catalyst for the conversion of acetic acid to acetone, and a ii) Co-based steam reforming catalyst, both catalytic beds placed in sequence within the same unit operation. Steam reforming catalysts are particularly prone to catalytic deactivation when steam reforming acetic acid, used here as a model compound for the aqueous fraction of bio-oil. Catalysts comprising MgAl2O4, ZnO, CeO2, and activated carbon (AC) both with and without Co-addition were evaluated for conversion of acetic acid and acetone, its ketonization product, in the presence of steam. It was found that over the bare oxide support only ketonization activity was observed and coke deposition was minimal. With addition of Co to the oxide support steam reforming activity was facilitated and coke deposition was significantly increased. Acetone steam reforming over the same Co-supported catalysts demonstrated more stable performance and with less coke deposition than with acetic acid feedstock. DFT analysis suggests that over Co surface CHxCOO species are more favorably formed from acetic acid versus acetone. These CHxCOO species are strongly bound to the Co catalyst surface and could explain the higher propensity for coke formation from acetic acid. Based on these findings, in order to enhance stability of the steam reforming catalyst a dual-bed (2-bed) catalyst system was implemented. Comparing the 2-bed and 1-bed (Co-supported catalyst only) systems under otherwise identical reaction conditions the 2-bed demonstrated significantly improved stability and coke deposition was decreased by a factor of 4.

  14. Staining of fluid-catalytic-cracking catalysts: localising Brønsted acidity within a single catalyst particle.

    Science.gov (United States)

    Buurmans, Inge L C; Ruiz-Martínez, Javier; van Leeuwen, Sanne L; van der Beek, David; Bergwerff, Jaap A; Knowles, William V; Vogt, Eelco T C; Weckhuysen, Bert M

    2012-01-23

    A time-resolved in situ micro-spectroscopic approach has been used to investigate the Brønsted acidic properties of fluid-catalytic-cracking (FCC) catalysts at the single particle level by applying the acid-catalysed styrene oligomerisation probe reaction. The reactivity of individual FCC components (zeolite, clay, alumina and silica) was monitored by UV/Vis micro-spectroscopy and showed that only clay and zeolites (Y and ZSM-5) contain Brønsted acid sites that are strong enough to catalyse the conversion of 4-fluorostyrene into carbocationic species. By applying the same approach to complete FCC catalyst particles, it has been found that the fingerprint of the zeolitic UV/Vis spectra is clearly recognisable. This almost exclusive zeolitic activity is confirmed by the fact that hardly any reactivity is observed for FCC particles that contain no zeolite. Confocal fluorescence microscopy images of FCC catalyst particles reveal inhomogeneously distributed micron-sized zeolite domains with a highly fluorescent signal upon reaction. By examining laboratory deactivated FCC catalyst particles in a statistical approach, a clear trend of decreasing fluorescence intensity, and thus Brønsted acidity, of the zeolite domains is observed with increasing severity of the deactivation method. By comparing the average fluorescence intensities obtained with two styrenes that differ in reactivity, it has been found that the Brønsted acid site strength within FCC catalyst particles containing ZSM-5 is more uniform than within those containing zeolite Y, as confirmed with temperature-programmed desorption of ammonia. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Surface treated carbon catalysts produced from waste tires for fatty acids to biofuel conversion

    Energy Technology Data Exchange (ETDEWEB)

    Hood, Zachary D.; Adhikari, Shiba P.; Wright, Marcus W.; Lachgar, Abdessadek; Li, Yunchao; Naskar, Amit K.; Paranthaman, Mariappan Parans

    2018-02-06

    A method of making solid acid catalysts includes the step of sulfonating waste tire pieces in a first sulfonation step. The sulfonated waste tire pieces are pyrolyzed to produce carbon composite pieces having a pore size less than 10 nm. The carbon composite pieces are then ground to produce carbon composite powders having a size less than 50 .mu.m. The carbon composite particles are sulfonated in a second sulfonation step to produce sulfonated solid acid catalysts. A method of making biofuels and solid acid catalysts are also disclosed.

  16. Esterification of free fatty acids in biodiesel production with sulphonated pyrolysed carbohydrate catalysts

    DEFF Research Database (Denmark)

    Madsen, Anders Theilgaard; Riisager, Anders; Fehrmann, Rasmus

    The pre-treatment of free fatty acids in oils and fats in biodiesel production is of pivotal importance, and esterification in acidic medium must be done prior to basic transesterification of glycerides. The free fatty acids may be converted over an acidic catalyst of sulphonated pyrolysed...... carbohydrates. These were prepared by pyrolysis of the carbohydrates in inert atmosphere at 300-450°C in 1-15 h and sulphonation in concentrated or fuming sulphuric acid at 150°C. A monophasic fatty model mixture of lauric acid, tricaprylate and methanol was subsequently treated with the prepared catalysts...

  17. In-situ Spectroscopic Studies and Modelling of Crystallization Processes of Sulphuric Acid Catalysts

    DEFF Research Database (Denmark)

    Oehlers, C.; Fehrmann, Rasmus; Masters, Stephen Grenville

    1996-01-01

    Deactivation of commercial and prototype sulphuric acid catalysts has been investigated in-situ by ESR spectroscopy. The influence of support pore structure,and the chemical composition of the catalyst and the gas phase was dicussed.A statistical lattice model was applied to describe...

  18. Aerobic Oxidation of Alcohols over Gold Catalysts: Role of Acid and Base

    DEFF Research Database (Denmark)

    Klitgaard, Søren Kegnæs; DeLa Riva, Andrew T.; Helveg, Stig

    2008-01-01

    Gold nanoparticles are deposited on potassium titanate nanowires and used as heterogeneous catalysts in the aerobic oxidation of benzyl alcohol in methanol to methyl benzoate at ambient conditions. The presence of a catalytic amount of base promotes the reaction and the formation of free benzoic ...... acid during the reaction poisons the catalyst. The activity however, of the catalyst can be restored again by addition of base.......Gold nanoparticles are deposited on potassium titanate nanowires and used as heterogeneous catalysts in the aerobic oxidation of benzyl alcohol in methanol to methyl benzoate at ambient conditions. The presence of a catalytic amount of base promotes the reaction and the formation of free benzoic...

  19. A comparative study of n-hexane isomerization over solid acids catalysts: Sulfated and phosphated zirconia

    Directory of Open Access Journals (Sweden)

    Stojkovic N.

    2012-01-01

    Full Text Available Two series of zirconia based catalysts promoted with either sulfates or phosphates were prepared, calcined at different temperatures (600 and 700°C and evaluated for the n-hexane isomerization reaction. The catalysts with different concentrations of sulfates or phosphates (4 or 10 wt. % were characterized by BET, XRD, SEM methods, and total acidity was evaluated by using the Hammett indicators. Their final catalytic performances were correlated with their physical-chemical properties (surface, structural, textural and morphological. It was found that sulfated zirconia catalyst calcined at lower temperature showed the highest initial activity of all tested catalysts as the result of favorable total acidity, mesopore texture and structural properties. Somewhat lower activity of the sulfated catalyst calcined at higher temperature is related to the content of acid groups partially removed during thermal treatment, thus, lower total acidity, and also to less favorable textural and structural features. Negligible activity of phosphated zirconia catalysts is connected with low total acidity despite the positive status of particular property showing the complexity of the active phase/site formation in the catalyst.

  20. Silica-supported sulfonic acids as recyclable catalyst for esterification of levulinic acid with stoichiometric amounts of alcohols

    Directory of Open Access Journals (Sweden)

    Raimondo Maggi

    2016-10-01

    Full Text Available Converting biomass into value-added chemicals holds the key to sustainable long-term carbon resource management. In this context, levulinic acid, which is easily obtained from cellulose, is valuable since it can be transformed into a variety of industrially relevant fine chemicals. Here we present a simple protocol for the selective esterification of levulinic acid using solid acid catalysts. Silica supported sulfonic acid catalysts operate under mild conditions and give good conversion and selectivity with stoichiometric amounts of alcohols. The sulfonic acid groups are tethered to the support using organic tethers. These tethers may help in preventing the deactivation of the active sites in the presence of water.

  1. Reaction catalyst for the elimination of oxyhydrogen gas in lead--acid storage batteries. [metal of Pt group

    Energy Technology Data Exchange (ETDEWEB)

    Lahme, N.; Sassmannshausen, G.

    1973-03-15

    A unitary catalyst element for catalytically recombining into water a gas mixture of oxygen and hydrogen formed during operation of lead--acid storage battery is described. It comprises a single elongated catalyst carrier body in the form of a permeable coherent solid, an active metallic catalyst material of the platinum group carried on the surface of the permeable catalyst carrier body, and an axially disposed core member of highly heat conductive material enclosed within said catalyst carrier body.

  2. Platinum nanoparticles–manganese oxide nanorods as novel binary catalysts for formic acid oxidation

    OpenAIRE

    El-Deab, Mohamed S.

    2012-01-01

    The current study proposes a novel binary catalyst system (composed of metal/metal oxide nanoparticles) as a promising electrocatalyst in formic acid oxidation. The electro-catalytic oxidation of formic acid is carried out with binary catalysts of Pt nanoparticles (nano-Pt) and manganese oxide nanorods (nano-MnOx) electrodeposited onto glassy carbon (GC) electrodes. Cyclic voltammetric (CV) measurements showed that unmodified GC and nano-MnOx/GC electrodes have no catalytic activity. While tw...

  3. Synthesis and characterization of new chiral ketopinic acid-derived catalysts immobilized on polystyrene-bound imidazole

    Directory of Open Access Journals (Sweden)

    Hassan Yusuf

    2017-02-01

    Full Text Available Four new chiral ketopinic acid-derived catalysts were anchored on a polystyrene-bound imidazole via non-covalent bond. The resulting heterogeneous catalysts were successfully characterized using IR, SEM, and TGA analyses.

  4. Alkaline earth layered benzoates as reusable heterogeneous catalysts for the methyl esterification of benzoic acid

    Directory of Open Access Journals (Sweden)

    Swamy Arêa Maruyama

    2012-01-01

    Full Text Available This paper describes the synthesis and characterization of layered barium, calcium and strontium benzoates and evaluates the potential of these materials as catalysts in the synthesis of methyl benzoate. The methyl esterification of benzoic acid was investigated, where the effects of temperature, alcohol:acid molar ratio and amount of catalyst were evaluated. Ester conversions of 65 to 70% were achieved for all the catalysts under the best reaction conditions. The possibility of recycling these metallic benzoates was also demonstrated, evidenced by unaltered catalytic activity for three consecutive reaction cycles.

  5. Acetic Acid Formation by Selective Aerobic Oxidation of Aqueous Ethanol over Heterogeneous Ruthenium Catalysts

    DEFF Research Database (Denmark)

    Gorbanev, Yury; Kegnæs, Søren; Hanning, Christopher William

    2012-01-01

    Heterogeneous catalyst systems comprising ruthenium hydroxide supported on different carrier materials, titania, alumina, ceria, and spinel (MgAl2O4), were applied in selective aerobic oxidation ethanol to form acetic acid, an important bulk chemical and food ingredient. The catalysts were...... of catalysts, oxidant pressure, reaction temperature, and substrate concentration were investigated. Quantitative yield of acetic acid was obtained with 1.2 wt % Ru(OH)x/CeO2 under optimized conditions (150 °C, 10 bar O2, 12 h of reaction time, 0.23 mol % Ru to substrate)....

  6. A microalgae residue based carbon solid acid catalyst for biodiesel production.

    Science.gov (United States)

    Fu, Xiaobo; Li, Dianhong; Chen, Jie; Zhang, Yuanming; Huang, Weiya; Zhu, Yi; Yang, Jun; Zhang, Chengwu

    2013-10-01

    Biodiesel production from microalgae is recognized as one of the best solutions to deal with the energy crisis issues. However, after the oil extraction from the microalgae, the microalgae residue was generally discarded or burned. Here a novel carbon-based solid acid catalyst derived from microalgae residue by in situ hydrothermal partially carbonization were synthesized. The obtained catalyst was characterized and subjected to both the esterification of oleic acid and transesterification of triglyceride to produce biodiesel. The catalyst showed high catalytic activity and can be regenerated while its activity can be well maintained after five cycles. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Synthesis of seaweed based carbon acid catalyst by thermal decomposition of ammonium sulfate for biodiesel production

    Science.gov (United States)

    Ee, Tang Zo; Lim, Steven; Ling, Pang Yean; Huei, Wong Kam; Chyuan, Ong Hwai

    2017-04-01

    Experiment was carried out to study the feasibility of biomass derived solid acid catalyst for the production of biodiesel using Palm Fatty Acid Distillate (PFAD). Malaysia indigenous seaweed was selected as the biomass to be carbonized as the catalyst support. Sulfonation of seaweed based carbon material was carried out by thermal decomposition of ammonium sulfate, (NH4)2SO4. The effects of carbonization temperature at 200 to 600°C on the catalyst physical and chemical properties were studied. The effect of reaction parameters on the fatty acid methyl ester (FAME) yield was studied by varying the concentration of ammonium sulfate (5.0 to 40.0 w/v%) and thermal decomposition time (15 to 90 min). Characterizations of catalyst were carried out to study the catalyst surface morphology with Scanning Electron Microscope (SEM), acid density with back titration and functional group attached with FT-IR. Results showed that when the catalyst sulfonated with 10.0 w/v% ammonium sulfate solution and heated to 235°C for 30 min, the highest FAME yield achieved was 23.7% at the reaction condition of 5.0 wt.% catalyst loading, esterification time of 4 h, methanol to PFAD molar ratio of 20:1 at 100°C reaction temperature.

  8. Carbon-based acid catalyst from waste seed shells: preparation and characterization

    Directory of Open Access Journals (Sweden)

    Wang Li H.

    2015-12-01

    Full Text Available A carbon-based solid acid catalyst was prepared by the sulfonation of carbonized seed shells of Jatropha curcas (J. curcas L.. The structure of amorphous carbon consisting of polycyclic aromatic carbon sheets attached a high density of acidic SO3H groups (2.0 mmol · g−1 was identified with scanning electron microscopy (SEM, fourier transform infrared (FTIR spectroscopy, powder X-ray diffraction (XRD, and X-ray photoelectron spectroscopy (XPS. The performance of the solid acid catalyst was evaluated for biodiesel production in the esterification of oleic acid with methanol. 95.7% yield of biodiesel was obtained after 2 h reaction and the conversions with reused catalyst varied in the range of 95.7% to 95.1%, showing better activity and stability than commercial catalyst amberlyst-46. It was also observed that the prepared catalyst showed enhanced activity in the transesterification of triolein with methanol when compared with other solid acid catalysts. A synergistic effect results from the high density of SO3H groups and the good access of reactants to the acidic sites can be used to explain the excellent catalytic activity, as well as the strong affinity between the hydrophilic reactants and the neutral OH groups bonded to the polycyclic aromatic carbon rings.

  9. Efficacy of Catalysts in the Batch Esterification of the Fatty Acids of ...

    African Journals Online (AJOL)

    The methyl, ethyl, propyl and butyl esters of the fatty acids of Thevetia peruviana seed oil were successfully prepared by the batch-esterification procedures. Various acid catalyst and various molar ratios of fatty acid to alcohol were investigated. H3PO4 was found to be ineffective to catalyze the esterification of the free fatty ...

  10. PROCESS FOR HYDROGENOLYSIS OF ALPHA-HYDROXY ESTERS OR ACIDS USING A HETEROGENEOUS CATALYST

    DEFF Research Database (Denmark)

    2017-01-01

    The present invention relates to a method for hydrogenolysis of alpha-hydroxy esters or acids, comprising reacting the alpha-hydroxy ester or acid in the presence of a heterogeneous catalyst. The present invention also relates to a method for producing propionic acid ester, and the use of any...

  11. Catalytic Ring Hydrogenation of Benzoic Acid with Supported Transition Metal Catalysts in scCO2

    Directory of Open Access Journals (Sweden)

    Fengyu Zhao

    2007-07-01

    Full Text Available The ring hydrogenation of benzoic acid to cyclohexanecarboxylic acid overcharcoal-supported transition metal catalysts in supercritical CO2 medium has been studiedin the present work. The cyclohexanecarboxylic acid can be produced efficiently insupercritical CO2 at the low reaction temperature of 323 K. The presence of CO2 increasesthe reaction rate and several parameters have been discussed.

  12. Hierarchical Porous Interlocked Polymeric Microcapsules: Sulfonic Acid Functionalization as Acid Catalysts

    Science.gov (United States)

    Wang, Xiaomei; Gu, Jinyan; Tian, Lei; Zhang, Xu

    2017-03-01

    Owing to their unique structural and surface properties, mesoporous microspheres are widely applied in the catalytic field. Generally, increasing the surface area of the specific active phase of the catalyst is a good method, which can achieve a higher catalytic activity through the fabrication of the corresponding catalytic microspheres with the smaller size and hollow structure. However, one of the major challenges in the use of hollow microspheres (microcapsules) as catalysts is their chemical and structural stability. Herein, the grape-like hypercrosslinked polystyrene hierarchical porous interlocked microcapsule (HPIM-HCL-PS) is fabricated by SiO2 colloidal crystals templates, whose structure is the combination of open mouthed structure, mesoporous nanostructure and interlocked architecture. Numerous microcapsules assembling together and forming the roughly grape-like microcapsule aggregates can enhance the structural stability and recyclability of these microcapsules. After undergoing the sulfonation, the sulfonated HPIM-HCL-PS is served as recyclable acid catalyst for condensation reaction between benzaldehyde and ethylene glycol (TOF = 793 h-1), moreover, exhibits superior activity, selectivity and recyclability.

  13. Lanthanide(III) complexes of aromatic sulfonic acids as catalysts for the nitration of toluene

    Energy Technology Data Exchange (ETDEWEB)

    Parac-Vogt, Tatjana N.; Deleersnyder, Karen; Binnemans, Koen

    2004-07-14

    Ytterbium(III) complexes of benzenesulfonic acid, Yb(BSA){sub 3}, p-toluenesulfonic acid, Yb(Tos){sub 3}, and 2-naphthalenesulfonic acid, Yb(NSA){sub 3}, were prepared and tested as possible catalyst for the nitration of toluene. With a loading of 5-10 mol% of Yb(BSA){sub 3} and Yb(NSA){sub 3}, a quantitative conversion of toluene to nitrotoluene was achieved within 5 h, while Yb(Tos){sub 3} was slightly less active and 77% of nitrated products were obtained. The catalysts can be easily recovered after the reaction, and {sup 1}H NMR spectroscopy of analogous diamagnetic lanthanide(III) catalysts showed that the recovered catalysts were identical to the freshly prepared ones. The ratio of ortho:meta:para products was in all reactions 52:6:42, which is consistent with a direct electrophilic attack by the nitronium ion, NO{sub 2}{sup +}.

  14. Production of biodiesel and lactic acid from rapeseed oil using sodium silicate as catalyst.

    Science.gov (United States)

    Long, Yun-Duo; Guo, Feng; Fang, Zhen; Tian, Xiao-Fei; Jiang, Li-Qun; Zhang, Fan

    2011-07-01

    Biodiesel and lactic acid from rapeseed oil was produced using sodium silicate as catalyst. The transesterification in the presence of the catalyst proceeded with a maximum yield of 99.6% under optimized conditions [3% (w/w) sodium silicate, methanol/oil molar ratio 9/1, reaction time 60 min, reaction temperature 60°C, and stirring rate 250 rpm]. After six consecutive transesterification reactions, the catalyst was collected and used for catalysis of the conversion of glycerol to lactic acid. A maximum yield of 80.5% was achieved when the reaction was carried out at a temperature of 300°C for 90 min. Thus, sodium silicate is an effective catalyst for transesterification and lactic acid production from the biodiesel by-product, glycerol. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Biodiesel production from wet microalgae by using graphene oxide as solid acid catalyst.

    Science.gov (United States)

    Cheng, Jun; Qiu, Yi; Huang, Rui; Yang, Weijuan; Zhou, Junhu; Cen, Kefa

    2016-12-01

    In order to produce biodiesel from lipids in wet microalgae with graphene oxide (GO) as solid acid catalyst, the effects on lipids conversion efficiencies of catalyst dosage, transesterification temperature, reaction time, methanol dosage and chloroform dosage were investigated. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and elemental analysis revealed that GO contained 0.997mmol SO3H groups per gram and high amounts of OH groups. Scanning electron microscopy showed that wet microalgae cells were adsorbed on hydrophilic GO surfaces covered with many OH groups. Lipids extracted by chloroform from microalgal cells were transformed into fatty acids methyl esters (FAMEs) through transesterification catalyzed by the acid centers (SO3H groups) in GO catalysts. The lipids conversion efficiency into FAMEs was 95.1% in microwave-assisted transesterification reactions of 5wt.% GO catalyst at 90°C for 40min. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Hydrolysis of Straw in Ionic Liquids with Acid as Catalyst under Microwave Irradiation

    Directory of Open Access Journals (Sweden)

    Yuanjing Zhang

    2015-01-01

    Full Text Available With ionic liquids as solvents and corn straw as raw material, different processes of lignocellulose pretreatment with acid as catalyst were studied under conventional heating/microwave irradiation and the reducing sugar was measured. The results indicated that acid can accelerate hydrolysis reaction of corn straw into reducing sugar with ionic liquids as solvent, and microwave irradiation was more efficient in pretreatment of corn straw than conventional heating. The influences of different acid catalysts, the concentration of acid, temperature, mass ratio of straw/[Bmim]Cl, and the amount of refill water were mainly tested, and the optimum experimental conditions are thus determined.

  17. Direct production of biodiesel from high-acid value Jatropha oil with solid acid catalyst derived from lignin

    Directory of Open Access Journals (Sweden)

    Pua Fei-ling

    2011-12-01

    Full Text Available Abstract Background Solid acid catalyst was prepared from Kraft lignin by chemical activation with phosphoric acid, pyrolysis and sulfuric acid. This catalyst had high acid density as characterized by scanning electron microscope (SEM, energy-dispersive x-ray spectrometry (EDX and Brunauer, Emmett, and Teller (BET method analyses. It was further used to catalyze the esterification of oleic acid and one-step conversion of non-pretreated Jatropha oil to biodiesel. The effects of catalyst loading, reaction temperature and oil-to-methanol molar ratio, on the catalytic activity of the esterification were investigated. Results The highest catalytic activity was achieved with a 96.1% esterification rate, and the catalyst can be reused three times with little deactivation under optimized conditions. Biodiesel production from Jatropha oil was studied under such conditions. It was found that 96.3% biodiesel yield from non-pretreated Jatropha oil with high-acid value (12.7 mg KOH/g could be achieved. Conclusions The catalyst can be easily separated for reuse. This single-step process could be a potential route for biodiesel production from high-acid value oil by simplifying the procedure and reducing costs.

  18. Direct production of biodiesel from high-acid value Jatropha oil with solid acid catalyst derived from lignin

    Science.gov (United States)

    2011-01-01

    Background Solid acid catalyst was prepared from Kraft lignin by chemical activation with phosphoric acid, pyrolysis and sulfuric acid. This catalyst had high acid density as characterized by scanning electron microscope (SEM), energy-dispersive x-ray spectrometry (EDX) and Brunauer, Emmett, and Teller (BET) method analyses. It was further used to catalyze the esterification of oleic acid and one-step conversion of non-pretreated Jatropha oil to biodiesel. The effects of catalyst loading, reaction temperature and oil-to-methanol molar ratio, on the catalytic activity of the esterification were investigated. Results The highest catalytic activity was achieved with a 96.1% esterification rate, and the catalyst can be reused three times with little deactivation under optimized conditions. Biodiesel production from Jatropha oil was studied under such conditions. It was found that 96.3% biodiesel yield from non-pretreated Jatropha oil with high-acid value (12.7 mg KOH/g) could be achieved. Conclusions The catalyst can be easily separated for reuse. This single-step process could be a potential route for biodiesel production from high-acid value oil by simplifying the procedure and reducing costs. PMID:22145867

  19. A highly active bagasse-derived solid acid catalyst with properties suitable for production of biodiesel.

    Science.gov (United States)

    Lou, Wen-Yong; Guo, Qiang; Chen, Wen-Jing; Zong, Min-Hua; Wu, Hong; Smith, Thomas J

    2012-08-01

    A novel bagasse-based solid acid catalyst was successfully prepared through sulfonation of incompletely carbonized bagasse. A range of conditions for producing the catalyst were investigated, and the optimized catalyst, produced under carbonization at 648 K for 0.5 h and sulfonation at 423 K for 15 h, showed excellent catalytic activity and resulted in around 95 % yield of methyl oleate. Its activity was not only substantially greater than that of niobic acid and Amberlyst-15, but also comparable to or superior to that of catalysts made from pure starch or glucose, respectively. Additionally, the bagasse-derived catalyst could be repeatedly employed for at least eight cycles and still retained around 90 % of its original activity, exhibiting excellent operational stability. Furthermore, the catalyst efficiently converted waste cooking oils with 38.6 wt % free fatty acids into biodiesel and afforded a high yield of about 93.8 % within 12 h. These results clearly show that the bagasse-derived catalyst is economic, eco-friendly, and promising for biodiesel production from low-cost feedstocks and may find wide applications. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Synthesis of Ricinoleic Acid Estolides by the Esterification of Ricinoleic Acids Using Functional Acid Ionic Liquids as Catalysts.

    Science.gov (United States)

    Wang, Gaoshang; Sun, Shangde

    2017-07-01

    Estolides of ricinoleic acid (RA) have been used as lubricants and pigment dispersant in many industries. In this paper, functional acid ionic liquids (ILs) were firstly used as catalysts to prepare RA estolides by the esterification of RAs in solvent-free system. Different ILs were used as catalysts for the esterification. Effect of reaction variables (IL amount, reaction temperature and reaction time) on the esterification were also investigated and optimized using response surface methodology (RSM). Among all tested ILs, [BSO3HMIM]TS showed the best performance for the esterification. Arrhenius equation for the esterification was lnV0 =14.897-7558.7/T, and the activation energy (Ea) was 62.84 kJ/mol. A high degree of polymerization with an acid value of 48.0±2.5 mg KOH/g was achieved at the optimized conditions (IL load 12%, reaction temperature 140°C, and reaction time 12 h). The effect of reaction variables on the esterification decreased in the order of catalyst loading of IL > reaction temperature > reaction time.

  1. Production of Oleic Acid Based Wax Ester Using Acidic Homogeneous Catalysts

    Directory of Open Access Journals (Sweden)

    Naowara Al-Arafi

    2012-01-01

    Full Text Available Four homogeneous acidic catalysts were tested for their ability to catalyze the esterification reaction of oleic acid and oleyl alcohol to produce oleyl oleate, a wax ester. Sulfuric acid showed relatively higher specific activity. Various reaction parameters were optimised to obtain high percentage yield of oleyl oleate. The optimum condition to produce oeyl oleate was reaction time; 5 h, temperture; 90°C, amount of sulforic acid 0.15 g and molar ratio of oleyl alcohol to oleic acid; 1:1. Percentage yield of wax ester obtained at these optimum reaction conditions was 93.88. Disappearance of carboxylic acid (C=O peak has confirmed by FTIR with appearance of ester (C=O peak at 1739 cm−1. 1H NMR spectra analyses confirmed the result of oleyl oleate with appearance of ester (-CH2OCOR at 4.02 ppm and also the 13C-NMR confirmed the result with appearance of ester (C=O peak at 173.2 ppm. The low-temperture behavior of compound synthesized was determined through its pour point (PP, viscosity index (VI and flash point (FP values. The results showed that oleyl oleate exhibited the most favorable low-temperture performance of PP, VI and FP with −31°C, 197.5 and 320°C respectively. This is due to increase of the molacular weight thus improve the low temperture property significantly.

  2. Hydrogenation of Levulinic Acid over Nickel Catalysts Supported on Aluminum Oxide to Prepare γ-Valerolactone

    Directory of Open Access Journals (Sweden)

    Jie Fu

    2015-12-01

    Full Text Available Four types of nickel catalysts supported on aluminum oxide (Ni/Al2O3 with different nickel loadings were synthesized using the co-precipitation method and were used for the hydrogenation of levulinic acid (LA to prepare γ-valerolactone (GVL. The synthesized Ni/Al2O3 catalysts exhibited excellent catalytic activity in dioxane, and the activity of the catalysts was excellent even after being used four times in dioxane. The catalytic activity in dioxane as a solvent was found to be superior to the activity in water. Nitrogen physisorption, X-ray diffraction, and transmission electron microscopy were employed to characterize the fresh and used catalysts. The effects of the nickel loading, temperature, hydrogen pressure, and substrate/catalyst ratio on the catalytic activity were investigated.

  3. Synthesis of a nano-crystalline solid acid catalyst from fly ash and its catalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Chitralekha Khatri; Ashu Rani [Government P.G. College, Kota (India). Environmental Chemistry Laboratory

    2008-10-15

    The synthesis of nano-crystalline activated fly ash catalyst (AFAC) with crystallite size of 12 nm was carried out by chemical and thermal treatment of fly ash, a waste material generated from coal-burning power plants. Fly ash was chemically activated using sulfuric acid followed by thermal activation at 600{sup o}C. The variation of surface and physico-chemical properties of the fly ash by activation methods resulted in improved acidity and therefore, catalytic activity for acid catalyzed reactions. The AFAC was characterized by X-ray diffraction, FT-IR spectroscopy, N{sub 2}-adsorption-desorption isotherm, scanning electron microscopy, flame atomic absorption spectrophotometry and sulfur content by CHNS/O elemental analysis. It showed amorphous nature due to high silica content (81%) and possessed high BET surface area (120 m{sup 2}/g). The catalyst was found to be highly active solid acid catalyst for liquid phase esterification of salicylic acid with acetic anhydride and methanol giving acetylsalicylic acid and methyl salicylate respectively. A maximum yield of 97% with high purity of acetylsalicylic acid (aspirin) and a very high conversion 87% of salicylic acid to methyl salicylate (oil of wintergreen) was obtained with AFAC. The surface acidity and therefore, catalytic activity in AFAC was originated by increased silica content, hydroxyl content and higher surface area as compared to fly ash. The study shows that coal generated fly ash can be converted into potential solid acid catalyst for acid catalyzed reactions. Furthermore, this catalyst may replace conventional environmentally hazardous homogeneous liquid acids making an ecofriendly; solvent free, atom efficient, solid acid based catalytic process. 27 refs., 5 figs., 2 tabs.

  4. Synthesis of quinoxalines in the presence of heteropoly acids

    Directory of Open Access Journals (Sweden)

    Fatemeh Hakimia

    2013-04-01

    Full Text Available Efficient synthesis of quinoxaline derivatives from the reaction of α-diketones and o-phenylenediamines in the presence of Keggin-type heteropolyacids (HPA such as H3PMo12O40, H4SiW12O40, K7PMo2W9O40, H3PW12O40.SiO2 and H3PW12O40 in high yields and short reaction times, and at room temperature is introduced.

  5. KSF-SUPPORTED HETEROPOLY ACIDS CATALYZED ONE-POT ...

    African Journals Online (AJOL)

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    (SiW) from Aldrich (USA), Merck (Germany) and KSF montmorillonite from Fluka. (Switzerland) were used. NMR Spectra were recorded on a Bruker Avance 200 MHz NMR instrument (Germany). FTIR spectra were performed using Bomem MB 104 spectrophotometer. (Germany). Tungsten and carbon coked content in the ...

  6. Reusable and Efficient Polystryrene-supported Acidic Ionic Liquid Catalyst for Mononitration of Aromatic Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Li, Li Xia; Ling, Qi Long; Liu, Zu Liang; Xing, Xiao Dong; Zhu, Xiao Qin; Meng, Xiao [Nanjing Univ. of Science and Technology, Nanjing (China)

    2012-10-15

    A series of polystyrene-supported 1-(propyl-3-sulfonate)-3-methyl-imidazolium hydrosulfate acidic ionic liquid (PS-[SO{sub 3}H-PMIM][HSO{sub 4}]) catalysts were prepared and tested for mononitration of simple aromatics compounds with nitric acid. It was found that the reactivity of the catalysts increased with increasing [SO{sub 3}HPMIM][HSO{sub 4}] content. The para-selectivity was not only related to the [SO{sub 3}H-PMIM][HSO{sub 4}] content but also the substituent groups in aromatics. A reaction mechanism of nitration over this new catalyst was proposed. The catalytic activity of this catalyst decreased slightly after fifth runs in the synthesis of nitrotoluene.

  7. Nanocomposite catalyst with palladium nanoparticles encapsulated in a polymeric acid: A model for tandem environmental catalysis

    KAUST Repository

    Isimjan, Tayirjan T.

    2013-04-01

    The synthesis and characterization of a novel hybrid nanocomposite catalyst comprised of palladium nanoparticles embedded in polystyrene sulfonic acid (PSSH) and supported on metal oxides is reported. The catalysts are intended for application in green catalysis, and they are shown to be effective in the hydrolysisreduction sequence of tandem catalytic reactions required for conversion of 2-phenyl-1,3-dioxolane to toluene or of phenol to cyclohexane. The two distinct components in the catalyst, Pd nanoparticles and acidic PSSH, are capable of catalyzing sequential reactions in one pot under mild conditions. This work has demonstrated a powerful approach toward designing highperformance, multifunctional, scalable, and environmentally friendly nanostructured tandem catalysts. © 2013 American Chemical Society.

  8. Formic Acid Modified Co3O4-CeO2 Catalysts for CO Oxidation

    Directory of Open Access Journals (Sweden)

    Ruishu Shang

    2016-03-01

    Full Text Available A formic acid modified catalyst, Co3O4-CeO2, was prepared via facile urea-hydrothermal method and applied in CO oxidation. The Co3O4-CeO2-0.5 catalyst, treated by formic acid at 0.5 mol/L, performed better in CO oxidation with T50 obtained at 69.5 °C and T100 obtained at 150 °C, respectively. The characterization results indicate that after treating with formic acid, there is a more porous structure within the Co3O4-CeO2 catalyst; meanwhile, despite of the slightly decreased content of Co, there are more adsorption sites exposed by acid treatment, as suggested by CO-TPD and H2-TPD, which explains the improvement of catalytic performance.

  9. Direct Mannich-Type Reactions Promoted by Frustrated Lewis Acid/Brønsted Base Catalysts.

    Science.gov (United States)

    Chan, Jessica Z; Yao, Wenzhi; Hastings, Brian T; Lok, Charles K; Wasa, Masayuki

    2016-10-24

    Direct Mannich-type reactions that afford both α- and β-amino esters by the reaction of a broad range of carbonyl compounds and aldimines are disclosed. The transformation is promoted by a sterically frustrated Lewis acid/Brønsted base pair, which is proposed to operate cooperatively: Within the catalyst complex, an enolate is generated that then reacts with a hydrogen-bond-activated imine. Noncovalent interactions between reactants and the catalyst provide selectivity and new opportunities for future catalyst design. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Kinetics of acetic acid synthesis from ethanol over a Cu/SiO2 catalyst

    DEFF Research Database (Denmark)

    Voss, Bodil; Schjødt, Niels Christian; Grunwaldt, Jan-Dierk

    2011-01-01

    . The dehydrogenation experiments were carried out in a flow through lab scale tubular reactor. Based on 71 data sets a power law kinetic expression has been derived for the description of the dehydrogenation of acetaldehyde to acetic acid. The apparent reaction order was 0.89 with respect to water and 0......The dehydrogenation of ethanol via acetaldehyde for the synthesis of acetic acid over a Cu based catalyst in a new process is reported. Specifically, we have studied a Cu on SiO2 catalyst which has shown very high selectivity to acetic acid via acetaldehyde compared to competing condensation routes...

  11. Novel Approach: Tungsten Oxide Nanoparticle as a Catalyst for Malonic Acid Ester Synthesis via Ozonolysis

    Directory of Open Access Journals (Sweden)

    Bilal A. Wasmi

    2014-01-01

    Full Text Available Malonic acid ester was synthesized via the one-step ozonolysis of palm olein. Malonic acid ester was spectroscopically characterized using gas chromatography mass spectroscopy (GC-MS. Tungsten oxide nanoparticles were used as the catalyst, which was characterized via X-ray powder diffraction (XRD and field emission scanning electron microscopy (FE-SEM. Tungsten oxide provided several advantages as a catalyst for the esterification malonic acid such as simple operation for a precise ozonation method, an excellent yield of approximately 10%, short reaction times of 2 h, and reusability due to its recyclability.

  12. Highly Selective Hydrogenation of Levulinic Acid to gamma-Valerolactone Over Ru/ZrO2 Catalysts

    NARCIS (Netherlands)

    Filiz, Bilge Coskuner; Gnanakumar, Edwin S.; Martinez-Arias, Arturo; Gengler, Regis; Rudolf, Petra; Rothenberg, Gadi; Shiju, N. Raveendran

    We studied the catalytic hydrogenation of levulinic acid over zirconia supported ruthenium catalysts. Four different Ru/ZrO2 catalysts were prepared by different pre-treatments and using different zirconium supports (ZrOx(OH)(4-2x) and ZrO2). Although the final compositions of the catalysts are the

  13. Highly Selective Hydrogenation of Levulinic Acid to γ-Valerolactone Over Ru/ZrO2 Catalysts

    NARCIS (Netherlands)

    Filiz, B.C.; Gnanakumar, E.S.; Martinez-Arias, A.; Gengler, R.; Rudolf, P.; Rothenberg, G.; Shiju, N.R.

    We studied the catalytic hydrogenation of levulinic acid over zirconia supported ruthenium catalysts. Four different Ru/ZrO2 catalysts were prepared by different pre-treatments and using different zirconium supports (ZrOx(OH)4−2x and ZrO2). Although the final compositions of the catalysts are the

  14. La2O3 Promoted Pd/rGO Electro-catalysts for Formic Acid Oxidation.

    Science.gov (United States)

    Ali, Hassan; Kanodarwala, Fehmida K; Majeed, Imran; Stride, John Arron; Nadeem, Muhammad Arif

    2016-11-30

    High activity, a low rate of CO poisoning, and long-term stability of Pd electro-catalysts are necessary for practical use as an anode material in direct formic acid fuel cells. Achieving a high degree of Pd nanoparticle dispersion on a carbon support, without agglomeration, while maintaining a facile electron transfer through the catalyst surface are two challenging tasks to be overcome in fulfilling this aim. Herein, we report the effect of addition of La/La-oxides on the efficiency of Pd nanoparticles supported on reduced graphene oxide (rGO) for formic acid electro-oxidation reaction. A series of electro-catalysts with different Pd-La molar ratios were successfully synthesized and characterized using a range of techniques including PXRD, XPS, TEM, FTIR, and Raman spectroscopy and then tested as anode materials for direct formic acid fuel cells. We explore that the lanthanum species (La/La-oxide) significantly promote the activity and stability of Pd catalyst toward electrocatalytic oxidation of formic acid. The metallic ratio is found to be critical, and the activity order of various catalysts is observed as follows; Pd30La70/rGO > Pd80La20/rGO > Pd70La30 rGO. The obtained mass specific activity for Pd30La70/rGO (986.42 A/g) is 2.18 times higher than that for Pd/rGO (451 A/g) and 16 times higher than that for Pd/C (61.5 A/g) at given onset peak potentials. The high activity and stability of the electro-catalysts are attributed to the uniform dispersion of Pd nanoparticles over the rGO support, as evidenced from TEM images. It is believed that the role of La species in promoting the catalyst activity is to disperse the catalyst particles during synthesis and to facilitate the electron transfer via providing a suitable pathway during electrochemical testing.

  15. An effective low Pd-loading catalyst for hydrogen generation from formic acid

    DEFF Research Database (Denmark)

    Huang, Yunjie; Xu, Junlei; Ma, Xin

    2017-01-01

    As an interesting hydrogen carrier, formic acid is bio-renewable, non-toxic and available in the liquid state at room temperature. The development of active and low-cost catalyst is of significance for hydrogen generation from formic acid. In this study, both a relatively cheap metal (Ag...

  16. The utilization of leftover as acid catalyst to catalyse the transesterification and esterification reactions

    Science.gov (United States)

    Leung, K. K.; Yau, Y. H.

    2017-08-01

    Biodiesel (Fatty Acid Methyl Ester, FAME) is a green and renewable energy. It is carbon neutral and produces less air pollutants in combustion. In my project, the selected feedstock of biodiesel production is grease trap oil (GTO). It is extracted from restaurants, and needs pre-treatment. The triglycerides and free fatty acid (FFA) are the main components of GTO. Both triglycerides and free fatty acid can be converted to biodiesel (Fatty Acid Methyl Ester) by transesterification and esterification, through reaction with alcohol (methanol) and catalyst. In the processes, acidic catalyst is chosen to speed up the reactions. The catalyst used In the study, a heterogeneous solid acid is applied. It is waste cooked rice (WCR) collected from leftover. The WCR powder is pyrolysed in 400°C furnace 15 hours and blown with nitrogen gas (incomplete carbonization). The WCR black powder is then mixed with concentrated sulphuric acid and heat in 160°C furnace 15 hours and continuous blown with nitrogen gas (sulphonation). This heterogeneous solid acid is used in the both transesterification and esterification to produce FAME. Moreover, in the optimal reaction conditions, this catalyst offers a stable catalytic effect. After 20 times usage in optimal reaction condition, the catalytic activity remains unchanged.

  17. succinimide-n-sulfonic acid as an efficient recyclable catalyst for the ...

    African Journals Online (AJOL)

    -amino-4,5-dihydro-4- phenylpyrano[3,2-b]indole-3-carbonitrile derivatives with coumarin-3-carboxylic acid employing succinimide-N- sulfonic acid (SuSA) as catalyst for the synthesis of a series of 5 ...

  18. Efficacy of pretreating oil palm fronds with an acid-base mixture catalyst.

    Science.gov (United States)

    Jung, Young Hoon; Park, Hyun Min; Park, Yong-Cheol; Park, Kyungmoon; Kim, Kyoung Heon

    2017-07-01

    Oil palm fronds are abundant but recalcitrant to chemical pretreatment. Herein, an acid-base mixture was applied as a catalyst to efficiently pretreat oil palm fronds. Optimized conditions for the pretreatment were a 0.1M acidic acid-base mixture and 3min ramping to 190°C and 12min holding. The oil palm fronds pretreated and washed with the acid-base mixture exhibited an enzymatic digestibility of 85% by 15 FPU Accellerase 1000/g glucan after 72h hydrolysis, which was significantly higher than the enzymatic digestibilities obtained by acid or alkali pretreatment alone. This could be attributed to the synergistic actions of the acid and base, producing an 87% glucose recovery with 100% and 40.3% removal of xylan and lignin, respectively, from the solids. Therefore, an acid-base mixture can be a feasible catalyst to deconstruct oil palm fronds for sugar production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Green biodiesel production from waste cooking oil using an environmentally benign acid catalyst.

    Science.gov (United States)

    Tran, Thi Tuong Vi; Kaiprommarat, Sunanta; Kongparakul, Suwadee; Reubroycharoen, Prasert; Guan, Guoqing; Nguyen, Manh Huan; Samart, Chanatip

    2016-06-01

    The application of an environmentally benign sulfonated carbon microsphere catalyst for biodiesel production from waste cooking oil was investigated. This catalyst was prepared by the sequential hydrothermal carbonization and sulfonation of xylose. The morphology, surface area, and acid properties were analyzed. The surface area and acidity of the catalyst were 86m(2)/g and 1.38mmol/g, respectively. In addition, the presence of sulfonic acid on the carbon surface was confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The catalytic activity was tested for biodiesel production from waste cooking oil via a two-step reaction to overcome reaction equilibrium. The highest biodiesel yield (89.6%) was obtained at a reaction temperature of 110°C, duration time of 4h, and catalyst loading of 10wt% under elevated pressure 2.3bar and 1.4bar for first and second step, respectively. The reusability of the catalyst was investigated and showed that the biodiesel yield decreased by 9% with each cycle; however, this catalyst is still of interest because it is an example of green chemistry, is nontoxic, and makes use of xylose waste. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. N-doped carbon nanomaterials are durable catalysts for oxygen reduction reaction in acidic fuel cells

    Science.gov (United States)

    Shui, Jianglan; Wang, Min; Du, Feng; Dai, Liming

    2015-01-01

    The availability of low-cost, efficient, and durable catalysts for oxygen reduction reaction (ORR) is a prerequisite for commercialization of the fuel cell technology. Along with intensive research efforts of more than half a century in developing nonprecious metal catalysts (NPMCs) to replace the expensive and scarce platinum-based catalysts, a new class of carbon-based, low-cost, metal-free ORR catalysts was demonstrated to show superior ORR performance to commercial platinum catalysts, particularly in alkaline electrolytes. However, their large-scale practical application in more popular acidic polymer electrolyte membrane (PEM) fuel cells remained elusive because they are often found to be less effective in acidic electrolytes, and no attempt has been made for a single PEM cell test. We demonstrated that rationally designed, metal-free, nitrogen-doped carbon nanotubes and their graphene composites exhibited significantly better long-term operational stabilities and comparable gravimetric power densities with respect to the best NPMC in acidic PEM cells. This work represents a major breakthrough in removing the bottlenecks to translate low-cost, metal-free, carbon-based ORR catalysts to commercial reality, and opens avenues for clean energy generation from affordable and durable fuel cells. PMID:26601132

  1. PYRIDINES USING NANO-CRYSTALLINE SOLID ACID CATALYST ...

    African Journals Online (AJOL)

    Preferred Customer

    dihydropyridines in the condensation of aromatic aldehydes with β-dicarbonyl compounds and ammonium acetate in the presence of nano-sulfated zirconia, nano-structured ZnO, nano-γ-alumina and nano-ZSM-5 zeolites, as catalyst in the ethanol.

  2. Preparation of solid acid catalyst from glucose-starch mixture for biodiesel production.

    Science.gov (United States)

    Chen, Guo; Fang, Baishan

    2011-02-01

    The aim of this work is to study the catalyst prepared by glucose-starch mixture. Assessment experiments showed that solid acid behaved the highest esterification activity when glucose and corn powder were mixed at ratio of 1:1, carbonized at 400°C for 75 min and sulfonated with concentrated H(2)SO(4) (98%) at 150°C for 5 h. The catalyst was characterized by acid activity measurement, XPS, TEM and FT-IR. The results indicated that solid acid composed of CS(0.073)O(0.541) has both Lewis acid sites and Bronsted acid sites caused by SO(3)H and COOH. The conversions of oleic acid esterification and triolein transesterification are 96% and 60%, respectively. Catalyst for biodiesel production from waste cottonseed oil containing high free fatty acid (FFA 55.2 wt.%) afforded the methyl ester yield of about 90% after 12h. The catalyst deactivated gradually after recycles usage, but it could be regenerated by H(2)SO(4) treatment. Copyright © 2010 Elsevier Ltd. All rights reserved.

  3. In situ biodiesel production from greasy sewage sludge using acid and enzymatic catalysts.

    Science.gov (United States)

    Sangaletti-Gerhard, Naiane; Cea, Mara; Risco, Vicky; Navia, Rodrigo

    2015-03-01

    This study proposes to select the most appropriate sewage sludge (greasy, primary and secondary) for in situ transesterification and to compare the technical, economic and energetic performance of an enzymatic catalyst (Novozym®435) with sulfuric acid. Greasy sludge was selected as feedstock for biodiesel production due to its high lipid content (44.4%) and low unsaponifiable matter. Maximum methyl esters yield (61%) was reached when processing the wet sludge using sulfuric acid as catalyst and n-hexane, followed by dried-greasy sludge catalyzed by Novozym®435 (57% methyl esters). Considering the economic point of view, the process using acid catalyst was more favorable compared to Novozym®435 catalyst due to the high cost of lipase. In general, greasy sludge (wet or dried) showed high potential to produce biodiesel. However, further technical adjustments are needed to make biodiesel production by in situ transesterification using acid and enzymatic catalyst feasible. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Removal of free fatty acid in waste frying oil by esterification with methanol on zeolite catalysts.

    Science.gov (United States)

    Chung, Kyong-Hwan; Chang, Duck-Rye; Park, Byung-Geon

    2008-11-01

    The removal of free fatty acid (FFA) in waste frying oil by esterification with methanol was conducted using various zeolite catalysts. The ZSM-5 (MFI), mordenite (MOR), faujasite (FAU), beta (BEA) zeolites, and silicalite were employed with different Si/Al molar ratio in the reaction. The effects of acidic properties and pore structure of the zeolite catalysts were discussed relating to the conversion of the FFA. The MFI zeolite induced an improvement of the removal efficiency of FFA by cracking to the FFA in its pore structure due to its narrow pore mouth. The catalytic activity for FFA removal was lowered with decreasing of acid strength of the zeolites. The strong acid sites of zeolites induced the high conversion of FFA comparatively. The acid strength and pore structure of acidic zeolites affected the catalytic activity in FFA removal.

  5. Palladium Catalysts for Fatty Acid Deoxygenation: Influence of the Support and Fatty Acid Chain Length on Decarboxylation Kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Ford, JP; Immer, JG; Lamb, HH

    2012-03-29

    Supported metal catalysts containing 5 wt% Pd on silica, alumina, and activated carbon were evaluated for liquid-phase deoxygenation of stearic (octadecanoic), lauric (dodecanoic), and capric (decanoic) acids under 5 % H-2 at 300 A degrees C and 15 atm. On-line quadrupole mass spectrometry (QMS) was used to measure CO + CO2 yield, CO2 selectivity, H-2 consumption, and initial decarboxylation rate. Post-reaction analysis of liquid products by gas chromatography was used to determine n-alkane yields. The Pd/C catalyst was highly active and selective for stearic acid (SA) decarboxylation under these conditions. In contrast, SA deoxygenation over Pd/SiO2 occurred primarily via decarbonylation and at a much slower rate. Pd/Al2O3 exhibited high initial SA decarboxylation activity but deactivated under the test conditions. Similar CO2 selectivity patterns among the catalysts were observed for deoxygenation of lauric and capric acids; however, the initial decarboxylation rates tended to be lower for these substrates. The influence of alkyl chain length on deoxygenation kinetics was investigated for a homologous series of C-10-C-18 fatty acids using the Pd/C catalyst. As fatty acid carbon number decreases, reaction time and H-2 consumption increase, and CO2 selectivity and initial decarboxylation rate decrease. The increase in initial decarboxylation rates for longer chain fatty acids is attributed to their greater propensity for adsorption on the activated carbon support.

  6. Model heterogeneous acid catalysts and metal-support interactions: A combined surface science and catalysis study

    Energy Technology Data Exchange (ETDEWEB)

    Boszormenyi, Istvan [Univ. of California, Berkeley, CA (United States)

    1991-05-01

    This (<100Å) silica-alumina layers were tested as potential model heterogeneous acid catalysts for combined surface science and catalysis studies. Three preparation methods were used: oxidation of r3 x r3 R30 Al/Si(111) structure in UHV; deposition on Si(lll) from aqueous solution; and argon ion beam sputter deposition in UHV. The homogeneous thin layers are amorphous, and the chemical environment of surface atoms is similar to that of Si, Al and oxygen atoms on high surface area acid catalysts. Since the ion beam-deposited thin layer of silica-alumina has the same composition as the target zeolite this deposition method is a promising tool to prepare model catalysts using practical catalyst targets. The silica-alumina layers are active in cumene cracking, a typical acid catalyzed reaction. In order to clearly distinguish background reactions and the acid catalyzed reaction at least 20 cm2 catalyst surface area is needed. Two series of model platinum-alumina catalysts were prepared in a combined UHV -- high pressure reactor cell apparatus by depositing alumina on polycrystalline Pt foil and by vapor depositing Pt on a thin alumina layer on Au. Both model surfaces have been prepared with and without chlorine. AES, CO desorption as well as methyl cyclopentane (MCP) hydrogenolysis studies indicate that the Pt surface area is always higher if a chlorination step is involved. Selectivity patterns in MCP ring opening on ``Pt-on-alumina`` and on ``alumina-on-Pt`` are different; only the former is a linear combination of selective and statistical ring opening. Product distribution, however, changes with coverage and reaction time. The properties of the two model catalyst systems and role of chlorine in MCP hydrogenolysis are also discussed.

  7. Model heterogeneous acid catalysts and metal-support interactions: A combined surface science and catalysis study

    Energy Technology Data Exchange (ETDEWEB)

    Boszormenyi, I.

    1991-05-01

    This (<100 [Angstrom]) silica-alumina layers were tested as potential model heterogeneous acid catalysts for combined surface science and catalysis studies. Three preparation methods were used: oxidation of r3 [times] r3 R30 Al/Si(111) structure in UHV; deposition on Si(lll) from aqueous solution; and argon ion beam sputter deposition in UHV. The homogeneous thin layers are amorphous, and the chemical environment of surface atoms is similar to that of Si, Al and oxygen atoms on high surface area acid catalysts. Since the ion beam-deposited thin layer of silica-alumina has the same composition as the target zeolite this deposition method is a promising tool to prepare model catalysts using practical catalyst targets. The silica-alumina layers are active in cumene cracking, a typical acid catalyzed reaction. In order to clearly distinguish background reactions and the acid catalyzed reaction at least 20 cm[sup 2] catalyst surface area is needed. Two series of model platinum-alumina catalysts were prepared in a combined UHV -- high pressure reactor cell apparatus by depositing alumina on polycrystalline Pt foil and by vapor depositing Pt on a thin alumina layer on Au. Both model surfaces have been prepared with and without chlorine. AES, CO desorption as well as methyl cyclopentane (MCP) hydrogenolysis studies indicate that the Pt surface area is always higher if a chlorination step is involved. Selectivity patterns in MCP ring opening on Pt-on-alumina'' and on alumina-on-Pt'' are different; only the former is a linear combination of selective and statistical ring opening. Product distribution, however, changes with coverage and reaction time. The properties of the two model catalyst systems and role of chlorine in MCP hydrogenolysis are also discussed.

  8. Continuous Catalyst-Free Esterification of Oleic Acid in Compressed Ethanol

    OpenAIRE

    Ana Carolina de Araujo Abdala; Vitor Augusto dos Santos Garcia; Caroline Portilho Trentini; Lúcio Cardozo Filho; Edson Antonio da Silva; Camila da Silva

    2014-01-01

    The esterification of oleic acid in a continuous catalyst-free process using compressed ethanol was investigated in the present study. Experiments were performed in a tubular reactor and variables investigated were temperature, pressure, and oleic acid to ethanol molar ratio for different residence time. Results demonstrated that temperature, in the range of 473 K to 573 K, and pressure had a positive effect on fatty acid ethyl esters (FAEE) production. In the experimental range investigated,...

  9. A Microwave-Sensitive Solid Acid Catalyst Prepared from Sweet Potato via a Simple Method

    Directory of Open Access Journals (Sweden)

    Hai-Ying Chen

    2016-12-01

    Full Text Available In this study, a microwave-sensitive solid acid catalyst was successfully synthesized from sweet potatoes via a simple process. The catalyst was proven to have superior microwave-sensitive and homogeneous properties. The physicochemical properties were characterized by Brunauer–Emmett–Teller (BET, X-ray diffraction (XRD, Fourier-transform infrared spectra (FT-IR, thermogravimetric (TGA, scanning electron microscope (SEM and elemental analysis (EA. Results showed that the total acid density and specific surface area for the catalyst were 6.35 mmol/g and 78.35 m2/g, respectively. The elemental sulfur content reached 7.449% after sulfonation and the catalytic activity could reach over 91% within 30 min with microwave power density of 1.0 W/mL. The catalytic reaction temperature should not exceed 200 °C, as shown in TGA curve, and the moisture content in the oil raw material should be within 1%–2%. The catalyst deactivated gradually to 64.38% after reutilization five times, but the catalytic activity could be simply regenerated by re-sulfonation, albeit slightly reduced (87.56%. The shift of diffraction peaks in the XRD patterns and new absorption peaks at 619.98 and 1190.49 cm−1 of FT-IR spectra demonstrated that the –SO3H group was effectively attached to the catalyst. The SEM images displayed a loose and porous amorphous structure in the end catalyst.

  10. Acetalization of 2-Hydroxybenzaldehyde mechanism using halogen acid catalysts based on ab initio methods

    Science.gov (United States)

    Yusuf, Muhammad; Roza, Destria; Nasution, Ahmad Kamil

    2017-11-01

    The computational calculation was performed on the acetalization of 2-hydroxybenzaldehyde by using ab initio method. Ab initio method is derived directly from theoretical principles with no inclusion of experimental data and this is an approximate quantum mechanical calculation. The aim of this research was to studies the acetalization of 2-hydroxybenzaldehyde mechanism using halogen acid catalysts. Computational calculation which was applied on the acetalization of 2-hydroxybenzaldehyde using halogen acid catalysts provided possible reaction steps. The first step was formation of a labile hemiacetal because it is essentially tetrahedral intermediates containing a leaving group. The second step was formation of a stable acetal. The results of computational calculation of acetalization of 2-hydroxybenzaldehyde provided possible energy change in the each step of the reaction process. A labile hemiacetal showed higher energy (481.04 kJ/mol) than 2-hydroxybenzaldehyde dimethyl acetal (65.32 kJ/mol) and 2-hydroxybenzaldehyde (0 kJ/mol) due to its instability. In general, acetalization of 2-hydroxybenzaldehyde reaction is a reversible reaction. The effect of Lewis acidity on halogen acid catalysts was also studied in this research. Based on the Mulliken charge on the H atom, it is found that HF has the highest Lewis acidity compared to other halogen acids with order HF> HCl> HBr> HI. As a result, HF was the efficient catalysts for acetalization of 2-Hydroxybenzaldehyde.

  11. Methanol oxidation at platinum electrodes in acid solution: comparison between model and real catalysts

    Directory of Open Access Journals (Sweden)

    A. V. TRIPKOVIC

    2006-12-01

    Full Text Available Methanol oxidation in acid solution was studied at platinum single crystals, Pt(hkl, as the model catalyst, and at nanostructural platinum supported on high surface area carbon, Pt/C, as the real catalyst. The linear extrapolation method was used to determine the beginning of hydroxyl anion adsorption. Structural sensitivity of the adsorption was proved and a correlation with the onset of the methanol oxidation current was established at all catalysts. Bisulfate and chloride anions were found to decrease the methanol oxidation rate, but probably did not influence the reaction parth. The specific activity for the reaction increased in the sequence Pt(110 < Pt/C < Pt(111, suggesting that the activity of the supported Pt catalyst can be correlated with the activities of the dominating crystal planes on its surface.

  12. Conversion of bio-feedstocks through acid and basic zeolites and catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Buzzoni, R.; Bosetti, A.; Delledonne, D.; Perego, C. [eni S.p.A. Research Centre for Non-Conventional Energy, Novara (Italy). Ist. eni Donegani

    2012-07-01

    Not far in the future, a significant part of fuels and chemicals will be originated by renewable biomass resources. In this respect, zeolite catalysts may help to develop a new generation of bio-fuel and chemical processes. In the new bio-paradigm not only acid but also basic materials will have an important and dominant role. Just to give some examples, basic zeolites based catalysts have been proposed for transesterification of triglyceride esters of fatty acids to biodiesel, for disrupting the lignin polymer by base catalyzed depolymerisation and for one pot lignin liquefaction by hydrogenation. (orig.)

  13. Enhanced Catalyst Activity of WO3 Using Polypyrrole as Support for Acidic Esterification of Glycerol with Acetic Acid

    Directory of Open Access Journals (Sweden)

    Khadijeh Beigom Ghoreishi

    2013-01-01

    Full Text Available A series of polypyrrole supported WO3 were fabricated and characterized by FT-IR, XRD, XPS, BET, TGA, and FESEM-EDX. The activity of the catalysts was tested in glycerol esterification with acetic acid, and it found that WO3-Ppy-20 (nanocomposite with 20% WO3 loaded showed the maximum catalyst activity with 98% and selectivity of 70% to triacetin at 110°C with a reaction duration of 10 h and also recorded the highest selectivity (75% for acetylation of glycerol to monoacetin with about 59% conversion only. The highest acidity of WO3-Ppy-20 is also confirmed using TPD-NH3 analysis. The activity and selectivity to triacetin of the catalyst were enhanced by increasing WO3 loading amount, resulting in 82% conversion for WO3-Ppy-5 with about 32 and 50% selectivity to monoacetin and diacetin and about 18% selectivity to triacetin; in case of WO3-Ppy-20, these amounts were changed to 5, 25, and 70% selectivity to monoacetin, diacetin, and triacetin, respectively with the conversion of 98%. TPD-NH3 analysis found that polypyrrole supported WO3 increases the catalyst acidity of WO3. BET and FESEM analyses revealed that WO3 particles were well dispersed with the smallest average size in nanocomposite compared to pure WO3, which could contribute to the high activity of WO3-Ppy catalyst for esterification of glycerol.

  14. Mild oxidation of methane to methanol or acetic acid on supported isolated rhodium catalysts

    Science.gov (United States)

    Shan, Junjun; Li, Mengwei; Allard, Lawrence F.; Lee, Sungsik; Flytzani-Stephanopoulos, Maria

    2017-11-01

    An efficient and direct method of catalytic conversion of methane to liquid methanol and other oxygenates would be of considerable practical value. However, it remains an unsolved problem in catalysis, as typically it involves expensive or corrosive oxidants or reaction media that are not amenable to commercialization. Although methane can be directly converted to methanol using molecular oxygen under mild conditions in the gas phase, the process is either stoichiometric (and therefore requires a water extraction step) or is too slow and low-yielding to be practical. Methane could, in principle, also be transformed through direct oxidative carbonylation to acetic acid, which is commercially obtained through methane steam reforming, methanol synthesis, and subsequent methanol carbonylation on homogeneous catalysts. However, an effective catalyst for the direct carbonylation of methane to acetic acid, which might enable the economical small-scale utilization of natural gas that is currently flared or stranded, has not yet been reported. Here we show that mononuclear rhodium species, anchored on a zeolite or titanium dioxide support suspended in aqueous solution, catalyse the direct conversion of methane to methanol and acetic acid, using oxygen and carbon monoxide under mild conditions. We find that the two products form through independent pathways, which allows us to tune the conversion: three-hour-long batch-reactor tests conducted at 150 degrees Celsius, using either the zeolite-supported or the titanium-dioxide-supported catalyst, yield around 22,000 micromoles of acetic acid per gram of catalyst, or around 230 micromoles of methanol per gram of catalyst, respectively, with selectivities of 60–100 per cent. We anticipate that these unusually high activities, despite still being too low for commercial application, may guide the development of optimized catalysts and practical processes for the direct conversion of methane to methanol, acetic acid and other

  15. Mild oxidation of methane to methanol or acetic acid on supported isolated rhodium catalysts.

    Science.gov (United States)

    Shan, Junjun; Li, Mengwei; Allard, Lawrence F; Lee, Sungsik; Flytzani-Stephanopoulos, Maria

    2017-11-29

    An efficient and direct method of catalytic conversion of methane to liquid methanol and other oxygenates would be of considerable practical value. However, it remains an unsolved problem in catalysis, as typically it involves expensive or corrosive oxidants or reaction media that are not amenable to commercialization. Although methane can be directly converted to methanol using molecular oxygen under mild conditions in the gas phase, the process is either stoichiometric (and therefore requires a water extraction step) or is too slow and low-yielding to be practical. Methane could, in principle, also be transformed through direct oxidative carbonylation to acetic acid, which is commercially obtained through methane steam reforming, methanol synthesis, and subsequent methanol carbonylation on homogeneous catalysts. However, an effective catalyst for the direct carbonylation of methane to acetic acid, which might enable the economical small-scale utilization of natural gas that is currently flared or stranded, has not yet been reported. Here we show that mononuclear rhodium species, anchored on a zeolite or titanium dioxide support suspended in aqueous solution, catalyse the direct conversion of methane to methanol and acetic acid, using oxygen and carbon monoxide under mild conditions. We find that the two products form through independent pathways, which allows us to tune the conversion: three-hour-long batch-reactor tests conducted at 150 degrees Celsius, using either the zeolite-supported or the titanium-dioxide-supported catalyst, yield around 22,000 micromoles of acetic acid per gram of catalyst, or around 230 micromoles of methanol per gram of catalyst, respectively, with selectivities of 60-100 per cent. We anticipate that these unusually high activities, despite still being too low for commercial application, may guide the development of optimized catalysts and practical processes for the direct conversion of methane to methanol, acetic acid and other useful

  16. Efficient conversion of triacylglycerols and fatty acids to biodiesel in a microwave reactor using metal triflate catalysts.

    Science.gov (United States)

    Socha, Aaron M; Sello, Jason K

    2010-10-21

    We report that catalytic quantities of the Lewis acidic metal catalysts scandium triflate and bismuth triflate promote conversion of oleic, linoleic, palmitic and myristic acids and their glyceryl triesters to the corresponding methyl esters (biodiesel) in greater than 90% yield upon microwave heating. Additionally, both catalysts could be recovered and reused in esterification reactions at least six times.

  17. Functionalized carbon nanofibers as solid-acid catalysts for transesterification

    NARCIS (Netherlands)

    Stellwagen, D.R.; Klis, van der F.; Es, van D.S.; Jong, de K.P.; Bitter, J.H.

    2013-01-01

    Carbon nanofibers (CNFs) were functionalized with aryl sulfonic acid groups using in situ diazonium coupling. The use of diazonium coupling yielded an acidic carbon material, in which the introduced acidic groups are readily accessible to the triglyceride substrate. The material is an efficient

  18. Formic acid electrooxidation on carbon supported platinum catalyst with preferential plane orientation

    Directory of Open Access Journals (Sweden)

    Krstajić Mila N.

    2015-01-01

    Full Text Available Pt-based nanocatalysts supported on Vulcan XC-72R carbon, were prepared by water-in-oil microemulsion method, with addition of various amounts of HCl in the water phase. Polyethileneglycoldodecylether (BRIJ 30 was used as a surfactant, which influenced the Pt surface structure, along with HCl. Catalysts prepared with addition of 0, 15, 25 and 35 % of HCl during the synthesis, were electrochemically characterised in 0,5 M H2SO4 using cyclic voltammetry and CO oxidation. Formic acid electrooxidation was examined on all investigated catalysts, in terms of their electrocatalytic activity and stability. Platinum loading on carbon support was examined by Thermogravimetric analysis. Catalysts showed different features in hydrogen region, and slight differences in formic acid oxidation mechanisms.

  19. An improved solvent-free synthesis of flunixin and 2-(arylamino) nicotinic acid derivatives using boric acid as catalyst.

    Science.gov (United States)

    Yarhosseini, Mahsa; Javanshir, Shahrzad; Dolatkhah, Zahra; Dekamin, Mohammad G

    2017-12-01

    A simple solvent-free protocol for the preparation of flunixin, a potent non-narcotic, non-steroidal anti-inflammatory drugs is reported using boric acid as catalyst. Its salt, flunixin meglumine are then prepared under reflux in EtOH. This sustainable method are then extended for the synthesis of a series of 2-(arylamino) nicotinic acid derivatives. The present protocol combines non-hazardous neat conditions with associated benefits like excellent yield, straightforward workup, and use of readily available and safe catalyst in the absence of any solvent, which are important factors in the pharmaceutical industry. The pathway for catalytic activation of 2-chloronicotic acid with boric acid was also investigated using Gaussian 03 program package.

  20. Screening of Catalyst and Important Variable for The Esterification of Acrylic Acid with 2 Ethylhexanol

    Science.gov (United States)

    Ahmad, M. A. A.; Chin, S. Y.

    2017-06-01

    The global demand of 2-ethylhexyl acrylate (2EHA) market has witnessed a significant growth in the past few years and this growth is anticipated to increase in the coming years. 2EHA is one of the basic organic building blocks that mainly used in the production of coatings, adhesives, superabsorbents, thickeners and plastic additives. Homogenous acid-catalysed esterification of acrylic acid (AA) with 2-ethylhexanol (2EH) is commonly used for the production of 2EHA. The homogeneous catalysts such as sulfuric and para-toluene sulfonic acid have resulted the costly and complicated downstream process that generates acidic, corrosive and non-environmental friendly waste. Therefore, it is importance to develop a cheaper process that employing heterogeneous catalysts and alternative raw material from wastewater containing acrylic acid. In this research, the study for the esterification of AA with 2EH catalysed by ion-exchange resin was conducted. The best sulfonic acid functional cation-exchange resin among SK104, SK1B, PK208, PK216, PK228, RCP145, and RCP160 was screened. PK208 outperformed the other resins and it was used subsequently in the parametric studies. The effect of important parameters (initial concentration of acrylic acid (AA), temperature, molar ratio of reactant (AA and 2EH), catalyst loading, and polymerisation inhibitor loading) was studied using 2 factorial design to determine the significant parameters to the esterification. It was found that the initial concentration of AA and temperature were most significantly affecting the esterification of AA with 2EH.

  1. Nano-silica sulfuric acid as an efficient catalyst for the synthesis of substituted pyrazoles

    Directory of Open Access Journals (Sweden)

    Hamideh Emtiazi

    2015-11-01

    Full Text Available A convenient and direct approach has been developed for the preparation of pyrazole derivatives by condensing 1,3-diketones and hydrazines in the presence of nano-silica sulfuric acid. This thermal solvent-free procedure offers some advantages such as short reaction time, simple work-up, high yields, and reusability of the catalyst.

  2. Highly Selective Liquid-Phase Benzylation of Anisole with Solid-Acid Zeolite Catalysts

    DEFF Research Database (Denmark)

    Poreddy, Raju; Shunmugavel, Saravanamurugan; Riisager, Anders

    2015-01-01

    Zeolites were evaluated as solid acid catalysts for the liquid-phase benzylation of anisole with benzyl alcohol, benzyl bromide, and benzyl chloride at 80 °C. Among the examined zeolites, H-mordenite-10 (H-MOR-10) demonstrated particular high activity (>99 %) and excellent selectivity (>96...

  3. Silica Sulfuric Acid: An Eco-Friendly and Reusable Catalyst for Synthesis of Benzimidazole Derivatives

    Directory of Open Access Journals (Sweden)

    Bahareh Sadeghi

    2013-01-01

    Full Text Available Silica sulfuric acid (SiO2-OSO3H as an eco-friendly, readily available, and reusable catalyst is applied to benzimidazole derivatives synthesis under reflux in ethanol. The procedure is very simple and the products are isolated with an easy workup in good-to-excellent yields.

  4. Catalyst deactivation during steam reforming of acetic acid over Pt/ZrO2.

    NARCIS (Netherlands)

    Takanabe, K.; Takanabe, Kazuhiro; Aika, Ken-ichi; Seshan, Kulathuiyer; Lefferts, Leonardus

    2006-01-01

    Steam reforming of acetic acid as a model compound present in bio-oil over Pt/ZrO2 catalysts has been investigated. Pt/ZrO2 yields steam reforming products (i.e., H2, CO, CO2) to the amounts predicted by thermodynamic equilibrium; however, conversion and yields dropped rapidly with time on course.

  5. Nano-TiCl4/SiO2: an efficient heterogeneous solid acid catalyst for ...

    Indian Academy of Sciences (India)

    Mirjalili

    Nano-TiCl4/SiO2: an efficient heterogeneous solid acid catalyst for the one pot cascade five-component synthesis of densely functionalized tetrahydropyridines. ABDOLHAMID BAMONIRIa,*, BI BI FATEMEH MIRJALILIb and REZA TARAZIANa. aDepartment of Organic Chemistry, Faculty of Chemistry, University of Kashan, ...

  6. Nano-TiCl4/SiO2: An efficient heterogeneous solid acid catalyst for ...

    Indian Academy of Sciences (India)

    Abstract. Nano-TiCl4/SiO2 was found to be an inexpensive and efficient heterogeneous solid acid catalyst for the synthesis of one-pot cascade synthesis of highly functionalized asymmetric tetrahydropyridines from the five-component condensation reaction of the para-substituted anilines and aromatic aldehydes with ethyl.

  7. Boric acid as a mild and efficient catalyst for one-pot synthesis of 1 ...

    Indian Academy of Sciences (India)

    Abstract. An efficient green chemistry method has been developed for the synthesis of 1-amidoalkyl-2-naphthol derivatives via a one-pot three-component condensation of 2-naphthol, aldehydes and amide in the presence of boric acid as a mild catalyst.

  8. Solid Silica-based Sulphonic Acid as an Efficient Green Catalyst for ...

    African Journals Online (AJOL)

    NJD

    Introduction. Solid supported reagents are unique acid catalysts that have become popular over the last two decades. The activity and selectivity of a reagent dispersed on the surface of a solid support is improved as the effective surface area of the reagent is increased significantly, and hence the reagents are expected to.

  9. Modular, active, and robust Lewis acid catalysts supported on a metal-organic framework.

    Science.gov (United States)

    Tanabe, Kristine K; Cohen, Seth M

    2010-07-19

    Metal-organic frameworks (MOFs) have shown promise as heterogeneous catalysts because of their high crystallinity, uniform pores, and ability to be chemically and physically tuned for specific chemical transformations. One of the challenges with MOF-based catalysis is few systems achieve all of the desired features for a heterogeneous catalyst, including high activity, robustness (recyclability), and excellent selectivity. Herein, postsynthetic modification (PSM) of a MOF is used to synthesize a series of MOF catalysts that are highly robust and active for epoxide ring-opening reactions. In the following study, four metalated MOFs (UMCM-1-AMInpz, UMCM-1-AMInsal, UMCM-1-AMFesal, and UMCM-1-AMCupz) are examined as catalysts for beta-azido and beta-amino alcohol synthesis with epoxides of varying sizes and shapes using two different nucleophiles (TMSN(3) and aniline). The four MOFs are isostructural, exhibit good thermal and structural stability, and display different catalytic activities based on the combination of metal ion and chelating ligand immobilized within the framework. In particular, UMCM-1-AMInpz and UMCM-1-AMInsal act as robust, single-site catalysts with distinct selectivity for ring-opening reactions with specific nucleophiles. More importantly, one of these catalysts, UMCM-1-AMInpz, selectively promotes the ring-opening of cis-stilbene oxide in the presence of trans-stilbene oxide, which cannot be achieved with a comparable molecular Lewis acid catalyst. The results show that PSM is a promising, modular, and highly tunable approach for the discovery of robust, active, and selective MOF catalysts that combine the best aspects of homogeneous and heterogeneous systems.

  10. Dehydration of D-xylose to furfural using acid-functionalized MWCNTs catalysts

    Science.gov (United States)

    Termvidchakorn, Chompoopitch; Itthibenchapong, Vorranutch; Songtawee, Siripit; Chamnankid, Busaya; Namuangruk, Supawadee; Faungnawakij, Kajornsak; Charinpanitkul, Tawatchai; Khunchit, Radchadaporn; Hansupaluk, Nanthiya; Sano, Noriaki; Hinode, Hirofumi

    2017-09-01

    Acid-functionalized multi-wall carbon nanotubes (MWCNTs) catalysts were prepared by a wet chemical sonication with various acid solutions, i.e. H2SO4, H3PO4, HNO3, and HCl. Sulfonic groups and carboxyl groups were detected on MWCNTs with H2SO4 treatment (s-MWCNTs), while only carboxyl groups were presented from other acid treatments. The catalytic dehydration of D-xylose into furfural was evaluated using a batch reactor at 170 °C for 3 h under N2 pressure of 15 bar. The highest furfural selectivity was achieved around 57% by s-MWCNTs catalyst, suggesting a positive role of the sulfonic functionalized groups. The effect of Co species was related to their Lewis acid property resulting in the enhancement of xylose conversion with low selectivity to furfural product. Invited talk at 5th Thailand International Nanotechnology Conference (Nano Thailand-2016), 27-29 November 2016, Nakhon Ratchasima, Thailand.

  11. Molybdenum phosphosulfide: an active, acid-stable, earth-abundant catalyst for the hydrogen evolution reaction.

    Science.gov (United States)

    Kibsgaard, Jakob; Jaramillo, Thomas F

    2014-12-22

    Introducing sulfur into the surface of molybdenum phosphide (MoP) produces a molybdenum phosphosulfide (MoP|S) catalyst with superb activity and stability for the hydrogen evolution reaction (HER) in acidic environments. The MoP|S catalyst reported herein exhibits one of the highest HER activities of any non-noble-metal electrocatalyst investigated in strong acid, while remaining perfectly stable in accelerated durability testing. Whereas mixed-metal alloy catalysts are well-known, MoP|S represents a more uncommon mixed-anion catalyst where synergistic effects between sulfur and phosphorus produce a high-surface-area electrode that is more active than those based on either the pure sulfide or the pure phosphide. The extraordinarily high activity and stability of this catalyst open up avenues to replace platinum in technologies relevant to renewable energies, such as proton exchange membrane (PEM) electrolyzers and solar photoelectrochemical (PEC) water-splitting cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Catalyst evaluation for oxygen reduction reaction in concentrated phosphoric acid at elevated temperatures

    Science.gov (United States)

    Hu, Yang; Jiang, Yiliang; Jensen, Jens Oluf; Cleemann, Lars N.; Li, Qingfeng

    2018-01-01

    Phosphoric acid is the common electrolyte for high-temperature polymer electrolyte fuel cells (HT-PEMFCs) that have advantages such as enhanced CO tolerance and simplified heat and water management. The currently used rotating disk electrode technique is limited to tests in dilute solutions at low temperatures and hence is not suitable for catalyst evaluation for HT-PEMFCs. In this study, we have designed and constructed a half-cell setup to measure the intrinsic activities of catalysts towards the oxygen reduction reaction (ORR) in conditions close to HT-PEMFC cathodes. By optimization of the hydrophobic characteristics of electrodes and the catalyst layer thickness, ORR activities of typical Pt/C catalysts are successfully measured in concentrated phosphoric acid at temperatures above 100 °C. In terms of mass-specific activities, the catalyst exhibits about two times higher activity in the half-cell electrode than that observed in fuel cells, indicating the feasibility of the technique as well as the potential for further improvement of fuel cell electrode performance.

  13. Efficient bifunctional catalyst lipase/organophosphonic acid-functionalized silica for biodiesel synthesis by esterification of oleic acid with ethanol.

    Science.gov (United States)

    Yin, Ping; Chen, Wen; Liu, Wei; Chen, Hou; Qu, Rongjun; Liu, Xiguang; Tang, Qinghua; Xu, Qiang

    2013-07-01

    An efficient bifunctional catalyst lipase/organophosphonic acid-functionalized silica (SG-T-P-LS) has been successfully developed, and biodiesel production of fatty acid ethyl ester (FAEE) from free fatty acid (FFA) oleic acid with short-chain alcohol ethanol catalyzed by SG-T-P-LS was investigated. The process optimization using response surface methodology (RSM) was performed and the interactions between the operational variables were elucidated, and it was found that the molar ratio of alcohol to acid was the most significant factor. The optimum values for maximum conversion ratio can be obtained by using a Box-Behnken center-united design, and the conversion ratio could reach 89.94 ± 0.42% under the conditions that ethanol/acid molar ratio was 1.05:1 and SG-T-P-LS to FFA weight ratio was 14.9 wt.% at 28.6°C. The research results show that SG-T-P and LS-20 could work cooperatively to promote the esterification reaction, and the bifunctional catalyst SG-T-P-LS is a potential catalyst for biodiesel production. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. STARCH SULFURIC ACID: AN ALTERNATIVE, ECO-FRIENDLY CATALYST FOR BIGINELLI REACTION

    Directory of Open Access Journals (Sweden)

    Ramin Rezaei

    2013-12-01

    Full Text Available The one-pot multicomponent synthesis of 3,4-dihydropyrimidinone derivatives using starch sulfuric acid as an environmentally friendly biopolymer-based solid acid catalyst from aldehydes, β-keto esters and urea/ thiourea without solvent is described. Compared with classical Biginelli reaction conditions, this new method has the advantage of minimizing the cost operational hazards and environmental pollution, good yields, shorter reaction times and simple work-up.

  15. Improved synthesis of isostearic acid using zeolite catalysts

    Science.gov (United States)

    Isostearic acids are unique and important biobased products with superior properties. Unfortunately, they are not widely utilized in industry because they are produced as byproducts from a process called clay-catalyzed oligomerization of tall oil fatty acids. Generally, this clay method results in...

  16. Solid-supported sulfonic acid-containing catalysts efficiently ...

    Indian Academy of Sciences (India)

    Silica-functionalized sulfonic acid (SFSA) and sulfuric acid-modified polyethylene glycol-6000 (PEG-OSO3H) efficiently catalysed one-pot multi-component condensation of enolizable ketones or alkyl acetoacetates with arylaldehydes, acetonitrile and acetyl chloride to afford the corresponding -acetamido ketone or ester ...

  17. Layered metal laurates as active catalysts in the methyl/ethyl esterification reactions of lauric acid

    Energy Technology Data Exchange (ETDEWEB)

    Lisboa, Fabio da Silva; Cordeiro, Claudiney S.; Wypych, Fernando, E-mail: wypych@ufpr.br [Centro de Pesquisas em Quimica Aplicada (CEPESQ), Departamento de Quimica, Universidade Federal do Parana, Curitiba, PR (Brazil); Gardolinski, Jose Eduardo F. da Costa [Laboratorio de Analise de Minerais e Rochas (LAMIR), Departamento de Geologia, Universidade Federal do Parana, Curitiba, PR (Brazil)

    2012-07-01

    In this work we report the synthesis, characterization and investigation of the catalytic activity of layered copper(II), manganese(II), lanthanum(III) and nickel(II) laurates in the methyl and ethyl esterification reactions of lauric acid. In the methyl esterification, conversions between 80 and 90% were observed for all catalysts, while for the ethyl esterification only manganese laurate showed reasonable catalytic activity, with conversions close to 75%. Reuse of copper and lanthanum laurates in three cycles of reaction was also investigated and both catalysts preserved the structure and retained catalytic activity close to that observed for the first reaction cycle. (author)

  18. Synthesis of bio-based methacrylic acid by decarboxylation of itaconic acid and citric acid catalyzed by solid transition-metal catalysts

    NARCIS (Netherlands)

    Notre, le J.E.L.; Witte-van Dijk, S.C.M.; Haveren, van J.; Scott, E.L.; Sanders, J.P.M.

    2014-01-01

    Methacrylic acid, an important monomer for the plastics industry, was obtained in high selectivity (up to 84%) by the decarboxylation of itaconic acid using heterogeneous catalysts based on Pd, Pt and Ru. The reaction takes place in water at 200–2508C without any external added pressure, conditions

  19. Exploratory catalyst screening studies on the base free conversion of glycerol to lactic acid and glyceric acid in water using bimetallic Au-Pt compounds on acidic zeolites

    NARCIS (Netherlands)

    Pazhavelikkakath Purushothaman, Rajeesh Kumar; van Haveren, J.; Mayoral, A.; Melian Cabrera, I.; Heeres, H.J.

    2014-01-01

    The base free oxidation of glycerol with molecular oxygen in water using bimetallic Au-Pt catalysts on three different acidic zeolite supports (H-mordenite, H-beta and H-USY) was explored in a batch setup. At temperatures between 140 and 180 degrees C, lactic acid formation was significant and

  20. Exploratory Catalyst Screening Studies on the Base Free Conversion of Glycerol to Lactic Acid and Glyceric Acid in Water Using Bimetallic Au–Pt Nanoparticles on Acidic Zeolites

    NARCIS (Netherlands)

    Purushothaman, R.K.P.; Haveren, van J.; Mayoral, A.; Melian-Cabrera, I.; Heeres, H.J.

    2014-01-01

    The base free oxidation of glycerol with molecular oxygen in water using bimetallic Au-Pt catalysts on three different acidic zeolite supports (H-mordenite, H-beta and H-USY) was explored in a batch setup. At temperatures between 140 and 180 degrees C, lactic acid formation was significant and

  1. Hydrogenation of carboxylic acids with a homogeneous cobalt catalyst.

    Science.gov (United States)

    Korstanje, Ties J; van der Vlugt, Jarl Ivar; Elsevier, Cornelis J; de Bruin, Bas

    2015-10-16

    The reduction of esters and carboxylic acids to alcohols is a highly relevant conversion for the pharmaceutical and fine-chemical industries and for biomass conversion. It is commonly performed using stoichiometric reagents, and the catalytic hydrogenation of the acids previously required precious metals. Here we report the homogeneously catalyzed hydrogenation of carboxylic acids to alcohols using earth-abundant cobalt. This system, which pairs Co(BF4)2·6H2O with a tridentate phosphine ligand, can reduce a wide range of esters and carboxylic acids under relatively mild conditions (100°C, 80 bar H2) and reaches turnover numbers of up to 8000. Copyright © 2015, American Association for the Advancement of Science.

  2. Monodispersed Hollow SO3H-Functionalized Carbon/Silica as Efficient Solid Acid Catalyst for Esterification of Oleic Acid.

    Science.gov (United States)

    Wang, Yang; Wang, Ding; Tan, Minghui; Jiang, Bo; Zheng, Jingtang; Tsubaki, Noritatsu; Wu, Mingbo

    2015-12-09

    SO3H-functionalized monodispersed hollow carbon/silica spheres (HS/C-SO3H) with primary mesopores were prepared with polystyrene as a template and p-toluenesulfonic acid (TsOH) as a carbon precursor and -SO3H source simultaneously. The physical and chemical properties of HS/C-SO3H were characterized by N2 adsorption, TEM, SEM, XPS, XRD, Raman spectrum, NH3-TPD, element analysis and acid-base titration techniques. As a solid acid catalyst, HS/C-SO3H shows excellent performance in the esterification of oleic acid with methanol, which is a crucial reaction in biodiesel production. The well-defined hollow architecture and enhanced active sites accessibility of HS/C-SO3H guarantee the highest catalytic performance compared with the catalysts prepared by activation of TsOH deposited on the ordered mesoporous silicas SBA-15 and MCM-41. At the optimized conditions, high conversion (96.9%) was achieved and no distinct activity drop was observed after 5 recycles. This synthesis strategy will provide a highly effective solid acid catalyst for green chemical processes.

  3. Characterization and Design of Zeolite Catalysts Solid Acidity, Shape Selectivity and Loading Properties

    CERN Document Server

    Niwa, Miki; Okumura, Kazu

    2010-01-01

    Zeolites are microporous, aluminosilicate minerals commonly used as commercial adsorbents. Zeolite-based catalysts are used by industrial chemical companies in the interconversion of hydrocarbons and the alkylation of aromatic compounds. The current book deals with the characterization of specific properties of Zeolites and calculations for the design of catalysts. Measurements and utilization of solid acidity, shape selectivity, and loading properties, that are three prominent properties of a Zeolite catalyst, are treated in detail. These features concern chemical vapor deposition of silica, shape selectivity, loading properties, solid activity, Brønsted or Lewis character, ammonia temperature programmed desorption, control of the pore-opening size by chemical vapor deposition of silica and XAFS analysis of metals being highly dispersed inside and outside a framework.

  4. Direct transformation of carbohydrates to the biofuel 5-ethoxymethylfurfural by solid acid catalysts

    DEFF Research Database (Denmark)

    Li, Hu; Shunmugavel, Saravanamurugan; Yang, Song

    2016-01-01

    -step reaction protocol. Alternative biomass-based mono-, di- and polysaccharides formed also moderate to good yields of EMF with the catalytic systems, including fructose which yielded 67 % of EMF and 4% of ethyl levulinate (ELevu) along with 10 % 5-hydroxymethylfurfural (HMF) in the combined reaction protocol......The direct conversion of glucose to 5-ethoxymethylfurfural (EMF) is a promising biomass transformation due to the products potential application as a biofuel. Here, the conversion of glucose to EMF was examined over several solid acid catalysts in ethanol between 96 and 125 oC. Among the catalysts....... A significant amount of ELevu (1-16 %), a rehydrated product of EMF and promising fuel additive, was observed in this study. Recyclability studies suggested that it was possible to reuse the DeAl-H-beta-12.5 (700) catalyst in consecutive reactions without significant changes in product yields due to its easy...

  5. Fuel cell catalyst layers containing short-side-chain perfluorosulfonic acid ionomers

    Energy Technology Data Exchange (ETDEWEB)

    Peron, Jennifer; Edwards, Dave; Haldane, Mark; Shi, Zhiqing [Institute for Fuel Cell Innovation, National Research Council (Canada); Luo, Xiaoyan [Department of Chemistry, Simon Fraser University, Burnaby, British Columbia (Canada); Zhang, Yongming [School of Chemistry and Chemical Technology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Holdcroft, Steven [Institute for Fuel Cell Innovation, National Research Council (Canada); Department of Chemistry, Simon Fraser University, Burnaby, British Columbia (Canada)

    2011-01-01

    Porous catalyst layers (CLs) containing short-side-chain (SSC) perfluorosulfonic acid (PFSA) ionomers of different ion exchange capacity (IEC: 1.3, 1.4 and 1.5 meq g{sup -1}) were deposited onto Nafion 211 to form catalyst-coated membranes. The porosity of SSC-PFSA-based CLs is larger than Nafion-CL analogues. CLs incorporating SSC ionomer extend the current density of fuel cell polarization curves at elevated temperature and lower relative humidity compared to those based on long-side chain PFSA (e.g., Nafion)-based CLs. Fuel cell polarization performance was greatly improved at 110 C and 30% relative humidity (RH) when SSC PFSI was incorporated into the catalyst layer. (author)

  6. Catalyst Degradation in High Temperature Proton Exchange Membrane Fuel Cells Based on Acid Doped Polybenzimidazole Membranes

    DEFF Research Database (Denmark)

    Cleemann, Lars Nilausen; Buazar, F.; Li, Qingfeng

    2013-01-01

    contribution of the membrane degradation to the performance losses during the potential cycling tests. As the major mechanism of the fuel cell performance degradation, the electrochemical active area of the cathodic catalysts showed a steady decrease in the cyclic voltammetric measurements, which was also...... and multi‐walled carbon nanotubes were used as supports for electrode catalysts and evaluated in accelerated durability tests under potential cycling at 150 °C. Measurements of open circuit voltage, area specific resistance and hydrogen permeation through the membrane were carried out, indicating little......Degradation of carbon supported platinum catalysts is a major failure mode for the long term durability of high temperature proton exchange membrane fuel cells based on phosphoric acid doped polybenzimidazole membranes. With Vulcan carbon black as a reference, thermally treated carbon black...

  7. Biodiesel production in a membrane reactor using MCM-41 supported solid acid catalyst.

    Science.gov (United States)

    Xu, Wei; Gao, Lijing; Wang, Songcheng; Xiao, Guomin

    2014-05-01

    Production of biodiesel from the transesterification between soybean oil and methanol was conducted in this study by a membrane reactor, in which ceramic membrane was packed with MCM-41 supported p-toluenesulfonic acid (PTSA). Box-Behnken design and response surface methodology (RSM) were used to investigate the effects of reaction temperature, catalyst amount and circulation velocity on the yield of biodiesel. A reduced cubic model was developed to navigate the design space. Reaction temperature was found to have most significant effect on the biodiesel yield while the interaction of catalyst amount and circulation velocity have minor effect on it. 80°C of reaction temperature, 0.27 g/cm(3) of catalyst amount and 4.15 mL/min of circulation velocity were proved to be the optimum conditions to achieve the highest biodiesel yield. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. ESTERIFICATION OF FATTY ACID FROM PALM OIL WASTE (SLUDGE OIL BY USING ALUM CATALYST

    Directory of Open Access Journals (Sweden)

    Thamrin Usman

    2010-06-01

    Full Text Available Esterification of fatty acids from palm oil waste (sludge oil as biodiesel liquid base has been done by using alum [Al2(SO43.14H2O] catalyst. Some reaction variables like reaction time, catalyst quantity, and molar ratio of sample-reactant was applied for optimal reaction. Yield of 94.66% was obtained at reaction condition 65 °C, 5 h, sample-reactant ratio 1:20, and catalyst quantity 3% (w/w. GC-MS analysis request showed that composition of methyl esters biodiesel are methyl caproic (0.67%, methyl lauric (0.21%, methyl miristic (1.96%, methyl palmitic (49.52%, methyl oleic (41.51%, and methyl stearic (6.13%. Physical properties of synthesized product (viscosity, refraction index and density are similar with those of commercial product.   Keywords: alum, biodiesel, esterification, sludge oil

  9. Single Atomic Iron Catalysts for Oxygen Reduction in Acidic Media: Particle Size Control and Thermal Activation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hanguang; Hwang, Sooyeon; Wang, Maoyu; Feng, Zhenxing; Karakalos, Stavros; Luo, Langli; Qiao, Zhi; Xie, Xiaohong; Wang, Chongmin; Su, Dong; Shao, Yuyan; Wu, Gang (BNL); (Oregon State U.); (SC); (PNNL); (Buffalo)

    2017-09-26

    It remains a grand challenge to replace platinum group metal (PGM) catalysts with earth-abundant materials for the oxygen reduction reaction (ORR) in acidic media, which is crucial for large-scale deployment of proton exchange membrane fuel cells (PEMFCs). Here, we report a high-performance atomic Fe catalyst derived from chemically Fe-doped zeolitic imidazolate frameworks (ZIFs) by directly bonding Fe ions to imidazolate ligands within 3D frameworks. Although the ZIF was identified as a promising precursor, the new synthetic chemistry enables the creation of well-dispersed atomic Fe sites embedded into porous carbon without the formation of aggregates. The size of catalyst particles is tunable through synthesizing Fe-doped ZIF nanocrystal precursors in a wide range from 20 to 1000 nm followed by one-step thermal activation. Similar to Pt nanoparticles, the unique size control without altering chemical properties afforded by this approach is able to increase the number of PGM-free active sites. The best ORR activity is measured with the catalyst at a size of 50 nm. Further size reduction to 20 nm leads to significant particle agglomeration, thus decreasing the activity. Using the homogeneous atomic Fe model catalysts, we elucidated the active site formation process through correlating measured ORR activity with the change of chemical bonds in precursors during thermal activation up to 1100 °C. The critical temperature to form active sites is 800 °C, which is associated with a new Fe species with a reduced oxidation number (from Fe3+ to Fe2+) likely bonded with pyridinic N (FeN4) embedded into the carbon planes. Further increasing the temperature leads to continuously enhanced activity, linked to the rise of graphitic N and Fe–N species. The new atomic Fe catalyst has achieved respectable ORR activity in challenging acidic media (0.5 M H2SO4), showing a half-wave potential of 0.85 V vs RHE and leaving only a 30 mV gap with Pt/C (60 μgPt/cm2). Enhanced stability

  10. Enhanced furfural production from raw corn stover employing a novel heterogeneous acid catalyst.

    Science.gov (United States)

    Li, Wenzhi; Zhu, Yuanshuai; Lu, Yijuan; Liu, Qiyu; Guan, Shennan; Chang, Hou-Min; Jameel, Hasan; Ma, Longlong

    2017-12-01

    With the aim to enhance the direct conversion of raw corn stover into furfural, a promising approach was proposed employing a novel heterogeneous strong acid catalyst (SC-CaC t -700) in different solvents. The novel catalyst was characterized by elemental analysis, N 2 adsorption-desorption, FT-IR, XPS, TEM and SEM. The developed catalytic system demonstrated superior efficacy for furfural production from raw corn stover. The effects of reaction temperature, residence time, catalyst loading, substrate concentration and solvent were investigated and optimized. 93% furfural yield was obtained from 150mg corn stover at 200°C in 100min using 45mg catalyst in γ-valerolactone (GVL). In comparison, 51.5% furfural yield was achieved in aqueous media under the same conditions (200°C, 5h, and 45mg catalyst), which is of great industrial interest. Furfural was obtained from both hemicelluloses and cellulose in corn stover, which demonstrated a promising routine to make the full use of biomass. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Carbon-supported PtAu alloy nanoparticle catalysts for enhanced electrocatalytic oxidation of formic acid

    Science.gov (United States)

    Chen, Guoqin; Li, Yunhua; Wang, Dong; Zheng, Li; You, Guirong; Zhong, Chuan-Jian; Yang, Lefu; Cai, Fan; Cai, Junxiu; Chen, Bing H.

    2011-10-01

    The understanding of the electrocatalytic activity of bimetallic nanoparticle catalysts requires the ability to precisely control the composition and phase properties. In this report, we describe a new strategy in the preparation of a series of carbon supported platinum-gold bimetallic nanoparticles with various bimetallic compositions which were loaded onto a carbon black support and subjected subsequently by thermal treatment (Pt100-mAum/C). The Pt100-mAum/C catalysts are characterized by X-ray diffraction (XRD), transmission electron spectroscopy (TEM), and induced coupled plasma-atomic emission spectroscopy (ICP-AES). The XRD pattern for the bimetallic nanoparticles shows single-phase alloy character. This ability enabled us to establish the correlation between the bimetallic composition and the electrocatalytic activity for formic acid (FA) electrooxidation. The electrocatalytic activities of the catalysts toward FA oxidation reaction are shown to strongly depend on the bimetallic PtAu composition. Within a wide range of bimetallic composition, the Pt50Au50/C catalyst shows the highest electrocatalytic activity for the FA oxidation, with a mass activity eight times higher than that of Pt/C. The high performance of the PtAu/C catalyst can be ascribed to the increased selectivity toward the FA dehydrogenation at the decreased availability of adjacent Pt atoms.

  12. The Comparison of Hydrochloric Acid and Phosphoric Acid Treatments in the Preparation of Montmorillonite Catalysts for RNA Synthesis

    Science.gov (United States)

    Aldersley, Michael Frank; Joshi, Prakash C.; Huang, Yixing

    2017-09-01

    The treatment of clay minerals with a preliminary acid wash and titration to pH 7 has proven to generate catalysts for the most interesting of oligomerization reactions in which activated RNA-nucleotides generate oligomers up to 40-mers. Significantly, not all clay minerals become catalytic following this treatment and none are catalytic in the absence of such treatment. The washing procedure has been modified and explored further using phosphoric acid and the outcomes are compared to those obtained when clay samples are prepared following a hydrochloric acid wash.

  13. The Comparison of Hydrochloric Acid and Phosphoric Acid Treatments in the Preparation of Montmorillonite Catalysts for RNA Synthesis.

    Science.gov (United States)

    Aldersley, Michael Frank; Joshi, Prakash C; Huang, Yixing

    2017-09-01

    The treatment of clay minerals with a preliminary acid wash and titration to pH 7 has proven to generate catalysts for the most interesting of oligomerization reactions in which activated RNA-nucleotides generate oligomers up to 40-mers. Significantly, not all clay minerals become catalytic following this treatment and none are catalytic in the absence of such treatment. The washing procedure has been modified and explored further using phosphoric acid and the outcomes are compared to those obtained when clay samples are prepared following a hydrochloric acid wash.

  14. Effects of Weight Hourly Space Velocity and Catalyst Diameter on Performance of Hybrid Catalytic-Plasma Reactor for Biodiesel Synthesis over Sulphated Zinc Oxide Acid Catalyst

    Directory of Open Access Journals (Sweden)

    Luqman Buchori

    2017-05-01

    Full Text Available Biodiesel synthesis through transesterification of soybean oil with methanol on hybrid catalytic-plasma reactor over sulphated zinc oxide (SO42-/ZnO active acid catalyst was investigated. This research was aimed to study effects of Weight Hourly Space Velocity (WHSV and the catalyst diameter on performance of the hybrid catalytic-plasma reactor for biodiesel synthesis. The amount (20.2 g of active sulphated zinc oxide solid acid catalysts was loaded into discharge zone of the reactor. The WHSV and the catalyst diameter were varied between 0.89 to 1.55 min-1 and 3, 5, and 7 mm, respectively. The molar ratio of methanol to oil as reactants of 15:1 is fed to the reactor, while operating condition of the reactor was kept at reaction temperature of 65 oC and ambient pressure. The fatty acid methyl ester (FAME component in biodiesel product was identified by Gas Chromatography - Mass Spectrometry (GC-MS. The results showed that the FAME yield decreases with increasing WHSV. It was found that the optimum FAME yield was achieved of 56.91 % at WHSV of 0.89 min-1 and catalyst diameter of 5 mm and reaction time of 1.25 min. It can be concluded that the biodiesel synthesis using the hybrid catalytic-plasma reactor system exhibited promising the FAME yield. Copyright © 2017 BCREC Group. All rights reserved Received: 15th November 2016; Revised: 24th December 2016; Accepted: 16th February 2017 How to Cite: Buchori, L., Istadi, I., Purwanto, P. (2017. Effects of Weight Hourly Space Velocity and Catalyst Diameter on Performance of Hybrid Catalytic-Plasma Reactor for Biodiesel Synthesis over Sulphated Zinc Oxide Acid Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (2: 227-234 (doi:10.9767/bcrec.12.2.775.227-234 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.12.2.775.227-234

  15. Efficiencies of acid catalysts in the hydrolysis of lignocellulosic biomass over a range of combined severity factors

    Science.gov (United States)

    Jae-Won Lee; Thomas W. Jeffries

    2011-01-01

    Dicarboxylic organic acids have properties that differ from those of sulfuric acid during hydrolysis of lignocellulose. To investigate the effects of different acid catalysts on the hydrolysis and degradation of biomass compounds over a range of thermochemical pretreatments, maleic, oxalic and sulfuric acids were each used at the same combined severity factor (CSF)...

  16. Silica sulfuric acid: a versatile and reusable heterogeneous catalyst ...

    African Journals Online (AJOL)

    Silica sulfuric acid catalyzes efficiently the reaction of carbamates and oxazolidinones with anhydrides under solvent-free conditions. All the reactions were done at room temperature and the N-acyl carbamates and oxazolidinones were obtained with high yields and purity via an easy work-up procedure. This method is ...

  17. Cellulose sulphuric acid as a biodegradable catalyst for conversion ...

    Indian Academy of Sciences (India)

    This article describes simple and efficient method for the diazotization and azidation of different aromatic amines over cellulose sulphuric acid, sodium nitrite and sodium azide under mild conditions at room temperature. Various aryl amines possessing electron-withdrawing groups or electron-donating groups have been ...

  18. Noble metal-free bifunctional oxygen evolution and oxygen reduction acidic media electro-catalysts

    Science.gov (United States)

    Patel, Prasad Prakash; Datta, Moni Kanchan; Velikokhatnyi, Oleg I.; Kuruba, Ramalinga; Damodaran, Krishnan; Jampani, Prashanth; Gattu, Bharat; Shanthi, Pavithra Murugavel; Damle, Sameer S.; Kumta, Prashant N.

    2016-07-01

    Identification of low cost, highly active, durable completely noble metal-free electro-catalyst for oxygen reduction reaction (ORR) in proton exchange membrane (PEM) fuel cells, oxygen evolution reaction (OER) in PEM based water electrolysis and metal air batteries remains one of the major unfulfilled scientific and technological challenges of PEM based acid mediated electro-catalysts. In contrast, several non-noble metals based electro-catalysts have been identified for alkaline and neutral medium water electrolysis and fuel cells. Herein we report for the very first time, F doped Cu1.5Mn1.5O4, identified by exploiting theoretical first principles calculations for ORR and OER in PEM based systems. The identified novel noble metal-free electro-catalyst showed similar onset potential (1.43 V for OER and 1 V for ORR vs RHE) to that of IrO2 and Pt/C, respectively. The system also displayed excellent electrochemical activity comparable to IrO2 for OER and Pt/C for ORR, respectively, along with remarkable long term stability for 6000 cycles in acidic media validating theory, while also displaying superior methanol tolerance and yielding recommended power densities in full cell configurations.

  19. Transformation of Unsaturated Fatty Acids/Esters to Corresponding Keto Fatty Acids/Esters by Aerobic Oxidation with Pd(II)/Lewis Acid Catalyst.

    Science.gov (United States)

    Senan, Ahmed M; Zhang, Sicheng; Zeng, Miao; Chen, Zhuqi; Yin, Guochuan

    2017-08-16

    Utilization of renewable biomass to partly replace the fossil resources in industrial applications has attracted attention due to the limited fossil feedstock with the increased environmental concerns. This work introduced a modified Wacker-type oxidation for transformation of unsaturated fatty acids/esters to the corresponding keto fatty acids/esters, in which Cu2+ cation was replaced with common nonredox metal ions, that is, a novel Pd(II)/Lewis acid (LA) catalyst. It was found that adding nonredox metal ions can effectively promote Pd(II)-catalyzed oxidation of unsaturated fatty acids/esters to the corresponding keto fatty acids/esters, even much better than Cu2+, and the promotional effect is highly dependent on the Lewis acidity of added nonredox metal ions. The improved catalytic efficiency is attributed to the formation of heterobimetallic Pd(II)/LA species, and the oxidation mechanism of this Pd(II)/LA catalyst is also briefly discussed.

  20. Esterification of Palmitic Acid with Methanol in the Presence of Macroporous Ion Exchange Resin as Catalyst

    Directory of Open Access Journals (Sweden)

    Amelia Qarina Yaakob and Subhash Bhatia

    2012-10-01

    Full Text Available The esterification of palmitic acid with methanol was studied in a batch reactor using macro porous ion exchange resin Amberlyst 15 as a catalyst. Methyl palmitate was produced from the reaction between palmitic acid and methanol in the presence of catalyst. The effects of processing parameters, molar ratio of alcohol to acid M, (4-10, catalyst loading (0-10 g cat/liter, water inhibition (0-2 mol/liter, agitator speed (200-800 rpm and reaction temperature (343-373K were studied. The experimental kinetic data were correlated using homogenous as well as heterogeneous models (based on single as well as dual site mechanisms. The activation energy of the reaction was 11.552 kJ/mol for forward reaction whilst 5.464 kJ/mol for backward reaction. The experimental data fitted well with the simulated data obtained from the kinetic models. Keywords: Palmitic Acid, Methanol, Esterification, Ion Exchange Resin, Kinetics.

  1. Enhancement of biodiesel production from marine alga, Scenedesmus sp. through in situ transesterification process associated with acidic catalyst.

    Science.gov (United States)

    Kim, Ga Vin; Choi, Woonyong; Kang, Dohyung; Lee, Shinyoung; Lee, Hyeonyong

    2014-01-01

    The aim of this study was to increase the yield of biodiesel produced by Scenedesmus sp. through in situ transesterification by optimizing various process parameters. Based on the orthogonal matrix analysis for the acidic catalyst, the effects of the factors decreased in the order of reaction temperature (47.5%) > solvent quantity (26.7%) > reaction time (17.5%) > catalyst amount (8.3%). Based on a Taguchi analysis, the effects of the factors decreased in the order of solvent ratio (34.36%) > catalyst (28.62%) > time (19.72%) > temperature (17.32%). The overall biodiesel production appeared to be better using NaOH as an alkaline catalyst rather than using H2SO4 in an acidic process, at 55.07 ± 2.18% (based on lipid weight) versus 48.41 ± 0.21%. However, in considering the purified biodiesel, it was found that the acidic catalyst was approximately 2.5 times more efficient than the alkaline catalyst under the following optimal conditions: temperature of 70 °C (level 2), reaction time of 10 hrs (level 2), catalyst amount of 5% (level 3), and biomass to solvent ratio of 1 : 15 (level 2), respectively. These results clearly demonstrated that the acidic solvent, which combined oil extraction with in situ transesterification, was an effective catalyst for the production of high-quantity, high-quality biodiesel from a Scenedesmus sp.

  2. Enhancement of Biodiesel Production from Marine Alga, Scenedesmus sp. through In Situ Transesterification Process Associated with Acidic Catalyst

    Directory of Open Access Journals (Sweden)

    Ga Vin Kim

    2014-01-01

    Full Text Available The aim of this study was to increase the yield of biodiesel produced by Scenedesmus sp. through in situ transesterification by optimizing various process parameters. Based on the orthogonal matrix analysis for the acidic catalyst, the effects of the factors decreased in the order of reaction temperature (47.5% > solvent quantity (26.7% > reaction time (17.5% > catalyst amount (8.3%. Based on a Taguchi analysis, the effects of the factors decreased in the order of solvent ratio (34.36% > catalyst (28.62% > time (19.72% > temperature (17.32%. The overall biodiesel production appeared to be better using NaOH as an alkaline catalyst rather than using H2SO4 in an acidic process, at 55.07 ± 2.18% (based on lipid weight versus 48.41 ± 0.21%. However, in considering the purified biodiesel, it was found that the acidic catalyst was approximately 2.5 times more efficient than the alkaline catalyst under the following optimal conditions: temperature of 70°C (level 2, reaction time of 10 hrs (level 2, catalyst amount of 5% (level 3, and biomass to solvent ratio of 1 : 15 (level 2, respectively. These results clearly demonstrated that the acidic solvent, which combined oil extraction with in situ transesterification, was an effective catalyst for the production of high-quantity, high-quality biodiesel from a Scenedesmus sp.

  3. Structure and acidity of individual Fluid Catalytic Cracking catalyst particles studied by synchrotron-based infrared micro-spectroscopy

    NARCIS (Netherlands)

    Buurmans, I.L.C.|info:eu-repo/dai/nl/31406592X; Soulimani, F.|info:eu-repo/dai/nl/313889449; Ruiz Martinez, J.|info:eu-repo/dai/nl/341386405; van der Bij, H.E.|info:eu-repo/dai/nl/328201294; Weckhuysen, B.M.|info:eu-repo/dai/nl/285484397

    2013-01-01

    A synchrotron-based infrared micro-spectroscopy study has been conducted to investigate the structure as well as the Brønsted and Lewis acidity of Fluid Catalytic Cracking (FCC) catalyst particles at the individual particle level. Both fresh and laboratory-deactivated catalyst particles have been

  4. Enhancement of Biodiesel Production from Marine Alga, Scenedesmus sp. through In Situ Transesterification Process Associated with Acidic Catalyst

    Science.gov (United States)

    Kim, Ga Vin; Choi, WoonYong; Kang, DoHyung; Lee, ShinYoung; Lee, HyeonYong

    2014-01-01

    The aim of this study was to increase the yield of biodiesel produced by Scenedesmus sp. through in situ transesterification by optimizing various process parameters. Based on the orthogonal matrix analysis for the acidic catalyst, the effects of the factors decreased in the order of reaction temperature (47.5%) > solvent quantity (26.7%) > reaction time (17.5%) > catalyst amount (8.3%). Based on a Taguchi analysis, the effects of the factors decreased in the order of solvent ratio (34.36%) > catalyst (28.62%) > time (19.72%) > temperature (17.32%). The overall biodiesel production appeared to be better using NaOH as an alkaline catalyst rather than using H2SO4 in an acidic process, at 55.07 ± 2.18% (based on lipid weight) versus 48.41 ± 0.21%. However, in considering the purified biodiesel, it was found that the acidic catalyst was approximately 2.5 times more efficient than the alkaline catalyst under the following optimal conditions: temperature of 70°C (level 2), reaction time of 10 hrs (level 2), catalyst amount of 5% (level 3), and biomass to solvent ratio of 1 : 15 (level 2), respectively. These results clearly demonstrated that the acidic solvent, which combined oil extraction with in situ transesterification, was an effective catalyst for the production of high-quantity, high-quality biodiesel from a Scenedesmus sp. PMID:24689039

  5. Production of Adipic Acid from Mixtures of Cyclohexanol-Cyclohexanone using Polyoxometalate Catalysts

    Directory of Open Access Journals (Sweden)

    Aldes Lesbani

    2015-06-01

    Full Text Available Adipic acid production through catalytic conversion of cyclohexanol-cyclohexanone using polyoxometalate H5[a-BW12O40] and H4[a-SiW12O40] as catalysts was carried out systematically. Polyoxometalates H5[a-BW12O40] and H4[a-SiW12O40] were synthesized using an inorganic synthesis method and were characterized using Fourier transform infrared spectroscopy (FTIR. Adipic acid was formed from conversion of cyclohexanol-cyclohexanone and was characterized by using melting point measurement, identification of functional group using FTIR spectrophotometer, analysis of gas chromatography-mass spectrometry (GC-MS, and 1H and 13C NMR (nuclear magnetic resonance spectrophotometer. This research investigated the influence of reaction time and temperature on the conversion. The results showed that adipic acid was formed successfully with a yield of 68% by using H5[a-BW12O40] as the catalyst with a melting point of 150-152 °C after optimization. In contrast, using H4[a-SiW12O40] as the catalyst, the formation was only 3.7%. Investigation of time and temperature showed 9 h as the optimum reaction time and 90 °C as the optimum temperature for conversion of up to 68%. Identification using FTIR, 1H, and 13C NMR showed that the adipic acid from conversion of cyclohexanol-cyclohexanone was in agreement with the standard adipic acid data in the literatures. GC-MS analysis indicated that several by-products were formed in conversion of cyclohexanol-cyclohexanone using H5[a-BW12O40] and H4[a-SiW12O40] as the catalysts.

  6. Iodination of Alcohols over Keggin-type Heteropoly Compounds: A ...

    African Journals Online (AJOL)

    NICO

    137. S. Afr. J. Chem., 2010, 63, 135–140,. . Table 1 Effect of different HPA-catalysts in iodination of benzyl alcohol.a. Group. Catalyst. Time (min). Yield (%)b. Single-addenda HPCs. PW12. 17. 90. H3PMo12O40. 30. 65. H4SiW12O40. 30. 80. HPC with paramagnetic ion. K5CoW12O40.

  7. Conversion of biomass into 5-hydroxymethylfurfural using solid acid catalyst.

    Science.gov (United States)

    Yang, Fengli; Liu, Qishun; Bai, Xuefang; Du, Yuguang

    2011-02-01

    5-Hydroxymethylfurfural (HMF) was produced from monosaccharide (fructose and glucose), polysaccharide (inulin) and the Jerusalem artichoke juice by a simple one-pot reaction including hydrolysis and dehydration using solid acid under mild condition. Hydrated niobium pentoxide (Nb(2)O(5)·nH(2)O(2)) after pretreatment showed high catalytic activities for dehydration of mono- and polysaccharide to HMF at 433 K in water-2-butanol (2:3 v/v) biphasic system, giving high HMF yield of 89% and 54% from fructose and inulin, respectively. The HMF yield was up to 74% and 65% when inulin and Jerusalem artichoke juice were hydrolyzed by exoinulinase. The solid acid made the process environment-friendly and energy-efficient to convert carbohydrates into bio-fuels and platform chemicals. Copyright © 2010 Elsevier Ltd. All rights reserved.

  8. Surface hydrophobicity and acidity effect on alumina catalyst in catalytic methanol dehydration reaction.

    Science.gov (United States)

    Osman, Ahmed I; Abu-Dahrieh, Jehad K; Rooney, David W; Thompson, Jillian; Halawy, Samih A; Mohamed, Mohamed A

    2017-12-01

    Methanol to dimethyl ether (MTD) is considered one of the main routes for the production of clean bio-fuel. The effect of copper loading on the catalytic performance of different phases of alumina that formed by calcination at two different temperatures was examined for the dehydration of methanol to dimethyl ether (DME). A range of Cu loadings of (1, 2, 4, 6, 10 and 15% Cu wt/wt) on Al 2 O 3 calcined at 350 and 550 °C were prepared and characterized by TGA, XRD, BET, NH 3 -TPD, TEM, H 2 -TPR, SEM, EDX, XPS and DRIFT-Pyridine techniques. The prepared catalysts were used in a fixed bed reactor under reaction conditions in which the temperature ranged from 180-300 °C with weight hourly space velocity (WHSV) = 12.1 h -1 . It was observed that all catalysts calcined at 550 °C (γ-Al 2 O 3 support phase) exhibited higher activity than those calcined at 350 °C (γ-AlOOH), and this is due to the phase support change. Furthermore, the optimum Cu loading was found to be 6% Cu/γ-Al 2 O 3 with this catalyst also showing a high degree of stability under steady state conditions and this is attributed to the enhancement in surface acidity and hydrophobicity. The addition of copper to the support improved the catalyst properties and activity. For all the copper modified catalysts, the optimum catalyst with high degree of activity and stability was 6% copper loaded on gamma alumina. © 2017 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

  9. Efficient solid acid catalyst containing Lewis and Brønsted Acid sites for the production of furfurals.

    Science.gov (United States)

    Mazzotta, Michael G; Gupta, Dinesh; Saha, Basudeb; Patra, Astam K; Bhaumik, Asim; Abu-Omar, Mahdi M

    2014-08-01

    Self-assembled nanoparticulates of porous sulfonated carbonaceous TiO2 material that contain Brønsted and Lewis acidic sites were prepared by a one-pot synthesis method. The material was characterized by XRD, FTIR spectroscopy, NH3 temperature-programmed desorption, pyridine FTIR spectroscopy, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, N2 -sorption, atomic absorbance spectroscopy, and inductively coupled plasma optical emission spectroscopy. The carbonaceous heterogeneous catalyst (Glu-TsOH-Ti) with a Brønsted-to-Lewis acid density ratio of 1.2 and more accessible acid sites was effective to produce 5-hydroxymethylfurfural and furfural from biomass-derived mono- and disaccharides and xylose in a biphasic solvent that comprised water and biorenewable methyltetrahydrofuran. The catalyst was recycled in four consecutive cycles with a total loss of only 3 % activity. Thus, Glu-TsOH-Ti, which contains isomerization and dehydration catalytic sites and is based on a cheap and biorenewable carbon support, is a sustainable catalyst for the production of furfurals, platform chemicals for biofuels and chemicals. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Molten Salt Catalysts for Sulfuric Acid Production and SO2 Removal From Flue Gas

    DEFF Research Database (Denmark)

    Eriksen, Kim Michael; Fehrmann, Rasmus

    1996-01-01

    The report summarises the results obtained during 3 years of collaboration between ICE/HT,University of Patras,GR and Department of Chemistry,DTU,DK , supported by EU through a BRITE/EURAM project.The project has been concerned with fundamental investigations on the complex , redox and compound c...... chemistry of the V2O5 based sulfuric acid catalysts and model systems...

  11. Steam reforming of biomass based oxygenates - Mechanism of acetic acid activation on supported platinum catalysts.

    NARCIS (Netherlands)

    Matas Güell, B.; Babych, Igor V.; Seshan, Kulathuiyer; Lefferts, Leonardus

    2008-01-01

    The activation of acetic acid during steam reforming reactions over Pt-based catalysts has been probed by decomposing CH3COOD over Pt/C. The product mixture contained CO2, CH4 and its D-analogs (CH4−xDx, 0⩽x⩽4), H2, HD and D2. CO2, CH3D and D2 are typically primary desorption products whereas the

  12. Pd/C Synthesized with Citric Acid: An Efficient Catalyst for Hydrogen Generation from Formic Acid/Sodium Formate

    Science.gov (United States)

    Wang, Zhi-Li; Yan, Jun-Min; Wang, Hong-Li; Ping, Yun; Jiang, Qing

    2012-01-01

    A highly efficient hydrogen generation from formic acid/sodium formate aqueous solution catalyzed by in situ synthesized Pd/C with citric acid has been successfully achieved at room temperature. Interestingly, the presence of citric acid during the formation and growth of the Pd nanoparticles on carbon can drastically enhance the catalytic property of the resulted Pd/C, on which the conversion and turnover frequency for decomposition of formic acid/sodium formate system can reach the highest values ever reported of 85% within 160 min and 64 mol H2 mol−1 catalyst h−1, respectively, at room temperature. The present simple, low cost, but highly efficient CO-free hydrogen generation system at room temperature is believed to greatly promote the practical application of formic acid system on fuel cells. PMID:22953041

  13. Pd/C Synthesized with Citric Acid: An Efficient Catalyst for Hydrogen Generation from Formic Acid/Sodium Formate

    Science.gov (United States)

    Wang, Zhi-Li; Yan, Jun-Min; Wang, Hong-Li; Ping, Yun; Jiang, Qing

    2012-08-01

    A highly efficient hydrogen generation from formic acid/sodium formate aqueous solution catalyzed by in situ synthesized Pd/C with citric acid has been successfully achieved at room temperature. Interestingly, the presence of citric acid during the formation and growth of the Pd nanoparticles on carbon can drastically enhance the catalytic property of the resulted Pd/C, on which the conversion and turnover frequency for decomposition of formic acid/sodium formate system can reach the highest values ever reported of 85% within 160 min and 64 mol H2 mol-1 catalyst h-1, respectively, at room temperature. The present simple, low cost, but highly efficient CO-free hydrogen generation system at room temperature is believed to greatly promote the practical application of formic acid system on fuel cells.

  14. Single Atomic Iron Catalysts for Oxygen Reduction in Acidic Media: Particle Size Control and Thermal Activation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hanguang [Department; Hwang, Sooyeon [Center; Wang, Maoyu [School; Feng, Zhenxing [School; Karakalos, Stavros [Department; Luo, Langli [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Qiao, Zhi [Department; Xie, Xiaohong [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Wang, Chongmin [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Su, Dong [Center; Shao, Yuyan [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Wu, Gang [Department

    2017-09-26

    To significantly reduce the cost of proton exchange membrane (PEM) fuel cells, current Pt must be replaced by platinum-metal-group (PGM)-free catalysts for the oxygen reduction reaction (ORR) in acid. We report here a new class of high-performance atomic iron dispersed carbon catalysts through controlled chemical doping of iron ions into zinc-zeolitic imidazolate framework (ZIF), a type of metal-organic framework (MOF). The novel synthetic chemistry enables accurate size control of Fe-doped ZIF catalyst particles with a wide range from 20 to 1000 nm without changing chemical properties, which provides a great opportunity to increase the density of active sites that is determined by the particle size. We elucidated the active site formation mechanism by correlating the chemical and structural changes with thermal activation process for the conversion from Fe-N4 complex containing hydrocarbon networks in ZIF to highly active FeNx sites embedded into carbon. A temperature of 800oC was identified as the critical point to start forming pyridinic nitrogen doping at the edge of the graphitized carbon planes. Further increasing heating temperature to 1100oC leads to increase of graphitic nitrogen, generating possible synergistic effect with FeNx sites to promote ORR activity. The best performing catalyst, which has well-defined particle size around 50 nm and abundance of atomic FeNx sites embedded into carbon structures, achieve a new performance milestone for the ORR in acid including a half-wave potential of 0.85 V vs RHE and only 20 mV loss after 10,000 cycles in O2 saturated H2SO4 electrolyte. The new class PGM-free catalyst with approaching activity to Pt holds great promise for future PEM fuel cells.

  15. Synthesis of N-hydroxysuccinimide from succinic acid and hydroxylammonium chloride using Amberlyst A21 as reusable solid base catalyst

    Science.gov (United States)

    Le, Son Dinh; Nishimura, Shun; Ebitani, Kohki

    2018-01-01

    Solid base catalysts were studied for the first time to synthesize N-hydroxysuccinimide (NHS) through the reaction of succinic acid with hydroxylammonium chloride. The highest yield of 42% (±3%) with 65% (±4%) selectivity toward NHS production was achieved by using Amberlyst A21, which is a weak base anion-exchange resin. The present catalyst could be recycled during five runs without significant decreases in activity. Also, efficacy for the Amberlyst A21 mediated reaction was also explored with other dicarboxylic acids such as phthalic acid, glutaric acid, and maleic acid.

  16. The glmS Ribozyme Cofactor is a General Acid-Base Catalyst

    Science.gov (United States)

    Viladoms, Julia; Fedor, Martha J.

    2012-01-01

    The glmS ribozyme is the first natural self-cleaving ribozyme known to require a cofactor. The D-glucosamine-6-phosphate (GlcN6P) cofactor has been proposed to serve as a general acid, but its role in the catalytic mechanism has not been established conclusively. We surveyed GlcN6P-like molecules for their ability to support self-cleavage of the glmS ribozyme and found a strong correlation between the pH dependence of the cleavage reaction and the intrinsic acidity of the cofactors. For cofactors with low binding affinities the contribution to rate enhancement was proportional to their intrinsic acidity. This linear free-energy relationship between cofactor efficiency and acid dissociation constants is consistent with a mechanism in which the cofactors participate directly in the reaction as general acid-base catalysts. A high value for the Brønsted coefficient (β ~ 0.7) indicates that a significant amount of proton transfer has already occurred in the transition state. The glmS ribozyme is the first self-cleaving RNA to use an exogenous acid-base catalyst. PMID:23113700

  17. Comparison of sulfuric and hydrochloric acids as catalysts in hydrolysis of Kappaphycus alvarezii (cottonii).

    Science.gov (United States)

    Meinita, Maria Dyah Nur; Hong, Yong-Ki; Jeong, Gwi-Taek

    2012-01-01

    In this study, hydrolysis of marine algal biomass Kappaphhycus alvarezii using two different acid catalysts was examined with the goal of identifying optimal reaction conditions for the formation of sugars and by-products. K. alvarezii were hydrolyzed by autoclave using sulfuric acid or hydrochloric acid as catalyst with different acid concentrations (0.1-1.0 M), substrate concentrations (1.0-13.5%), hydrolysis time (10-90 min) and hydrolysis temperatures (100-130 (°)C). A difference in galactose, glucose, reducing sugar and total sugar content was observed under the different hydrolysis conditions. Different by-product compounds such as 5-hydroxymethylfurfural and levulinic acid were also observed under the different reaction conditions. The optimal conditions for hydrolysis were achieved at a sulfuric acid concentration, temperature and reaction time of 0.2 M, 130 °C and 15 min, respectively. These results may provide useful information for the development of more efficient systems for biofuel production from marine biomass.

  18. Continuous Catalyst-Free Esterification of Oleic Acid in Compressed Ethanol

    Directory of Open Access Journals (Sweden)

    Ana Carolina de Araujo Abdala

    2014-01-01

    Full Text Available The esterification of oleic acid in a continuous catalyst-free process using compressed ethanol was investigated in the present study. Experiments were performed in a tubular reactor and variables investigated were temperature, pressure, and oleic acid to ethanol molar ratio for different residence time. Results demonstrated that temperature, in the range of 473 K to 573 K, and pressure had a positive effect on fatty acid ethyl esters (FAEE production. In the experimental range investigated, high conversions can be obtained at low ethanol concentrations in the reaction medium and it was observed that oleic acid to ethanol molar ratios greater than 1 : 6 show no significant increase in conversion. Nonnegligible reaction conversions (>90% were achieved at 573 K, 20 MPa, oleic acid to ethanol molar ratio of 1 : 6, and 20 minutes of residence time.

  19. Liquefaction of kraft lignin by hydrocracking with simultaneous use of a novel dual acid-base catalyst and a hydrogenation catalyst.

    Science.gov (United States)

    Wang, Jindong; Li, Wenzhi; Wang, Huizhen; Ma, Qiaozhi; Li, Song; Chang, Hou-Min; Jameel, Hasan

    2017-11-01

    In this study, a novel catalyst, S 2 O 8 2- -KNO 3 /TiO 2 , which has active acidic and basic sites, was prepared and used in lignin hydrocracking with a co-catalyst, Ru/C. Ru/C is an efficient hydrogenation catalyst and S 2 O 8 2- -KNO 3 /TiO 2 is a dual catalyst, which could efficiently degrade lignin. This catalytic hydrogenation system can reduce solid products to less than 1%, while giving a high liquid product yield of 93%. Catalytic hydrocracking of kraft lignin at 320°C for 6h gave 93% liquid product with 0.5% solid product. Most of this liquid product was soluble in petroleum ether (60% of 93%), which is a clear liquid and comprises mainly of monomeric and dimeric degradation products. These results demonstrated that the combination of the two catalysts is an efficient catalyst for liquefaction of lignin, with little char formation (∼1%). This concept has the potential to produce valuable chemicals and fuels from lignin under moderate conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Carbon supported ruthenium chalcogenide as cathode catalyst in a microfluidic formic acid fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Gago, A.S.; Alonso-Vante, N. [Laboratory of Electrocatalysis, UMR-CNRS 6503, Universite de Poitiers, 40 Avenue du Recteur Pineau, F-86022 Potiers Cedex (France); Morales-Acosta, D.; Arriaga, L.G. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, S.C. Parque Tecnologico Queretaro Sanfandila, P.O. Box 064, Pedro Escobedo, 76703, Queretaro (Mexico)

    2011-02-01

    This work reports the electrochemical measurements of 20 wt.% Ru{sub x}Se{sub y}/C for oxygen reduction reaction (ORR) in presence of different concentration of HCOOH and its use as cathode catalyst in a microfluidic formic acid fuel cell ({mu}FAFC). The results were compared to those obtained with commercial Pt/C. Half-cell electrochemical measurements showed that the chalcogenide catalyst has a high tolerance and selectivity towards ORR in electrolytes containing up to 0.1 M HCOOH. The depolarization effect was higher on Pt/C than on Ru{sub x}Se{sub y}/C by a factor of ca. 23. Both catalysts were evaluated as cathode of a {mu}FAFC operating with different concentrations of HCOOH. When 0.5 M HCOOH was used, maximum current densities of 11.44 mA cm{sup -2} and 4.44 mA cm{sup -2} were obtained when the cathode was Ru{sub x}Se{sub y}/C and Pt/C, respectively. At 0.5 M HCOOH, the peak power density of the {mu}FAFC was similar for both catalysts, ca. 1.9 mW cm{sup -2}. At 5 M HCOOH the power density of the {mu}FAFC using Ru{sub x}Se{sub y}, was 9.3 times higher than the obtained with Pt/C. (author)

  1. Enhanced formic acid electro-oxidation reaction on ternary Pd-Ir-Cu/C catalyst

    Science.gov (United States)

    Chen, Jinwei; Zhang, Jie; Jiang, Yiwu; Yang, Liu; Zhong, Jing; Wang, Gang; Wang, Ruilin

    2015-12-01

    Aim to further reduce the cost of Pd-Ir for formic acid electro-oxidation (FAEO), the Cu was used to construct a ternary metallic alloy catalyst. The prepared catalysts are characterized using XRD, TGA, EDX, TEM, XPS, CO-stripping, cyclic voltammetry and chronoamperometry. It is found that the Pd18Ir1Cu6 nanoparticles with a mean size of 3.3 nm are highly dispersed on carbon support. Componential distributions on catalyst are consistent with initial contents. Electrochemical measurements show that the PdIrCu/C catalyst exhibits the highest activity for FAEO. The mass activity of Pd in Pd18Ir1Cu6/C at 0.16 V (vs. SCE) is about 1.47, 1.62 and 2.08 times as high as that of Pd18Cu6/C, Pd18Ir1/C and Pd/C, respectively. The activity enhancement of PdIrCu/C should be attributed to the weakened CO adsorption strength and the removal of adsorbed intermediates at lower potential with the addition of Cu and Ir.

  2. Reversible Hydrogenation of Carbon Dioxide to Formic Acid and Methanol: Lewis Acid Enhancement of Base Metal Catalysts.

    Science.gov (United States)

    Bernskoetter, Wesley H; Hazari, Nilay

    2017-04-18

    New and sustainable energy vectors are required as a consequence of the environmental issues associated with the continued use of fossil fuels. H 2 is a potential clean energy source, but as a result of problems associated with its storage and transport as a gas, chemical H 2 storage (CHS), which involves the dehydrogenation of small molecules, is an attractive alternative. In principle, formic acid (FA, 4.4 wt % H 2 ) and methanol (MeOH, 12.6 wt % H 2 ) can be obtained renewably and are excellent prospective liquid CHS materials. In addition, MeOH has considerable potential both as a direct replacement for gasoline and as a fuel cell input. The current commercial syntheses of FA and MeOH, however, use nonrenewable feedstocks and will not facilitate the use of these molecules for CHS. An appealing option for the sustainable synthesis of both FA and MeOH, which could be implemented on a large scale, is the direct metal catalyzed hydrogenation of CO 2 . Furthermore, given that CO 2 is a readily available, nontoxic and inexpensive source of carbon, it is expected that there will be economic and environmental benefits from using CO 2 as a feedstock. One strategy to facilitate both the dehydrogenation of FA and MeOH and the hydrogenation of CO 2 and H 2 to FA and MeOH is to utilize a homogeneous transition metal catalyst. In particular, the development of catalysts based on first row transition metals, which are cheaper, and more abundant than their precious metal counterparts, is desirable. In this Account, we describe recent advances in the development of iron and cobalt systems for the hydrogenation of CO 2 to FA and MeOH and the dehydrogenation of FA and MeOH and provide a brief comparison between precious metal and base metal systems. We highlight the different ligands that have been used to stabilize first row transition metal catalysts and discuss the use of additives to promote catalytic activity. In particular, the Account focuses on the crucial role that

  3. Process Parameters Optimization of Potential SO42-/ZnO Acid Catalyst for Heterogeneous Transesterification of Vegetable Oil to Biodiesel

    Directory of Open Access Journals (Sweden)

    Istadi Istadi

    2012-12-01

    Full Text Available Among the possible renewable energy resources, diesel fuels derived from triglycerides of vegetable oils and animal fats have shown potential as substitutes for petroleum-based diesel fuels. The biodiesel could be produced from vegetable oils over homogeneous catalyst, heterogeneous catalyst, or enzymatic catalyst. In this study, the synthesized SO42-/ZnO catalyst was explored to be used in the heterogeneous biodiesel production by using the vegetable oils and methanol. The study began with the preparation of SO42-/ZnO catalyst followed by the transesterification reaction between vegetable oil with methanol. The independent variables (reaction time and the weight ratio of catalyst/oil were optimized to obtain the optimum biodiesel (fatty acid methyl ester yield. The results of this study showed that the acid catalyst SO42-/ZnO was potential to be used as catalyst for biodiesel production through heterogeneous transesterification of vegetable oils. Optimum operating condition for this catalytic reaction was the weight ratio of catalyst/oil of 8:1 and reaction time of 2.6 h with respect to 75.5% yield of methyl ester products. The biodiesel product was also characterized to identify the respected fatty acid methyl ester components. Copyright © 2012 by BCREC UNDIP. All rights reserved. (Selected Paper from International Conference on Chemical and Material Engineering (ICCME 2012Received: 23rd October 2012, Revised: 25th November 2012, Accepted: 25th November 2012[How to Cite: I. Istadi, Didi D. Anggoro, Luqman Buchori, Inshani Utami, Roikhatus Solikhah, (2012. Process Parameters Optimization of Potential SO42-/ZnO Acid Catalyst for Heterogeneous Transesterification of Vegetable Oil to Biodiesel. Bulletin of Chemical Reaction Engineering & Catalysis, 7(2: 150-157. (doi:10.9767/bcrec.7.2.4064.150-157][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.2.4064.150-157 ] | View in 

  4. Effects of Nafion loading in anode catalyst inks on the miniature direct formic acid fuel cell

    Science.gov (United States)

    Morgan, Robert D.; Haan, John L.; Masel, Richard I.

    Nafion, within the anode and cathode catalyst layers, plays a large role in the performance of fuel cells, especially during the operation of the direct formic acid fuel cell (DFAFC). Nafion affects the proton transfer in the catalyst layers of the fuel cell, and studies presented here show the effects of three different Nafion loadings, 10 wt.%, 30 wt.% and 50 wt.%. Short term voltage-current measurements using the three different loadings show that 30 wt.% Nafion loading in the anode shows the best performance in the miniature, passive DFAFC. Nafion also serves as a binder to help hold the catalyst nanoparticles onto the proton exchange membrane (PEM). The DFAFC anode temporarily needs to be regenerated by raising the anode potential to around 0.8 V vs. RHE to oxidize CO bound to the surface, but the Pourbaix diagram predicts that Pd will corrode at these potentials. We found that an anode loading of 30 wt.% Nafion showed the best stability, of the three Nafion loadings chosen, for reducing the amount of loss of electrochemically active area due to high regeneration potentials. Only 58% of the area was lost after 600 potential cycles in formic acid compared to 96 and 99% for 10 wt.% and 50 wt.% loadings, respectively. Lastly we present cyclic voltammetry data that suggest that the Nafion adds to the production of CO during oxidation of formic acid for 12 h at 0.3 V vs. RHE. The resulting data showed that an increase in CO coverage was observed with increasing Nafion content in the anode catalyst layer.

  5. Gas Phase Oligomerization of Isobutene over Acid Treated Kaolinite Clay Catalyst

    Directory of Open Access Journals (Sweden)

    Dhaifallah Aldhayan

    2017-04-01

    Full Text Available Natural Kaolin Clay was calcined and treated by sulfuric acid. The resulting solid acid catalyst was characterized by FTIR, TGA, and X-ray powder diffraction (XRD and tested for isobutene oligomerization in a gas phase. The characterization results showed that the acid treated clay underwent chemical and structural transformations. After acid treatment, the Si/Al ratio was increased, and the crystalline raw clay became amorphous. The effects of various parameters such as reaction temperature, reaction time and contact time on isobutene oligomerization were investigated. Catalytic tests showed that isobutene oligomerization led to dimers and trimers as major products. Tetramers were obtained as by- products. At relatively high reaction temperatures and long contact times, the conversion was enhanced while the selectivity of dimers was decreased in favor of higher oligomers. Copyright © 2017 BCREC GROUP. All rights reserved Received: 27th October 2016; Revised: 21st December 2016; Accepted: 22nd December 2016 How to Cite: Aldhayan, D., Aouissi, A. (2017. Gas Phase Oligomerization of Isobutene over Acid Treated Kaolinite Clay Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (1: 119-126 (doi:10.9767/bcrec.12.1.758.119-126 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.12.1.758.119-126

  6. Oxidation of ethoxylated fatty alcohols to alkylpolyglycol carboxylic acids using noble metals as catalysts

    Directory of Open Access Journals (Sweden)

    Sagredos, Angelos

    2009-09-01

    Full Text Available The conversion of ethoxylated fatty alcohols to the corresponding carboxylic acids through dehydrogenation/ oxidation using noble-metal catalysts has been studied. Ethoxylated primary aliphatic alcohols, ethoxylated random secondary aliphatic alcohols and ethoxylated alkylphenols have been converted to the corresponding acids in the presence of a base. The noble metal catalysts Palladium and Platinum were used without significant degradation of the ethoxyl chain in yields that exceeded 90%. On the other hand, the catalysts Rhodium and Ruthenium gave yields of about 80% and 60% respectively.La conversión de alcoholes grasos etoxilados a los correspondientes ácidos carboxílicos por deshidrogenación/ oxidación con metales nobles como catalizador ha sido estudiada. Alcoholes primarios alifáticos etoxilados, alcoholes alifáticos secundarios etoxilados al azar y alquilfenoles etoxilados han sido convertidos a los correspondientes ácidos en presencia de base. Los catalizadores paladio y platino fueron usados sin degradación significativa de las cadenas etoxiladas con un rendimiento que excedió del 90%. Por otra parte catalizadores de rodio y rutenio produjeron rendimientos del 80 y 60%, respectivamente.

  7. Comparison of different heterogeneous catalysts and different alcohols for the esterification reaction of oleic acid

    Energy Technology Data Exchange (ETDEWEB)

    J.M. Marchetti; A.F. Errazu [Planta Piloto de Ingenieria Quimica (UNS-CONICET), Bahia Blanca (Argentina)

    2008-11-15

    Oils with high amount of free fatty acid (FFA) are becoming one of the most promising alternatives to produced biodiesel; due, principally, to it low cost. However, because of the presence of FFA, the conventional basic homogenous catalyst should not be used with the aim to avoid the production of soaps. In this work, different catalysts, such as solid resins, zeolite and enzymes, as well as different alcohols: ethanol anhydrous, ethanol 96{sup o}, 1-propanol, 2-propanol and butanol, were tested for the direct esterification reaction of pure oleic acid. The influence of several variables, such as alcohol's carbon chain length, the presence of water, which has a negative effect on the final conversion shifting the final conversion to a lower level, and the location of the OH group were studied. The enzymatic catalyst, Lipozyme CALB, turned out to be the best one, achieving a final conversion of 98% after three days reaction. Short communication. 33 refs., 5 figs., 1 tab.

  8. Microwave-assisted degradation of acid orange using a conjugated polymer, polyaniline, as catalyst

    Directory of Open Access Journals (Sweden)

    Ufana Riaz

    2014-01-01

    Full Text Available Microwave-assisted photocatalytic degradation of dyes is one of the emerging technologies for waste water remediation. Microwave effectively accelerates photocatalytic degradation, when microwave electrodeless lamp (MEL substitutes traditional UV lamp as light source. This setup can be extremely simplified if MEL and photocatalyst can be replaced by a catalyst which can work under microwave irradiation in the absence of any light source. The present work reports for the first time degradation of acid orange 7 (AO under microwave irradiation using polyaniline (PANI as catalyst in the absence of any UV lamp as light source. The degradation/decolourization was carried out in neutral acidic and basic media and was monitored spectrophotometrically to evaluate the ability of microwave irradiation to degrade AO. Microwave irradiation showed excellent performance as it completely decolourizes AO dye solution in 10 min. With the advantages of low cost and rapid processing, this novel catalyst is expected to gain promising application in the treatment of various dyestuff wastewaters on a large scale.

  9. Tailor-Made Stereoblock Copolymers of Poly(lactic acid) by a Truly Living Polymerization Catalyst.

    Science.gov (United States)

    Rosen, Tomer; Goldberg, Israel; Venditto, Vincenzo; Kol, Moshe

    2016-09-21

    Poly(lactic acid) (PLA) is a biodegradable polymer prepared by the catalyzed ring opening polymerization of lactide. An ideal catalyst should enable a sequential polymerization of the lactide enantiomers to afford stereoblock copolymers with predetermined number and lengths of blocks. We describe a magnesium based catalyst that combines very high activity with a true-living nature, which gives access to PLA materials of unprecedented microstructures. Full consumption of thousands of equivalents of L-LA within minutes gave PLLA of expected molecular weights and narrow molecular weight distributions. Precise PLLA-b-PDLA diblock copolymers having block lengths of up to 500 repeat units were readily prepared within 30 min, and their thermal characterization revealed a stereocomplex phase only with very high melting transitions and melting enthalpies. The one pot sequential polymerization was extended up to precise hexablocks having "dialed-in" block lengths.

  10. Transesterification of waste oil to biodiesel using Brønsted acid ionic liquid as catalyst

    Directory of Open Access Journals (Sweden)

    C. Xie

    2013-05-01

    Full Text Available Brønsted acid ionic liquids were employed for the preparation of biodiesel using waste oil as the feedstock. It was found that IL 1–(3–sulfonic acidpropyl–3–methylimidazole hydrosulfate–[HO3S-pmim]HSO4 was an efficient catalyst for the reaction under the optimum conditions: n(oil:n(methanol 1:12, waste oil 15.0 g, ionic liquid 2.0 g, reaction temperature 120 oC and reaction time 8 h, the yield of biodiesel was more than 96%. The reusability of the ionic liquid was also investigated. When the ionic liquid was repeatedly used for five times, the yield of product was still more than 93%. Therefore, an efficient and environmentally friendly catalyst was provided for the synthesis of biodiesel from waste oils.

  11. Gas diffusion electrode setup for catalyst testing in concentrated phosphoric acid at elevated temperatures.

    Science.gov (United States)

    Wiberg, Gustav K H; Fleige, Michael; Arenz, Matthias

    2015-02-01

    We present a detailed description of the construction and testing of an electrochemical cell setup allowing the investigation of a gas diffusion electrode containing carbon supported high surface area catalysts. The setup is designed for measurements in concentrated phosphoric acid at elevated temperature, i.e., very close to the actual conditions in high temperature proton exchange membrane fuel cells (HT-PEMFCs). The cell consists of a stainless steel flow field and a PEEK plastic cell body comprising the electrochemical cell, which exhibits a three electrode configuration. The cell body and flow field are braced using a KF-25 vacuum flange clamp, which allows an easy assembly of the setup. As demonstrated, the setup can be used to investigate temperature dependent electrochemical processes on high surface area type electrocatalysts, but it also enables quick screening tests of HT-PEMFC catalysts under realistic conditions.

  12. Gas diffusion electrode setup for catalyst testing in concentrated phosphoric acid at elevated temperatures

    Science.gov (United States)

    Wiberg, Gustav K. H.; Fleige, Michael; Arenz, Matthias

    2015-02-01

    We present a detailed description of the construction and testing of an electrochemical cell setup allowing the investigation of a gas diffusion electrode containing carbon supported high surface area catalysts. The setup is designed for measurements in concentrated phosphoric acid at elevated temperature, i.e., very close to the actual conditions in high temperature proton exchange membrane fuel cells (HT-PEMFCs). The cell consists of a stainless steel flow field and a PEEK plastic cell body comprising the electrochemical cell, which exhibits a three electrode configuration. The cell body and flow field are braced using a KF-25 vacuum flange clamp, which allows an easy assembly of the setup. As demonstrated, the setup can be used to investigate temperature dependent electrochemical processes on high surface area type electrocatalysts, but it also enables quick screening tests of HT-PEMFC catalysts under realistic conditions.

  13. Comparison between liquid and solid acids catalysts on reducing sugars conversion from furfural residues via pretreatments.

    Science.gov (United States)

    Lin, Keying; Ma, Baojun; Sun, Yuan; Liu, Wanyi

    2014-09-01

    Liquid sulphuric acid is adopted and compared with carbon-based sulfonated solid acids (coal tar-based and active carbon-based) for furfural residues conversion into reducing sugars. The optimum hydrolysis conditions of liquid acid are at 4% of sulphuric acid, 25:1 of liquid and solid ratio, 175°C of reaction temperature and 120 min of reaction time. The reducing sugar yields are reached over 60% on liquid acid via NaOH/H2O2, NaOH/microwave and NaOH/ultrasonic pretreatments, whereas only over 30% on solid acids. The TOFs (turnover number frequency) via NaOH/H2O2 pretreatments are 0.093, 0.020 and 0.023 h(-1) for liquid sulphuric acid, coal tar-based and active carbon-based solid acids catalysts, respectively. Considering the efficiency, cost and environment factors, the liquid and solid acids have their own advantages of potential commercial application values. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Synthesis of bio-based methacrylic acid by decarboxylation of itaconic acid and citric acid catalyzed by solid transition-metal catalysts.

    Science.gov (United States)

    Le Nôtre, Jérôme; Witte-van Dijk, Susan C M; van Haveren, Jacco; Scott, Elinor L; Sanders, Johan P M

    2014-09-01

    Methacrylic acid, an important monomer for the plastics industry, was obtained in high selectivity (up to 84%) by the decarboxylation of itaconic acid using heterogeneous catalysts based on Pd, Pt and Ru. The reaction takes place in water at 200-250 °C without any external added pressure, conditions significantly milder than those described previously for the same conversion with better yield and selectivity. A comprehensive study of the reaction parameters has been performed, and the isolation of methacrylic acid was achieved in 50% yield. The decarboxylation procedure is also applicable to citric acid, a more widely available bio-based feedstock, and leads to the production of methacrylic acid in one pot in 41% selectivity. Aconitic acid, the intermediate compound in the pathway from citric acid to itaconic acid was also used successfully as a substrate. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Support Screening Studies on the Hydrogenation of Levulinic Acid to γ-Valerolactone in Water Using Ru Catalysts

    Directory of Open Access Journals (Sweden)

    Anna Piskun

    2016-08-01

    Full Text Available γ-Valerolactone (GVL has been identified as a sustainable platform chemical for the production of carbon-based chemicals. Here we report a screening study on the hydrogenation of levulinic acid (LA to GVL in water using a wide range of ruthenium supported catalysts in a batch set-up (1 wt. % Ru, 90 °C, 45 bar of H2, 2 wt. % catalyst on LA. Eight monometallic catalysts were tested on carbon based(C, carbon nanotubes (CNT and inorganic supports (Al2O3, SiO2, TiO2, ZrO2, Nb2O5 and Beta-12.5. The best result was found for Ru/Beta-12.5 with almost quantitative LA conversion (94% and 66% of GVL yield after 2 h reaction. The remaining product was 4-hydroxypentanoic acid (4-HPA. Catalytic activity for a bimetallic RuPd/TiO2 catalyst was by far lower than for the monometallic Ru catalyst (9% conversion after 2 h. The effects of relevant catalyst properties (average Ru nanoparticle size, Brunauer-Emmett-Teller (BET surface area, micropore area and total acidity on catalyst activity were assessed.

  16. Which controls the depolymerization of cellulose in ionic liquids: the solid acid catalyst or cellulose?

    Science.gov (United States)

    Rinaldi, Roberto; Meine, Niklas; vom Stein, Julia; Palkovits, Regina; Schüth, Ferdi

    2010-02-22

    Cellulose is a renewable and widely available feedstock. It is a biopolymer that is typically found in wood, straw, grass, municipal solid waste, and crop residues. Its use as raw material for biofuel production opens up the possibility of sustainable biorefinery schemes that do not compete with food supply. Tapping into this feedstock for the production of biofuels and chemicals requires--as the first-step--its depolymerization or its hydrolysis into intermediates that are more susceptible to chemical and/or biological transformations. We have shown earlier that solid acids selectively catalyze the depolymerization of cellulose solubilized in 1-butyl-3-methylimidazolium chloride (BMIMCl) at 100 degrees C. Here, we address the factors responsible for the control of this reaction. Both cellulose and solid acid catalysts have distinct and important roles in the process. Describing the depolymerization of cellulose by the equivalent number of scissions occurring in the cellulosic chains allows a direct correlation between the product yields and the extent of the polymer breakdown. The effect of the acid strength on the depolymerization of cellulose is discussed in detail. Practical aspects of the reaction, concerning the homogeneous nature of the catalysis in spite of the use of a solid acid catalyst, are thoroughly addressed. The effect of impurities present in the imidazolium-based ionic liquids on the reaction performance, the suitability of different ionic liquids as solvents, and the recyclability of Amberlyst 15DRY and BMIMCl are also presented.

  17. Platinum nanoparticles–manganese oxide nanorods as novel binary catalysts for formic acid oxidation

    Directory of Open Access Journals (Sweden)

    Mohamed S. El-Deab

    2012-01-01

    Full Text Available The current study proposes a novel binary catalyst system (composed of metal/metal oxide nanoparticles as a promising electrocatalyst in formic acid oxidation. The electro-catalytic oxidation of formic acid is carried out with binary catalysts of Pt nanoparticles (nano-Pt and manganese oxide nanorods (nano-MnOx electrodeposited onto glassy carbon (GC electrodes. Cyclic voltammetric (CV measurements showed that unmodified GC and nano-MnOx/GC electrodes have no catalytic activity. While two oxidation peaks were observed at nano-Pt/GC electrode at ca. 0.2 and 0.55 V (corresponding to the direct oxidation of formic acid and the oxidation of the poisoning CO intermediate, respectively. The combined use of nano-MnOx and nano-Pt results in superb enhancement of the direct oxidation pathway. Nano-MnOx is shown to facilitate the oxidation of CO (to CO2 by providing oxygen at low over-potential. This leads to retrieval of Pt active sites necessary for the direct oxidation of formic acid. The higher catalytic activity of nano-MnOx/nano-Pt/GC electrode (with Pt firstly deposited compared to its mirror image electrode (i.e., with MnOx firstly deposited, nano-Pt/nano-MnOx/GC reveals that the order of the electrodeposition is an essential parameter.

  18. Enhanced catalytic performance of Pd catalyst for formic acid electrooxidation in ionic liquid aqueous solution

    Science.gov (United States)

    Feng, Yuan-Yuan; Yin, Qian-Ying; Lu, Guo-Ping; Yang, Hai-Fang; Zhu, Xiao; Kong, De-Sheng; You, Jin-Mao

    2014-12-01

    A protic ionic liquid (IL), n-butylammonium nitrate (N4NO3), is prepared and employed as the electrolyte for formic acid electrooxidation reaction (FAOR) on Pd catalysts. The oxidation peak potential of FAOR in the IL solution shows about a 200 mV negative shift as compared with those in traditional H2SO4/HClO4 electrolytes, suggesting that FAOR can be more easily carried out on Pd catalysts in IL media. The catalytic properties of Pd toward FAOR are not only dependent on the concentration of IL, as a consequence of the varied electronic conductivity of the IL solution, but also on the high potential limit of the cyclic voltammograms. When the Pd catalyst is cycled up to 1.0 V (vs. SCE), which induces a significant oxidation of Pd, it shows ca. 4.0 times higher activity than that not subjected to the Pd oxidation (up to 0.6 V). The Pd oxides, which are more easily formed in IL solution than in traditional H2SO4/HClO4 electrolytes, may play a crucial role in increasing the catalytic activities of Pd toward FAOR. Our work would shed new light on the mechanism of FAOR and highlight the potential applications of IL as green and environment-friendly electrolytes in fuel cells and other technologies.

  19. Electrochemical oxidation of ethanol in acid media on titanium nitride supported fuel cell catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Thotiyl, M.M. Ottakam [Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, Karnataka 560012 (India); Sampath, S., E-mail: sampath@ipc.iisc.ernet.i [Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, Karnataka 560012 (India)

    2011-04-01

    In the present study, titanium nitride, TiN that possesses good electronic conductivity, high corrosion resistance combined with the ability to support metallic particles, has been used to anchor Pt catalysts and subsequently used for ethanol oxidation. Platinum deposited on TiN (Pt-TiN) surface is contrasted with the conventional support material, Vulcan carbon for the electrochemical oxidation of ethanol in acidic medium. Though the comparison is not straight forward due to different morphology/particle size of the Pt catalyst on the two supports, the present investigations reveal that the TiN support lead to surface Ti-OH type functional groups that help in reducing the accumulation of carbon monoxide on the catalyst surface. The Tafel slopes are similar but the exchange current density on Pt-TiN is approximately twice that of the value observed on Pt-C. X-ray photoelectron spectroscopy data support the long term stability and electrocatalytic activity of Pt-TiN electrocatalyst.

  20. Esterification free fatty acid in sludge palm oil using ZrO2/SO42- - rice husk ash catalyst

    Science.gov (United States)

    Hidayat, Arif; Sutrisno, Bachrun

    2017-05-01

    Indonesia, as one of the biggest palm oil producers and exporters in the world, is producing large amounts of low-grade oil such as sludge palm oil (SPO) from palm oil industries. The use of SPO can lower the cost of biodiesel production significantly, which makes SPO a highly potential alternative feedstock for biodiesel production. In this paper, the esterification of free fatty acid on sludge palm oil was studied using rice husk ash as heterogeneous solid catalysts. Heterogeneous solid catalysts offer significant advantages of eliminating separation, corrosion, toxicity and environmental problems. In this paper the esterification of SPO, a by-product from palm oil industry, in the presence of modified rice husk ash catalysts was studied. The rice husk ash catalysts were synthesized by impregnating of Zirconia (Zr) on rice husk ash followed by sulfonation. The rice husk ash catalysts were characterized by using different techniques, such as FT-IR, XRD, and porous analysis. The effects of the mass ratio of catalyst to oil (1 - 10%), the molar ratio of methanol to oil (4:1 - 10:1), and the reaction temperature (40 - 60°C) were studied for the conversion of free fatty acids (FFAs) to optimize the reaction conditions. The results showed that the optimal conditions were an methanol to oil molar ratio of 10:1, the amount of catalyst of 10%w, and reaction temperature of 60°C.

  1. Transesterification of soybean oil over WO3 supported on AlPO4 as a solid acid catalyst.

    Science.gov (United States)

    Xie, Wenlei; Yang, Dong

    2012-09-01

    WO(3)/AlPO(4) catalysts were prepared by impregnation of AlPO(4) with ammonium metatungstate. Powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and thermo gravimetric and differential thermal analysis (TG-DTA) demonstrated that the tungsten compound was incorporated into AlPO(4) forming the catalyst with an enhanced acidity. When transesterification of soybean oil over the catalysts was performed, the catalyst with 30 wt.% WO(3) loading and calcined at 1073 K, exhibited the best catalytic activity with a conversion of 72.5%. The transesterification was optimal at 453 K for 5h with a methanol/oil ratio of 30:1 and catalyst dosage of 5 wt.%. Free fatty acid (FFA) and water did not affect the catalytic activity. The catalyst proved to be stable over four transesterification cycles as it lost only 4% of its activity after being reused four times. The catalyst could be used for the transesterification of low-cost oils for biodiesel production. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Enhanced Fischer-Tropsch synthesis performance of iron-based catalysts supported on nitric acid treated N-doped CNTs

    Science.gov (United States)

    Li, Zhenhua; Liu, Renjie; Xu, Yan; Ma, Xinbin

    2015-08-01

    Iron-based catalysts supported on N-doped CNTs (NCNTs) treated by various concentrations of nitric acid for Fischer-Tropsch synthesis (FTS) were investigated. An improved catalytic performance for the iron catalyst supported on acid treated NCNTs was obtained and the suitable nitric acid concentration was 10 M. The physiochemical properties of the NCNTs and the corresponding catalysts were characterized by BET, TEM, XRD, XPS, TGA and H2-TPR. The acid treatment removed the impurity and amorphous carbon, damaged the bamboo-like structure and increased the number of oxygen-containing functional groups and graphitization degree on the NCNTs. The more iron particles located inside the channels of NCNTs, the better catalytic FTS performance due to high dispersion and reducibility.

  3. Sulfonated reduced graphene oxide as a highly efficient catalyst for direct amidation of carboxylic acids with amines using ultrasonic irradiation.

    Science.gov (United States)

    Mirza-Aghayan, Maryam; Tavana, Mahdieh Molaee; Boukherroub, Rabah

    2016-03-01

    Sulfonated reduced graphene oxide nanosheets (rGO-SO3H) were prepared by grafting sulfonic acid-containing aryl radicals onto chemically reduced graphene oxide (rGO) under sonochemical conditions. rGO-SO3H catalyst was characterized by Fourier-transform infrared (FT-IR) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and X-ray photoelectron spectroscopy (XPS). rGO-SO3H catalyst was successfully applied as a reusable solid acid catalyst for the direct amidation of carboxylic acids with amines into the corresponding amides under ultrasonic irradiation. The direct sonochemical amidation of carboxylic acid takes place under mild conditions affording in good to high yields (56-95%) the corresponding amides in short reaction times. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Gas diffusion electrode setup for catalyst testing in concentrated phosphoric acid at elevated temperatures

    DEFF Research Database (Denmark)

    Wiberg, Gustav Karl Henrik; Fleige, Michael; Arenz, Matthias

    2015-01-01

    We present a detailed description of the construction and testing of an electrochemical cell setup allowing the investigation of a gas diffusion electrode containing carbon supported high surface area catalysts. The setup is designed for measurements in concentrated phosphoric acid at elevated...... temperature, i.e., very close to the actual conditions in high temperature proton exchange membrane fuel cells (HT-PEMFCs). The cell consists of a stainless steel flow field and a PEEK plastic cell body comprising the electrochemical cell, which exhibits a three electrode configuration. The cell body and flow...

  5. Hydrodeoxygenation of phenol over Pd catalysts by in-situ generated hydrogen from aqueous reforming of formic acid

    DEFF Research Database (Denmark)

    Zeng, Ying; Wang, Ze; Lin, Weigang

    2016-01-01

    Hydrodeoxygenation of phenol, as model compound of bio-oil, was investigated over Pd catalysts, using formic acid as a hydrogen donor. The order of activity for deoxygenation of phenol with Pd catalysts was found to be: Pd/SiO2 > Pd/MCM-41 > Pd/CA > Pd/Al2O3 > Pd/HY approximate to Pd/ZrO2 ≈ Pd...

  6. Solvent-Free Esterification of Carboxylic Acids Using Supported Iron Oxide Nanoparticles as an Efficient and Recoverable Catalyst

    Directory of Open Access Journals (Sweden)

    Fatemeh Rajabi

    2016-07-01

    Full Text Available Supported iron oxide nanoparticles on mesoporous materials (FeNP@SBA-15 have been successfully utilized in the esterification of a variety carboxylic acids including aromatic, aliphatic, and long-chain carboxylic acids under convenient reaction conditions. The supported catalyst could be easily recovered after reaction completion and reused several times without any loss in activity after up to 10 runs.

  7. Sulfated Carbon Quantum Dots as Efficient Visible-Light Switchable Acid Catalysts for Room-Temperature Ring-Opening Reactions.

    Science.gov (United States)

    Li, Haitao; Sun, Chenghua; Ali, Muataz; Zhou, Fengling; Zhang, Xinyi; MacFarlane, Douglas R

    2015-07-13

    Acid catalytic processes play a classic and important role in modern organic synthesis. How well the acid can be controlled often plays the key role in the controllable synthesis of the products with high conversion yield and selectivity. The preparation of a novel, photo-switchable solid-acid catalyst based on carbon quantum dots is described. The carbon quantum dots are decorated with small amounts of hydrogensulfate groups and thus exhibit a photogenerated acidity that produces a highly efficient acid catalysis of the ring opening of epoxides with methanol and other primary alcohols. This reversible, light-switchable acidity is shown to be due to photoexcitation and charge separation in the carbon quantum dots, which create an electron withdrawing effect from the acidic groups. The catalyst is easily separated by filtration, and we demonstrate multiple cycles of its recovery and reuse. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Citric acid induced promoted dispersion of Pt on the support and enhanced catalytic activities for a Pt-based catalyst

    Science.gov (United States)

    Cheng, Tianqiong; Wang, Jianli; Wang, Suning; Cui, Yajuan; Zhang, Hailong; Yan, Shuang; Yuan, Shandong; Chen, Yaoqiang

    2017-12-01

    Citric acid (CA), as the chelating agent, was introduced to obtain the enhanced Pt dispersion and catalytic activities for the Pt-based catalysts supported on oxygen-storage material. The role and content of CA were investigated systematically. It was found that the citric acid-assisted catalysts showed better Pt dispersion and smaller nanoparticle size of Pt. Thus, the catalyst had lower reduction temperature, preferable thermostability and possessed more oxidation state of Pt species under the oxidation atmosphere. The citric acid-induced fresh catalysts were excellent to convert CO and the corresponding aged ones exhibited higher activities for the elimination of all the target pollutants. Among the aged catalysts, P2-a (the mole ratio of Pt/CA is 2:1) presented the best performance. Particularly, compared with the reference sample (Pc-a), the light-off temperatures (T50) of NO, HC and CO for P2-a decreased by 39 °C, 42 °C and 72 °C, respectively, and the full-conversion temperatures (T90) of NO, HC and CO for P2-a decreased by 44 °C, 44 °C and 48 °C, respectively. Therefore, this work provides a facile and valid method to manufacture advanced catalysts for purification of the vehicle exhaust in the future.

  9. Conversion of corn stalk into furfural using a novel heterogeneous strong acid catalyst in γ-valerolactone.

    Science.gov (United States)

    Xu, Zhiping; Li, Wenzhi; Du, Zhijie; Wu, Hao; Jameel, Hasan; Chang, Hou-Min; Ma, Longlong

    2015-12-01

    A novel solid acid catalyst was prepared by the copolymerization of p-toluenesulfonic acid and paraformaldehyde and then characterized by FT-IR, TG/DTG, HRTEM and N2-BET. Furfural was successfully produced by the dehydration of xylose and xylan using the novel catalyst in γ-valerolactone. This investigation focused on effects of various reaction conditions including solvent, acid catalyst, reaction temperature, residence time, water concentration, xylose loading and catalyst dosage on the dehydration of xylose to furfural. It was found that the solid catalyst displayed extremely high activity for furfural production. 80.4% furfural yield with 98.8% xylose conversion was achieved at 170°C for 10 min. The catalyst could be recycled at least five times without significant loss of activity. Furthermore, 83.5% furfural yield and 19.5% HMF yield were obtained from raw corn stalk under more severe conditions (190°C for 100 min). Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Sulfonated mesoporous silica-carbon composites and their use as solid acid catalysts

    Science.gov (United States)

    Valle-Vigón, Patricia; Sevilla, Marta; Fuertes, Antonio B.

    2012-11-01

    The synthesis of highly functionalized porous silica-carbon composites made up of sulfonic groups attached to a carbon layer coating the pores of three types of mesostructured silica (i.e. SBA-15, KIT-6 and mesocellular silica) is presented. The synthesis procedure involves the following steps: (a) removal of the surfactant, (b) impregnation of the silica pores with a carbon precursor, (c) carbonization and (d) sulfonation. The resulting silica-carbon composites contain ˜30 wt % of carbonaceous matter with a high density of acidic groups attached to the deposited carbon (i.e.sbnd SO3H, sbnd COOH and sbnd OH). The structural characteristics of the parent silica are retained in the composite materials, which exhibit a high surface area, a large pore volume and a well-ordered porosity made up uniform mesopores. The high density of the sulfonic groups in combination with the mesoporous structure of the composites ensures that a large number of active sites are easily accessible to reactants. These sulfonated silica-carbon composites behave as eco-friendly, active, selective, water tolerant and recyclable solid acids. In this study we demonstrate the usefulness of these composites as solid acid catalysts for the esterification of maleic anhydride, succinic acid and oleic acid with ethanol. These composites exhibit a superior intrinsic catalytic activity to other commercial solid acids such as Amberlyst-15.

  11. The Effect of K and Acidity of NiW-Loaded HY Zeolite Catalyst for Selective Ring Opening of 1-Methylnaphthalene.

    Science.gov (United States)

    Lee, You-Jin; Kim, Eun-Sang; Kim, Jeong-Rang; Kim, Joo-Wan; Kim, Tae-Wan; Chae, Ho-Jeong; Kim, Chul-Ung; Lee, Chang-Ha; Jeong, Soon-Yong

    2016-05-01

    Bi-functional catalysts were prepared using HY zeolites with various SiO2/Al2O3 ratios for acidic function, NiW for metallic function, and K for acidity control. 1-Methylnaphthalene was selected as a model compound for multi-ring aromatics in heavy oil, and its selective ring opening reaction was investigated using the prepared bi-functional catalysts with different levels of acidity in a fixed bed reactor system. In NiW/HY catalysts without K addition, the acidity decreased with the SiO2/Al2O3 mole ratio of the HY zeolite. Ni1.1W1.1/HY(12) catalyst showed the highest acidity but slightly lower yields for the selective ring opening than Ni1.1W1.1/HY(30) catalyst. The acidity of the catalyst seemed to play an important role as the active site for the selective ring opening of 1-methylnaphthalene but there should be some optimum catalyst acidity for the reaction. Catalyst acidity could be controlled between Ni1.1W1.1/HY(12) and Ni1.1W1.1/HY(30) by adding a moderate amount of K to Ni1.1W1.1/HY(12) catalyst. K0.3Ni1.1W1.1/HY(12) catalyst should have the optimum acidity for the selective ring opening. The addition of a moderate amount of K to the NiW/HY catalyst must improve the catalytic performance due to the optimization of catalyst acidity.

  12. Enhanced esterification of oleic acid and methanol by deep eutectic solvent assisted Amberlyst heterogeneous catalyst.

    Science.gov (United States)

    Pan, Ying; Alam, Md Asraful; Wang, Zhongming; Wu, Jingcheng; Zhang, Yi; Yuan, Zhenhong

    2016-11-01

    In present study, esterification of oleic acid with methanol using deep eutectic solvent (DES) assisted Amberlyst heterogeneous catalyst was investigated to produce biodiesel. Results showed that esterification efficiency was enhanced by the DES. The combined effect of DES on Amberlyst BD20 (BD20) is better than Amberlyst 15 (A-15) due to different structure. The optimal reaction conditions were 12:1M ratio of methanol to oleic acid, 20%(wt/wt) catalyst (BD20-DES (2:8) and A-15-DES (8:2)) at 85°C for 100min with agitating at 200rpm. The mechanism involved in catalysis and their capacity to reuse were studied. We proposed, Choline chloride-glycerol (Chcl-gly) DES could enhance the Amberlyst function due to the hydrogen bond effect on both DES and water. BD20 has fewer pores than A-15, have desirable performance in decreasing the inhibition the water during esterification of high FFA content and provide better performance in reuse. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Esterification of palm fatty acid distillate with epychlorohydrin using cation exchange resin catalyst

    Science.gov (United States)

    Budhijanto, Budhijanto; Subagyo, Albertus F. P. H.

    2017-05-01

    Palm Fatty Acid Distillate (PFAD) is one of the wastes from the conversion of crude palm oil (CPO) into cooking oil. The PFAD is currently only utilized as the raw material for low grade soap and biofuel. To improve the economic value of PFAD, it was converted into monoglyceride by esterification process. Furthermore, the monoglyceride could be polymerized to form alkyd resin, which is a commodity of increasing importance. This study aimed to propose a kinetics model for esterification of PFAD with epichlorohydrin using cation exchange resin catalyst. The reaction was the first step from a series of reactions to produce the monoglyceride. In this study, the reaction between PFAD and epichlorohydirne was run in a stirred batch reactor. The stirrer was operated at a constant speed of 400 RPM. The reaction was carried out for 180 minutes on varied temperatures of 60°C, 70°C, 80°C, dan 90°C. Cation exchange resin was applied as solid catalysts. Analysis was conducted periodically by measuring the acid number of the samples, which was further used to calculate PFAD conversion. The data were used to determine the rate constants and the equilibrium constants of the kinetics model. The kinetics constants implied that the reaction was reversible and controlled by the intrinsic surface reaction. Despite the complication of the heterogeneous nature of the reaction, the kinetics data well fitted the elementary rate law. The effect of temperature on the equilibrium constants indicated that the reaction is exothermic.

  14. An effective Pd-Ni(2)P/C anode catalyst for direct formic acid fuel cells.

    Science.gov (United States)

    Chang, Jinfa; Feng, Ligang; Liu, Changpeng; Xing, Wei; Hu, Xile

    2014-01-03

    The direct formic acid fuel cell is an emerging energy conversion device for which palladium is considered as the state-of-the-art anode catalyst. In this communication, we show that the activity and stability of palladium for formic acid oxidation can be significantly enhanced using nickel phosphide (Ni(2)P) nanoparticles as a cocatalyst. X-ray photoelectron spectroscopy (XPS) reveals a strong electronic interaction between Ni(2)P and Pd. A direct formic acid fuel cell incorporating the best Pd–Ni(2)P anode catalyst exhibits a power density of 550 mWcm(-2), which is 3.5 times of that of an analogous device using a commercial Pd anode catalyst.

  15. Esterification Reaction of Glycerol and Palm Oil Oleic Acid Using Methyl Ester Sulfonate Acid Catalyst as Drilling Fluid Formulation

    Science.gov (United States)

    Sari, V. I.; Hambali, E.; Suryani, A.; Permadi, P.

    2017-02-01

    Esterification reaction between glycerol with palm oil oleic acid to produce glycerol ester and one of the utilization of glycerol esters is as ingredients of drilling fluids formula for oil drilling needs. The purpose of this research is to get the best conditions of the esterification process. The esterification reaction does with the reactants is glycerol with purity of 97.6%, palm oil oleic acid with the molar ratio is 1:1, Methyl Ester Sulfonate Acid (MESA) catalyst 0.5%, and stirring speed 400 rpm. The temperature range of 180°C to 240°C and the processing time between 120 to 180 minutes. The results showed that the best conditions of the esterification reaction at the temperature 240°C and time process are 180 minute. The increasing temperature resulted that the acid number decreases and causing the conversion increased. The maximum conversion is 99.24%, density 0.93 g/cm3, flash point 241°C, pour point -3°C, the boiling point of 244 °C, the acid value of 1.90 mg KOH/g sample, kinematic viscosity 31.51 cSt (40°C), surface tension 37.0526 dyne/cm and GCMS identification, glycerol ester at 22,256 retention time (minutes) and wide area 73.75 (%). From the research results obtained glycerol ester with characteristics suitable for drilling fluid formulations.

  16. Influence of Sulfuric Acid on the Performance of Ruthenium-based Catalysts in the Liquid-Phase Hydrogenation of Levulinic Acid to γ-Valerolactone

    NARCIS (Netherlands)

    Ftouni, Jamal; Genuino, Homer C.|info:eu-repo/dai/nl/371571685; Muñoz-murillo, Ara; Bruijnincx, Pieter C. A.|info:eu-repo/dai/nl/33799529X; Weckhuysen, Bert M.|info:eu-repo/dai/nl/285484397

    2017-01-01

    The presence of biogenic or process-derived impurities poses a major problem on the efficient catalytic hydrogenation of biomass-derived levulinic acid to γ-valerolactone; hence, studies on their influence on catalyst stability are now required. Herein, the influence of sulfuric acid as feed

  17. An atom-economic approach to carboxylic acids via Pd-catalyzed direct addition of formic acid to olefins with acetic anhydride as a co-catalyst.

    Science.gov (United States)

    Wang, Yang; Ren, Wenlong; Shi, Yian

    2015-08-21

    An effective Pd-catalyzed hydrocarboxylation of olefins using formic acid with acetic anhydride as a co-catalyst is described. A variety of carboxylic acids are obtained in good yields with high regioselectivities under mild reaction conditions without the use of toxic CO gas.

  18. Catalytic pyrolysis of oil fractions separated from food waste leachate over nanoporous acid catalysts.

    Science.gov (United States)

    Kim, Seung-Soo; Heo, Hyeon Su; Kim, Sang Guk; Ryoo, Ryong; Kim, Jeongnam; Jeon, Jong-Ki; Park, Sung Hoon; Park, Young-Kwon

    2011-07-01

    Oil fractions, separated from food waste leachate, can be used as an energy source. Especially, high quality oil can be obtained by catalytic cracking. In this study, nanoporous catalysts such as Al-MCM-41 and mesoporous MFI type zeolite were applied to the catalytic cracking of oil fractions using the pyrolysis gas chromatography/mass spectrometry. Mesoporous MFI type zeolite showed better textural porosity than Al-MCM-41. In addition, mesoporous MFI type zeolite had strong Brönsted acidity while Al-MCM-41 had weak acidity. Significant amount of acid components in the food waste oil fractions were converted to mainly oxygenates and aromatics. As a result of its well-defined nanopores and strong acidity, the use of a mesoporous MFI type zeolite produced large amounts of gaseous and aromatic compounds. High yields of hydrocarbons within the gasoline range were also obtained in the case of mesoporous MFI type zeolite, whereas the use of Al-MCM-41, which exhibits relatively weak acidity, resulted in high yields of oxygenates and diesel range hydrocarbons.

  19. Wet oxidation of glycerol into fine organic acids: catalyst selection and kinetic evaluation

    Directory of Open Access Journals (Sweden)

    J. E. N. Brainer

    2014-12-01

    Full Text Available The liquid phase oxidation of glycerol was performed producing fine organic acids. Catalysts based on Pt, Pd and Bi supported on activated carbon were employed to perform the conversion of glycerol into organic acids at 313 K, 323 K and 333 K, under atmospheric pressure (1.0 bar, in a mechanically agitated slurry reactor (MASR. The experimental results indicated glycerol conversions of 98% with production of glyceric, tartronic and glycolic acids, and dihydroxyacetone. A yield of glyceric acid of 69.8%, and a selectivity of this compound of 70.6% were reached after 4 h of operation. Surface mechanisms were proposed and rate equations were formulated to represent the kinetic behavior of the process. Selective formation of glyceric acid was observed, and the kinetic parameter values indicated the lowest activation energy (38.5 kJ/mol for its production reaction step, and the highest value of the adsorption equilibrium constant of the reactant glycerol (10-4 dm³/mol.

  20. The Process of Acetonitrile Synthesis over γ-Al2O3 Promoted by Phosphoric Acid Catalysts

    OpenAIRE

    Galanov, Sergey I.; Sidorova, Olga I.; Gavrilenko, Mikhail A.

    2014-01-01

    The influence of principal parameters (reaction temperature, ratio of acetic acid and ammonia, composition of reactionary mixture and promotion of catalysts) on the selectivity and yield of the desired product was studied in the reaction of catalytic acetonitrile synthesis by ammonolysis of acetic acid. The processing of [gamma]-Al[2]O[3] by phosphoric acid increases amount of the centers, on which carries out reaction of acetamide dehydration. The kinetic model of a limiting stage of reactio...

  1. Mesoporous Silica Supported Pd-MnOx Catalysts with Excellent Catalytic Activity in Room-Temperature Formic Acid Decomposition

    OpenAIRE

    Min-Ho Jin; Duckkyu Oh; Ju-Hyoung Park; Chun-Boo Lee; Sung-Wook Lee; Jong-Soo Park; Kwan-Young Lee; Dong-Wook Lee

    2016-01-01

    For the application of formic acid as a liquid organic hydrogen carrier, development of efficient catalysts for dehydrogenation of formic acid is a challenging topic, and most studies have so far focused on the composition of metals and supports, the size effect of metal nanoparticles, and surface chemistry of supports. Another influential factor is highly desired to overcome the current limitation of heterogeneous catalysis for formic acid decomposition. Here, we first investigated the effec...

  2. An Effective Pd–Ni2P/C Anode Catalyst for Direct Formic Acid Fuel Cells

    OpenAIRE

    Chang, Jinfa; Feng, Ligang; Liu, Changpeng; Xing, Wei; Hu, Xile

    2014-01-01

    The direct formic acid fuel cell is an emerging energy conversion device for which palladium is considered as the state-of-the-art anode catalyst. In this communication, we show that the activity and stability of palladium for formic acid oxidation can be significantly enhanced using nickel phosphide (Ni2P) nanoparticles as a cocatalyst. X-ray photoelectron spectroscopy (XPS) reveals a strong electronic interaction between Ni2P and Pd. A direct formic acid fuel cell incorporating the best Pd-...

  3. Catalytic conversion of xylose and corn stalk into furfural over carbon solid acid catalyst in γ-valerolactone.

    Science.gov (United States)

    Zhang, Tingwei; Li, Wenzhi; Xu, Zhiping; Liu, Qiyu; Ma, Qiaozhi; Jameel, Hasan; Chang, Hou-min; Ma, Longlong

    2016-06-01

    A novel carbon solid acid catalyst was synthesized by the sulfonation of carbonaceous material which was prepared by carbonization of sucrose using 4-BDS as a sulfonating agent. TEM, N2 adsorption-desorption, elemental analysis, XPS and FT-IR were used to characterize the catalyst. Then, the catalyst was applied for the conversion of xylose and corn stalk into furfural in GVL. The influence of the reaction time, temperature and dosage of catalyst on xylose dehydration were also investigated. The Brønsted acid catalyst exhibited high activity in the dehydration of xylose, with a high furfural yield of 78.5% at 170°C in 30min. What's more, a 60.6% furfural yield from corn stalk was achieved in 100min at 200°C. The recyclability of the sulfonated carbon catalyst was perfect, and it could be reused for 5times without the loss of furfural yields. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Hydrogenation of biofuels with formic acid over a palladium-based ternary catalyst with two types of active sites.

    Science.gov (United States)

    Wang, Liang; Zhang, Bingsen; Meng, Xiangju; Su, Dang Sheng; Xiao, Feng-Shou

    2014-06-01

    A composite catalyst including palladium nanoparticles on titania (TiO2) and on nitrogen-modified porous carbon (Pd/TiO2@N-C) is synthesized from palladium salts, tetrabutyl titanate, and chitosan. N2 sorption isotherms show that the catalyst has a high BET surface area (229 m(2)  g(-1)) and large porosity. XPS and TEM characterization of the catalyst shows that palladium species with different chemical states are well dispersed across the TiO2 and nitrogen-modified porous carbon, respectively. The Pd/TiO2@N-C catalyst is very active and shows excellent stability towards hydrogenation of vanillin to 2-methoxy-4-methylphenol using formic acid as hydrogen source. This activity can be attributed to a synergistic effect between the Pd/TiO2 (a catalyst for dehydrogenation of formic acid) and Pd/N-C (a catalyst for hydrogenation of vanillin) sites. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. The Use of Heterogeneous Catalysts of Chitosan Sulfonate Bead on the Esterification Reaction of Oleic Acid and Methanol

    Science.gov (United States)

    Chamidy, H. N.; Riniati

    2017-05-01

    Biodiesel is one of the ester compounds with physical properties closer to a biodiesel which can be produced by the esterification reaction between methanol and oleic acid (one of major components present in Palm Fatty Acid Distillate, PFAD). The purpose of this study was to obtain an optimum condition of esterification reaction by using chitosan sulfonate bead as heterogeneous catalysts. Chitosan sulfonate bead was made from chitosan undergo sulfonation process using acidic reagents cross-linked with sulfosalicylic and glutaraldehyde with a high enough value of ion exchange capacity. The stage of esterification reactions was carried by varying the amount of catalyst being added (4, 6, 8, 10, 12% by oleic acid), the operating temperature was varied of 40, 50 and 60 °C, and the reaction time of 1, 2, 3, 4 and 5 hours. Conversion determination of the products was done by analysing the free fatty acids content in each sample. Having obtained from the optimum amount of catalyst being added, temperature, and time, it was found that the catalyst was at 8%, 50 °C, during 5 hours in operation. The maximum conversion of oleic acid into biodiesel was 73.12%.

  6. Studies on electron transfer reactions: Reduction of heteropoly 10 ...

    Indian Academy of Sciences (India)

    Rates of electron transfer reaction of thioglycolic acid with vanadium(V) substituted Keggintype heteropolyanion, [PVVVVW10O40]5-, in acetate-acetic acid buffers have been measured spectrophotometrically at 25°C. The order of the reaction with respect to substrate and oxidant is unity. The reaction shows simple second ...

  7. Production of biodiesel from mixed waste vegetable oil using an aluminium hydrogen sulphate as a heterogeneous acid catalyst.

    Science.gov (United States)

    Ramachandran, Kasirajan; Sivakumar, Pandian; Suganya, Tamilarasan; Renganathan, Sahadevan

    2011-08-01

    Al(HSO(4))(3) heterogeneous acid catalyst was prepared by the sulfonation of anhydrous AlCl(3). This catalyst was employed to catalyze transesterification reaction to synthesis methyl ester when a mixed waste vegetable oil was used as feedstock. The physical and chemical properties of aluminum hydrogen sulphate catalyst were characterized by scanning electron microscopy (SEM) measurements, energy dispersive X-ray (EDAX) analysis and titration method. The maximum conversion of triglyceride was achieved as 81 wt.% with 50 min reaction time at 220°C, 16:1 molar ratio of methanol to oil and 0.5 wt.% of catalyst. The high catalytic activity and stability of this catalyst was related to its high acid site density (-OH, Brönsted acid sites), hydrophobicity that prevented the hydration of -OH group, hydrophilic functional groups (-SO(3)H) that gave improved accessibility of methanol to the triglyceride. The fuel properties of methyl ester were analyzed. The fuel properties were found to be observed within the limits of ASTM D6751. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. Pulse electrodeposition to prepare core-shell structured AuPt@Pd/C catalyst for formic acid fuel cell application

    Science.gov (United States)

    Lu, Xueyi; Luo, Fan; Song, Huiyu; Liao, Shijun; Li, Hualing

    2014-01-01

    A novel core-shell structured AuPt@Pd/C catalyst for the electrooxidation of formic acid is synthesized by a pulse electrodeposition process, and the AuPt core nanoparticles are obtained by a NaBH4 reduction method. The catalyst is characterized with X-ray powder diffraction and transmission electron microscopy, thermogravimetric analysis, cyclic voltammetry, CO stripping and X-ray photoelectron spectroscopy. The core-shell structure of the catalyst is revealed by the increase in particle size resulting from a Pd layer covering the AuPt core, and by a negative shift in the CO stripping peaks. The addition of a small amount of Pt improves the dispersion of Au and results in smaller core particles. The catalyst's activity is evaluated by cyclic voltammetry in formic acid solution. The catalyst shows excellent activity towards the anodic oxidation of formic acid, the mass activity reaches 4.4 A mg-1Pd and 0.83 A mg-1metal, which are 8.5 and 1.6 times that of commercial Pd/C. This enhanced electrocatalytic activity could be ascribed to the good dispersion of Au core particles resulting from the addition of Pt, as well as to the interaction between the Pd shell layer and the Au and Pt in the core nanoparticles.

  9. Microwave assisted conversion of microcrystalline cellulose into value added chemicals using dilute acid catalyst.

    Science.gov (United States)

    Ching, Teck Wei; Haritos, Victoria; Tanksale, Akshat

    2017-02-10

    One of the grand challenges of this century is to transition fuels and chemicals production derived from fossil feedstocks to renewable feedstocks such as cellulosic biomass. Here we describe fast microwave conversion of microcrystalline cellulose (MCC) in water, with dilute acid catalyst to produce valuable platform chemicals. Single 10min microwave assisted treatment was able to convert >60% of MCC, with >50mol% yield of desirable products such as glucose, HMF, furfural and levulinic acid. Recycling of residual MCC with make-up fresh MCC resulted in an overall conversion of >93% after 5 cycles while maintaining >60% conversion in each cycle. Addition of isopropanol (70%v/v) as a co-solvent increased the yields of HMF and levulinic acid. This work shows for the first time proof of concept for complete conversion of recalcitrant microcrystalline cellulose in mild conditions of low temperature, dilute acid and short residence time using energy efficient microwave technology. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Catalytic decolorization of Acid blue 29 dye by H2O2 and a heterogeneous catalyst

    Directory of Open Access Journals (Sweden)

    Ibrahim A. Salem

    2014-09-01

    Full Text Available The montmorillonite K10-Cu(IIethylenediamine (MMTK10-Cu(en2 catalyst has been prepared by intercalation of copper-ethylenediamine [Cu(en2]2+ complex onto the montmorillonite K10. The intercalation process is confirmed by scanning electron microscopy (SEM, fourier transforms infrared spectroscopy (FTIR, X-ray diffraction (XRD, and thermogravimetric analysis (TGA measurements. The decolorization of the Acid blue29 was conducted using MMTK10-Cu(en2 in the presence of hydrogen peroxide. The effect of reactants concentrations and the temperature on the decolorization efficiency was studied. It was found that the efficiency of decolorization process increases with increasing the concentration of H2O2 and the dye and the temperature. The results indicated that complete removal of AB29 was achieved in 15 min when the concentrations of H2O2 and AB29 were 0.4 and 5 × 10−5 M respectively and 0.1 g of the catalyst at 30 °C. The activation parameters of the decolorization process were determined. Two possible mechanisms were proposed.

  11. One-step preparation of carbon-based solid acid catalyst from water hyacinth leaves for esterification of oleic acid and dehydration of xylose.

    Science.gov (United States)

    Laohapornchaiphan, Jutitorn; Smith, Christopher; Smith, Siwaporn Meejoo

    2017-10-25

    Carbon-based solid acid catalysts were successfully obtained via one step hydrothermal carbonization (HTC) of water hyacinth (WH) in the presence of p-toluenesulfonic acid (PTSA). Increasing HTC temperatures from 180 to 240°C resulted in carbonaceous materials with increased sulfur content, and less adsorbed water. Material obtained at 220°C (WH-PTSA-220) contains the highest amount of acid sites, and promotes the highest initial rate of two transformations, methanolysis of oleic acid, and dehydration of xylose to furfural. While all PSTA treated WH catalysts gave comparable fatty acid conversions (97%) and furfural yields (60%) after prolonged reaction times, the WH-PTSA-240 system bearing a relatively low acid density maintains the most favorable reusability profile. Higher HTC temperatures (220-240°C) improved catalyst reusability profiles due to graphitization and hydrophobicity of the carbon surface. The catalyst systems derived herein from biomass may have potential applications in biorefining platforms, utilizing the conversion of waste biomass to chemicals. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Ultrasound-assisted production of biodiesel from soybean oil using Brønsted acidic ionic liquid as catalyst.

    Science.gov (United States)

    Guo, Weilin; Li, Helian; Ji, Guanglei; Zhang, Guangyou

    2012-12-01

    Biodiesel production from soybean oil with methanol was performed in the presence of a Brønsted acidic ionic liquid-based catalyst under ultrasound irradiation. The influences of various parameters on the transesterification reaction, including the amount of catalyst, the molar ratio of methanol to oil, the temperature and the ultrasound power, were investigated. The optimal conditions were: methanol/oil molar ratio of 9:1, 1.0 wt.% catalyst in oil, ultrasound power of 200 W, and reaction temperature of 60°C. Under these conditions, the conversion of triglycerides to fatty acid methyl esters was about 93.2% within the reaction time of 60 min. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. A comparative study of solid carbon acid catalysts for the esterification of free fatty acids for biodiesel production. Evidence for the leaching of colloidal carbon.

    Science.gov (United States)

    Deshmane, Chinmay A; Wright, Marcus W; Lachgar, Abdessadek; Rohlfing, Matthew; Liu, Zhening; Le, James; Hanson, Brian E

    2013-11-01

    The preparation of a variety of sulfonated carbons and their use in the esterification of oleic acid is reported. All sulfonated materials show some loss in activity associated with the leaching of active sites. Exhaustive leaching shows that a finite amount of activity is lost from the carbons in the form of colloids. Fully leached catalysts show no loss in activity upon recycling. The best catalysts; 1, 3, and 6; show initial TOFs of 0.07 s(-1), 0.05 s(-1), and 0.14 s(-1), respectively. These compare favorably with literature values. Significantly, the leachate solutions obtained from catalysts 1, 3, and 6, also show excellent esterification activity. The results of TEM and catalyst poisoning experiments on the leachate solutions associate the catalytic activity of these solutions with carbon colloids. This mechanism for leaching active sites from sulfonated carbons is previously unrecognized. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Performance increase of microfluidic formic acid fuel cell using Pd/MWCNTs as catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Morales-Acosta, D.; Rodriguez G., H.; Godinez, Luis A.; Arriaga, L.G. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, S.C. Parque Tecnologico Queretaro Sanfandila, P.O. Box 064, Pedro Escobedo, 76703 Queretaro (Mexico)

    2010-04-02

    This paper shows that the combination of an O{sub 2} saturated acidic fluid setup (O{sub 2}-setup) and a composite of Pd nanoparticles supported on multiwalled-carbon nanotubes (Pd/MWCNTs) as anode catalyst material, results in the improvement of microfluidic fuel cell performance. Microfluidic fuel cells were constructed and evaluated at low HCOOH concentrations (0.1 and 0.5 M) using Pd/V XC-72 and Pd/MWCNTs as anode and Pt/V XC-72 as cathode electrode materials, respectively. The results show a higher power density (2.9 mW cm{sup -2}) for this cell when compared to the value reported in the literature that considers a commercial Pd/V XC-72 and 3.3 mW cm{sup -2} using a Pd/MWCNTs with a 50% less Pd loading than that commercial Pd/V XC-72. (author)

  15. Enhanced electrochemical oxidation of Acid Red 3R wastewater with iron phosphomolybdate supported catalyst.

    Science.gov (United States)

    Wang, Li; Yue, Lin; Shi, Feng; Guo, Jianbo; Yang, Jingliang; Lian, Jing; Luo, Xiao; Guo, Yankai

    2015-01-01

    Electrochemical oxidation of Acid Red 3R (AR3R) was investigated with the new catalyst of iron phosphomolybdate (FePMo12) supported on modified molecular sieves type 4 Å (4A) as packing materials in the reactor. The results of the Fourier transform infrared spectroscopy and X-ray diffraction indicated that the heteropolyanion had a Keggin structure. The optimal conditions for decolorization of simulated AR3R wastewater were as follows: current density 35 mA/cm², initial pH 4.0, airflow 0.08 m³/hour and inter-electrode distance 3.0 cm. With the addition of NaCl to the system, the decolorization efficiency increased. But Na₂SO₄had a negative effect on the decolorization efficiency, which was attributed to the negative salt effect. The degradation mechanisms of AR3R were also discussed in detail.

  16. Highly efficient hydrogen release from formic acid using a graphitic carbon nitride-supported AgPd nanoparticle catalyst

    Science.gov (United States)

    Yao, Fang; Li, Xiao; Wan, Chao; Xu, Lixin; An, Yue; Ye, Mingfu; Lei, Zhao

    2017-12-01

    Bimetallic AgPd nanoparticles with various molar ratios immobilized on graphitic carbon nitride (g-C3N4) were successfully synthesized via a facile co-reduction approach. The powder XRD, XPS, TEM, EDX, ICP-AES and BET were employed to characterize the structure, size, composition and loading metal electronic states of the AgPd/g-C3N4 catalysts. The catalytic property of as-prepared catalysts for the dehydrogenation of formic acid (FA) with sodium formate (SF) as the additive was investigated. The performance of these catalysts, as indicated by the turnover frequency (TOF), depended on the composition of the prepared catalysts. Among all the AgPd/g-C3N4 catalysts tested, Ag9Pd91/g-C3N4 was found to be an exceedingly high activity for decomposing FA into H2 with TOF up to 480 h-1 at 323 K. The prepared catalyst is thus a potential candidate for triggering the widespread use of FA for H2 storage.

  17. In situ reactive extraction of cottonseeds with methyl acetate for biodiesel production using magnetic solid acid catalysts.

    Science.gov (United States)

    Wu, Haitang; Liu, Yanping; Zhang, Junhua; Li, Guanglu

    2014-12-01

    A magnetic solid acid catalyst S2O8(2)(-)/ZrO2-TiO2-Fe3O4 was prepared by coprecipitation and impregnation methods and its catalytic activity was investigated for the reactive extraction of cottonseeds with methyl acetate to produce biodiesel. The physicochemical properties of the catalyst were characterized in detail. The influences of Zr/Ti molar ratio and calcination temperature on the catalytic performance were investigated. Moreover, optimization of the reactive extraction process was performed using response surface methodology coupled with central composite design. The catalyst with a Zr/Ti molar ratio of 3/1 calcined at 550°C showed the best activity. An optimum biodiesel yield of 98.5% was obtained under the reaction temperature of 50°C, catalyst amount of 21.3wt.%, methyl acetate/seed ratio of 13.8ml/g and 10.8h of reaction time. Reuse of this catalyst indicated that it had steady catalytic activity and high recovery rate which could be a promising catalyst for biodiesel production from oilseeds. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Catalytic hydrodeoxygenation and hydrocracking of Alcell (R) lignin in alcohol/formic acid mixtures using a Ru/C catalyst

    NARCIS (Netherlands)

    Kloekhorst, Arjan; Shen, Yu; Yie, Yao; Fang, Ma; Heeres, Hero Jan

    The catalytic conversion of Alcell (R) lignin in iso-propanol/formic acid mixtures (1: 1 mass ratio) was explored in a batch set-up using Ru/C as the catalyst (673 K, 4 h, 28% mass lignin intake on solvent). Lignin oils were obtained in good yields (71% mass yields on lignin input) and shown to

  19. Esterification of oil adsorbed on palm decanter cake into methyl ester using sulfonated rice husk ash as heterogeneous acid catalyst

    Science.gov (United States)

    Hindryawati, Noor; Erwin, Maniam, Gaanty Pragas

    2017-02-01

    Palm Decanter cake (PDC) which is categorized as the waste from palm oil mill has been found to contain residual crude palm oil. The oil adsorbed on the PDC (PDC-oil) can be extracted and potentially used as feedstock for biodiesel production. Feedstock from waste like PDC-oil is burdened with high free fatty acids (FFAs) which make the feedstock difficult to be converted into biodiesel using basic catalyst. Therefore, in this study, a solid acid, RHA-SO3H catalyst was synthesized by sulfonating rice husk ash (RHA) with concentrated sulfuric acid. The RHA-SO3H prepared was characterized with TGA, FTIR, BET, XRD, FE-SEM, and Hammett indicators (methyl red, bromophenol blue, and crystal violet). PDC was found to have about 11.3 wt. % oil recovered after 1 hour extraction using ultrasound method. The presence of sulfonate group was observed in IR spectrum, and the surface area of RHA-SO3H was reduced to 37 m2.g-1 after impregnation of sulfonate group. The RHA-SO3H catalyst showed that it can work for both esterification of free fatty acid which is present in PDC-oil, and transesterification of triglycerides into methyl ester. The results showed highest methyl ester content of 70.2 wt.% at optimal conditions, which was 6 wt.% catalyst amount, methanol to oil molar ratio of 17:1 for 5 hours at 120 °C.

  20. Toward an Active and Stable Catalyst for Oxygen Evolution in Acidic Media: Ti-Stabilized MnO2

    DEFF Research Database (Denmark)

    Frydendal, Rasmus; Paoli, Elisa Antares; Chorkendorff, Ib

    2015-01-01

    Catalysts are required for the oxygen evolution reaction, which are abundant, active, and stable in acid. MnO2 is a promising candidate material for this purpose. However, it dissolves at high overpotentials. Using first-principles calculations, a strategy to mitigate this problem by decorating...

  1. Biomass to fuels : Upgrading of flash pyrolysis oil by reactive distillation using a high boiling alcohol and acid catalysts

    NARCIS (Netherlands)

    Mahfud, F.H.; Melian Cabrera, I.V.; Manurung, R.M.; Heeres, H.J.

    We here report our studies on the upgrading of flash pyrolysis oil using an improved alcohol treatment method. The method consists of treating pyrolysis oil with a high boiling alcohol like n-butanol in the presence of a (solid) acid catalyst at 323-353 K under reduced pressure (<10 kPa). Using this

  2. Influence of Catalyst Acid/Base Properties in Acrolein Production by Oxidative Coupling of Ethanol and Methanol.

    Science.gov (United States)

    Lilić, Aleksandra; Bennici, Simona; Devaux, Jean-François; Dubois, Jean-Luc; Auroux, Aline

    2017-05-09

    Oxidative coupling of methanol and ethanol represents a new route to produce acrolein. In this work, the overall reaction was decoupled in two steps, the oxidation and the aldolization, by using two consecutive reactors to investigate the role of the acid/base properties of silica-supported oxide catalysts. The oxidation of a mixture of methanol and ethanol to formaldehyde and acetaldehyde was performed over a FeMoO x catalyst, and then the product mixture was transferred without intermediate separation to a second reactor, in which the aldol condensation and dehydration to acrolein were performed over the supported oxides. The impact of the acid/base properties on the selectivity towards acrolein was investigated under oxidizing conditions for the first time. The acid/base properties of the catalysts were investigated by NH 3 -, SO 2 -, and methanol-adsorption microcalorimetry. A MgO/SiO 2 catalyst was the most active in acrolein production owing to an appropriate ratio of basic to acidic sites. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Antisolvent Precipitation for the Synthesis of Monodisperse Mesoporous Niobium Oxide Spheres as Highly Effective Solid Acid Catalysts

    KAUST Repository

    Li, Cheng Chao

    2012-03-20

    We have developed a low-cost reaction protocol to synthesize mesoporous Nb 2O 5-based solid acid catalysts with external shape control. In the synthesis, monodisperse glycolated niobium oxide spheres (GNOS) were prepared by means of a simple antisolvent precipitation approach and subsequently converted to mesoporous niobium oxide spheres (MNOS) with a large surface area of 312m 2g -1 by means of the hydrothermal treatment. The antisolvent acetone used to obtain GNOS was recovered through distillation at high purity. The obtained mesoporous MNOS were functionalized further with sulfate anions at different temperatures or incorporated with tungstophosphoric acid to obtain recyclable solid acid catalysts. These MNOS-based catalysts showed excellent performance in a wide range of acid-catalyzed reactions, such as Friedel-Crafts alkylation, esterification, and hydrolysis of acetates. As they are monodisperse spheres with diameters in the submicrometer range, the catalysts can be easily separated and reused. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Support screening studies on the hydrogenation of levulinic acid to γ‐valerolactone in water using RU catalysts

    NARCIS (Netherlands)

    Piskun, Anna; Winkelman, Jozef G M; Tang, Zhenchen; Heeres, Hero Jan

    2016-01-01

    γ-Valerolactone (GVL) has been identified as a sustainable platform chemical for the production of carbon-based chemicals. Here we report a screening study on the hydrogenation of levulinic acid (LA) to GVL in water using a wide range of ruthenium supported catalysts in a batch set-up (1 wt. % Ru,

  5. One-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones using chloroacetic acid as catalyst.

    Science.gov (United States)

    Yu, Yang; Liu, Di; Liu, Chunsheng; Luo, Genxiang

    2007-06-15

    A simple and effective synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives from aldehydes, 1,3-dicarbonyl compounds and urea or thiourea using chloroacetic acid as catalyst under solvent-free conditions is described. Compared with the classical Biginelli reaction conditions, this new method has the advantage of good to excellent yields and short reaction time.

  6. Effect of Citric Acid on MoO3/Al2O3 Catalysts for Sulfur-Resistant Methanation

    National Research Council Canada - National Science Library

    Dajun Meng; Baowei Wang; Wenxia Yu; Weihan Wang; Zhenhua Li; Xinbin Ma

    2017-01-01

    A series of MoO3/Al2O3 catalysts with different amounts (molar ratio of CA/Mo = 0, 1, 1.5, and 2) of citric acid (CA) prepared by simultaneous impregnation were evaluated for sulfur-resistant methanation...

  7. Acid Activation of Natural Zeolite with High Content of Iron Oxides in Creation of Selective Sorbents and Catalysts

    Directory of Open Access Journals (Sweden)

    Kadirbekov Kairat

    2017-01-01

    Full Text Available The paper studies the influence of the nature of modifying acids (mineral, organic and heteropolyacids, and their combination on the composition and structure of the iron oxide rich clinoptilolit from Shankanay field in Kazakhstan for creation of selective catalysts in hydracarbon processing and sorbents for extracting ions of lanthanide and actinide elements. It is shown that sequential processing of natural zeolite in optimal conditions, by hydrochloric and sulfosalicylic acids lead to intensive decationization and dealumination, as well as maximum removal of iron ions from the zeolite framework without destroying it. It is found that the combination of activated clinoptilolite with hydrochloric acid and phosphotungstic heteropolyacid contributes to obtain catalyst system with high surface area and acidity.

  8. Development of Pd and Pd-Co catalysts supported on multi-walled carbon nanotubes for formic acid oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Morales-Acosta, D.; Godinez, Luis A.; Rodriguez, H.G.; Arriaga, L.G. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Parque Tecnologico Queretaro, Sanfandila, Pedro Escobedo, C.P. 76703 Queretaro (Mexico); Ledesma-Garcia, J. [Division de Investigacion y Posgrado, Facultad de Ingenieria, Universidad Autonoma de Queretaro, Cerro de las Campanas S/N, C.P. 76010, Queretaro, Qro. (Mexico); Alvarez-Contreras, L. [Centro de Investigacion en Materiales Avanzados S. C., Complejo Industrial Chihuahua, C.P. 31109, Chihuahua, Chih. (Mexico)

    2010-01-15

    Pd-Co and Pd catalysts were prepared by the impregnation synthesis method at low temperature on multi-walled carbon nanotubes (MWCNTs). The nanotubes were synthesized by spray pyrolysis technique. Both catalysts were obtained with high homogeneous distribution and particle size around 4 nm. The morphology, composition and electrocatalytic properties were investigated by transmission electron microscopy, scanning electron microscopy-energy dispersive X-ray analysis, X-ray diffraction and electrochemical measurements, respectively. The electrocatalytic activity of Pd and PdCo/MWCNTs catalysts was investigated in terms of formic acid electrooxidation at low concentration in H{sub 2}SO{sub 4} aqueous solution. The results obtained from voltamperometric studies showed that the current density achieved with the PdCo/MWCNTs catalyst is 3 times higher than that reached with the Pd/MWCNTs catalyst. The onset potential for formic acid electrooxidation on PdCo/MWCNTs electrocatalyst showed a negative shift ca. 50 mV compared with Pd/MWCNTs. (author)

  9. Cassava Pulp Hydrolysis under Microwave Irradiation with Oxalic Acid Catalyst for Ethanol Production

    Directory of Open Access Journals (Sweden)

    Euis Hermiati

    2014-07-01

    Full Text Available Microwave irradiation is an alternative method of starch hydrolysis that offers a rapid process. The aim of this research was to improve microwave-assisted hydrolysis of cassava pulp by using oxalic acid as a catalyst. Suspension of cassava pulp in 0.5% oxalic acid (1 g/20 mL was subjected to microwave irradiation at 140-230 °C for 5 minutes, with 4 minutes of pre-heating. One gram of fractured activated carbon made of coconut shell was added into a number of suspensions that were subjected to the same conditions of microwave irradiation. The soluble fraction of the hydrolysates was analyzed for its total soluble solids, malto-oligomer distribution, glucose content, pH value, and formation of brown compounds. The effects of the combined severity parameter at a substrate concentration of 5-12.5% on the glucose yield were also evaluated. The highest glucose yield (78% of dry matter was obtained after hydrolysis at 180 °C without activated carbon addition. Heating above 180 °C reduced the glucose yield and increased the pH and the formation of brown compounds. The use of activated carbon in microwave-assisted acid hydrolysis of cassava pulp reduced the glucose yield, but suppressed the formation of brown compounds. The highest glucose yield (70-80% of dry matter was attained at a severity parameter of 1.3-1.5.

  10. Efficient Deprotection of Phenol Methoxymethyl Ethers Using a Solid Acid Catalyst with Wells-Dawson Structure

    Directory of Open Access Journals (Sweden)

    H. Thomas

    2001-11-01

    Full Text Available Deprotection of various phenols from their respective methoxymethyl ethers using an heteropolyacid catalyst was studied. The catalyst was the Wells-Dawson heteropolyacid, used both in bulk or supported on silica. Yields were high to quantitative after less than one hour reaction time and the catalyst was easily recoverable and reusable.

  11. Synthesis and Characterization of Tin (IV Tungstate Nanoparticles – A Solid Acid Catalyst

    Directory of Open Access Journals (Sweden)

    Manoj Sadanandan

    2012-12-01

    Full Text Available Tin (IV tungstate, a tetravalent metal acid salt was synthesized in the nanoform by chemical coprecipitation method using EDTA as capping agent. The material was found to be stable in mineral acids, bases and organic solvents except  in HF and aquaregia. The material was characterized using EDS, TG/DTA, FTIR, XRD, SEM, HRTEM and BET surface area measurement. The molecular formula of the compound is 2SnO2 3WO3.5H2O determined from elemental analysis using TG/DTA. Surface morphology and particle size were obtained using SEM and HRTEM. The surface area was found to be 205-225m2/g. The Na+ exchange capacity found to be 3.8 meq/g, indicates the presence of surface hydroxyl group and hence the presence of Bronsted acid sites. The catalytic activity of the material was tested by using esterification and oxidation as model reactions. For the esterification of different alcohols, the percentage yield was found to be high for n-alcohol compared to isomeric alcohols. Oxidation of benzyl alcohol gives benzaldehyde and benzoic acid as the only products. Copyright © 2012 by BCREC UNDIP. All rights reservedReceived: 12nd June 2012, Revised: 23rd July 2012, Accepted: 29th July 2012[How to Cite: S. Manoj, R. Beena, (2012. Synthesis and Characterization of tin(IV Tungstate Nanoparticles – A Solid Acid Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (2: 105-111. doi:10.9767/bcrec.7.2.3622.105-111] [How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.2.3622.105-111 ] | View in 

  12. Ethanol electro-oxidation on Pt/C and PtSn/C catalysts in alkaline and acid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, L.; Hsu, A.; Chen, R. [Richard G. Lugar Center for Renewable Energy, Indiana University - Purdue University Indianapolis, Indianapolis, IN 46202 (United States); Chu, D. [Army Research Laboratory, Adelphi, Maryland, MD 20783 (United States)

    2010-01-15

    Carbon supported Pt and PtSn were prepared by a modified polyol method. The electrocatalytic activities and stabilities of the Pt/C and PtSn/C catalysts towards ethanol electro-oxidation reactions (EORs) were investigated by potentiodynamic and potentiostatic methods in a 0.1 M NaOH solution (or 0.5 M H{sub 2}SO{sub 4}) containing 0.01 M ethanol. On both catalysts, the EOR currents in the alkaline solutions were much higher than those in the acid solutions, and the onset potentials of the EOR in alkaline solutions were less positive than those in acid solutions, indicating that the kinetics of the EOR improve in alkaline solutions. Even though a significant improvement was observed in acid media on PtSn/C, compared with Pt/C, only negligible improvement was observed in alkaline media. The apparent activation energies of the EOR on the PtSn/C catalyst varies from 21 to 33 kJ mol{sup -1}, depending on the potentials, which are slightly lower than the corresponding values on the Pt/C catalyst (25{proportional_to}42 kJ mol{sup -1}) under the same conditions. The Tafel slopes are divided into two parts-at low overpotentials, Tafel slopes on both catalysts are close to 120 mV dec{sup -1}, which is in agreement with the proposed mechanism-Temkin-type adsorption for both OH{sub ad} and ethoxi at low overpotentials; in contrast, at high overpotentials, Tafel slopes on both catalysts are over 300 mV dec{sup -1} due to the oxide formation on the surface. (author)

  13. Fe2P as a novel efficient catalyst promoter in Pd/C system for formic acid electro-oxidation in fuel cells reaction

    Science.gov (United States)

    Wang, Fulong; Xue, Huaiguo; Tian, Zhiqun; Xing, Wei; Feng, Ligang

    2018-01-01

    Developing catalyst promoter for Pd/C catalyst is significant for the catalytic ability improvement in energy transfer related electrochemical reactions. Herein, we demonstrate Fe2P as an efficient catalyst promoter in Pd/C catalyst system for formic acid electro-oxidation in fuel cells reactions. Adding Fe2P in the Pd/C catalyst system greatly increases the performances for formic acid oxidation by 3-4 times; the CO stripping technique displays two kinds of active sites formation in the Pd-Fe2P/C catalyst system coming from the interaction of Pd, Fe2P and Pd oxide species and both are more efficient for formic acid and CO-species electrooxidation. The smaller charge transfer resistance and Tafel slope for formic acid oxidation indicate the improvements in kinetics by Fe2P in the Pd-Fe2P/C system. The nanostructured hybrid units of Pd, Fe2P and carbon are evidently visible in the high resolution microscopy images and XPS technique confirmes the electronic effect in the catalyst system. The promotion effect of Fe2P in the catalyst system arising from the structure, composition and electronic effect changes is discussed with the help from multiple physical and electrochemical techniques. It is concluded that Fe2P as a significant catalyst promoter will have potential application in energy transfer related electrochemical reactions.

  14. Production of Jet Fuel-Range Hydrocarbons from Hydrodeoxygenation of Lignin over Super Lewis Acid Combined with Metal Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hongliang [Department of Biological Systems Engineering, Washington State University, Richland WA 99354 USA; Current address: Center of Biomass Engineering/College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193 PR China; Wang, Huamin [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; Kuhn, Eric [National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway Golden CO 80401 USA; Tucker, Melvin P. [National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway Golden CO 80401 USA; Yang, Bin [Department of Biological Systems Engineering, Washington State University, Richland WA 99354 USA

    2017-11-14

    Super Lewis acids containing the triflate anion [e.g., Hf(OTf)4, Ln(OTf)3, In(OTf)3, Al(OTf)3] and noble metal catalysts (e.g., Ru/C, Ru/Al2O3) formed efficient catalytic systems to generate saturated hydrocarbons from lignin in high yields. In such catalytic systems, the metal triflates mediated rapid ether bond cleavage through selective bonding to etheric oxygens while the noble metal catalyzed subsequent hydrodeoxygenation (HDO) reactions. Near theoretical yields of hydrocarbons were produced from lignin model compounds by the combined catalysis of Hf(OTf)4 and ruthenium-based catalysts. When a technical lignin derived from a pilot-scale biorefinery was used, more than 30 wt % of the hydrocarbons produced with this catalytic system were cyclohexane and alkylcyclohexanes in the jet fuel range. Super Lewis acids are postulated to strongly interact with lignin substrates by protonating hydroxyl groups and ether linkages, forming intermediate species that enhance hydrogenation catalysis by supported noble metal catalysts. Meanwhile, the hydrogenation of aromatic rings by the noble metal catalysts can promote oxygenation reactions catalyzed by super Lewis acids.

  15. Low-grade oils and fats: effect of several impurities on biodiesel production over sulfonic acid heterogeneous catalysts.

    Science.gov (United States)

    Morales, Gabriel; Bautista, L Fernando; Melero, Juan A; Iglesias, Jose; Sánchez-Vázquez, Rebeca

    2011-10-01

    Different lipidic wastes and low-grade oils and fats have been characterized and evaluated as feedstocks for the acid-catalyzed production of FAME. The characterization of these materials has revealed significant contents of free fatty acids, Na, K, Ca, Mg, P, unsaponifiable matter and humidity. Arenesulfonic acid-functionalized SBA-15 silica catalyst has provided yields to FAME close to 80% in the simultaneous esterification-transesterification of the different feedstocks, regardless of their nature and properties, using methanol under the following reaction conditions: 160 °C, 2 h, methanol to oil molar ratio of 30, 8 wt.% catalyst loading, and 2000 rpm stirring rate. Nevertheless, reutilization of the catalyst is compromised by high levels of impurities, especially because of deactivation by strong interaction of unsaponifiable matter with the catalytic sites. The conditioning of these materials by aqueous washing in the presence of cationic-exchange resin Amberlyst-15, followed by a drying step, resulted in a lower deactivation of the catalyst. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Production of Jet Fuel-Range Hydrocarbons from Hydrodeoxygenation of Lignin over Super Lewis Acid Combined with Metal Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hongliang [Department of Biological Systems Engineering, Washington State University, Richland WA 99354 USA; Current address: Center of Biomass Engineering/College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193 PR China; Wang, Huamin [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; Kuhn, Eric [National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway Golden CO 80401 USA; Tucker, Melvin P. [National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway Golden CO 80401 USA; Yang, Bin [Department of Biological Systems Engineering, Washington State University, Richland WA 99354 USA

    2017-11-14

    Super Lewis acids containing the triflate anion (e.g. Hf(OTf)4, Ln(OTf)3, Al(OTf)3) and noble metal catalysts (e.g. Ru/C, Ru/Al2O3) formed efficient catalytic systems to generate saturated hydrocarbons from lignin in high yields. In such catalytic systems, the metal triflates mediated rapid ether bond cleavage via selective bonding to etheric oxygens while the noble metal catalysed subsequent hydrodeoxygenation (HDO) reactions. Near theoretical yields of hydrocarbons were produced from lignin model compounds by the combined catalysis of Hf(OTf)4 and ruthenium-based catalysts. When a technical lignin derived from a pilot-scale biorefinery was used, more than 30 wt% of the hydrocarbons produced with this catalytic system were cyclohexane and alkylcyclohexanes in the jet fuel range. Super Lewis acids are postulated to strongly interact with lignin substrates via protonating hydroxyls and ether linkages, forming intermediate species that enhance hydrogenation catalysis by supported noble metal catalysts. Meanwhile, the hydrogenation of aromatic rings by the noble metal catalysts can promote oxygenation reactions catalysed by super Lewis acids.

  17. Effect of Porous Structure and Acidity of ZSM-5/SBA-15 Catalyst on 1,3,5-Triisopropylbenzene Cracking Catalytic Activity.

    Science.gov (United States)

    Vinh, Tran Quang; Nam, Le Thi Hoai; Nhiem, Nguyen Thi; Duc, Pham Minh; Trang, Nguyen Thi Thu; Hieu, Do Trung

    2018-02-01

    ZSM-5/SBA-15 composite materials with different acidities and mesoporous system formations were successfully synthesized by three-step method. The catalysts were characterized by XRD, HR-TEM, BET, EDX and TPD-NH3 methods. It showed that the Si/Al molar ratio had effect on the formation and property of materials. Among synthesized catalysts with the different Si/Al molar ratios of 30 (HZSC-30), 50 (HZSC-50), 70 (HZSC-70), HZSC-50 catalyst had better mesoporous system formation and acidity. These properties helped this catalyst to have higher catalytic activity in 1,3,5-triisopropylbenzene cracking reaction than other studied catalysts in term of higher benzene product yield. In comparison to HZSM-5 microporous material that had the similar Si/Al molar ratio of 50, it showed that the formation of mesopore system of HZSC-50 catalyst had a major improvement on the cracking catalytic activity.

  18. Acidic ionic liquids as sustainable approach of cellulose and lignocellulosic biomass conversion without additional catalysts.

    Science.gov (United States)

    Lopes, André M da Costa; Bogel-Łukasik, Rafał

    2015-03-01

    The use of ionic liquids (ILs) for biomass processing has attracted considerable attention recently as it provides distinct features for pre-treated biomass and fractionated materials in comparison to conventional processes. Process intensification through integration of dissolution, fractionation, hydrolysis and/or conversion in one pot should be accomplished to maximise economic and technological feasibility. The possibility of using alternative ILs capable not only of dissolving and deconstructing selectively biomass but also of catalysing reactions simultaneously are a potential solution of this problem. In this Review a critical overview of the state of the art and perspectives of the hydrolysis and conversion of cellulose and lignocellulosic biomass using acidic ILs using no additional catalyst are provided. The efficiency of the process is mainly considered with regard to the hydrolysis and conversion yields obtained and the selectivity of each reaction. The process conditions can be easily tuned to obtain sugars and/or platform chemicals, such as furans and organic acids. On the other hand, product recovery from the IL and its purity are the main challenges for the acceptance of this technology as a feasible alternative to conventional processes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. A highly efficient magnetic solid acid catalyst for synthesis of 2,4,5-trisubstituted imidazoles under ultrasound irradiation.

    Science.gov (United States)

    Safari, Javad; Zarnegar, Zohre

    2013-03-01

    Fe(3)O(4) nanoparticles were prepared by chemical coprecipitation method and subsequently coated with 3-aminopropyltriethoxysilane (APTES) via silanization reaction. Grafting of chlorosulfuric acid on the amino-functionalized Fe(3)O(4) nanoparticles afforded sulfamic acid-functionalized magnetic nanoparticles (SA-MNPs). SA-MNPs was found to be a mild and effective solid acid catalyst for the efficient, one-pot, three-component synthesis of 2,4,5-trisubstituted imidazoles under ultrasound irradiation. This protocol afforded corresponding imidazoles in shorter reaction durations, and in high yields. This green procedure has many obvious advantages compared to those reported in the previous literatures, including avoiding the use of harmful catalysts, easy and quick isolation of the products, excellent yields, short routine, and simplicity of the methodology. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Aerobic oxidation of aqueous ethanol using heterogeneous gold catalysts: Efficient routes to acetic acid and ethyl acetate

    DEFF Research Database (Denmark)

    Jørgensen, Betina; Christiansen, Sofie Egholm; Thomsen, M.L.D.

    2007-01-01

    conditions, yields of 90-95% of acetic acid could be achieved at moderate temperatures and pressures. Based on our findings, a reaction pathway for the catalytic oxidation of ethanol via acetaldehyde to acetic acid is proposed, and the rate-determining step (RDS) in the mechanism is found to be the (possibly......The aerobic oxidation of aqueous ethanol to produce acetic acid and ethyl acetate was studied using heterogeneous gold catalysts. Comparing the performance of Au/MgAl2O4 and Au/TiO2 showed that these two catalysts exhibited similar performance in the reaction. By proper selection of the reaction...... oxygen-assisted) dehydrogenation of ethanol to produce acetaldehyde. It also is concluded that most of the CO2 formed as a byproduct in the reaction results from the absorbed intermediate in the dehydrogenation of ethanol to produce acetaldehyde. By varying the amount of water in the reaction mixture...

  1. Acidic and basic properties of zeolite-containing cracking catalyst in the process of butene-1 isomerization

    Science.gov (United States)

    Mursalova, L. A.; Guseinova, E. A.; Adzhamov, K. Yu.

    2016-08-01

    The process of butene-1 isomerization in the presence of two groups of samples of zeolite-containing catalyst (ZCC) that earlier participated in the traditional and oxidative catalytic cracking of vacuum gasoil is investigated. It is established that the nature of the reaction mixture and conditions of the cracking process are key factors in forming the acidic and basic properties of the catalyst. It is shown that the highest activity in the butene-1 isomerization into cis-/ trans-butene-2 is demonstrated by ZCC samples that participated in the oxidative catalytic cracking (oxycracking). It is suggested that the enhanced catalytic activity of this group of ZCC samples was related to the availability of acid-base centers in the form of radical-like oxygen along with protic- and aprotic-type acidic centers in the structure of the oxidative compaction products.

  2. Low-quality vegetable oils as feedstock for biodiesel production using K-pumice as solid catalyst. Tolerance of water and free fatty acids contents.

    Science.gov (United States)

    Díaz, L; Borges, M E

    2012-08-15

    Waste oils are a promising alternative feedstock for biodiesel production due to the decrease of the industrial production costs. However, feedstock with high free fatty acids (FFA) content presents several drawbacks when alkaline-catalyzed transesterification reaction is employed in biodiesel production process. Nowadays, to develop suitable processes capable of treating oils with high free fatty acids content, a two-step process for biodiesel production is being investigated. The major problem that it presents is that two catalysts are needed to carry out the whole process: an acidic catalyst for free fatty acids esterification (first step) and a basic catalyst for pretreated product transesterification (second step). The use of a bifunctional catalyst, which allows both reactions to take place simultaneously, could minimize the production costs and time. In the present study, the behavior of pumice, a natural volcanic material used as a heterogeneous catalyst, was tested using oils with several FFA and water contents as feedstock in the transesterification reaction to produce biodiesel. Pumice as a bifunctional solid catalyst, which can catalyze simultaneously the esterification of FFA and the transesterification of fatty acid glycerides into biodiesel, was shown to be an efficient catalyst for the conversion of low-grade, nonedible oil feedstock into biodiesel product. Using this solid catalyst for the transesterification reaction, high FAME yields were achieved when feedstock oils presented a FFA content until approximately 2% wt/wt and a water content until 2% wt/wt.

  3. A novel method for synthesis of phosphomolybdic acid-modified Pd/C catalysts for oxygen reduction reaction

    Science.gov (United States)

    Zhu, Mingyuan; Gao, Xiaoling; Luo, Guangqin; Dai, Bin

    2013-03-01

    This manuscript reports a convenient method for immobilizing phosphomolybdic acid (HPMo) on polyaniline (PAN-) functionalized carbon supports. The obtained HPMo-PAN-C sample is used as the support to prepare a Pd/HPMo-PAN-C catalyst. The samples are characterized by Fourier transform infrared spectroscopy, transmission electron microscopy and X-ray diffraction analysis. The results suggest that HPMo retains its Keggin structure and that the presence of HPMo reduces the average particle size of the Pd nano-particles in the obtained Pd/HPMo-PAN-C catalyst. Electro-chemical measurements in 0.5 M HClO4 solution reveal that the Pd/HPMo-PAN-C catalyst has higher catalytic activity for oxygen reduction reactions than does a Pd/C catalyst prepared using a similar procedure. The stability of the Pd/HPMo-PAN-C catalyst is evaluated by multiple-cycle voltammetry techniques; the mass catalytic activity decreases by only 10% after 100 scanning cycles.

  4. Multifunctional Pd/Ni-Co catalyst for hydrogen production by chemical looping coupled with steam reforming of acetic acid.

    Science.gov (United States)

    Fermoso, Javier; Gil, María V; Rubiera, Fernando; Chen, De

    2014-11-01

    High yield of high-purity H2 from acetic acid, a model compound of bio-oil obtained from the fast pyrolysis of biomass, was produced by sorption-enhanced steam reforming (SESR). An oxygen carrier was introduced into a chemical loop (CL) coupled to the cyclical SESR process to supply heat in situ for the endothermic sorbent regeneration to increase the energy efficiency of the process. A new multifunctional 1 %Pd/20 %Ni-20 %Co catalyst was developed for use both as oxygen carrier in the CL and as reforming catalyst in the SESR whereas a CaO-based material was used as CO2 sorbent. In the sorbent-air regeneration step, the Ni-Co atoms in the catalyst undergo strong exothermic oxidation reactions that provide heat for the CaO decarbonation. The addition of Pd to the Ni-Co catalyst makes the catalyst active throughout the whole SESR-CL cycle. Pd significantly promotes the reduction of Ni-Co oxides to metallic Ni-Co during the reforming stage, which avoids the need for a reduction step after regeneration. H2 yield above 90 % and H2 purity above 99.2 vol % were obtained. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Recovery of Nickel from Reformer Catalysts of Direct Reduction, Using the Pressurized Dissolving Method in Nitric Acid

    Directory of Open Access Journals (Sweden)

    B. Abrar

    2016-10-01

    Full Text Available In the process of direct reduction of iron pellet and production of sponge iron, NiO/Al2O3 act as a catalyst for the generation of carbon monoxide and hydrogen by vapor and natural gas. As an expensive material used in MIDREX method for steel units, this type of catalyst has major environmental problems after accumulation. The steel industry in Iran hopes to employ the MIDREX technique for the 80 percent of the 50 million tons of steel. Thus, the problem of spent catalysts will become a serious environmental challenge. Through the hydrometallurgy method, the present study investigates a possible solution to the problem of catalyst depot (due to heavy metals such as nickel via nickel recovery, which may increase the possibility of selling or re-using the precious and expensive metal. The present research studied the Nickel recovery from spent catalysts of NiO/Al2O¬3 used in reduction gas reliefs of the production of sponge iron unit. In this study, the parameters of temperature, concentration, time and Rpm were studied using pressurized dissolving method. 100% efficiency was achieved at 140 °C for 120 minutes, nitric acid concentration of 1.5 mm, Rpm of 600 and 40 s/l 40 grams per liter.

  6. Trifluoromethanesulfonic acid promoted Dakin–West reaction: An ...

    Indian Academy of Sciences (India)

    BiOCl,10 ZrOCl2.8H2O,11 heteropoly acid,12,13 I2,14 amberlyst-15,15 ZnO,16 and CeCl3. 17 Although all these methods are useful, they suffer from limitations such as long reaction times and the handling and disposal of inorganic acids. Trifluoromethanesulfonic acid or triflic acid is a well- known Bronsted super acid and ...

  7. Oil palm trunk and sugarcane bagasse derived solid acid catalysts for rapid esterification of fatty acids and moisture-assisted transesterification of oils under pseudo-infinite methanol.

    Science.gov (United States)

    Ezebor, Francis; Khairuddean, Melati; Abdullah, Ahmad Zuhairi; Boey, Peng Lim

    2014-04-01

    The use of pseudo-infinite methanol in increasing the rate of esterification and transesterification reactions was studied using oil palm trunk (OPT) and sugarcane bagasse (SCB) derived solid acid catalysts. The catalysts were prepared by incomplete carbonisation at 400°C for 8h, followed by sulfonation at 150°C for 15h and characterised using TGA/DTA, XRD, FT-IR, SEM-EDS, EA and titrimetric determinations of acid sites. Under optimal reaction conditions, the process demonstrated rapid esterification of palmitic acid, with FAME yields of 93% and 94% in 45min for OPT and SCB catalysts, respectively. With the process, moisture levels up to 16.7% accelerated the conversion of low FFA oils by sulfonated carbon catalysts, through moisture-induced violent bumping. Moisture assisted transesterification of palm olein containing 1.78% FFA and 8.33% added water gave FAME yield of 90% in 10h, which was two folds over neat oil. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. A smart strategy to fabricate Ru nanoparticle inserted porous carbon nanofibers as highly efficient levulinic acid hydrogenation catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ying; Sun, Cheng-Jun; Brown, Dennis E.; Zhang, Liqiang; Yang, Feng; Zhao, Hairui; Wang, Yue; Ma, Xiaohui; Zhang, Xin; Ren, Yang

    2016-01-01

    Herein, we first put forward a smart strategy to in situ fabricate Ru nanoparticle (NP) inserted porous carbon nanofibers by one-pot conversion of Ru-functionalized metal organic framework fibers. Such fiber precursors are skillfully constructed by cooperative assembly of different proportional RuCl3 and Zn(Ac)2·2H2O along with trimesic acid (H3BTC) in the presence of N,N-dimethylformamide. The following high-temperature pyrolysis affords uniform and evenly dispersed Ru NPs (ca. 12-16 nm), which are firmly inserted into the hierarchically porous carbon nanofibers formed simultaneously. The resulting Ru-carbon nanofiber (Ru-CNF) catalysts prove to be active towards the liquid-phase hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL), a biomass-derived platform molecule with wide applications in the preparation of renewable chemicals and liquid transportation fuels. The optimal GVL yield of 96.0% is obtained, corresponding to a high activity of 9.23 molLAh–1gRu–1, 17 times of that using the commercial Ru/C catalyst. Moreover, the Ru-CNF catalyst is extremely stable, and can be cycled up to 7 times without significant loss of reactivity. Our strategy demonstrated here reveals new possibilities to make proficient metal catalysts, and provides a general way to fabricate metal-carbon nanofiber composites available for other applications.

  9. A Comparative Study of Basic, Amphoteric, and Acidic Catalysts in the Oxidative Coupling of Methanol and Ethanol for Acrolein Production.

    Science.gov (United States)

    Lilić, Aleksandra; Wei, Tiantian; Bennici, Simona; Devaux, Jean-François; Dubois, Jean-Luc; Auroux, Aline

    2017-09-11

    The impact of acid/base properties (determined by adsorption microcalorimetry) of various catalysts on the cross-aldolization of acetaldehyde and formaldehyde leading to acrolein was methodically studied in oxidizing conditions starting from a mixture of methanol and ethanol. The aldol condensation and further dehydration to acrolein were carried out on catalysts presenting various acid/base properties (MgO, Mg-Al oxides, Mg/SiO 2 , NbP, and heteropolyanions on silica, HPA/SiO 2 ). Thermodynamic calculations revealed that cross-aldolization is always favored compared with self-aldolization of acetaldehyde, which leads to crotonaldehyde formation. The presence of strong basic sites is shown to be necessary, but a too high amount drastically increases CO x production. On strong acid sites, production of acrolein and carbon oxides (CO x ) does not increase with temperature. The optimal catalyst for this process should be amphoteric with a balanced acid/base cooperation of medium strength sites and a small amount (150 kJ mol -1 ). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Development of biomimetic catalytic oxidation methods and non-salt methods using transition metal-based acid and base ambiphilic catalysts

    Science.gov (United States)

    MURAHASHI, Shun-Ichi

    2011-01-01

    This review focuses on the development of ruthenium and flavin catalysts for environmentally benign oxidation reactions based on mimicking the functions of cytochrome P-450 and flavoenzymes, and low valent transition-metal catalysts that replace conventional acids and bases. Several new concepts and new types of catalytic reactions based on these concepts are described. PMID:21558760

  11. Development of biomimetic catalytic oxidation methods and non-salt methods using transition metal-based acid and base ambiphilic catalysts.

    Science.gov (United States)

    Murahashi, Shun-Ichi

    2011-01-01

    This review focuses on the development of ruthenium and flavin catalysts for environmentally benign oxidation reactions based on mimicking the functions of cytochrome P-450 and flavoenzymes, and low valent transition-metal catalysts that replace conventional acids and bases. Several new concepts and new types of catalytic reactions based on these concepts are described. (Communicated by Ryoji Noyori, M.J.A.).

  12. Synthesis of long alkyl chain ethers through direct etherification of biomass-based alcohols with 1-octene over heterogeneous acid catalysts

    NARCIS (Netherlands)

    Ruppert, A.M.; Parvulescu, A.N.; Arias, M.J.; Bruijnincx, P.C.A.; Klein Gebbink, R.J.M.; Weckhuysen, B.M.

    2009-01-01

    Heterogeneous etherification of various biomass-based alcohols with 1-octene was investigated as a direct route for the synthesis of long alkyl chain ethers. Several acid catalyst materials including Amberlyst resins and various zeolites were screened as etherification catalysts in a solventless

  13. Conversion of polar and non-polar algae oil lipids to fatty acid methyl esters with solid acid catalysts--A model compound study.

    Science.gov (United States)

    Asikainen, Martta; Munter, Tony; Linnekoski, Juha

    2015-09-01

    Bio-based fuels are becoming more and more important due to the depleting fossil resources. The production of biodiesel from algae oil is challenging compared to terrestrial vegetable oils, as algae oil consists of polar fatty acids, such as phospholipids and glycolipids, as well as non-polar triglycerides and free fatty acids common in vegetable oils. It is shown that a single sulphonated solid acid catalyst can perform the esterification and transesterification reactions of both polar and non-polar lipids. In mild reaction conditions (60-70 °C) Nafion NR50 catalyst produces methyl palmitate (FAME) from the palmitic acid derivatives of di-, and tri-glyceride, free fatty acid, and phospholipid with over 80% yields, with the glycolipid derivative giving nearly 40% yields of FAME. These results demonstrate how the polar and non-polar lipid derivatives of algal oil can be utilised as feedstocks for biodiesel production with a single catalyst in one reaction step. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Metal Fluorides, Metal Chlorides and Halogenated Metal Oxides as Lewis Acidic Heterogeneous Catalysts. Providing Some Context for Nanostructured Metal Fluorides.

    Science.gov (United States)

    Lennon, David; Winfield, John M

    2017-01-28

    Aspects of the chemistry of selected metal fluorides, which are pertinent to their real or potential use as Lewis acidic, heterogeneous catalysts, are reviewed. Particular attention is paid to β-aluminum trifluoride, aluminum chlorofluoride and aluminas γ and η, whose surfaces become partially fluorinated or chlorinated, through pre-treatment with halogenating reagents or during a catalytic reaction. In these cases, direct comparisons with nanostructured metal fluorides are possible. In the second part of the review, attention is directed to iron(III) and copper(II) metal chlorides, whose Lewis acidity and potential redox function have had important catalytic implications in large-scale chlorohydrocarbons chemistry. Recent work, which highlights the complexity of reactions that can occur in the presence of supported copper(II) chloride as an oxychlorination catalyst, is featured. Although direct comparisons with nanostructured fluorides are not currently possible, the work could be relevant to possible future catalytic developments in nanostructured materials.

  15. Formic Acid Oxidation over Hierarchical Porous Carbon Containing PtPd Catalysts

    Directory of Open Access Journals (Sweden)

    Elena Pastor

    2013-10-01

    Full Text Available The use of high surface monolithic carbon as support for catalysts offers important advantage, such as elimination of the ohmic drop originated in the interparticle contact and improved mass transport by ad-hoc pore design. Moreover, the approach discussed here has the advantage that it allows the synthesis of materials having a multimodal porous size distribution, with each pore size contributing to the desired properties. On the other hand, the monolithic nature of the porous support also imposes new challenges for metal loading. In this work, the use of Hierarchical Porous Carbon (HPC as support for PtPd nanoparticles was explored. Three hierarchical porous carbon samples (denoted as HPC-300, HPC-400 and HPC-500 with main pore size around 300, 400 and 500 nm respectively, are used as porous support. PtPd nanoparticles were loaded by impregnation and subsequent chemical reduction with NaBH4. The resulting material was characterized by EDX, XRD and conventional electrochemical techniques. The catalytic activity toward formic acid and methanol electrooxidation was evaluated by electrochemical methods, and the results compared with commercial carbon supported PtPd. The Hierarchical Porous Carbon support discussed here seems to be promising for use in DFAFC anodes.

  16. Poly (Ethylene Glycol)-Bound Sulphonic Acid as a Novel Catalyst for ...

    African Journals Online (AJOL)

    NICO

    cient, reusable, economic and eco-friendly catalyst has led to development of polymer-bound catalyst. They are used in solu- tion phase, solid phase synthesis, microwave-assisted synthesis because these methods offer benefits such as enhanced reaction rate, greater selectivity, ease at experimental work-up and com-.

  17. Versatile and sustainable synthesis of cyclic imides from dicarboxylic acids and amines by Nb2O5 as a base-tolerant heterogeneous Lewis acid catalyst.

    Science.gov (United States)

    Ali, Md Ayub; Siddiki, S M A Hakim; Kon, Kenichi; Hasegawa, Junya; Shimizu, Ken-Ichi

    2014-10-27

    Catalytic condensation of dicarboxylics acid and amines without excess amount of activating reagents is the most atom-efficient but unprecedented synthetic method of cyclic imides. Here we present the first general catalytic method, proceeding selectively and efficiently in the presence of a commercial Nb2 O5 as a reusable and base-tolerant heterogeneous Lewis acid catalyst. The method is effective for the direct synthesis of pharmaceutically or industrially important cyclic imides, such as phensuximide, N-hydroxyphthalimide (NHPI), and unsubstituted cyclic imides from dicarboxylic acid or anhydrides with amines, hydroxylamine, or ammonia. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Photoreduction of mercury metal (Hg) using catalyst of oxalic acid from cellulose of rice husks (Oryza sativa L.)

    Energy Technology Data Exchange (ETDEWEB)

    Sumiardi, Ade, E-mail: zulfasalmasaodah@gmail.com [Departement of Biology, Faculty of Sciences and Pharmacy, Math’laul Anwar University, Banten (Indonesia); Novi, Cory; Sukaesih, Esih [Departement of Chemistry, Faculty of Sciences and Pharmacy, Math’laul Anwar University, Banten (Indonesia); Humaedi, Aji [Departement of Pharmacy, Faculty of Sciences and Pharmacy, Math’laul Anwar University, Banten (Indonesia)

    2016-04-19

    Photoreduction of mercury metal using catalyst of oxalic acid from cellulose of rice husks (Oryza sativa L.) is one of methods to reduce toxicity properties of the mercury metal in the society. The purpose of this research is to enhance photoreduction of mercury metal using catalyst of oxalic acid from cellulose of rice husks (Oryza sativa L.) at various concentrations. Photoreduction process is carried out in a closed reactor equipped with UV light and magnetic stirrer. Analysis of the influence of oxalic acid is determined by adding 25 mL of Hg (II) 5 ppm without oxalic acid, 25 mL of Hg (II) 5 ppm + 25 mL of oxalic acid 3 ppm, 25 mL of Hg (II) 5 ppm + 25 mL of oxalic acid 6 ppm, 25 mL of Hg (II) 5 ppm + 25 mL of oxalic acid 9 ppm, 25 mL of Hg (II) 5 ppm + 25 mL of oxalic acid 12 ppm and 25 mL of Hg (II) 5 ppm + 25 mL of oxalic acid 15 ppm. All treatments are followed by centrifugation for 15 minutes, then the concentration of Hg residual in the solution is measured by mercury analyzer. The research results showed that addition of oxalic acid concentration from the cellulose of rice husks (Oryza sativa L.) can enhance photoreduction of mercury metal. Optimum concentration reduction of mercury metal with addition of oxalic acid is obtained as many as 9-12 ppm. It can reduce the concentration of mercury metal (II) by 68.8% to 88.6%.

  19. Nano-Silica Phosphoric Acid: An Efficient Catalyst for One-Pot Synthesis of Tetrahydrobenzo[a]xanthenes-11-one Under Solvent- Free or Sonication Conditions

    Directory of Open Access Journals (Sweden)

    A. Bamoniri

    2012-12-01

    Full Text Available Two simple protocols for the synthesis of tetrahydrobenzo[a]xanthenes-11-ones using nano silica phosphoric acid are reported. Short reaction times, high yields, reusability of catalyst and easy workup are some advantages of these protocols.

  20. B(HSO4)3: a novel and efficient solid acid catalyst for the regioselective conversion of epoxides to thiocyanohydrins under solvent-free conditions

    National Research Council Canada - National Science Library

    Ali Reza Kiasat; Mehdi Fallah-Mehrjardi

    2008-01-01

    B(HSO4)3 was easily prepared and used as a novel and efficient solid acid catalyst for conversion of epoxides to the corresponding thiocyanohydrins under solvent-free conditions with high isolated yields...

  1. Chiral Zn(II)-bisamidine complex as a Lewis-Brønsted combined acid catalyst: application to asymmetric Mukaiyama aldol reactions of α-ketoesters

    National Research Council Canada - National Science Library

    Gotoh, Ryo; Yamanaka, Masahiro

    2012-01-01

    Focusing on the steric and electronic properties of the resonance-stabilized amidine framework, a cationic metal-bisamidine complex was designed as a conjugated combined Lewis-Brønsted acid catalyst. The chiral Zn(II...

  2. Chiral Zn(II)-Bisamidine Complex as a Lewis-Br?nsted Combined Acid Catalyst: Application to Asymmetric Mukaiyama Aldol Reactions of [alpha]-Ketoesters

    National Research Council Canada - National Science Library

    Ryo Gotoh; Masahiro Yamanaka

    2012-01-01

      Focusing on the steric and electronic properties of the resonance-stabilized amidine framework, a cationic metal-bisamidine complex was designed as a conjugated combined Lewis-Brønsted acid catalyst. The chiral Zn(II...

  3. Continuous esterification of free fatty acids in crude biodiesel by an integrated process of supercritical methanol and sodium methoxide catalyst.

    Science.gov (United States)

    Zeng, Dan; Li, Ruosong; Feng, Mingjun; Fang, Tao

    2014-10-01

    An integrated process of supercritical methanol (SCM) and sodium methoxide catalyst was developed to produce fatty acid methyl esters (FAMEs) via continuous esterification from crude biodiesel. The crude biodiesel with high free fatty acid (FFA) content must be refined to reduce the acid value (AV) for meeting the quality standards. The process parameters were studied by Box-Behnken design (BBD) of response surface methodology (RSM). The experimental results revealed that the AV of crude biodiesel decreased from 18.66 to 0.55 mg KOH g(-1) at the reaction conditions of 350 °C, 0.5 % amount of sodium methoxide catalyst, and 10 MPa. Temperature shows the most significant effect on the esterification, followed by pressure and amount of sodium methoxide catalyst. This integrated process proved to be a potential route to refine the crude biodiesel because of its continuity, high efficiency, and less energy consumption with relatively moderate reaction conditions compared with conventional methods.

  4. Preparation of nanobiochar as magnetic solid acid catalyst by pyrolysis-carbonization from oil palm empty fruit bunches

    Science.gov (United States)

    Jenie, S. N. Aisyiyah; Kristiani, Anis; Kustomo, Simanungkalit, Sabar; Mansur, Dieni

    2017-11-01

    Nanomaterials based on carbon exhibits unique properties, both physical and chemical, that can be utilized in various application, including catalyst. These nanomaterials were prepared through pyrolysis-carbonization process of biomass, oil palm empty fruit bunches. The effect of carbonization temperature in range of 500°C-600°C were also studied. The magnetic nanobiochar samples, MBC, were sulfonated by using sulfuric acid to increase their properties as solid acid catalyst. Their chemical and physical properties were characterized by Surface Area Analyzer and Porositymeter, X-Ray Diffraction, Scanning Electron Microscopy, Fourier Transform Infra-Red. The magnetic biochar samples obtained from carbonization at 873 K, MBC02-SO3H, was proven to have higher surface area, crystallinity properties and surface chemical composition after sulfonation process, which were confirmed by the BET, XRD and FT-IR analysis. Moreover, sample MBC02-SO3H exhibit promising catalytic acitivity in a catalysed esterification reaction, producing an ester yield of 64%. The result from this work opens new opportunities for the development of magnetic heterogenous acid catalyst from biomass waste.

  5. Nb-Based Zeolites: Efficient bi-Functional Catalysts for the One-Pot Synthesis of Succinic Acid from Glucose

    Directory of Open Access Journals (Sweden)

    Magdi El Fergani

    2017-12-01

    Full Text Available The one-pot production of succinic acid from glucose was investigated in pure hot water as solvent using Nb (0.02 and 0.05 moles%-Beta zeolites obtained by a post-synthesis methodology. Structurally, they are comprised of residual framework Al-acid sites, extra-framework isolated Nb (V and Nb2O5 pore-encapsulated clusters. The Nb-modified Beta-zeolites acted as bi-functional catalysts in which glucose is dehydrated to levulinic acid (LA which, further, suffers an oxidation process to succinic acid (SA. After the optimization of the reaction conditions, that is, at 180 °C, 18 bar O2, and 12 h reaction time, the oxidation of glucose occurred with a selectivity to succinic acid as high as 84% for a total conversion.

  6. Catalytic Upgrading of bio-oil using 1-octene and 1-butanol over sulfonic acid resin catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhijun; Wang, Qingwen; Tripathi, Prabhat; Pittman, Charles U.

    2011-02-04

    Raw bio-oil from fast pyrolysis of biomass must be refined before it can be used as a transporation fuel, a petroleum refinery feed or for many other fuel uses. Raw bio-oil was upgraded with the neat model olefin, 1-octene, and with 1-octene/1-butanol mixtures over sulfonic acid resin catalysts frin 80 to 150 degrees celisus in order to simultaneously lower water content and acidity and to increase hydrophobicity and heating value. Phase separation and coke formation were key factors limiting the reaction rate during upgrading with neat 1-octene although octanols were formed by 1-octene hydration along with small amounts of octyl acetates and ethers. GC-MS analysis confirmed that olefin hydration, carboxylic acid esterification, acetal formation from aldehydes and ketones and O- and C-alkylations of phenolic compounds occurred simultaneously during upgrading with 1-octene/1-butanol mixtures. Addition of 1-butanol increased olefin conversion dramatically be reducing mass transfer restraints and serving as a cosolvent or emulsifying agent. It also reacted with carboxylic acids and aldehydes/ketones to form esters, and acetals, respectively, while also serving to stabilize bio-oil during heating. 1-Butanol addition also protected the catalysts, increasing catalyst lifetime and reducing or eliminationg coking. Upgrading sharply increased ester content and decreased the amounts of levoglucosan, polyhydric alcohols and organic acids. Upgrading lowered acidity (pH value rise from 2.5 to >3.0), removed the uppleasant ordor and increased hydrocarbon solubility. Water content decreased from 37.2% to < 7.5% dramatically and calorific value increased from 12.6 MJ kg to about 30.0 MJ kg.

  7. Sulfonic Acid Functionalized Nano-γ-Al2O3: A New, Efficient, and Reusable Catalyst for Synthesis of 3-Substituted-2H-1,4-Benzothiazines

    Directory of Open Access Journals (Sweden)

    Wei Lin Li

    2013-01-01

    Full Text Available A simple and efficient synthetic protocol has been developed for the synthesis of 3-substituted-2H-1,4-benzothiazines by using a novel sulfonic acid functionalized nano-γ-Al2O3 catalyst, devoid of corrosive acidic, and basic reagents. The developed method has the advantages of good to excellent yields, short reaction times, operational simplicity, and a recyclable catalyst. The catalyst can be prepared by a simple procedure from inexpensive and readily available nano-γ-Al2O3 and has been shown to be recoverable and reusable up to six cycles without any loss of activity.

  8. Rhodium fluorapatite catalyst for the synthesis of trisubstituted olefins via cross coupling of Baylis-Hillman adducts and arylboronic acids.

    Science.gov (United States)

    Kantam, M Lakshmi; Kumar, K B Shiva; Sreedhar, B

    2008-01-04

    Treatment of fluorapatite (prepared by incorporating basic species F(-) in apatite in situ by coprecipitation) with an aqueous solution of RhCl(3) resulted in rhodium-exchanged fluorapatite catalyst (RhFAP), which successfully promoted cross coupling of Baylis-Hillman adducts with arylboronic acids to yield trisubstituted olefins. A variety of arylboronic acids and Baylis-Hillman adducts were converted to the corresponding trisubstituted olefins, demonstrating the versatility of the reaction. The reaction is highly stereoselective. RhFAP was recovered quantitatively by simple filtration and reused with almost consistent activity.

  9. A novel mesoporous sulfated zirconium solid acid catalyst for Friedel-Crafts benzylation reaction

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Zhichao; Zhou, Jin; Zhao, Jinping; Liu, Dandan; Bi, Xu [School of Chemical Engineering, Shandong University of Technology, Zibo, 255049 (China); Chou, Lingjun, E-mail: ljchou@licp.cas.cn [State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China); Zhuo, Shuping, E-mail: zhuosp_academic@yahoo.com [School of Chemical Engineering, Shandong University of Technology, Zibo, 255049 (China)

    2017-07-31

    Highlights: • A novel mesoporous ZrO{sub 2}/SO{sub 4}{sup 2−} has been prepared via a facile one-pot EISA strategy. • The M-ZrO{sub 2}/SO{sub 4}{sup 2−} exhibited excellent textural and acidic properties. • The introduced S species were homogeneously dispersed in mesoporous skeleton. • The M-ZrO{sub 2}/SO{sub 4}{sup 2−} exhibited excellent catalytic performance and reusability. - Abstract: In this paper, a novel mesoporous sulfated zirconium (M-ZrO{sub 2}/SO{sub 4}{sup 2−}) has been gotten by one-pot evaporation-induced self-assembly (one-pot EISA) strategy. The SXRD, N{sub 2}-physisorption and TEM characterization techniques indicated that M-ZrO{sub 2}/SO{sub 4}{sup 2−} possessed distinct mesostructure with big specific surface area (133.5 m{sup 2} g{sup −1}), large pore volume (0.18 cm{sup 3} g{sup −1}) and narrow pore size distribution (4.90 nm). Moreover, the existing states and the influence in mesostructure of introduced S species were detailedly investigated by the XRD, N{sub 2}-physisorption, TEM, TG-DSC, FT-IR and XPS techniques and the results showed that the S species, which existed as the type of SO{sub 4}{sup 2−}, improved the textural properties of prepared materials. In addition, the NH{sub 3}-TPD and IR spectra of adsorbed pyridine indicated the existence of strong Brønsted and Lewis acid sites in M-ZrO{sub 2}/SO{sub 4}{sup 2−} even evacuated at 400 °C. Furthermore, the M-ZrO{sub 2}/SO{sub 4}{sup 2−} was used as a promise solid acid catalyst and displayed excellent catalytic performance and reusability in Friedel-Crafts benzylation reaction.

  10. Methanetrisulfonic Acid: A Highly Efficient Strongly Acidic Catalyst for Wagner-Meerwein Rearrangement, Friedel-Crafts Alkylation and Acylation Reactions. Examples from Vitamin E Synthesis

    Directory of Open Access Journals (Sweden)

    Francesco Pace

    2009-04-01

    Full Text Available Methanetrisulfonic acid had been prepared for the first time over 140 years ago, but it was used only scarcely in chemical transformations. In the course of our activities dealing with key-steps of industrial syntheses of vitamins, e.g. economically important vitamin E (acetate, we found that methanetrisulfonic acid is an extremely effective catalyst in a variety of reactions. Examples of its applications are Wagner-Meerwein rearrangements, Friedel-Crafts alkylations and ring closures, as well as acylation reactions. Use of this catalyst in truly catalytic amounts (0.04-1.0 mol% resulted in highly selective transformations and yields over 95%. (Remark by the authors: We are describing only one example each for the various types of reactions. Therefore, it would be more appropriate to write (here and in the Introduction and in the Conclusion sections: “Wagner-Meerwein rearrangement, Friedel-Crafts alkylation and ring closure, as well as acylation reactions”

  11. Nano carbon supported platinum catalyst interaction behavior with perfluorosulfonic acid ionomer and their interface structures

    DEFF Research Database (Denmark)

    Andersen, Shuang Ma

    2016-01-01

    , the ionomer may have an adsorption preference to the platinum nano particle rather than to the overall catalyst. This was verified by a close examination on the decomposition temperature of the carbon support and the ionomer. The electrochemical stability of the catalyst ionomer composite electrode suggests...... behavior of Nafion ionomer on platinized carbon nano fibers (CNFs), carbon nano tubes (CNTs) and amorphous carbon (Vulcan). The interaction is affected by the catalyst surface oxygen groups as well as porosity. Comparisons between the carbon supports and platinized equivalents are carried out. It reveals...

  12. Esterification of oleic acid in a three-phase, fixed-bed reactor packed with a cation exchange resin catalyst.

    Science.gov (United States)

    Son, Sung Mo; Kimura, Hiroko; Kusakabe, Katsuki

    2011-01-01

    Esterification of oleic acid was performed in a three-phase fixed-bed reactor with a cation exchange resin catalyst (Amberlyst-15) at high temperature, which was varied from 80 to 120 °C. The fatty acid methyl ester (FAME) yields in the fixed-bed reactor were increased with increases in the reaction temperature, methanol flow rate and bed height. Moreover, the FAME yields were higher than those obtained using a batch reactor due to an equilibrium shift toward the product that resulted from continuous evaporation of the produced water. In addition, there was no catalyst deactivation during the esterification of oleic acid. However, addition of sunflower oil to the oleic acid reduced the FAME yield obtained from simultaneous esterification and transesterification. The FAME yield was 97.5% at a reaction temperature of 100 °C in the fixed-bed with a height of 5 cm when the methanol and oleic acid feed rates were 8.6 and 9.0 mL/h, respectively. Copyright © 2010 Elsevier Ltd. All rights reserved.

  13. Statistical Optimization for Acid Hydrolysis of Microcrystalline Cellulose and Its Physiochemical Characterization by Using Metal Ion Catalyst

    Directory of Open Access Journals (Sweden)

    Md. Ziaul Karim

    2014-10-01

    Full Text Available Hydrolyzing the amorphous region while keeping the crystalline region unaltered is the key technology for producing nanocellulose. This study investigated if the dissolution properties of the amorphous region of microcrystalline cellulose can be enhanced in the presence of Fe3+ salt in acidic medium. The process parameters, including temperature, time and the concentration of metal chloride catalyst (FeCl3, were optimized by using the response surface methodology (RSM. The experimental observation demonstrated that temperature and time play vital roles in hydrolyzing the amorphous sections of cellulose. This would yield hydrocellulose with higher crystallinity. The factors that were varied for the production of hydrocellulose were the temperature (x1, time (x2 and FeCl3 catalyst concentration (x3. Responses were measured in terms of percentage of crystallinity (y1 and the yield (y2 of the prepared hydrocellulose. Relevant mathematical models were developed. Analysis of variance (ANOVA was carried out to obtain the most significant factors influencing the responses of the percentage of crystallinity and yield. Under optimum conditions, the percentage of crystallinity and yield were 83.46% and 86.98% respectively, at 90.95 °C, 6 h, with a catalyst concentration of 1 M. The physiochemical characteristics of the prepared hydrocellulose were determined in terms of XRD, SEM, TGA and FTIR analyses. The addition of FeCl3 salt in acid hydrolyzing medium is a novel technique for substantially increasing crystallinity with a significant morphological change.

  14. Commercial- and whitewashing-grade limestone as a heterogeneous catalyst for synthesis of fatty acid methyl esters from used frying oil (UFO)

    Energy Technology Data Exchange (ETDEWEB)

    Agrawal, Shweta; Singh, Bhaskar; Sharma, Yogesh C. [Banaras Hindu University, Department of Applied Chemistry, Institute of Technology, Varanasi (India); Frometa, Amado Enrique N. [Universidad Tecnologica de Izucar de Matamoros, Puebla (Mexico)

    2012-12-15

    Commercial-grade limestone used in whitewashing which is a low-cost material has been used as a catalyst for the synthesis of fatty acid methyl esters. The catalyst was characterized by differential thermal analysis/thermogravimetric analysis, X-ray diffraction, and Fourier transform infrared spectroscopy for the study of its physicochemical nature. The catalyst was calcined at 900 C for 2.5 h for the decomposition of calcium carbonate to calcium oxide. The catalyst was further activated by dissolving 1.5 wt% of catalyst in 30 ml methanol (7.5:1, methanol to used frying oil molar ratio) and stirred at 25 C for 1 h on a magnetic stirrer. The transesterification reaction was performed using calcium oxide as a catalyst and then with the ''activated calcium oxide.'' The conversion obtained was 94.4 % with calcium oxide and was found to be lower for the ''activated calcium oxide'' (i.e., 87.36 %). The conversion increased to 96.8 % on increasing the catalyst amount to 2.0 wt% in 5 h. A high yield (>95 %) of fatty acid methyl esters was observed when either calcium oxide or ''activated calcium oxide'' was taken as catalyst. The catalytic activity of calcium oxide obtained from low-grade limestone has been found to be comparable with the laboratory-grade CaO. (orig.)

  15. A novel 3D inorganic heteropoly blue as visible light responsive photocatalyst.

    Science.gov (United States)

    Fei, Bao-Li; Li, Wen; Wang, Jinag-Hong; Liu, Qing-Bo; Long, Jiang-Ying; Li, Yang-Guang; Shao, Kui-Zhan; Su, Zhong-Min; Sun, Wei-Yin

    2014-07-14

    A new 3D extended heteropoly blue Ba4[SiW(V)4W(VI)8O40]·H2O (1) composed of twelve-coordinated α-Keggin anions [SiW(V)4W(VI)8O40](8-) and eight-coordinated Ba sites {BaO8} has been hydrothermally synthesized and fully characterized by elemental analysis, IR spectroscopy, XPS, single crystal X-ray and X-ray powder (XRPD) diffraction. 1 represents the first inorganic 3D framework constructed from four-electron reduced α-Keggin anions linked by alkaline earth metals. The photocatalytic activity of 1 has been evaluated for rhodamine B (RhB) degradation. 1 exhibits excellent catalytic activity for the degradation of RhB in the presence of H2O2and the involvement of visible light makes a more complete degradation. The results of the current study suggest that multi-electron reduced polyoxometalates can catalyze efficient degradation of an organic dye with H2O2.

  16. Graphene nanosheets-polypyrrole hybrid material as a highly active catalyst support for formic acid electro-oxidation

    Science.gov (United States)

    Yang, Sudong; Shen, Chengmin; Liang, Yanyu; Tong, Hao; He, Wei; Shi, Xuezhao; Zhang, Xiaogang; Gao, Hong-Jun

    2011-08-01

    A novel electrode material based on graphene oxide (GO)-polypyrrole (PPy) composites was synthesized by in situ chemical oxidation polymerization. Palladium nanoparticles (NPs) with a diameter of 4.0 nm were loaded on the reduced graphene oxide(RGO)-PPy composites by a microwave-assisted polyol process. Microstructure analysis showed that a layer of coated PPy film with monodisperse Pd NPs is present on the RGO surface. The Pd/RGO-PPy catalysts exhibit excellent catalytic activity and stability for formic acid electro-oxidation when the weight feed ratio of GO to pyrrole monomer is 2 : 1. The superior performance of Pd/RGO-PPy catalysts may arise from utilization of heterogeneous nucleation sites for NPs and the greatly increased electronic conductivity of the supports.

  17. Highly efficient Brønsted acidic ionic liquid-based catalysts for biodiesel synthesis from vegetable oils.

    Science.gov (United States)

    Ghiaci, M; Aghabarari, B; Habibollahi, S; Gil, A

    2011-01-01

    Biodiesel has been produced by transesterification of canola oil with methanol in the presence of highly Brønsted acidic ionic liquids based on 1-benzyl-1H-benzimidazole, and the effect of reaction temperature, type and amount of catalyst, molar ratio and reaction time investigated. The results show that the 4B ionic liquid has the highest catalytic activity and best recyclability under the optimised reaction conditions. Thus, this ionic liquid is able to catalyze the transesterification of canola oil to its methyl esters in 5 h with yields of more than 95%. Density functional calculations (B3LYP), using the 6-311G basis set, have been performed to have a better understanding on the reactivity of these catalysts. The catalytic activity of 4B for the transesterification of other vegetable oils and alcohols has also been studied. Copyright © 2010 Elsevier Ltd. All rights reserved.

  18. Effect of phosphoric acid as a catalyst on the hydrothermal pretreatment and acidogenic fermentation of food waste.

    Science.gov (United States)

    Shen, Dongsheng; Wang, Kun; Yin, Jun; Chen, Ting; Yu, Xiaoqin

    2016-05-01

    The hydrothermal method was applied to food waste (FW) pretreatment with phosphoric acid as a catalyst. The content of soluble substances such as protein and carbohydrate in the FW increased after the hydrothermal pretreatment with phosphoric acid addition (⩽5%). The SCOD approached approximately 29.0g/L in 5% phosphoric acid group, which is almost 65% more than the original FW. The hydrothermal condition was 160°C for 10min, which means that at least 40% of energy and 60% of reaction time were saved to achieve the expected pretreatment effect. Subsequent fermentation tests showed that the optimal dosage of phosphoric acid was 3% with a VFA yield of 0.763g/gVSremoval, but the increase in salinity caused by phosphoric acid could adversely affect the acidogenesis. With an increase in the quantity of phosphoric acid, among the VFAs, the percentage of propionic acid decreased and that of butyric acid increased. The PCR-DGGE analysis indicated that the microbial diversity could decrease with excessive phosphoric acid, which resulted in a low VFA yield. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Preparation and characterization oF Ru-Sn/Al2O3 catalysts for the hydrogenation of fatty acid methyl esters

    Directory of Open Access Journals (Sweden)

    Vanina A. Mazzieri

    2010-01-01

    Full Text Available Ru-Sn/Al2O3 catalysts with different Sn loadings were prepared by the coimpregnation method. Several characterization techniques such as TPR, pyridine TPD and catalytic tests for dehydrogenation and hydrogenolysis were used to evaluate and compare such catalysts. TPR results indicate that Sn is deposited both onto the support and as species strongly interacting with Ru. Such non selective deposition modifies the acid and metallic functions of the catalysts. Both total acidity and acid strength distribution are affected: total acidity decreases and new sites of lower acid strength are created. Both dehydrogenating and hydrogenolytic activities are strongly diminished by the addition of Sn. Results of catalytic tests for methyl oleate hydrogenation indicate that methyl stearate is the main product, with only minute amounts of oleyl alcohol produced, and that the addition of Sn diminishes the hydrogenation activity.

  20. Preparation and characterization of Ru-Sn/Al{sub 2}O{sub 3} catalysts for the hydrogenation of fatty acid methyl esters

    Energy Technology Data Exchange (ETDEWEB)

    Mazzieri, Vanina A.; Sad, Mario R.; Vera, Carlos R.; Pieck, Carlos L. [Consejo Nacional de Investigaciones Cientificas y Tecnicas, Santa Fe (Argentina). Universidad Nacional del Litoral. Inst. de Investigaciones en Catalisis y Petroquimica; Grau, Ricardo [Consejo Nacional de Investigaciones Cientificas y Tecnicas, Santa Fe (Argentina). Universidad Nacional del Litoral. Inst. de Desarrollo Tecnologico para la Industria Quimica

    2010-07-01

    Ru-Sn/Al{sub 2}O{sub 3} catalysts with different Sn loadings were prepared by the coimpregnation method. Several characterization techniques such as TPR, pyridine TPD and catalytic tests for dehydrogenation and hydrogenolysis were used to evaluate and compare such catalysts. TPR results indicate that Sn is deposited both onto the support and as species strongly interacting with Ru. Such non selective deposition modifies the acid and metallic functions of the catalysts. Both total acidity and acid strength distribution are affected: total acidity decreases and new sites of lower acid strength are created. Both dehydrogenating and hydrogenolytic activities are strongly diminished by the addition of Sn. Results of catalytic tests for methyl oleate hydrogenation indicate that methyl stearate is the main product, with only minute amounts of oleyl alcohol produced, and that the addition of Sn diminishes the hydrogenation activity. (author)

  1. Catalyst mixtures

    Science.gov (United States)

    Masel, Richard I.; Rosen, Brian A.

    2017-02-14

    Catalysts that include at least one catalytically active element and one helper catalyst can be used to increase the rate or lower the overpotential of chemical reactions. The helper catalyst can simultaneously act as a director molecule, suppressing undesired reactions and thus increasing selectivity toward the desired reaction. These catalysts can be useful for a variety of chemical reactions including, in particular, the electrochemical conversion of CO.sub.2 or formic acid. The catalysts can also suppress H.sub.2 evolution, permitting electrochemical cell operation at potentials below RHE. Chemical processes and devices using the catalysts are also disclosed, including processes to produce CO, OH.sup.-, HCO.sup.-, H.sub.2CO, (HCO.sub.2).sup.-, H.sub.2CO.sub.2, CH.sub.3OH, CH.sub.4, C.sub.2H.sub.4, CH.sub.3CH.sub.2OH, CH.sub.3COO.sup.-, CH.sub.3COOH, C.sub.2H.sub.6, O.sub.2, H.sub.2, (COOH).sub.2, or (COO.sup.-).sub.2, and a specific device, namely, a CO.sub.2 sensor.

  2. Synthesis of mesoporous Cr/ZSM-5 and W-Cr/ZSM-5 zeolite catalysts for oxidation of unsaturated fatty acid

    Science.gov (United States)

    Hoang, Phan Huy; Nhung, Nguyen Thi; Dien, Le Quang

    2017-10-01

    The mesoporous Cr/ZSM-5 and W-Cr/ZSM-5 zeolites have been successfully synthesized by loading chromium and tungsten on zeolite support. The metal loaded ZSM-5 catalysts were analyzed by several characterizations such as XRD, SEM-EDS, TEM, and BET. The catalytic activities and recycle efficiency were also investigated by applying catalysts for oxidation of oleic acid. These catalysts exhibited the high catalytic efficiency for cleavage of double bond with the use of H2O2. The oleic conversion of 88.7% and 93.3% could be achieved for Cr/ZSM-5 and W-Cr/ZSM-5 catalyst, respectively. Moreover, the modified ZSM-5 catalysts also demonstrated a long life time and high stability.

  3. Synthesis of mesoporous Cr/ZSM-5 and W-Cr/ZSM-5 zeolite catalysts for oxidation of unsaturated fatty acid

    Directory of Open Access Journals (Sweden)

    Phan Huy Hoang

    2017-10-01

    Full Text Available The mesoporous Cr/ZSM-5 and W-Cr/ZSM-5 zeolites have been successfully synthesized by loading chromium and tungsten on zeolite support. The metal loaded ZSM-5 catalysts were analyzed by several characterizations such as XRD, SEM-EDS, TEM, and BET. The catalytic activities and recycle efficiency were also investigated by applying catalysts for oxidation of oleic acid. These catalysts exhibited the high catalytic efficiency for cleavage of double bond with the use of H2O2. The oleic conversion of 88.7% and 93.3% could be achieved for Cr/ZSM-5 and W-Cr/ZSM-5 catalyst, respectively. Moreover, the modified ZSM-5 catalysts also demonstrated a long life time and high stability.

  4. Metaloxide--ZrO2 catalysts for the esterification and transesterification of free fatty acids and triglycerides to obtain bio-diesel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Manhoe; Salley, Steven O.; Ng, K. Y. Simon

    2016-09-06

    Mixed metal oxide catalysts (ZnO, CeO, La2O3, NiO, Al203, SiO2, TiO2, Nd2O3, Yb2O3, or any combination of these) supported on zirconia (ZrO2) or hydrous zirconia are provided. These mixed metal oxide catalysts can be prepared via coprecipitation, impregnation, or sol-gel methods from metal salt precursors with/without a Zirconium salt precursor. Metal oxides/ZrO2 catalyzes both esterification and transesterification of oil containing free fatty acids in one batch or in single stage. In particular, these mixed metal oxides supported or added on zirconium oxide exhibit good activity and selectivity for esterification and transesterification. The low acid strength of this catalyst can avoid undesirable side reaction such as alcohol dehydration or cracking of fatty acids. Metal oxides/ZrO2 catalysts are not sensitive to any water generated from esterification. Thus, esterification does not require a water free condition or the presence of excess methanol to occur when using the mixed metal oxide catalyst. The FAME yield obtained with metal oxides/ZrO2 is higher than that obtained with homogeneous sulfuric acid catalyst. Metal oxides/ZrO2 catalasts can be prepared as strong pellets and in various shapes for use directly in a flow reactor. Furthermore, the pellet has a strong resistance toward dissolution to aqueous or oil phases.

  5. Catalytic Epoxidation of Limonene

    Directory of Open Access Journals (Sweden)

    E. Herrero

    2000-03-01

    Full Text Available The epoxidation of limonene with hidrogen peroxide was studied over zeolite Tibeta (a large pore material and heteropoly acids on carbono and alumina supported. PW11/C was catalyst the best tested.

  6. Hazardous waste to materials: recovery of molybdenum and vanadium from acidic leach liquor of spent hydroprocessing catalyst using alamine 308.

    Science.gov (United States)

    Sahu, K K; Agrawal, Archana; Mishra, D

    2013-08-15

    Recovery of valuable materials/metals from waste goes hand in hand with environmental protection. This paper deals with the development of a process for the recovery of metals such as Mo, V, Ni, Al from spent hydroprocessing catalyst which may otherwise cause a nuisance if dumped untreated. A detailed study on the separation of molybdenum and vanadium from the leach solution of spent hydroprocessing catalyst of composition: 27.15% MoO₃, 1.7% V₂O₅, 3.75% NiO, 54.3% Al₂O₃, 2.3% SiO₂ and 10.4% LOI is reported in this paper. The catalyst was subjected to roasting under oxidizing atmosphere at a temperature of about 550 °C and leaching in dilute sulphuric acid to dissolve molybdenum, vanadium, nickel and part of aluminium. Metals from the leach solution were separated by solvent extraction. Both molybdenum and vanadium were selectively extracted with a suitable organic solvent leaving nickel and dissolved aluminium in the raffinate. Various parameters such as initial pH of the aqueous feed, organic to aqueous ratio (O:A), solvent concentration etc. were optimized for the complete extraction and recovery of Mo and V. Molybdenum and vanadium from the loaded organic were stripped by ammonia solution. They were recovered as their corresponding ammonium salt by selective precipitation, and were further calcined to get the corresponding oxides in pure form. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Insight into the Effect of Sn on CO and Formic Acid Oxidation at PtSn Catalysts

    DEFF Research Database (Denmark)

    Stevanović, S.; Tripković, D.; Tripkovic, Vladimir

    2014-01-01

    The role of Sn on the catalytic activity for CO and formic acid oxidation is studied by comparing the activities of differently treated PtSn/C and Pt/C catalysts. The catalysts are prepared by a microwave-assisted polyol synthesis method. As revealed by scanning tunneling and transmission electron...... microscopic (STM and TEM) characterization, the outcomes of the synthesis procedure for both Pt and PtSn are small particles, ∼1.5 nm in diameter. Upon deposition on the carbon support, the particle size increases to ∼2.5 nm due to sintering. X-ray diffraction (XRD) analysis shows that PtSn/C has a low...... alloying degree and is mainly composed of Pt and Pt3Sn phases. The remaining Sn is present in the form of very small tin oxide particles. Different surfaces are obtained by double-layer, oxide, and CO annealing of the Pt/C and PtSn/C catalysts and by modifying the CO-annealed surfaces with irreversibly...

  8. Synthesis of carbon supported palladium nanoparticles catalyst using a facile homogeneous precipitation-reduction reaction method for formic acid electrooxidation

    Science.gov (United States)

    Ma, Juan; Ji, Yigang; Sun, Hanjun; Chen, Yu; Tang, Yawen; Lu, Tianhong; Zheng, Junwei

    2011-10-01

    A highly dispersed and ultrafine carbon supported Pd nanoparticles (Pd/C) catalyst is synthesized by a facile homogeneous precipitation-reduction reaction method. Under the appropriate pH conditions, [PdCl 4] 2- species in PdCl 2 solution are slowly transformed into the insoluble palladium oxide hydrate (PdO·H 2O) precipitation by heat treatment due to a slow hydrolysis reaction, which results in the generation of carbon supported PdO·H 2O nanoparticles (PdO·H 2O/C) sample with the high dispersion and small particle size. Consequently, a highly dispersed and ultrafine Pd/C catalyst can be synthesized by PdO·H 2O → Pd 0 in situ reduction reaction path in the presence of NaBH 4. As a result, the resulting Pd/C catalyst possesses a significantly electrocatalytic performance for formic acid electrooxidation, which is attributed to the uniformly sized and highly dispersed nanostructure.

  9. Acidic Zeolite L as a Highly Efficient Catalyst for Dehydration of Fructose to 5-Hydroxymethylfurfural in Ionic Liquid.

    Science.gov (United States)

    Ma, Zhongsen; Hu, Hualei; Sun, Zhongqiang; Fang, Wenting; Zhang, Jian; Yang, Longfei; Zhang, Yajie; Wang, Lei

    2017-04-22

    Zeolite L was synthesized by the hydrothermal method and post-treated by NH4 exchange to adjust its acidity. The samples were systematic characterized by various techniques including XRD, X-ray fluorescence spectroscopy, N2 adsorption-desorption, scanning electron microscopy, pyridine IR spectroscopy, and NH3 temperature-programmed desorption. The results demonstrated that the NH4 -exchange post-treatment increased the surface area, micropore volume, and acidity of zeolite L. The catalytic performance of the samples was tested in the dehydration of fructose to 5-hydroxymethylfurfural (HMF) in ionic liquid (1-butyl-3-methylimidazolium bromide, [bmim]Br). 99.1 % yield of HMF was obtained when the KL-80 °C-1 h sample (KL zeolite treated with 1 m NH4 NO3 solution at 80 °C for 1 h) was used. The high efficiency could be attributed to the appropriate acid properties of the catalyst. The zeolite catalyst could be reused four times without significant decrease in activity. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Synthesis, Acidity and Catalytic of the Rare Earth Ce Loaded on the Composite Pore Zeolite Catalyst for Hydrogenation Cracking

    Science.gov (United States)

    Shi, Chunwei; Wu, Wenyuan; Bian, Xue; Pei, Mingyuan; Zhao, Shanlin; Chen, Ping

    2017-07-01

    Composite molecular sieve Y/SBA-15(C-Y) was prepared by microwave method, while Ce was loaded by ion exchange method to the composite molecular sieves (Ce-Y/SBA-15 (C-X)). Productive-type middle distillate hydrocracking catalyst was prepared from C-X and C-Y loaded. FI-IR, XPS, Pyridine IR, and TG-DTG had been used to characterize the C-X's and C-Y's structure and acidity. The results showed that Ce loaded not only had not broken the original structure of C-Y, but also improved silica alumina ratio of C-X, furthermore improved its total acid content. Through polarization and entrainment, Ce increased the skeleton and hydroxyl silicon aluminum hydroxy on electronic probability of migration to the cage, thus enhance the C-X's B acid strength, make it more suitable for heavy oil processing. As compared with C-Y, the selectivity and yield of middle distillates over C-X was 0.7 % and 1.8 % higher, respectively. C-X have the greatest relief wax oil viscosity index, best once cracking selectivity, and lowest levels of diesel oil solidifying point in the three catalysts.

  11. Synthesis of multi-functionalized benzofurans through the condensation of ninhydrin and phenols using SSA as a recyclable heterogeneous acid catalyst.

    Science.gov (United States)

    Kundu, Ashis; Pramanik, Animesh

    2016-08-01

    A simple and efficient one-pot methodology has been developed for the synthesis of biologically important multi-functionalized 3-(2[Formula: see text]-hydroxyaryl)-2-(2[Formula: see text]-carboxyphenyl)benzofurans using silica sulfuric acid (SSA) as a heterogeneous acid catalyst in DMF medium. The significant advantages of this methodology are the use of SSA as a recyclable solid acid catalyst, operational simplicity, easy availability of the starting materials, and good yield of the products with high atom-economy.

  12. Effects of acid catalyst type on structural, morphological, and optoelectrical properties of spin-coated TiO{sub 2} thin film

    Energy Technology Data Exchange (ETDEWEB)

    Golobostanfard, Mohammad Reza, E-mail: Bostanfr@ut.ac.ir [School of Metallurgy and Materials Engineering, College of engineering, University of Tehran, PO Box: 14395-553, Tehran (Iran, Islamic Republic of); Abdizadeh, Hossein [School of Metallurgy and Materials Engineering, College of engineering, University of Tehran, PO Box: 14395-553, Tehran (Iran, Islamic Republic of)

    2013-03-15

    The effects of different acid catalysts of nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, boric acid, acetic acid, and citric acid on structural, morphological, and optoelectrical properties of nanocrystalline spin-coated TiO{sub 2} thin films synthesized via alkoxide sol–gel route were investigated. It was found that only the sols with HNO{sub 3} and HCl are suitable for film preparation. The X-ray diffractometry and Raman analysis showed that crystalline phases could be controlled by the type of acid catalyst. Although the H{sub 2}SO{sub 4} sol shows good stability, it causes extremely different morphology to form due to its different sol nature and high contact angle. Fourier transformed infrared spectra confirmed the presence of acid anion species in all samples even after calcination. Furthermore, it was inferred from UV–visable absorption spectra that although the band gap and thickness of the films are independent of acid catalyst type, the refractive index and porosity of the films are strongly affected by the type of acids.

  13. Steam reforming of acetic acid as a biomass derived oxygenate: Bifunctional pathway for hydrogen formation over Pt/ZrO2 catalysts.

    NARCIS (Netherlands)

    Takanabe, K.; Aika, Ken-ichi; Inazu, Koji; Baba, Toshihide; Seshan, Kulathuiyer; Lefferts, Leonardus

    2006-01-01

    Mechanistic studies on steam reforming of acetic acid over Pt/ZrO2 catalysts were performed as extension of our previous work [K. Takanabe, K. Aika, K. Seshan, L. Lefferts, J. Catal. 227 (2004) 101]. An overall picture of the bifunctional mechanism is established for steam reforming of acetic acid,

  14. Amine grafted silica supported CrAuPd alloy nanoparticles: superb heterogeneous catalysts for the room temperature dehydrogenation of formic acid.

    Science.gov (United States)

    Yurderi, Mehmet; Bulut, Ahmet; Caner, Nurdan; Celebi, Metin; Kaya, Murat; Zahmakiran, Mehmet

    2015-07-21

    Herein we show that a previously unappreciated combination of CrAuPd alloy nanoparticles and amine-grafted silica support facilitates the liberation of CO-free H2 from dehydrogenation of formic acid with record activity in the absence of any additives at room temperature. Furthermore, their excellent catalytic stability makes them isolable and reusable heterogeneous catalysts in the formic acid dehydrogenation.

  15. Conversion of succinic acid to 1,4-butanediol via dimethyl succinate over rhenium nano-catalyst supported on copper-containing mesoporous carbon.

    Science.gov (United States)

    Hong, Ung Gi; Kim, Jeong Kwon; Lee, Joongwon; Lee, Jong Kwon; Yi, Jongheop; Song, In Kyu

    2014-11-01

    Copper-containing mesoporous carbons (XCu-MC) with different copper content (X = 8.0, 12.7, 15.9, 23.3, and 26.8 wt%) were prepared by a single-step surfactant-templating method. Rhenium nano-catalysts supported on copper-containing mesoporous carbons (Re/XCu-MC) were then prepared by an incipient wetness method. Re/XCu-MC (X = 8.0, 12.7, 15.9, 23.3, and 26.8 wt%) catalysts were characterized by nitrogen adsorption-desorption isotherm, HR-TEM, FT-IR, and H2- TPR analyses. Liquid-phase hydrogenation of succinic acid to 1,4-butanediol (BDO) via dimethyl succinate (DMS) was carried out over Re/XCu-MC catalysts in a batch reactor. The effect of copper content on the physicochemical properties and catalytic activities of Re/XCu-MC catalysts in the hydrogenation of succinic acid to BDO was investigated. Re/XCu-MC catalysts retained different physicochemical properties depending on copper content. In the hydrogenation of succinic acid to BDO, yield for BDO showed a volcano-shaped trend with respect to copper content. Thus, an optimal copper content was required to achieve maximum catalytic performance of Re/XCu-MC. It was also observed that yield for BDO increased with increasing the amount of hydrogen consumption by copper in the Re/XCu-MC catalysts.

  16. Conversion of Sugars to Lactic Acid Derivatives Using Heterogeneous Zeotype Catalysts

    DEFF Research Database (Denmark)

    Holm, Martin Spangsberg; Shunmugavel, Saravanamurugan; Taarning, Esben

    2010-01-01

    of mono-and disaccharides that are dissolved in methanol to methyl lactate at 160 C. With sucrose as the substrate, methyl lactate yield reaches 68%, and the heterogeneous catalyst can be easily recovered by filtration and reused multiple times after calcination without any substantial change...

  17. Permanganic acid: a novel precursor for the preparation of manganese oxide catalysts

    NARCIS (Netherlands)

    Kappenstein, C.; Wahdan, T.; Duprez, D.; Zaki, M.I.; Brands, D.; Poels, E.; Bliek, A.

    1995-01-01

    Unsupported and ψ-alumina supported MnOx catalysts (1-10 wt-% Mn) were preparedfrom aqueous solutions of HMnO4 and compared with nitrate based samples. They were characterized by XRD, XPS, BET area, oxygen storage capacity and by their catalytic behaviour versus ammonia DeNOx reaction. The

  18. Acid-activated Bentonite (Maghnite-H+) as a Novel Catalyst for the ...

    Indian Academy of Sciences (India)

    31

    which causes the broadening of the MMD [10,11], the yield of cyclic structures depends primarily on the type of catalyst ..... indicating the formation of ethylene bridges between linear polymer chains. These results .... can be explained by backbiting degradation in the growing polymer chains, which generates oligomers and ...

  19. Silica Sulphuric Acid as an Efficient Catalyst for the Catalytic and ...

    African Journals Online (AJOL)

    NJD

    azoxy and other compounds.12–17. The product composition depends on the oxidants, catalysts and reaction conditions employed and the selective oxidation of amines is consequently very rare and valuable. However, for production of the nitro compounds, the best reaction conditions and reagents should be chosen and ...

  20. The utilization of catalyst sorbent in scrubbing acid gases from incineration flue gas.

    Science.gov (United States)

    Wey, Ming-Yen; Lu, Chi-Yuan; Tseng, Hui-Hsin; Fu, Cheng-Hao

    2002-04-01

    Catalyst sorbents based on alumina-supported CuO, CeO2, and CuO-CeO2 were applied to a dry scrubber to clean up the SO2/HCl/NO simultaneously from pilot-scale fluidized-bed incineration flue gas. In the presence of organic compounds, CO and the submicron particles SO2 and HCI removed by the fresh catalyst sorbents and NO reduced to N2 by NH3 under the catalysis of fresh and spent desulfurization/dechloridization (DeSO2/DeHCl) catalyst sorbents (copper compounds, Cu, CuO, and CuSO4) were evaluated in this paper. The fresh and spent catalyst sorbents were characterized by the Brunner-Emmett-Teller method (BET), X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), inductively coupled plasma-mass spectrometry (ICP-MS), and the elemental analyzer (EA). The study showed that the performances of CuO, CeO2, and CuO-CeO2/gamma-Al2O3 were better than that of Ca(OH)2. The removal efficiency of SO2 and HCl was 80-95% in the dry scrubber system. Under NH3/NO = 1, NO could not be reduced to N2 because it was difficult to control the ratio of air/fuel in the flue gas. For estimating the feasibility of regenerating the spent catalyst sorbents, BET and EA analyses were used. They indicated that the pore structures were nearly maintained and a small amount of carbon accumulated on their surface.

  1. The Aerobic Oxidation of Bromide to Dibromine Catalyzed by Homogeneous Oxidation Catalysts and Initiated by Nitrate in Acetic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Partenheimer, Walt; Fulton, John L.; Sorensen, Christina M.; Pham, Van Thai; Chen, Yongsheng

    2014-06-01

    A small amount of nitrate, ~0.002 molal, initiates the Co/Mn catalyzed aerobic oxidation of bromide compounds (HBr,NaBr,LiBr) to dibromine in acetic acid at room temperature. At temperatures 40oC or less , the reaction is autocatalytic. Co(II) and Mn(II) themselves and mixed with ionic bromide are known homogeneous oxidation catalysts. The reaction was discovered serendipitously when a Co/Br and Co/Mn/Br catalyst solution was prepared for the aerobic oxidation of methyaromatic compounds and the Co acetate contained a small amount of impurity i.e. nitrate. The reaction was characterized by IR, UV-VIS, MALDI and EXAFS spectroscopies and the coordination chemistry is described. The reaction is inhibited by water and its rate changed by pH. The change in these variables, as well as others, are identical to those observed during homogeneous, aerobic oxidation of akylaromatics. A mechanism is proposed. Accidental addition of a small amount of nitrate compound into a Co/Mn/Br/acetic acid mixture in a large, commercial feedtank is potentially dangerous.

  2. Hydrometallurgical route to recover molybdenum, nickel, cobalt and aluminum from spent hydrotreating catalysts in sulphuric acid medium.

    Science.gov (United States)

    Valverde, Ivam Macedo; Paulino, Jéssica Frontino; Afonso, Julio Carlos

    2008-12-30

    This work describes a hydrometallurgical route for processing spent commercial catalysts (CoMo and NiMo/Al2O3), for recovering the active phase and support components. They were initially pre-oxidized (500 degrees C, 5h) in order to eliminate coke and other volatile species present. Pre-oxidized catalysts were dissolved in H2SO4 (9molL-1) at approximately 90 degrees C, and the remaining residues separated from the solution. Molybdenum was recovered by solvent extraction using tertiary amines. Alamine 304 presented the best performance at pH around 1.8. After this step, cobalt (or nickel) was separated by adding aqueous ammonium oxalate in the above pH. Before aluminum recovery, by adding NaOH to the acid solution, phosphorus (H2PO4-) was removed by passing the liquid through a strong anion exchange column. Final wastes occur as neutral and colorless sodium sulphate solutions and the insoluble solid in the acid leachant. The hydrometallurgical route presented in this work generates less final aqueous wastes, as it is not necessary to use alkaline medium during the metal recovery steps. The metals were isolated in very high yields (>98wt.%).

  3. Selective oxidation of lignocellulosic biomass to formic acid and high-grade cellulose using tailor-made polyoxometalate catalysts.

    Science.gov (United States)

    Albert, Jakob

    2017-09-21

    The main goal of this project was to identify and optimize tailor-made polyoxometalate catalysts for a fractionated oxidation of lignocellulosic biomass (i.e. wood and residues from sugar or paper industries) to produce formic acid (FA) and high-grade cellulose for further processing e.g. in white biotechnology to provide bio-ethanol. Homogeneous vanadium precursors like sodium metavanadate and vanadyl sulfate as well as Keggin-type polyoxometalates (POMs) and more exotic structures like Anderson-, Wells-Dawson- and Lindqvist-type POMs were screened for the desired catalytic performance. The most promising behaviour was found using the Lindqvist-type POM K5V3W3O19, showing for the first time in the literature a selective oxidation of only hemicellulose and lignin to formic acid, while the cellulose fraction was untrapped. However, this can only be a first step towards the project goal as low product yields were obtained.

  4. Visible-light-driven Photocatalytic N-arylation of Imidazole Derivatives and Arylboronic Acids on Cu/graphene catalyst.

    Science.gov (United States)

    Cui, Yan-Li; Guo, Xiao-Ning; Wang, Ying-Yong; Guo, Xiang-Yun

    2015-07-20

    N-aryl imidazoles play an important role as structural and functional units in many natural products and biologically active compounds. Herein, we report a photocatalytic route for the C-N cross-coupling reactions over a Cu/graphene catalyst, which can effectively catalyze N-arylation of imidazole and phenylboronic acid, and achieve a turnover frequency of 25.4 h(-1) at 25°C and the irradiation of visible light. The enhanced catalytic activity of the Cu/graphene under the light irradiation results from the localized surface plasmon resonance of copper nanoparticles. The Cu/graphene photocatalyst has a general applicability for photocatalytic C-N, C-O and C-S cross-coupling of arylboronic acids with imidazoles, phenols and thiophenols. This study provides a green photocatalytic route for the production of N-aryl imidazoles.

  5. One-Pot Synthesis of Graphene-Supported Monodisperse Pd Nanoparticles as Catalyst for Formic Acid Electro-oxidation

    Science.gov (United States)

    Yang, Sudong; Dong, Jing; Yao, Zhaohui; Shen, Chengmin; Shi, Xuezhao; Tian, Yuan; Lin, Shaoxiong; Zhang, Xiaogang

    2014-03-01

    To synthesize monodisperse palladium nanoparticles dispersed on reduced graphene oxide (RGO) sheets, we have developed an easy and scalable solvothermal reduction method from an organic solution system. The RGO-supported palladium nanoparticles with a diameter of 3.8 nm are synthesized in N-methyl-2-pyrrolidone (NMP) and in the presence of oleylamine and trioctylphosphine, which facilitates simultaneous reduction of graphene oxide and formation of Pd nanocrystals. So-produced Pd/RGO was tested for potential use as electrocatalyst for the electro-oxidation of formic acid. Pd/RGO catalyzes formic acid oxidation very well compared to Pd/Vulcan XC-72 catalyst. This synthesis method is a new way to prepare excellent electrocatalysts, which is of great significance in energy-related catalysis.

  6. Development of acidity on sol-gel prepared TiO{sub 2}-SiO{sub 2} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Calvino, J.J.; Cauqui, M.A.; Gatica, J.M.; Perez, J.A.; Rodriguez-Izquierdo, J.M. [Univ. de Cadiz, Puerto Real (Spain)

    1994-12-31

    Three different TiO{sub 2}-SiO{sub 2} gels (Xerogel, Carbogel and Aerogel) are more active acid catalysts than other reference samples used here. As deduced from FTIR, XRD and XANES studies, the structural properties of these gels are quite different to each other, thus revealing the strong influence of the drying treatment. It is found that the degree of Si-O-Ti linking and the surface acidity follows the same trend (X > C > A). The authors conclude that supercritical drying at 600 K and 190 bars can induce Ti leaching followed by redeposition in the narrower pores of the gel. These effects modify both the textural and surface chemical properties of the resulting material.

  7. Brønsted Acid Ionic Liquids (BAILs) as Efficient and Recyclable Catalysts in the Conversion of Glycerol to Solketal at Room Temperature

    DEFF Research Database (Denmark)

    Gui, Zhenyou; Zahrtmann, Nanette; Shunmugavel, Saravanamurugan

    2016-01-01

    Brønsted acid ionic liquids (BAILs) have been prepared and applied for the first time - to the best of our knowledge - as efficient catalysts in the acetylation of glycerol with acetone to form solketal ((2,2-dimethyl-1,3-dioxolan-4-yl)methanol) at very mild reaction conditions (room temperature......) and short reaction times. The BAILs showed a superior catalytic performance in terms of both conversion and selectivity compared to the common mineral acid methanesulfonic acid as well as to other reported homogeneous and heterogeneous catalysts. Catalyst reusability was demonstrated with one of the BAILs...... (BAIL-1), which was recovered and reused by a simple procedure in four consecutive reaction runs without any loss of catalytic activity and selectivity. Thus, the BAILs combine the advantages of both homogeneous and heterogeneous catalysis with respect to excellent conversion and selectivity as well...

  8. [Catalytic stability in wet air oxidation of carboxylic acids over ZnFe0.25Al1.75 O4 catalyst].

    Science.gov (United States)

    Xu, Ai-hua; Yang, Min; Du, Hong-zhang; Peng, Fu-yong; Sun, Cheng-lin

    2007-07-01

    Oxalic, formic and acetic acid are main intermediate products in catalytic wet air oxidation process (CWAO). The catalytic activity and stability in CWAO of the three short-chain organic acids over ZnFe0.25Al1.75O4 catalyst were studied. Oxalic acid is the only oxidizable intermediate and the largest amount of Fe leaching is 9.5 mg L(-1) at 160 degrees C during CWAO process. Formic and acetic acid have little influence on Fe leaching. Due to the strong reducible ability of oxalic acid, the amount of Fe leaching is larger in nitrogen atmosphere than that in oxygen atmosphere. Salicylic acid can be also degraded by ZnFe0.25Al1.75O4 catalyst with a high catalytic activity and stability.

  9. High-throughput reaction optimisation and activity screening of ferrocene-based Lewis acid-catalyst complexes by using continuous-flow reaction detection mass spectrometry.

    Science.gov (United States)

    Martha, Cornelius T; Heemskerk, Anton; Hoogendoorn, Jan-Carel; Elders, Niels; Niessen, Wilfried M A; Orru, Romano V A; Irth, Hubertus

    2009-07-27

    Optimising synthetic conversions and assessing catalyst performance is a tedious and laborious endeavour. Herein, we present an automated alternative to the commonly applied sequential approaches that are used to increase catalyst discovery process efficiencies by increasing the number of entities that can be tested. This new approach combines conversion of the reactants and determination of product formation into a single comprehensive reaction detection system that can be operated with minimal catalyst and reactant consumption. With this approach, rudimentary reaction conditions can be quickly optimised and the same system can then be used to screen for the optimal homogenous catalyst in a selected solution-phase synthetic conversion. The system, which is composed of standard HPLC components, can be used to screen catalyst libraries at a repetition rate of five minutes and can be run unsupervised. The sensitive mass spectrometric detection that is implemented in the reaction detection methodology can be used for the simultaneous monitoring of reactants, catalysts and product ions. In the experiments, the three-component reaction that gives a substituted 2-imidazoline was optimised. Afterwards, the same method was used to assess a library of ferrocene-based Lewis acid catalysts for performance in the aforementioned conversion in six different solvents. We demonstrate the feasibility of using this methodology to directly compare the performance results obtained in different solvents by calibrating the solvent-specific MS responses.

  10. Biodiesel production from the lipid of wastewater sludge using an acidic heterogeneous catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Siddiquee, M.N.; Kazemian, H.; Rohani, S. [University of Western Ontario, Department of Chemical and Biochemical Engineering, London, ON (Canada)

    2011-12-15

    The production of biodiesel from the lipid of wastewater sludge was studied using SBA-15 impregnated with the heteropolyacid H{sub 3}PO{sub 4}.12WO{sub 3}.xH{sub 2}O (PW{sub 12}) as a mesoporous heterogeneous catalyst. X-ray diffraction, Brunauer-Emmett-Teller surface area, thermalgravimetric analysis, and scanning electron microscopy were applied to characterize the prepared catalysts. Catalytic performances were evaluated in a microreactor setup under different experimental conditions. The biodiesel yield for a sample impregnated with 15 % PW{sub 12} was 30.14 wt-% at a temperature of 135 C and a pressure of 135 psi for 3 h reaction time. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Efficacy of Catalysts in the Batch Esterit'tcatiott of the Fatty Acids of ...

    African Journals Online (AJOL)

    11C] gas and cone. ll;SOt both proved very effective in catalyzing the reaction. Concentrated 11180.1 however, proved better ... catalysts ~ dry 11C] gas, cone. 112504 and cone. Htl'Oi were also used with each of the ... supportive evidence to the idea that l~l2$O4 is superior to l'lCl in the catalysis of esterilication of the fatty.

  12. Mesoporous Silica Supported Pd-MnOx Catalysts with Excellent Catalytic Activity in Room-Temperature Formic Acid Decomposition

    Science.gov (United States)

    Jin, Min-Ho; Oh, Duckkyu; Park, Ju-Hyoung; Lee, Chun-Boo; Lee, Sung-Wook; Park, Jong-Soo; Lee, Kwan-Young; Lee, Dong-Wook

    2016-09-01

    For the application of formic acid as a liquid organic hydrogen carrier, development of efficient catalysts for dehydrogenation of formic acid is a challenging topic, and most studies have so far focused on the composition of metals and supports, the size effect of metal nanoparticles, and surface chemistry of supports. Another influential factor is highly desired to overcome the current limitation of heterogeneous catalysis for formic acid decomposition. Here, we first investigated the effect of support pore structure on formic acid decomposition performance at room temperature by using mesoporous silica materials with different pore structures such as KIE-6, MCM-41, and SBA-15, and achieved the excellent catalytic activity (TOF: 593 h-1) by only controlling the pore structure of mesoporous silica supports. In addition, we demonstrated that 3D interconnected pore structure of mesoporous silica supports is more favorable to the mass transfer than 2D cylindrical mesopore structure, and the better mass transfer provides higher catalytic activity in formic acid decomposition. If the pore morphology of catalytic supports such as 3D wormhole or 2D cylinder is identical, large pore size combined with high pore volume is a crucial factor to achieve high catalytic performance.

  13. A comparative study of alumina-supported Ni catalysts prepared by photodeposition and impregnation methods on the catalytic ozonation of 2,4-dichlorophenoxyacetic acid

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez, Julia L., E-mail: ozliliana@yahoo.com.mx [Lab. Ing. Química Ambiental. ESIQIE–Instituto Politécnico Nacional (Mexico); Valenzuela, Miguel A. [Lab.Catálisis y Materiales. ESIQIE–Instituto Politécnico Nacional. Zacatenco (Mexico); Tiznado, Hugo [Centro de Nanociencias y Nanotecnología. CNyN Universidad Nacional Autónoma de México (Mexico); Poznyak, Tatiana [Lab. Ing. Química Ambiental. ESIQIE–Instituto Politécnico Nacional (Mexico); Chairez, Isaac [Departamento de Bioprocesos, UPIBI- Instituto Politécnico Nacional (Mexico); Magallanes, Diana [Lab. Ing. Química Ambiental. ESIQIE–Instituto Politécnico Nacional (Mexico)

    2017-02-15

    The heterogeneous catalytic ozonation on unsupported and supported oxides has been successfully tested for the removal of several refractory compounds in aqueous solution. In this work, alumina-supported nickel catalysts prepared by photodeposition and impregnation methods were compared in the catalytic ozonation of 2,4-dichlorophenoxyacetic acid (2,4-D). The catalysts were characterized by high-resolution electron microscopy and X-ray photoelectron spectroscopy. The photochemical decomposition of Ni acetylacetonate to produce Ni(OH){sub 2}, NiO, and traces of Ni° deposited on alumina was achieved in the presence of benzophenone as a sensitizer. A similar surface composition was found with the impregnated catalyst after its reduction with hydrogen at 500 °C and exposed to ambient air. Results indicated a higher initial activity and maleic acid (byproduct) concentration with the photodeposited catalyst (1 wt% Ni) compared to the impregnated catalyst (3 wt% Ni). These findings suggest the use of the photodeposition method as a simple and reliable procedure for the preparation of supported metal oxide/metal catalysts under mild operating conditions.

  14. The effect of preparation method on the performance of PtSn/Al2O3 catalysts for acetic acid hydrogenation

    Directory of Open Access Journals (Sweden)

    Zhang Ke

    2015-03-01

    Full Text Available PtSn/Al2O3 catalysts with a given loading of 1 wt% Pt and 1 wt% Sn were prepared by co-impregnation or successive impregnation with aqueous solutions of Pt, Sn precursors and a commercial alumina. The catalysts were characterized by N2 adsorption, H2-TPR (H2 temperature-programmed reduction, H2-pulse chemisorption, XPS (X-ray photoelectron spectroscopy and CO-FTIR (Fourier transform infrared spectroscopy, and tested in the hydrogenation of acetic acid. The results showed that the preparation method affected both the chemical properties and their performance in the hydrogenation of acetic acid. Sn enrichment on the catalysts surface was observed on the co-impregnated catalyst and catalyst in which the Pt precursor had been loaded first. It was found that the modification of Pt was a function of the sequence of Sn addition as revealed by CO-FTIR. Co-impregnated catalyst showed the highest activity and ethanol selectivity.

  15. ACIDIC REMOVAL OF METALS FROM FLUIDIZED CATALYTIC CRACKING CATALYST WASTE ASSISTED BY ELECTROKINETIC TREATMENT

    Directory of Open Access Journals (Sweden)

    R. B. G. Valt

    2015-06-01

    Full Text Available AbstractOne of the main uses of catalysts in the oil industry is in the fluidized catalytic cracking process, which generates large quantities of waste material after use and regeneration cycles and that can be treated by the electrokinetic remediation technique, in which the contaminant metals are transported by migration. In this study, deactivated FCC catalyst was characterized before and after the electrokinetic remediation process to evaluate the amount of metal removed, and assess structural modifications, in order to indicate a possible use as an adsorbent material. The analyses included pH measurement and the concentration profile of vanadium ions along the reactor, X-ray microtomography, X-ray fluorescence, BET analysis and DTA analysis. The results indicated that 40% of the surface area of the material was recovered in relation to the disabled material, showing an increase in the available area for the adsorption. The remediation process removed nearly 31% of the vanadium and 72% of the P2O5 adhering to the surface of the catalyst, without causing structural or thermal stability changes.

  16. Synthesis of fatty acid methyl ester from palm oil (Elaeis guineensis) with Ky(MgCa)2xO3 as heterogeneous catalyst.

    Science.gov (United States)

    Olutoye, M A; Lee, S C; Hameed, B H

    2011-12-01

    Fatty acid methyl esters (FAME) were produced from palm oil using eggshell modified with magnesium and potassium nitrates to form a composite, low-cost heterogeneous catalyst for transesterification. The catalyst, prepared by the combination of impregnation/co-precipitation was calcined at 830 °C for 4 h. Transesterification was conducted at a constant temperature of 65 °C in a batch reactor. Design of experiment (DOE) was used to optimize the reaction parameters, and the conditions that gave highest yield of FAME (85.8%) was 5.35 wt.% catalyst loading at 4.5 h with 16:1 methanol/oil molar ratio. The results revealed that eggshell, a solid waste, can be utilized as low-cost catalyst after modification with magnesium and potassium nitrates for biodiesel production. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Pt-Ni and Pt-M-Ni (M = Ru, Sn Anode Catalysts for Low-Temperature Acidic Direct Alcohol Fuel Cells: A Review

    Directory of Open Access Journals (Sweden)

    Ermete Antolini

    2017-01-01

    Full Text Available In view of a possible use as anode materials in acidic direct alcohol fuel cells, the electro-catalytic activity of Pt-Ni and Pt-M-Ni (M = Ru, Sn catalysts for methanol and ethanol oxidation has been widely investigated. An overview of literature data regarding the effect of the addition of Ni to Pt and Pt-M on the methanol and ethanol oxidation activity in acid environment of the resulting binary and ternary Ni-containing Pt-based catalysts is presented, highlighting the effect of alloyed and non-alloyed nickel on the catalytic activity of these materials.

  18. Recovery of nickel from spent NiO/Al2O3 catalyst through sulfuric acid leaching, precipitation and solvent extraction.

    Science.gov (United States)

    Nazemi, M K; Rashchi, F

    2012-05-01

    Effective recovery of nickel (Ni) from spent NiO/Al(2)O(3) catalyst in a simple hydrometallurgical route is suggested. Nickel recovery of 99.5% was achieved with sulfuric acid leaching. The leach liquor was partly neutralized and nickel ammonium sulfate was precipitated by adding ammonia. The nickel in the supernatant was concentrated by solvent extraction using D2EHPA and subsequently stripped back into sulfuric acid and returned to the precipitation stage. Necessary counter current extraction and stripping stages were determined in McCabe-Thiele diagrams. The suggested method appears simple and very effective in recovering nickel from spent catalysts from the petrochemical industry.

  19. Effect of tungsten carbide in carbon Pt catalyst support on electrochemical oxygen reduction in acid solution

    Directory of Open Access Journals (Sweden)

    Obradović Maja D.

    2013-01-01

    Full Text Available Tungsten carbide was synthesized by calcination of carbon cryogel with embedded tungsten in a form of metatungstate. This material was used as a support for Pt nanoparticles. XRD pattern of W-C support indicates the presence of WC, W2C, and unreacted W, as well as graphitized carbon. According to the previous TEM analysis of W-C support, it contains particles with core-shell structure, where W particle was covered with the shell of a mixture of WC and W2C. The average Pt grain size calculated from XRD pattern was about 6 nm. Cyclic voltammogram of W-C support was recorded within potential range relevant for its application as a catalyst support in fuel cells. Pair of anodic/cathodic peaks close to the negative potential limit could be ascribed to the intercalation of hydrogen within hydrous tungsten oxide, which is always present on the surface of WC in aqueous solutions. Cyclic voltammogram of Pt/W-C indicated that tungsten oxide species are present on tungsten carbide shell as well as on the surface of Pt nanoparticles. Pt surface is only partially covered by hydrous tungsten oxide. Hydrogen intercalation in hydrous tungsten oxide is enhanced in the presence of Pt nanoparticles. Also, the presence of hydrated tungsten oxide leads to the decrease of OH chemisorbed on Pt surface. Stripping of underpotentially deposited copper was used for the assessment of Pt surface area and the specific surface area of Pt was estimated to 41 m2 g-1. Electrochemical oxygen reduction reaction was examined on the synthesized Pt/W-C catalyst and compared with the results on the commercial Pt/C catalyst. It was found that the current densities at Pt/W-C are almost double as those on Pt/C. The Tafel plots for both catalysts are characterized with two Tafel slopes: -0.060 V dec-1 at low current densities, and -0.120 V dec-1 at high current densities. From the rotational dependence of the reaction rate, it was found that oxygen reduction on both Pt/W-C and Pt

  20. Noble-metal-free Fe-N/C catalyst for highly efficient oxygen reduction reaction under both alkaline and acidic conditions.

    Science.gov (United States)

    Lin, Ling; Zhu, Qing; Xu, An-Wu

    2014-08-06

    In this work, we report the synthesis and assessment of a new non-precious-metal oxygen reduction reaction (ORR) catalyst from pyrolysis of an iron-coordinated complex which manifests superior activity in both alkaline and acidic media. 11,11'-bis(dipyrido[3,2-a:2',3'-c]phenazinyl) (bidppz) was selected as a ligand for the formation of a nitrogen-rich iron-coordinated coordination polymer (Fe-bidppz) which forms a self-supporting catalyst containing high densities of nitrogen and iron doping by pyrolysis. The catalyst pyrolyzed at 800 °C (Fe-N/C-800) shows the highest ORR activity with onset and half-wave potentials of 923 and 809 mV in 0.1 M KOH, respectively, which are comparable to those of Pt/C (half-wave potential 818 mV vs RHE) at the same catalyst loading. Besides, the Fe-N/C-800 catalyst has an excellent ORR activity with onset and half-wave potentials only 38 and 59 mV less than those of the Pt/C catalyst in 0.1 M HClO4. The optimal Fe-N/C-800 catalyst displays much greater durability and tolerance of methanol than Pt/C. We propose that the Fe-N/C-800 catalyst has a considerably high density of surface active sites because Fe-N/C-800 possesses excellent ORR activity while its specific surface area is not so high. Electrochemical measurements show that the Fe-N/C-800 catalyst in KOH and HClO4 follows the effective four-electron-transfer pathway.

  1. Two-Stage Conversion of High Free Fatty Acid Jatropha curcas Oil to Biodiesel Using Brønsted Acidic Ionic Liquid and KOH as Catalysts

    Science.gov (United States)

    Das, Subrata; Thakur, Ashim Jyoti; Deka, Dhanapati

    2014-01-01

    Biodiesel was produced from high free fatty acid (FFA) Jatropha curcas oil (JCO) by two-stage process in which esterification was performed by Brønsted acidic ionic liquid 1-(1-butylsulfonic)-3-methylimidazolium chloride ([BSMIM]Cl) followed by KOH catalyzed transesterification. Maximum FFA conversion of 93.9% was achieved and it reduced from 8.15 wt% to 0.49 wt% under the optimum reaction conditions of methanol oil molar ratio 12 : 1 and 10 wt% of ionic liquid catalyst at 70°C in 6 h. The ionic liquid catalyst was reusable up to four times of consecutive runs under the optimum reaction conditions. At the second stage, the esterified JCO was transesterified by using 1.3 wt% KOH and methanol oil molar ratio of 6 : 1 in 20 min at 64°C. The yield of the final biodiesel was found to be 98.6% as analyzed by NMR spectroscopy. Chemical composition of the final biodiesel was also determined by GC-MS analysis. PMID:24987726

  2. Two-Stage Conversion of High Free Fatty Acid Jatropha curcas Oil to Biodiesel Using Brønsted Acidic Ionic Liquid and KOH as Catalysts

    Directory of Open Access Journals (Sweden)

    Subrata Das

    2014-01-01

    Full Text Available Biodiesel was produced from high free fatty acid (FFA Jatropha curcas oil (JCO by two-stage process in which esterification was performed by Brønsted acidic ionic liquid 1-(1-butylsulfonic-3-methylimidazolium chloride ([BSMIM]Cl followed by KOH catalyzed transesterification. Maximum FFA conversion of 93.9% was achieved and it reduced from 8.15 wt% to 0.49 wt% under the optimum reaction conditions of methanol oil molar ratio 12 : 1 and 10 wt% of ionic liquid catalyst at 70°C in 6 h. The ionic liquid catalyst was reusable up to four times of consecutive runs under the optimum reaction conditions. At the second stage, the esterified JCO was transesterified by using 1.3 wt% KOH and methanol oil molar ratio of 6 : 1 in 20 min at 64°C. The yield of the final biodiesel was found to be 98.6% as analyzed by NMR spectroscopy. Chemical composition of the final biodiesel was also determined by GC-MS analysis.

  3. Pd/C Synthesized with Citric Acid: An Efficient Catalyst for Hydrogen Generation from Formic Acid/Sodium Formate

    OpenAIRE

    Wang, Zhi-Li; Yan, Jun-Min; Wang, Hong-Li; Ping, Yun; Jiang, Qing

    2012-01-01

    A highly efficient hydrogen generation from formic acid/sodium formate aqueous solution catalyzed by in situ synthesized Pd/C with citric acid has been successfully achieved at room temperature. Interestingly, the presence of citric acid during the formation and growth of the Pd nanoparticles on carbon can drastically enhance the catalytic property of the resulted Pd/C, on which the conversion and turnover frequency for decomposition of formic acid/sodium formate system can reach the highest ...

  4. H3PW12O40 (HPA, an efficient and reusable catalyst for biodiesel production related reactions: esterification of oleic acid and etherification of glycerol

    Directory of Open Access Journals (Sweden)

    Jorge H. Sepúlveda

    2011-01-01

    Full Text Available In esterification of oleic acid with methanol at 25 °C HPA displayed the highest activity. Moreover the HPA could be reused after being transformed into its cesium salt. In the reaction of etherification of glycerol HPA and Amberlyst 35W showed similar initial activity levels. The results of acid properties demonstrate that HPA is a strong protonic acid and that both surface and bulk protons contribute to the acidity. Because of its strong affinity for polar compounds, HPA is also seemingly dissolved in both oleic acid and methanol. The reaction in this case proceeds with the catalyst in the homogenous phase.

  5. Enhanced hydrolysis of bamboo biomass by chitosan based solid acid catalyst with surfactant addition in ionic liquid.

    Science.gov (United States)

    Si, Wenqing; Li, Yichen; Zheng, Jie; Wei, Shun'an; Wang, Dan

    2017-10-15

    Surfactants were used for the hydrolysis of bamboo biomass to enhance lignocellulose hydrolysis. Tween 80, polyethylene glycol 4000 (PEG 4000), and sodium dodecyl sulfate (SDS) were tested as surfactants for improving the bamboo hydrolysis with a novel sulfonated cross-linked chitosan solid acid catalyst (SCCAC) in ionic liquid (IL). Compared to the use of only SCCAC in 1-Butyl-3-methylimidazolium chloride ([BMIM]Cl), the surfactants facilitated hydrolysis and improved the yield of total reducing sugar (TRS) under the same conditions. Tween 80 was the most effective surfactant, with a TRS yield of 68.01% achieved at 120°C after 24h. Surfactants broke the lignocellulose structure, promoted lignin removal, and increased positive interactions between cellulose and the catalyst, which were favorable for hydrolysis. This novel surfactant-assisted hydrolysis strategy with SCCAC and IL as the solvent demonstrated a promise for the large-scale transformation of biomass into biofuels and bioproducts. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Dehydrogenation of Formic Acid over a Homogeneous Ru-TPPTS Catalyst: Unwanted CO Production and Its Successful Removal by PROX

    Directory of Open Access Journals (Sweden)

    Vera Henricks

    2017-11-01

    Full Text Available Formic acid (FA is considered as a potential durable energy carrier. It contains ~4.4 wt % of hydrogen (or 53 g/L which can be catalytically released and converted to electricity using a proton exchange membrane (PEM fuel cell. Although various catalysts have been reported to be very selective towards FA dehydrogenation (resulting in H2 and CO2, a side-production of CO and H2O (FA dehydration should also be considered, because most PEM hydrogen fuel cells are poisoned by CO. In this research, a highly active aqueous catalytic system containing Ru(III chloride and meta-trisulfonated triphenylphosphine (mTPPTS as a ligand was applied for FA dehydrogenation in a continuous mode. CO concentration (8–70 ppm in the resulting H2 + CO2 gas stream was measured using a wide range of reactor operating conditions. The CO concentration was found to be independent on the reactor temperature but increased with increasing FA feed. It was concluded that unwanted CO concentration in the H2 + CO2 gas stream was dependent on the current FA concentration in the reactor which was in turn dependent on the reaction design. Next, preferential oxidation (PROX on a Pt/Al2O3 catalyst was applied to remove CO traces from the H2 + CO2 stream. It was demonstrated that CO concentration in the stream could be reduced to a level tolerable for PEM fuel cells (~3 ppm.

  7. Depolymerization of lignin at low pressure using Lewis acid catalysts and under high pressure using hydrogen donor solvents

    Energy Technology Data Exchange (ETDEWEB)

    Davoudzadeh, F.; Coughlin, R.W.; Avni, E.; Smith, B.

    1985-06-01

    Adding phenol or guaiacol to the reaction mixture increased liquefaction of lignin from steam-exploded wood in tetralin at about 140 kg/cm/sup 2/ pressure and 300/sup 0/C. Phenol increased yields of filterable products from about 40 to 63%, guaiacol from about 30% to 50%. At one atmosphere and 110 to 200/sup 0/C only about 25% of the lignin could be converted to liquid regardless of whether phenol, tetralin or Lewis acid catalysts were employed. Of a variety of catalysts investigated at higher pressures NiO-MoO/sub 3/ supported on alumina gave the best results. Raising the temperature from 300 to 400/sup 0/C increased filtrate yields from the 30% to the 90% range at about 140 kg/cm/sup 2/ in H/sub 2/. The lower molecular weight lignin from steam-exploded wood (Iotech) gave somewhat larger conversions than Indulin, a Kraft lignin from Westvaco. The reaction products detected include methoxyphenols, cresols, alkyl cresols, guaiacol, toluenes, anisole, cinnamaldehyde and cumene.

  8. reaction between nitric acid and tin in presence of catalysts-part 1.

    Indian Academy of Sciences (India)

    Neither nitrous acid nor hydrazine were formed under the conditions studied. From the results it was pointed out that the variations in the stannic tin and the gaseous reduction products of the excess nitric acid go hand in hand; likewise the variations of stannous tin and the reduction products of excess nitric acid in solution.

  9. Deactivation of vanadia-based commercial SCR catalysts by polyphosphoric acids

    DEFF Research Database (Denmark)

    Castellino, Francesco; Rasmussen, Søren Birk; Jensen, Anker Degn

    2008-01-01

    Commercial vanadia-based SCR monoliths have been exposed to flue gases in a pilot-scale Setup into which phosphoric acid has been added and the deactivation has been followed during the exposure time. Separate measurements by SMPS showed that the phosphoric acid formed polyphosphoric acid aerosols...

  10. Insights into the interplay of Lewis and Brønsted acid catalysts in glucose and fructose conversion to 5-(hydroxymethyl)furfural and levulinic acid in aqueous media.

    Science.gov (United States)

    Choudhary, Vinit; Mushrif, Samir H; Ho, Christopher; Anderko, Andrzej; Nikolakis, Vladimiros; Marinkovic, Nebojsa S; Frenkel, Anatoly I; Sandler, Stanley I; Vlachos, Dionisios G

    2013-03-13

    5-(Hydroxymethyl)furfural (HMF) and levulinic acid production from glucose in a cascade of reactions using a Lewis acid (CrCl3) catalyst together with a Brønsted acid (HCl) catalyst in aqueous media is investigated. It is shown that CrCl3 is an active Lewis acid catalyst in glucose isomerization to fructose, and the combined Lewis and Brønsted acid catalysts perform the isomerization and dehydration/rehydration reactions. A CrCl3 speciation model in conjunction with kinetics results indicates that the hydrolyzed Cr(III) complex [Cr(H2O)5OH](2+) is the most active Cr species in glucose isomerization and probably acts as a Lewis acid-Brønsted base bifunctional site. Extended X-ray absorption fine structure spectroscopy and Car-Parrinello molecular dynamics simulations indicate a strong interaction between the Cr cation and the glucose molecule whereby some water molecules are displaced from the first coordination sphere of Cr by the glucose to enable ring-opening and isomerization of glucose. Additionally, complex interactions between the two catalysts are revealed: Brønsted acidity retards aldose-to-ketose isomerization by decreasing the equilibrium concentration of [Cr(H2O)5OH](2+). In contrast, Lewis acidity increases the overall rate of consumption of fructose and HMF compared to Brønsted acid catalysis by promoting side reactions. Even in the absence of HCl, hydrolysis of Cr(III) decreases the solution pH, and this intrinsic Brønsted acidity drives the dehydration and rehydration reactions. Yields of 46% levulinic acid in a single phase and 59% HMF in a biphasic system have been achieved at moderate temperatures by combining CrCl3 and HCl.

  11. New insights into Cu/SSZ-13 SCR catalyst acidity. Part I: Nature of acidic sites probed by NH 3 titration

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Jinyong; Gao, Feng; Kamasamudram, Krishna; Currier, Neal; Peden, Charles H. F.; Yezerets, Aleksey

    2017-04-01

    In this work we investigated an unusual acidity feature of a Cu/SSZ-13 catalyst used in selective catalytic reduction of NOx with NH3 (NH3-SCR). In particular, this catalyst showed two distinct NH3 desorption peaks in NH3-TPD measurements, in contrast to single, unresolved desorption peaks observed for other Cu-exchanged zeolites conventionally used in the SCR studies, including its isostructural but chemically different analogue Cu/SAPO-34. We further observed that the intensities of the two TPD peaks, which represented the amount of stored NH3, changed in opposite directions in response to progressive mild hydrothermal aging, while the total storage capacity was preserved. We proposed an explanation for this remarkable behavior, by using model reference samples and additional characterization techniques. At least three NH3 storage sites were identified: two distinct populations of Cu sites responsible for low-temperature NH3 storage, and Brønsted acid sites responsible for high-temperature NH3 storage. Contrary to the commonly accepted mechanism that Brønsted acid site loss during hydrothermal aging is driven by dealumination, we concluded that the decline in the number of Brønsted acid sites upon mild hydrothermal aging for Cu/SSZ-13 was not due to dealumination, but rather transformation of Cu sites, i.e., gradual conversion of ZCuOH (Cu2+ singly coordinated with Zeolite) to Z2Cu (Cu2+ doubly coordinated with Zeolite). This transformation was responsible for the increased low-temperature desorption peak in NH3-TPD since each ZCuOH adsorbed ~1 NH3 molecule while each Z2Cu adsorbed ~2 NH3 molecules under the conditions used here. These findings were used in Part II of this series of studies to develop a method for quantifying hydrothermal ageing of industrial Cu/SSZ-13 SCR catalysts. Authors would like to thank Randall Jines for his help with collecting the reactor data, Nancy W. Washton for measuring the NMR data and Tamas Varga for in-situ XRD measurements

  12. Probing Transition-Metal Silicides as PGM-Free Catalysts for Hydrogen Oxidation and Evolution in Acidic Medium

    Science.gov (United States)

    Mittermeier, Thomas; Madkikar, Pankaj; Wang, Xiaodong; Gasteiger, Hubert A.; Piana, Michele

    2017-01-01

    In this experimental study, we investigate various transition-metal silicides as platinum-group-metal-(PGM)-free electrocatalysts for the hydrogen oxidation reaction (HOR), and for the hydrogen evolution reaction (HER) in acidic environment for the first time. Using cyclic voltammetry in 0.1 M HClO4, we first demonstrate that the tested materials exhibit sufficient stability against dissolution in the relevant potential window. Further, we determine the HOR and HER activities for Mo, W, Ta, Ni and Mo-Ni silicides in rotating disk electrode experiments. In conclusion, for the HOR only Ni2Si shows limited activity, and the HER activity of the investigated silicides is considerably lower compared to other PGM-free HER catalysts reported in the literature. PMID:28773022

  13. Metal halide hydrates as lewis acid catalysts for the conjugated friedel-crafts reactions of indoles and activated olefins

    Energy Technology Data Exchange (ETDEWEB)

    Schwalm, Cristiane S.; Ceschi, Marco Antonio; Russowsky, Dennis, E-mail: dennis@iq.ufrgs.b [Universidade Federal do Rio Grande do Sul (IQ/UFRGS), Porto Alegre, RS (Brazil). Inst. de Quimica

    2011-07-01

    Metal halide hydrates such as SnCl{sub 2{center_dot}}2H{sub 2}O, MnCl{sub 2{center_dot}}4H{sub 2}O, SrCl{sub 2{center_dot}}6H{sub 2}O, CrCl{sub 2{center_dot}}6H{sub 2}O, CoCl{sub 2{center_dot}}6H{sub 2}O e CeCl{sub 3{center_dot}}7H{sub 2}O were investigated as mild Lewis acids catalysts for the conjugate Friedel-Crafts reaction between indoles and activated olefins. The reactions were carried out with aliphatic unsaturated ketones over a period of days at room temperature, while chalcones reacted only under reflux conditions. The reactions with nitrostyrene s were either performed in solvent or under solventless conditions. In all cases reasonable to good yields were obtained. (author)

  14. Hydrogenation of Levulinic Acid to gamma-Valerolactone in Water Using Millimeter Sized Supported Ru Catalysts in a Packed Bed Reactor

    NARCIS (Netherlands)

    Piskun, A. S.; de Haan, J. E.; Wilbers, E.; de Bovenkamp, H. H. van; Tang, Z.; Heeres, Hero

    gamma-Valerolactone (GVL) has been identified as a sustainable platform chemical for the production of carbon-based chemicals. We here report an experimental study on the catalytic hydrogenation of levulinic acid (LA) in water to GVL in a packed bed reactor using supported Ru catalysts (carbon,

  15. Mechanism of Alkene, Alkane, and Alcohol Oxidation with H2O2 by an in Situ Prepared Mn-II/Pyridine-2-carboxylic Acid Catalyst

    NARCIS (Netherlands)

    Saisaha, Pattama; Dong, Jia Jia; Meinds, Tim G.; de Boer, Johannes W.; Hage, Ronald; Mecozzi, Francesco; Kasper, Johann B.; Browne, Wesley R.

    The oxidation of alkenes, alkanes, and alcohols with H2O2 is catalyzed efficiently using an in situ prepared catalyst comprised of a MnII salt and pyridine-2-carboxylic acid (PCA) together with a ketone in a wide range of solvents. The mechanism by which these reactions proceed is elucidated, with a

  16. Highly Efficient Catalytic Synthesis of α-Amino Acids under Phase-Transfer Conditions with a Novel Catalyst/Substrate Pair

    NARCIS (Netherlands)

    Belokon, Yuri N.; Kochetkov, Konstantin A.; Churkina, Tatiana D.; Ikonnikov, Nikolai S.; Larionov, Oleg V.; Harutyunyan, Syuzanna R.; Vyskočil, Štepán; North, Michael; Kagan, Henri B.

    2001-01-01

    A facile and fast enantioselective synthesis of α-amino acids with high ee values was achieved by the asymmetric alkylation of the glycine derivative under phase-transfer conditions with (R)- or (S)-2-amino-2'-hydroxy-1,1'-binaphthyl (NOBIN). The ee value of the catalyst can be as little as 40 %

  17. Experimental and kinetic modeling studies on the biphasic hydrogenation of levulinic acid to gamma-valerolactone using a homogeneous water-soluble Ru-(TPPTS) catalyst

    NARCIS (Netherlands)

    Chalid, M.; Broekhuis, A. A.; Heeres, H. J.

    2011-01-01

    gamma-Valerolactone (GVL) is considered a very attractive biomass derived platform chemical. This paper describes the application of biphasic homogeneous catalysis for the hydrogenation of levulinic acid (LA) to GVL using molecular hydrogen. A water soluble Ru-catalyst made in situ from RuCl3 center

  18. A Green Solventless Protocol for the Synthesis of β-Enaminones and β-Enamino Esters Using Silica Sulfuric Acid as a Highly Efficient, Heterogeneous and Reusable Catalyst

    Directory of Open Access Journals (Sweden)

    Alireza Hasaninejad

    2010-01-01

    Full Text Available Silica sulfuric acid is utilized as a green, highly efficient, heterogeneous and recyclable catalyst for the preparation of β-enaminones and β-enamino esters from amines and β-dicarbonyl compounds under solvent-free conditions at 80 °C. Using this method, the title compounds are produced in high to excellent yields and in short reaction times.

  19. Melamine trisulfonic acid as a highly efficient catalyst for the synthe-sis of 14-aryl-14H-dibenzo[a,j]xanthenes under solvent-free conditions

    Directory of Open Access Journals (Sweden)

    Abdolkarim Zare

    2014-02-01

    Full Text Available Melamine trisulfonic acid (MTSA is utilized as a highly efficient catalyst for the solvent-free condensation of 2-naphthol with arylaldehydes under conventional thermal or microwave irradiation to give 14-aryl-14H-dibenzo[a,j]xanthenes in high to excellent yields and in short reaction times.

  20. Porous nitrogen-enriched carbonaceous material from marine waste: chitosan-derived layered CNX catalyst for aerial oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid

    Science.gov (United States)

    Chitosan derived porous layered nitrogen-enriched carbonaceous CNx catalyst (PLCNx) has been synthesized from marine waste and its use demonstrated in a metal-free heterogeneous selective oxidation of 5-hydroxymethyl-furfural (HMF) to 2,5-furandicarboxylic acid (FDCA) using aeria...

  1. Deoxyribonucleic acid directed metallization of platinum nanoparticles on graphite nanofibers as a durable oxygen reduction catalyst for polymer electrolyte fuel cells

    Science.gov (United States)

    Peera, S. Gouse; Sahu, A. K.; Arunchander, A.; Nath, Krishna; Bhat, S. D.

    2015-11-01

    Effective surface functionalization to the hydrophobic graphite nanofibers (GNF) is performed with the biomolecule, namely deoxy-ribo-nucleic-acid (DNA) via π-π interactions. Pt nanoparticles are impregnated on GNF-DNA composite by ethylene glycol reduction method (Pt/GNF-DNA) and its effect on electro catalytic activity for oxygen reduction reaction (ORR) is systemically studied. Excellent dispersion of Pt nanoparticles over GNF-DNA surfaces with no evidence on particle aggregation is a remarkable achievement in this study. This result in higher electro chemical surface area of the catalyst, enhanced ORR behavior with significant enhancement in mass activity. The catalyst is validated in H2-O2 polymer electrolyte fuel cell (PEFC) and a peak power density of 675 mW cm-2 is achieved at a load current density of 1320 mA cm-2 with a minimal catalyst loading of 0.1 mg cm-2 at a cell temperature of 70 °C and 2 bar absolute pressure. Repeated potential cycling up to 10000 cycles in acidic media is also performed for this catalyst and found excellent stability with only 60 mV drop in the ORR half wave potential. The superior behavior of Pt/GNF-DNA catalyst is credited to the robust fibrous structure of GNF and its effective surface functionalization process via π-π interaction.

  2. A kinetic study of plutonium dioxide dissolution in hydrochloric acid using iron (II) as an electron transfer catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Fife, K.W.

    1996-09-01

    Effective dissolution of plutonium dioxide has traditionally been accomplished by contact with strong nitric acid containing a small amount of fluoride at temperatures of {approximately} 100 C. In spite of these aggressive conditions, PuO{sub 2} dissolution is sometimes incomplete requiring additional contact with the solvent. This work focused on an alternative to conventional dissolution in nitric acid where an electron transfer catalyst, Fe(II), was used in hydrochloric acid. Cyclic voltammetry was employed as an in-situ analytical technique for monitoring the dissolution reaction rate. The plutonium oxide selected for this study was decomposed plutonium oxalate with > 95% of the material having a particle diameter (< 70 {micro}m) as determined by a scanning laser microscopy technique. Attempts to dry sieve the oxide into narrow size fractions prior to dissolution in the HCl-Fe(II) solvent system failed, apparently due to significant interparticle attractive forces. Although sieve splits were obtained, subsequent scanning laser microscopy analysis of the sieve fractions indicated that particle segregation was not accomplished and the individual sieve fractions retained a particle size distribution very similar to the original powder assemblage. This phenomena was confirmed through subsequent dissolution experiments on the various screen fractions which illustrated no difference in kinetic behavior between the original oxide assemblage and the sieve fractions.

  3. Effect of Acid Properties of Catalysts on Fluid Catalytic Cracking of Residual Oil

    National Research Council Canada - National Science Library

    Yoshifumi Hiramatsu; Youhei Aita; Takashi Umeki

    2012-01-01

      This article describes the relationship between the different acidic properties of catalytic active sites and their catalytic cracking ability using desulfurized atmospheric residue (DSAR) as a feed...

  4. Multidimensional crystal frameworks based on heteropoly blue building block of [SiW10Mo(V)2O40]6-: synthesis, structures and magnetic properties.

    Science.gov (United States)

    Wang, Yuchao; Li, Fengyan; Xu, Lin; Jiang, Ning; Liu, Xizheng

    2013-04-28

    Four heteropoly blue complexes constructed from Keggin-type heteropoly blue molybdenum-tungsten clusters and Cu(II) ions as linkers, H2[α-SiW10Mo(V)2O40][Cu(PDA)2·H2O]2 (1), H2[α-SiW10Mo(V)2O40][Cu(DEF)3·H2O][Cu(DEF)2·2H2O]·6H2O (2), H2[α-SiW10Mo(V)2O40][Cu(DMF)3H2O]2·6H2O (3), and H4[α-SiW10Mo(V)2O40]2[CuK2(DMF)6][Na0.75K3.25(DMF)6] (4) [PDA = propanediamide, DEF = N,N-diethylformamide and DMF = N,N-dimethylformamide], have been synthesized by conventional reactions and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, thermogravimetry, X-ray powder diffraction (XRD) and UV spectra. The amount of Cu(II) and the nature of the ligand (DMF, DEF and PDA) can control both the linkage pattern of Cu(II) ions and the dimensionality of the frameworks; this demonstrates for the first time the possibility to assemble heteropoly blue architectures in different dimensionality ranging from zero-dimensional (0D) to one-dimensional (1D), two-dimensional (2D) and three-dimensional (3D). The magnetic investigation showed that the positive magnetic moment could be observed at room temperature, which should be unusual results in magnetochemistry of the two-electron reduced heteropoly blue. The stability and formation conditions of the four compounds are also discussed.

  5. Electrochemical Production of Glycolic Acid from Oxalic Acid Using a Polymer Electrolyte Alcohol Electrosynthesis Cell Containing a Porous TiO2Catalyst.

    Science.gov (United States)

    Sadakiyo, Masaaki; Hata, Shinichi; Cui, Xuedong; Yamauchi, Miho

    2017-12-12

    A liquid flow-type electrolyser that continuously produces an alcohol from a carboxylic acid was constructed by employing a polymer electrolyte, named a polymer electrolyte alcohol electrosynthesis cell (PEAEC). Glycolic acid (GC, an alcoholic compound) is generated on anatase TiO 2 catalysts via four-electron reduction of oxalic acid (OX, a divalent carboxylic acid), accompanied with water oxidation, which achieves continuous electric power storage in easily stored GC. Porous anatase TiO 2 directly grown on Ti mesh (TiO 2 /Ti-M) or Ti felt (TiO 2 /Ti-F) was newly fabricated as a cathode having favourable substrate diffusivity. A membrane-electrode assembly composed of the TiO 2 /Ti-M, Nafion 117, and an IrO 2 supported on a gas-diffusion carbon electrode (IrO 2 /C) was applied to the PEAEC. We achieved a maximum energy conversion efficiency of 49.6% and a continuous 99.8% conversion of 1 M OX, which is an almost saturated aqueous solution at room temperature.

  6. Formation of acetic acid by aqueous-phase oxidation of ethanol with air in the presence of a heterogeneous gold catalyst

    DEFF Research Database (Denmark)

    Christensen, Claus H.; Jørgensen, Betina; Hansen, Jeppe Rass

    2006-01-01

    Wine into vinegar: It is possible to selectively oxidize ethanol into acetic acid in aqueous solution with air as the oxidant and a heterogeneous gold catalyst (see TEM image of supported gold particles) at temperatures of about 423 K and O2 pressures of 0.6 MPa. This reaction proceeds readily...... in aqueous acidic media with yields of up to 90 % and CO2 as the only major by-product....

  7. Synthesis of potential antioxidants by synergy of ultrasound and acidic graphene nanosheets as catalyst in water.

    Science.gov (United States)

    Naeimi, Hossein; Golestanzadeh, Mohsen; Zahraie, Zohreh

    2016-02-01

    Efficient synthesis of a set of bisphenolic compounds, resulting from the incorporation of 2,4-dialkylphenols and aromatic or aliphatic aldehydes, allowed the discovery of new bisphenols with relative modest to good antioxidant activity. Bisphenolic compounds were prepared via easy and simple approach under ultrasound irradiation in water. Sulfonated graphene nanosheets were employed as a catalyst for the synthesis of bisphenolic compounds. These compounds were obtained in high to excellent yields (88-98%) and relatively short reaction times (4-20 min). Moreover, some of the synthetic compounds were investigated and revealed outstanding antioxidant activity, when examined by a 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) decolorization assay system. The proposed method has a novel viewpoint in the preparation of potential antioxidant compounds. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Oxidation of positronium atoms on a surface of oxidic catalyst carrier containing acid centres

    CERN Document Server

    Paiziev, A A

    2000-01-01

    By Born approximation the cross section of positronium (Ps) oxidation on acid centres localized on the surface of oxide carriers is calculated. Analysis of the kinetics of elementary processes in porous carriers based on aluminum oxide including processes of annihilation of positron, formation of Ps and oxidation of Ps on acid centres is given.

  9. Effect of the Pd/MWCNTs anode catalysts preparation methods on their morphology and activity in a direct formic acid fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Lesiak, B., E-mail: blesiak-orlowska@ichf.edu.pl [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warszawa (Poland); Mazurkiewicz, M.; Malolepszy, A. [Faculty of Chemical and Process Engineering, Warsaw University of Technology, Waryńskiego 1, 00-645 Warszawa (Poland); Stobinski, L. [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warszawa (Poland); Faculty of Chemical and Process Engineering, Warsaw University of Technology, Waryńskiego 1, 00-645 Warszawa (Poland); Mierzwa, B.; Mikolajczuk-Zychora, A.; Juchniewicz, K.; Borodzinski, A. [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warszawa (Poland); Zemek, J.; Jiricek, P. [Institute of Physics, Academy of Sciences of the Czech Republic, 162-53 Prague 6, Cukrovarnicka 10 (Czech Republic)

    2016-11-30

    Highlights: • Catalysts properties studied by XRD, STEM, XPS methods. • Differences in Pd particle size, content of Pd, functional groups, PdC{sub x.}. • Catalytic activity studied in a Direct Formic Acid Fuel Cell. • Highest activity–catalyst prepared using a strong reducing agent (NaBH{sub 4}). - Abstract: Impact of Pd/MWCNTs catalysts preparation method on the catalysts morphology and activity in a formic acid electrooxidation reaction was investigated. Three reduction methods of Pd precursor involving reduction in a high pressure microwave reactor (Pd1), reduction with NaBH{sub 4} (Pd2) and microwave-assisted polyol method (Pd3) were used in this paper. Crystallites size and morphology were studied using the scanning transmission electron microscopy (STEM), X-ray diffraction (XRD), whereas elemental composition, Pd chemical state and functional groups content by the X-ray photoelectron spectroscopy (XPS). The prepared catalysts were tested in a direct formic acid fuel cell (DFAFC) as an anode material. The catalytic activity was correlated with a mean fraction of the total Pd atoms exposed at the surface (FE). The value of FE was calculated from the crystallites size distribution determined by the STEM measurements. Non-linear dependence of a current density versus FE, approaching the maximum at FE≈0.25 suggests that the catalytic process proceeded at Pd nanocrystallites faces, with inactive edges and corners. Pd2 catalyst exhibited highest activity due to its smallest Pd crystallites (3.2 nm), however the absence of Pd crystallites aggregation and low content of carbon in PdC{sub x} phase, i.e. x = 4 at.% may also affect the observed.

  10. Asymmetric catalysis in aqueous media: use of metal-chiral crown ethers as efficient chiral Lewis acid catalysts in asymmetric aldol reactions

    Directory of Open Access Journals (Sweden)

    Shu Kobayashi

    2001-01-01

    Full Text Available Metal-chiral crown ether complexes have been developed as efficient chiral Lewis acid catalysts for asymmetric aldol reactions of silyl enol ethers with aldehydes in aqueous media. While many excellent catalytic asymmetric reactions have been developed recently, most of them have to be carried out under strictly anhydrous conditions in organic solvents. This is probably due to the instability of many catalysts and/or intermediates in the presence of even a small amount of water. To address this issue, we searched for metal-crown ether complexes on the basis of our "multi-coordination" hypothesis, and found that lead(II and lanthanide(III catalysts worked well as chiral Lewis acids in aqueous media. To the best of our knowledge, these are the first examples of chiral crown-based Lewis acids that can be successfully used in catalytic asymmetric reactions. The catalysts have been characterized by X-ray diffraction, and their unique structures as chiral catalysts have been revealed. Use of water as a solvent is essential in these asymmetric catalysis, and the role of water on these reactions to explain the high reactivity and selectivity has been suggested. Another important point is that kinetic studies have shown the possibility that these types of crown ether complexes would be suitable as chiral catalysts employed in aqueous media. In addition, although the catalytic asymmetric aldol reactions are one of the most powerful carbon-carbon bond-forming methodologies and several successful examples have been reported, the use of aprotic anhydrous solvents and low reaction temperatures (-78 °C has been needed in almost all successful cases. On the other hand, the present reactions proceeded smoothly at -10-0 °C in water-alcohol solutions while retaining high levels of diastereo- and enantioselectivities.

  11. H3PO4/Al2O3 catalysts: characterization and catalytic evaluation of oleic acid conversion to biofuels and biolubricant

    Directory of Open Access Journals (Sweden)

    Lucia Regina Raddi de Araujo

    2006-06-01

    Full Text Available Al2O3 and H3PO4/Al2O3 catalysts were investigated in the conversion of oleic acid to biofuels and biolubricant at 1 atm and at 623 K. The catalytic tests were performed in a fixed bed and continuous flow reactor, using an oleic acid-catalyst ratio of 4 and N2 as the carrier gas. The reaction products were analyzed by gas chromatography and acidity measurements. N2 adsorption-desorption, X ray diffraction, 31P nuclear magnetic resonance and FT-IR spectroscopy were also employed to evaluate the textural, structural and acidic properties of the catalysts. The results showed that phosphoric acid impregnation improved the alumina decarboxylation activities, generating hydrocarbons in the range of gasoline, diesel oil and lubricant oil. The best catalytic performance was achieved with the highest surface area alumina impregnated with H3PO4, which was the solid that allied high total acidity with a large quantity of mesopores.

  12. Gas chromatography and silver-ion high-performance liquid chromatography analysis of conjugated linoleic acid isomers in free fatty acid form using sulphuric acid in methanol as catalyst.

    Science.gov (United States)

    Luna, Pilar; Juárez, Manuela; de la Fuente, Miguel Angel

    2008-09-12

    This study used GC and silver-ion HPLC to examine the effects of temperature and time on methylation of individual and mixtures of conjugated linoleic acid (CLA) isomers in free fatty acid form using sulphuric acid as catalyst. In the conditions tested (temperatures between 20 and 50 degrees C and times between 10 and 60 min) methylation was complete while avoiding isomerization of conjugated dienes and the formation of artefacts that could interfere with chromatographic determinations. An analytical method using solvent extraction of the lipids followed by selective elution of the free fatty acids from aminopropyl bonded phase columns and methylation with H(2)SO(4) in mild conditions was then applied to determine the CLA isomers in free fatty acid form in rumen fluid, and the results were evaluated.

  13. Substance and device for the absorption of catalyst poisoning gases out of the oxyhydrogen gas produced by lead-acid storage batteries

    Energy Technology Data Exchange (ETDEWEB)

    Lahme, N.W.; Sassmannshausen, G.C.

    1977-09-13

    A substance, a method of producing it, and a device for using the substance in the absorption of catalyst-poisoning gases out of the oxyhydrogen gas mixture produced by lead--acid storage batteries are described. The substance causes the oxidation of the unstable catalyst-poisoning gases SbH/sub 3/ and AsH/sub 3/ to produce hydrolysis-resistant intermetallic compounds. As absorbing substances they are usable heavy-metal manganites, heavy-metal oxides, and catalytic agents. As a device, the absorbing substance is combined with an oxygen and hydrogen recombination unit. 1 figure.

  14. Oxidation catalyst

    Science.gov (United States)

    Ceyer, Sylvia T.; Lahr, David L.

    2010-11-09

    The present invention generally relates to catalyst systems and methods for oxidation of carbon monoxide. The invention involves catalyst compositions which may be advantageously altered by, for example, modification of the catalyst surface to enhance catalyst performance. Catalyst systems of the present invention may be capable of performing the oxidation of carbon monoxide at relatively lower temperatures (e.g., 200 K and below) and at relatively higher reaction rates than known catalysts. Additionally, catalyst systems disclosed herein may be substantially lower in cost than current commercial catalysts. Such catalyst systems may be useful in, for example, catalytic converters, fuel cells, sensors, and the like.

  15. Biochemical Studies of Mycobacterial Fatty Acid Methyltransferase: A Catalyst for the Enzymatic Production of Biodiesel.

    Science.gov (United States)

    Petronikolou, Nektaria; Nair, Satish K

    2015-11-19

    Transesterification of fatty acids yields the essential component of biodiesel, but current processes are cost-prohibitive and generate waste. Recent efforts make use of biocatalysts that are effective in diverting products from primary metabolism to yield fatty acid methyl esters in bacteria. These biotransformations require the fatty acid O-methyltransferase (FAMT) from Mycobacterium marinum (MmFAMT). Although this activity was first reported in the literature in 1970, the FAMTs have yet to be biochemically characterized. Here, we describe several crystal structures of MmFAMT, which highlight an unexpected structural conservation with methyltransferases that are involved in plant natural product metabolism. The determinants for ligand recognition are analyzed by kinetic analysis of structure-based active-site variants. These studies reveal how an architectural fold employed in plant natural product biosynthesis is used in bacterial fatty acid O-methylation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. 3D-nanoarchitectured Pd/Ni catalysts prepared by atomic layer deposition for the electrooxidation of formic acid

    Directory of Open Access Journals (Sweden)

    Loïc Assaud

    2014-02-01

    Full Text Available Three-dimensionally (3D nanoarchitectured palladium/nickel (Pd/Ni catalysts, which were prepared by atomic layer deposition (ALD on high-aspect-ratio nanoporous alumina templates are investigated with regard to the electrooxidation of formic acid in an acidic medium (0.5 M H2SO4. Both deposition processes, Ni and Pd, with various mass content ratios have been continuously monitored by using a quartz crystal microbalance. The morphology of the Pd/Ni systems has been studied by electron microscopy and shows a homogeneous deposition of granularly structured Pd onto the Ni substrate. X-ray diffraction analysis performed on Ni and NiO substrates revealed an amorphous structure, while the Pd coating crystallized into a fcc lattice with a preferential orientation along the [220]-direction. Surface chemistry analysis by X-ray photoelectron spectroscopy showed both metallic and oxide contributions for the Ni and Pd deposits. Cyclic voltammetry of the Pd/Ni nanocatalysts revealed that the electrooxidation of HCOOH proceeds through the direct dehydrogenation mechanism with the formation of active intermediates. High catalytic activities are measured for low masses of Pd coatings that were generated by a low number of ALD cycles, probably because of the cluster size effect, electronic interactions between Pd and Ni, or diffusion effects.

  17. Carbon fiber cloth supported Au nano-textile fabrics as an efficient catalyst for hydrogen peroxide electroreduction in acid medium

    Science.gov (United States)

    Yang, Fan; Cheng, Kui; Wang, Guiling; Cao, Dianxue

    2015-09-01

    The size-controlled hierarchical textile-like Au nanostructures supported carbon fiber cloth (Au NTs/CFC) is successfully fabricated through a simple low-cost electrochemical route. The electrodes are characterised by scanning electron microscopy equipped with an energy dispersive X-ray spectrometer, transmission electron microscopy and X-ray diffractometer. Without any conducting carbons and polymer binders, the 3D electrode with unique structure is directly used as the electrocatalyst for H2O2 reduction in acid solution and the catalytic performance is evaluated by voltammetry and chronoamperometry. The Au NTs/CFC electrode exhibits much higher catalytic activity and remarkably improved utilization of Au than Au nanoparticles (Au NPs/CFC) prepared by the same method owing to its unique structure. In the solution of 3.0 mol L-1 H2SO4 + 0.1 mol L-1 H2O2, with the reduction potential of 0 V, the current of -0.72 A cm-2 mg-1 can be obtained on Au NTs/CFC electrode and only a current of -0.09 A cm-2 mg-1 can be achieved on Au NPs/CFC electrode. All these results reveal that the novel Au NTs/CFC electrode exhibits excellent catalytic performance and superior stability for H2O2 electroreduction in acid medium, benefitting from the unique 3D structure which can ensure high utilization of catalyst.

  18. Silica sulfuric acid: a reusable solid catalyst for one pot synthesis of densely substituted pyrrole-fused isocoumarins under solvent-free conditions

    Directory of Open Access Journals (Sweden)

    Sudipta Pathak

    2013-11-01

    Full Text Available A convenient and efficient methodology for the synthesis of densely substituted pyrrole-fused isocoumarins, which employs solid-supported silica sulfuric acid (SSA as catalyst, has been developed. When the mixture of ninhydrin adducts of acetylacetone/ethyl acetoacetate and primary amines was heated on the solid surface of SSA under solvent-free conditions, the pyrrole-fused isocoumarins were formed in good yields. This synthetic method has several advantages such as the employment of solvent-free reaction conditions without the use of any toxic reagents and metal catalysts, the ease of product isolation, the use of a recyclable catalyst, the low cost, the easy availability of the starting materials, and the excellent yields of products.

  19. Design and synthesis of palladium/graphitic carbon nitride/carbon black hybrids as high-performance catalysts for formic acid and methanol electrooxidation

    Science.gov (United States)

    Qian, Huayu; Huang, Huajie; Wang, Xin

    2015-02-01

    Here we report a facile two-step method to synthesize high-performance palladium/graphitic carbon nitride/carbon black (Pd/g-C3N4/carbon black) hybrids for electrooxidizing formic acid and methanol. The coating of g-C3N4 on carbon black surface is realized by a low-temperature heating treatment, followed by the uniform deposition of palladium nanoparticles (Pd NPs) via a wet chemistry route. Owning to the significant synergistic effects of the individual components, the preferred Pd/g-C3N4/carbon black electrocatalyst exhibits exceptional forward peak current densities as high as 2155 and 1720 mA mg-1Pd for formic acid oxidation in acid media and methanol oxidation in alkaline media, respectively, far outperforming the commercial Pd-C catalyst. The catalyst also shows reliable stability, demonstrating that the newly-designed hybrids have great promise in constructing high-performance portable fuel cell systems.

  20. Domain-confined catalytic soot combustion over Co3O4 anchored on a TiO2 nanotube array catalyst prepared by mercaptoacetic acid induced surface-grafting.

    Science.gov (United States)

    Ren, Jiale; Yu, Yifu; Dai, Fangfang; Meng, Ming; Zhang, Jing; Zheng, Lirong; Hu, Tiandou

    2013-12-21

    Herein, we introduce a specially designed domain-confined macroporous catalyst, namely, the Co3O4 nanocrystals anchored on a TiO2 nanotube array catalyst, which was synthesized by using the mercaptoacetic acid induced surface-grafting method. This catalyst exhibits much better performance for catalytic soot combustion than the conventional TiO2 powder supported one in gravitational contact mode (GMC).

  1. Catalyst Alloys Processing

    Science.gov (United States)

    Tan, Xincai

    2014-10-01

    Catalysts are one of the key materials used for diamond formation at high pressures. Several such catalyst products have been developed and applied in China and around the world. The catalyst alloy most widely used in China is Ni70Mn25Co5 developed at Changsha Research Institute of Mining and Metallurgy. In this article, detailed techniques for manufacturing such a typical catalyst alloy will be reviewed. The characteristics of the alloy will be described. Detailed processing of the alloy will be presented, including remelting and casting, hot rolling, annealing, surface treatment, cold rolling, blanking, finishing, packaging, and waste treatment. An example use of the catalyst alloy will also be given. Industrial experience shows that for the catalyst alloy products, a vacuum induction remelt furnace can be used for remelting, a metal mold can be used for casting, hot and cold rolling can be used for forming, and acid pickling can be used for metal surface cleaning.

  2. Design of an effective bifunctional catalyst organotriphosphonic acid-functionalized ferric alginate (ATMP-FA) and optimization by Box-Behnken model for biodiesel esterification synthesis of oleic acid over ATMP-FA.

    Science.gov (United States)

    Liu, Wei; Yin, Ping; Liu, Xiguang; Qu, Rongjun

    2014-12-01

    Biodiesel production has become an intense research area because of rapidly depleting energy reserves and increasing petroleum prices together with environmental concerns. This paper focused on the optimization of the catalytic performance in the esterification reaction of oleic acid for biodiesel production over the bifunctional catalyst organotriphosphonic acid-functionalized ferric alginate ATMP-FA. The reaction parameters including catalyst amount, ethanol to oleic acid molar ratio and reaction temperature have been optimized by response surface methodology (RSM) using the Box-Behnken model. It was found that the reaction temperature was the most significant factor, and the best conversion ratio of oleic acid could reach 93.17% under the reaction conditions with 9.53% of catalyst amount and 8.62:1 of ethanol to oleic acid molar ratio at 91.0 °C. The research results show that two catalytic species could work cooperatively to promote the esterification reaction, and the bifunctional ATMP-FA is a potential catalyst for biodiesel production. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Synthesis of waste cooking oil based biodiesel via ferric-manganese promoted molybdenum oxide / zirconia nanoparticle solid acid catalyst: influence of ferric and manganese dopants.

    Science.gov (United States)

    Alhassan, Fatah H; Rashid, Umer; Taufiq-Yap, Yun Hin

    2015-01-01

    The utilization of ferric-manganese promoted molybdenum oxide/zirconia (Fe-Mn- MoO3/ZrO2) (FMMZ) solid acid catalyst for production of biodiesel was demonstrated. FMMZ is produced through impregnation reaction followed by calcination at 600°C for 3 h. The characterization of FMMZ had been done using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA), temperature programmed desorption of NH3 (TPD-NH3), transmission electron microscopy(TEM) and Brunner-Emmett-Teller (BET) surface area measurement. The effect of waste cooking oil methyl esters (WCOME's) yield on the reactions variables such as reaction temperature, catalyst loading, molar ratio of methanol/oil and reusability were also assessed. The catalyst was used to convert the waste cooking oil into corresponding methyl esters (95.6%±0.15) within 5 h at 200℃ reaction temperature, 600 rpm stirring speed, 1:25 molar ratio of oil to alcohol and 4% w/w catalyst loading. The reported catalyst was successfully recycled in six connective experiments without loss in activity. Moreover, the fuel properties of WCOME's were also reported using ASTM D 6751 methods.

  4. Biodiesel from Hydrolyzed Waste Cooking Oil Using a S-ZrO2/SBA-15 Super Acid Catalyst under Sub-Critical Conditions

    Directory of Open Access Journals (Sweden)

    Muhammad Nobi Hossain

    2018-01-01

    Full Text Available Due to rapid changes in food habits, a substantial amount of waste fat and used oils are generated each year. Due to strong policies, the disposal of this material into nearby sewers causes ecological and environmental problems in many parts of the world. For efficient management, waste cooking oil, a less expensive, alternative and promising feedstock, can be used as a raw material for producing biofuel. In the present study, we produced a biodiesel from hydrolyzed waste cooking oil with a subcritical methanol process using a synthesized solid super acid catalyst, a sulfated zirconium oxide supported on Santa Barbara Amorphous silica (S-ZrO2/SBA-15. The characterization of the synthesized catalyst was carried out using scanning electron microscopy (SEM, X-ray diffraction (XRD, and the Brunauer-Emmett-Teller (BET method. The catalytic effect on biodiesel production was examined by varying the parameters: temperatures of 120 to 200 °C, 5–20 min times, oil-to-methanol mole ratios between 1:5 to 1:20, and catalyst loadings of 1–2.5%. The maximum biodiesel yield was 96.383%, obtained under optimum reaction conditions of 140 °C, 10 min, and a 1:10 oil-to-methanol molar ratio with a 2.0% catalyst loading. We successfully reused the catalyst five times without regeneration with a 90% efficiency. The fuel properties were found to be within the limits set by the biodiesel standard.

  5. Photodegradation of 4-chlorophenoxyacetic acid under visible LED activated N-doped TiO2 and the mechanism of stepwise rate increment of the reused catalyst.

    Science.gov (United States)

    Abdelhaleem, Amal; Chu, Wei

    2017-09-15

    Photodegradation of 4-chlorophenoxyacetic acid (4-CPA) was systematically investigated using N-doped TiO2 (N-TiO2) under commercially available visible light emitting diode (Vis LED) as a novel Vis LED illumination in photocatalysis applications. The synergetic effect of Vis LED/N-TiO2 process was studied in detail by varying reaction conditions including the initial concentration of 4-CPA, catalyst dosage, light intensity, and initial pH. Additionally, the influence of inorganic anions and radical scavengers on the performance of the Vis LED/N-TiO2 process was also evaluated. The Vis LED/N-TiO2 was found to be a promising process in terms of mineralization of 4-CPA. It is interesting to note that the performance of this process was not reduced after successive usage of the recycled catalyst; instead, the reaction rate of 4-CPA decay actually increased by using the spent catalyst. The mechanism behind rate enhancement after/during reuse was explored by XPS and FT-IR analyses and it was proven that hydroxyl groups can be incorporated into the catalyst surface by the repeated wetting of N-TiO2 after each reuse. This facilitates the formation of hydrogen bonds between the 4-CPA molecules and N-TiO2, thereby allowing more collisions between the trapped 4-CPA and radicals at the interface of bulk solution and catalyst, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Synthesis and characterization of 12-phosphotungstic acid supported on BEA zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Jović, A.; Bajuk-Bogdanović, D.; Nedić Vasiljević, B. [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade (Serbia); Milojević-Rakić, M., E-mail: maja@ffh.bg.ac.rs [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade (Serbia); Krajišnik, D. [Department of Pharmaceutical Technology and Cosmetology, University of Belgrade-Faculty of Pharmacy, Vojvode Stepe 450, 11000 Belgrade (Serbia); Dondur, V. [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade (Serbia); Popa, A. [Institute of Chemistry Timisoara, Bl. Mihai Viteazul 24, 300223 Timisoara (Romania); Uskoković-Marković, S. [Department of Analytical Chemistry, University of Belgrade-Faculty of Pharmacy, Vojvode Stepe 450, 11000 Belgrade (Serbia); Holclajtner-Antunović, I. [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade (Serbia)

    2017-01-15

    An optimized synthetic route for obtaining heteropoly acid (HPA) species supported on BEA zeolite was applied, and different samples, comprising 20 to 50 wt% of 12-phosphotungstic acid (HPW) were prepared. The as-synthesized supported HPW were subjected to different post-synthesis routes, which involved calcination and ultrasound treatment. Characterization of these materials was performed by means of Scanning Electron Microscopy, zeta potential measurements, Infrared Spectroscopy and X-ray Powder Diffraction analysis. Results suggest strong interaction of HPW with the support and revealed that ultrasound treatment resulted in better dispersion of active phase and thus homogeneous morphology of the samples. The zeta potential was found to be dependent on the preparation procedure and HPW content in these materials, while higher HPW loadings induced its agglomeration. Catalytic activity of the synthesized materials was investigated in an ethanol dehydration reaction, where lower HPW loadings induced higher ethanol conversion. Acid sites distribution and accessibility for ethanol molecules were found to be more essential for catalytic activity than HPW loadings, i.e., amount of active sites present in these hybrid materials. - Highlights: • An optimized route for supporting heteropoly acid on beta zeolite is applied. • Ultrasound treatment of the composites gives dispersed morphology. • Lower heteropoly acid amount induces higher conversion in ethanol dehydration. • Acid sites distribution and accessibility for ethanol are essential for catalytic activity.

  7. Sulfuric acid as a catalyst for ring-opening of biobased bis-epoxides

    Science.gov (United States)

    Vegetable oils can be relatively and easily transformed into bio-based epoxides. Because of this, the acid-catalyzed epoxide ring-opening has been explored for the preparation of bio-based lubricants and polymers. Detailed model studies are carried out only with mono-epoxide made from methyl oleate,...

  8. 2-Substituted-1,3,2-dithioborolans as Chiral Lewis Acid Catalysts

    Directory of Open Access Journals (Sweden)

    Paul Glynn

    2000-08-01

    Full Text Available 1,3,2-Dithioborolans substituted at the 2-position with various homochiral groups can act as chiral Lewis acids in the Diels-Alder reaction between crotonaldehyde or methacrolein with cyclopentadiene. The endo:exo selectivities obtained were good although the enantiomeric excesses were low to moderate.

  9. Dolomite-Derived Ni-Based Catalysts with Fe Modification for Hydrogen Production via Auto-Thermal Reforming of Acetic Acid

    Directory of Open Access Journals (Sweden)

    Xinyan Zhong

    2016-06-01

    Full Text Available Bio-oil can be obtained via fast pyrolysis of biomass, and typically contains acetic acid (~30 mass %. The acetic acid has often been tested as a model compound for hydrogen production via reforming bio-oil, in which catalysts are a key factor for stable hydrogen production. However, deactivation of catalysts by coking and oxidation hinders the application of the reforming process. Dolomite-derived Ni-based catalysts with Fe additive, MgNi0.2Ca0.8−xFexO2±δ (x = 0–0.8, were successfully synthesized by the hydrothermal synthesis method, and then tested in auto-thermal reforming (ATR of acetic acid (AC. The MgNi0.2Ca0.5Fe0.3O2±δ catalyst performed a stable reactivity in ATR: the conversion of AC reached 100%, and the H2 yield remained stable around 2.6 mol-H2/mol-AC. The catalysts were characterized by X-ray diffraction (XRD, N2 physisorption, X-ray photoelectron spectra (XPS, H2-temperature-programmed reduction (TPR, inductively coupled plasma- atomic emission spectroscopy (ICP-AES and Thermogravimetry (TG; the results show that a periclase-like solid solution of Mg(Ni,FeO and lime were formed via the precursors of dolomite and hydrotalcite, and then transformed into Fe-rich Ni-Fe alloy with basic support of MgO-CaO after reduction. The stable Ni0 spices with basic support can explain the stability and resistance to coking during ATR of AC.

  10. Catalytic Hydrogenation of Levulinic Acid in Water into g-Valerolactone over Bulk Structure of Inexpensive Intermetallic Ni-Sn Alloy Catalysts

    Directory of Open Access Journals (Sweden)

    Rodiansono Rodiansono

    2015-07-01

    Full Text Available A bulk structure of inexpensive intermetallic nickel-tin (Ni-Sn alloys catalysts demonstrated highly selective in the hydrogenation of levulinic acid in water into g-valerolactone. The intermetallic Ni-Sn catalysts were synthesized via a very simple thermochemical method from non-organometallic precursor at low temperature followed by hydrogen treatment at 673 K for 90 min. The molar ratio of nickel salt and tin salt was varied to obtain the corresponding Ni/Sn ratio of 4.0, 3.0, 2.0, 1.5, and 0.75. The formation of Ni-Sn alloy species was mainly depended on the composition and temperature of H2 treatment. Intermetallics Ni-Sn that contain Ni3Sn, Ni3Sn2, and Ni3Sn4 alloy phases are known to be effective heterogeneous catalysts for levulinic acid hydrogenation giving very excellence g-valerolactone yield of >99% at 433 K, initial H2 pressure of 4.0 MPa within 6 h. The effective hydrogenation was obtained in H2O without the formation of by-product. Intermetallic Ni-Sn(1.5 that contains Ni3Sn2 alloy species demonstrated very stable and reusable catalyst without any significant loss of its selectivity. © 2015 BCREC UNDIP. All rights reserved. Received: 26th February 2015; Revised: 16th April 2015; Accepted: 22nd April 2015  How to Cite: Rodiansono, R., Astuti, M.D., Ghofur, A., Sembiring, K.C. (2015. Catalytic Hydrogenation of Levulinic Acid in Water into g-Valerolactone over Bulk Structure of Inexpensive Intermetallic Ni-Sn Alloy Catalysts. Bulletin of Chemical Reaction Engineering & Catalysis, 10 (2: 192-200. (doi:10.9767/bcrec.10.2.8284.192-200Permalink/DOI: http://dx.doi.org/10.9767/bcrec.10.2.8284.192-200  

  11. Facile and Low-Cost Preparation of Nb/Al Oxide Catalyst with High Performance for the Conversion of Kiwifruit Waste Residue to Levulinic Acid

    Directory of Open Access Journals (Sweden)

    Rui Wang

    2015-09-01

    Full Text Available The kiwifruit industry is booming worldwide. As a result, a great deal of kiwifruit waste residue (KWR containing monosaccharides is produced and discarded. This material shows great potential for the production of platform chemicals. In this study, a series of Nb/Al oxide catalysts were synthesized via a facile and low-cost coprecipitation method, and their structures were characterized using: thermal gravimetric analysis (TGA, XRD, FESEM, TEM, X-ray photoelectron spectroscopy (XPS, NH3-TPD, N2 adsorption-desorption, and FTIR-Pyridine adsorption. Experimental results of sugar-to-levulinic acid (LA conversion revealed that the 20%Nb/Al oxide catalyst provided the highest catalytic performance and durability in terms of LA yield from fructose (74.2% at 463 K after 10 min and from glucose (47.5% at 473 K after 15 min. Notably, the 20% Nb/Al oxide catalyst with a 10% dosage is capable of converting kiwifruit waste residue to LA at 473 K after 10 min. In conclusion, the enhanced catalytic performance was obtained due to the high acidity, and large surface areaof Nb/Al oxide catalyst.

  12. Oxidative degradation of different chlorinated phenoxyalkanoic acid herbicides by a hybrid ZrO2 gel-derived catalyst without light irradiation.

    Science.gov (United States)

    Sannino, Filomena; Pernice, Pasquale; Minieri, Luciana; Camandona, Gaia Aurora; Aronne, Antonio; Pirozzi, Domenico

    2015-01-14

    The oxidative degradation of 2-methyl-4-chlorophenoxyacetic acid (MCPA), 4-(4-chloro-2-methylphenoxy)butanoic acid (MCPB), 4-chlorophenoxyacetic acid (4-CPA) and 2,4-dichlorophenoxyacetic acid (2,4 D) by ZrO2-acetylacetonate hybrid catalyst (HSGZ) without light irradiation was assessed. The thermal stability of the catalyst was investigated by thermogravimetry, differential thermal analysis, and Fourier transform infrared spectroscopy. For each herbicide, a virtually complete removal in about 3 days without light irradiation at room temperature was achieved. The removal kinetics of the herbicides has been satisfactorily characterized by a double-stage physico-mathematical model, in the hypothesis that a first-order adsorption on HSGZ surface is followed by the herbicide degradation, catalytically driven by HSGZ surface groups. The long-term use of the HSGZ catalyst was assessed by repeated-batch tests. The specific cost for unit-volume removal of herbicide was evaluated by a detailed cost analysis showing that it is comparable with those pertaining to alternative methods.

  13. The oxidation of tetrabromobisphenol A by potassium monopersulfate with an iron(III)-phthalocyanine-tetrasulfonic acid catalyst in the presence of humic acid.

    Science.gov (United States)

    Maeno, Shohei; Mizutani, Yusuke; Zhu, Qianqian; Miyamoto, Takafumi; Fukushima, Masami; Kuramitz, Hideki

    2014-01-01

    Tetrabromobisphenol A (TBBPA), a type of brominated flame retardant that shows endocrine disruption effects, has been identified in leachates from landfills. Iron(III)-porphyrins that mimic the active site of peroxidases have been shown to be effective in oxidizing halogenated phenols, such as TBBPA. In the present study, TBBPA was subjected to oxidation with potassium monopersulfate (KHSO5) using an iron(III)-phthalocyanine-tetrasulfonic acid (FePcTS), structural analogue of iron(III)-porphyrin, in the presence of humic acid (HA), a major component in landfill leachates. When TBBPA was oxidized using the above system, the levels of degradation and debromination increased with increasing pH in the presence of HA. Because of landfill leachates are weakly alkaline (around pH 8), oxidation products derived from TBBPA were investigated at pH 8. Approximately 48% of the bromine in the degraded TBBPA was incorporated into HA, and hydroxy-tribromobisphenol A was determined to be the major brominated intermediate in the HA fraction. In the iron(III)-porphyrin catalytic systems, the brominated intermediate incorporated into HA is mainly TBBPA, and no hydroxy-substituted bromophenols are found. Thus, the catalytic power of FePcTS is higher than that of iron(III)-porphyrin catalysts.

  14. Highly dispersed supported ruthenium oxide as an aerobic catalyst for acetic acid synthesis

    DEFF Research Database (Denmark)

    Laursen, Anders Bo; Gorbanev, Yury; Cavalca, Filippo

    2012-01-01

    for the selective aerobic oxidation of ethanol to acetic acid. The RuOx was deposited onto different oxide supports using a new gas-phase reaction, which in all cases resulted in homogeneous nanoparticulate films. The RuOx particle size ranged from 0.3 to 1.5nm. The catalytic activity was evaluated on TiO2, Mg6Al2......(CO3)(OH)16·4(H2O), MgAl2O4, Na2Ti6O13 nanotubes, ZnO, γ-Al2O3, WO3, CeO2, and Ce0.5Zr0.5O2 supports. The CeO2 supported RuOx had the highest activity, and selectivity toward acetic acid, of all the materials when normalized with respect to Ru-loading. This high activity was independent of the surface...

  15. Preparation and evaluation of advanced catalysts for phosphoric acid fuel cells

    Science.gov (United States)

    Stonehart, P.; Baris, J.; Hockmuth, J.; Pagliaro, P.

    1984-01-01

    The platinum electrocatalysts were characterized for their crystallite sizes and the degree of dispersion on the carbon supports. One application of these electrocatalysts was for anodic oxidation of hydrogen in hot phosphoric acid fuel cells, coupled with the influence of low concentrations of carbon monoxide in the fuel gas stream. In a similar way, these platinum on carbon electrocatalysts were evaluated for oxygen reduction in hot phosphoric acid. Binary noble metal alloys were prepared for anodic oxidation of hydrogen and noble metal-refractory metal mixtures were prepared for oxygen reduction. An exemplar alloy of platinum and palladium (50/50 atom %) was discovered for anodic oxidation of hydrogen in the presence of carbon monoxide, and patent disclosures were submitted. For the cathode, platinum-vanadium alloys were prepared showing improved performance over pure platinum. Preliminary experiments on electrocatalyst utilization in electrode structures showed low utilization of the noble metal when the electrocatalyst loading exceeded one weight percent on the carbon.

  16. High efficient conversion of furfural to 2-methylfuran over Ni-Cu/Al2O3 catalyst with formic acid as a hydrogen donor

    DEFF Research Database (Denmark)

    Fu, Zhaolin; Wang, Ze; Lin, Weigang

    2017-01-01

    Conversion of furfural to 2-methylfuran over Cu/Al2O3, Ni/Al2O3 and Ni-Cu/Al2O3 catalysts were investigated with formic acid as a hydrogen donor. Ni/Al2O3 showed a high catalytic activity but a moderate selectivity to 2-methylfuran. Contrarily, Cu/Al2O3 showed a low catalytic activity but a high...... selectivity for carbonyl reduction. Over the bimetallic catalysts Ni-10%Cu/Al2O3, by increasing Ni content, more furfural was converted with the reduction of carbonyl primarily. The effect of reaction solvent and the fraction of formic acid were also studied. The result showed that isopropanol solvent could...

  17. Core-shell Fe3O4@MIL-101(Fe) composites as heterogeneous catalysts of persulfate activation for the removal of Acid Orange 7.

    Science.gov (United States)

    Yue, Xinxin; Guo, Weilin; Li, Xianghui; Zhou, Haihong; Wang, Ruiqin

    2016-08-01

    In this study, a novel core-shell Fe3O4@MIL-101 (MIL stands for Materials of Institute Lavoisier) composite was successfully synthesized by hydrothermal method and was fully characterized by X-ray diffraction, transmission electron microscopy, Fourier-transform infrared spectra, and X-ray photoelectron spectroscopy. The composite was introduced as a catalyst to generate powerful radicals from persulfate for the removal of Acid Orange 7 in an aqueous solution. Effects of the central metal ions of MIL-101, amino group content of MIL-101, and pH were evaluated in batch experiments. It was found that both hydroxyl and sulfate radicals were generated; importantly, sulfate radicals were speculated to serve as the dominant active species in the catalytic oxidation of Acid Orange 7. In addition, a possible mechanism was proposed. This study provides new physical insights for the rational design of advanced metal-organic frameworks (MOF)-based catalysts for improved environmental remediation.

  18. Use of Pyrolyzed Iron Ethylenediaminetetraacetic Acid Modified Activated Carbon as Air–Cathode Catalyst in Microbial Fuel Cells

    KAUST Repository

    Xia, Xue

    2013-08-28

    Activated carbon (AC) is a cost-effective catalyst for the oxygen reduction reaction (ORR) in air-cathode microbial fuel cells (MFCs). To enhance the catalytic activity of AC cathodes, AC powders were pyrolyzed with iron ethylenediaminetetraacetic acid (FeEDTA) at a weight ratio of FeEDTA:AC = 0.2:1. MFCs with FeEDTA modified AC cathodes and a stainless steel mesh current collector produced a maximum power density of 1580 ± 80 mW/m2, which was 10% higher than that of plain AC cathodes (1440 ± 60 mW/m 2) and comparable to Pt cathodes (1550 ± 10 mW/m2). Further increases in the ratio of FeEDTA:AC resulted in a decrease in performance. The durability of AC-based cathodes was much better than Pt-catalyzed cathodes. After 4.5 months of operation, the maximum power density of Pt cathode MFCs was 50% lower than MFCs with the AC cathodes. Pyridinic nitrogen, quaternary nitrogen and iron species likely contributed to the increased activity of FeEDTA modified AC. These results show that pyrolyzing AC with FeEDTA is a cost-effective and durable way to increase the catalytic activity of AC. © 2013 American Chemical Society.

  19. Synthesis of bio-additives: transesterification of ethyl acetate with glycerol using homogeneous or heterogeneous acid catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Meireles, Bruno A.; Pereira, Vera Lucia P., E-mail: patrocinio@nppn.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Centro de Ciencias da Saude. Nucleo de Pesquisas de Produtos Naturais

    2013-01-15

    A new catalytic route with potential practical interest to sustainable production of bioadditives from glycerol is described. Ethyl acetate was transesterified with glycerol, in the ratio glycerol:EtOAc 1:10, at 25 or 90 deg C using 0.1 equiv.of H{sub 2}SO{sub 4} or TsOH, as homogeneous catalysts. H{sub 2}SO{sub 4} led to the total glycerol consumption in 2 h. In the equilibrium, attained in 9 h, 100% yield of a diacetin:triacetin (55:45) mixture was formed. Using Amberlyst Registered-Sign 15 dry and Amberlyst Registered-Sign 16 wet in 1:30 glycerol:EtOAc ratio and reflux at 90 Degree-Sign C the total glycerol consumption was achieved in 2 and 10h, respectively. The lower reactivity of Amberlyst-16 wet was explained in terms of deactivation of acid sites and decrease in glycerol diffusion to the inner resin pores, both factors caused by adsorbed water. The kinetics of glycerol transformation and product distribution in the equilibrium in relation to the H{sub 2}SO{sub 4}, Amberlyst-15 (dry) and Amberlyst-16 (wet) catalyzed reactions were measured. (author)

  20. Tannic acid- and natural organic matter-coated magnetite as green Fenton-like catalysts for the removal of water pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Nadejde, C., E-mail: claudianadejde@gmail.com; Neamtu, M., E-mail: mariana.neamtu@uaic.ro [‘Alexandru Ioan Cuza’ University, Interdisciplinary Research Department – Field Science (Romania); Hodoroaba, V.-D.; Schneider, R. J.; Paul, A. [BAM Federal Institute for Materials Research and Testing (Germany); Ababei, G. [National Institute of Research and Development for Technical Physics (Romania); Panne, U. [BAM Federal Institute for Materials Research and Testing (Germany)

    2015-12-15

    The use of magnetic materials as heterogeneous catalysts has attracted increasing attention in the last years since they proved to be promising candidates for water treatment. In the present study, two types of surface-modified magnetite (Fe{sub 3}O{sub 4}) nanoparticles, coated with non-hazardous naturally occurring agents—either tannic acid (TA) or dissolved natural organic matter—were evaluated as magnetic heterogeneous catalysts. Chemical synthesis (co-precipitation) was chosen to yield the nanocatalysts due to its well-established simplicity and efficiency. Subsequently, the properties of the final products were fully assessed by various characterization techniques. The catalytic activity in heterogeneous oxidation of aqueous solutions containing a model pollutant, Bisphenol A (BPA), was comparatively studied. The effect of operational parameters (catalyst loading, H{sub 2}O{sub 2} dosage, and UV light irradiation) on the degradation performance of the oxidation process was investigated. The optimum experimental parameters were found to be 1.0 g/L of catalysts and 10 mM H{sub 2}O{sub 2}, under UV irradiation. The highest mineralization rates were observed for Fe{sub 3}O{sub 4}-TA catalyst. More than 80 % of BPA was removed after 30 min of reaction time under the specified experimental conditions. The obtained results showed that the two catalysts studied here are suitable candidates for the removal of pollutants in wastewaters by means of heterogeneous reaction using a green sustainable treatment method.

  1. Fluidized bed catalytic pyrolysis of eucalyptus over hzsm-5: effect of acid density and ga modification on catalyst deactivation

    Science.gov (United States)

    Catalytic fast pyrolysis of eucalyptus wood was performed on a continuous laboratory scale fluidized bed fast pyrolysis system. Catalytic activity was monitored from use of fresh catalyst up to a cumulative biomass to catalyst ratio (B/C) of 4/1 over extruded pellets of three different ZSM-5 catalys...

  2. Graphite-Supported Perchloric Acid (HClO4-C: An Efficient and Recyclable Heterogeneous Catalyst for the One-Pot Synthesis of Amidoalkyl Naphthols

    Directory of Open Access Journals (Sweden)

    Zhen-Kai Lei

    2013-01-01

    Full Text Available An efficient and direct protocol for the preparation of amidoalkylnaphthols employing a multi-component, one-pot condensation reaction of 2-naphthol, aromatic aldehydes and acetamide or benzamide in the presence of graphite supported perchloric acid under solvent-free conditions is described. The thermal solvent-free procedure offers advantages such as simple work-up, shorter reaction times and higher product yields, and the catalyst exhibited remarkable reactivity and can be recycled.

  3. Graphite-supported perchloric acid (HClO4-C): an efficient and recyclable heterogeneous catalyst for the one-pot synthesis of amidoalkyl naphthols.

    Science.gov (United States)

    Lei, Zhen-Kai; Xiao, Li; Lu, Xiao-Quan; Huang, He; Liu, Chen-Jiang

    2013-01-28

    An efficient and direct protocol for the preparation of amidoalkylnaphthols employing a multi-component, one-pot condensation reaction of 2-naphthol, aromatic aldehydes and acetamide or benzamide in the presence of graphite supported perchloric acid under solvent-free conditions is described. The thermal solvent-free procedure offers advantages such as simple work-up, shorter reaction times and higher product yields, and the catalyst exhibited remarkable reactivity and can be recycled.

  4. Novel Ion-Exchange Catalysts for Reactions Involving Lipophilic Reagents: Perspectives in the Reaction of Esterifications of Fatty Acids with Methanol

    Czech Academy of Sciences Publication Activity Database

    Centomo, P.; Bonato, I.; Hanková, Libuše; Holub, Ladislav; Jeřábek, Karel; Zecca, M.

    2013-01-01

    Roč. 56, 9-10 (2013), s. 611-617 ISSN 1022-5528. [Nordic Symposium on Catalysis /15./. Mariehamn, Åland, 10.06.2012-12.06.2012] Grant - others:IMUR(IT) 2008SXASBC_004 Institutional support: RVO:67985858 Keywords : sulfonated resins * acylation * lipophilic acid catalysts Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.220, year: 2013

  5. TUNGSTOPHOSPHORIC ACID HETEROGENIZED ONTO NH4ZSM5 AS AN EFFICIENT AND RECYCLABLE CATALYST FOR THE PHOTOCATALYTIC DEGRADATION OF DYES

    Directory of Open Access Journals (Sweden)

    Candelaria Leal Marchena

    2015-05-01

    Full Text Available Materials based on tungstophosphoric acid (TPA immobilized on NH4ZSM5 zeolite were prepared by wet impregnation of the zeolite matrix with TPA aqueous solutions. Their concentration was varied in order to obtain TPA contents of 5%, 10%, 20%, and 30% w/w in the solid. The materials were characterized by N2 adsorption-desorption isotherms, XRD, FT-IR, 31P MAS-NMR, TGA-DSC, DRS-UV-Vis, and the acidic behavior was studied by potentiometric titration with n-butylamine. The BET surface area (SBET decreased when the TPA content was raised as a result of zeolite pore blocking. The X-ray diffraction patterns of the solids modified with TPA only presented the characteristic peaks of NH4ZSM5 zeolites, and an additional set of peaks assigned to the presence of (NH43PW12O40. According to the Fourier transform infrared and 31P magic angle spinning-nuclear magnetic resonance spectra, the main species present in the samples was the [PW12O40]3- anion, which was partially transformed into the [P2W21O71]6- anion during the synthesis and drying steps. The thermal stability of the NH4ZSM5TPA materials was similar to that of their parent zeolites. Moreover, the samples with the highest TPA content exhibited band gap energy values similar to those reported for TiO2. The immobilization of TPA on NH4ZSM5 zeolite allowed the obtention of catalysts with high photocatalytic activity in the degradation of methyl orange dye (MO in water, at 25 ºC. These can be reused at least three times without any significant decrease in degree of degradation.

  6. Synthesis of fatty acid methyl ester from the transesterification of high- and low-acid-content crude palm oil (Elaeis guineensis) and karanj oil (Pongamia pinnata) over a calcium-lanthanum-aluminum mixed-oxides catalyst.

    Science.gov (United States)

    Syamsuddin, Y; Murat, M N; Hameed, B H

    2016-08-01

    The synthesis of fatty acid methyl ester (FAME) from the high- and low-acid-content feedstock of crude palm oil (CPO) and karanj oil (KO) was conducted over CaO-La2O3-Al2O3 mixed-oxide catalyst. Various reaction parameters were investigated using a batch reactor to identify the best reaction condition that results in the highest FAME yield for each type of oil. The transesterification of CPO resulted in a 97.81% FAME yield with the process conditions of 170°C reaction temperature, 15:1 DMC-to-CPO molar ratio, 180min reaction time, and 10wt.% catalyst loading. The transesterification of KO resulted in a 96.77% FAME yield with the conditions of 150°C reaction temperature, 9:1 DMC-to-KO molar ratio, 180min reaction time, and 5wt.% catalyst loading. The properties of both products met the ASTM D6751 and EN 14214 standard requirements. The above results showed that the CaO-La2O3-Al2O3 mixed-oxide catalyst was suitable for high- and low-acid-content vegetable oil. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Catalyst in Basic Oleochemicals

    Directory of Open Access Journals (Sweden)

    Eva Suyenty

    2007-10-01

    Full Text Available Currently Indonesia is the world largest palm oil producer with production volume reaching 16 million tones per annum. The high crude oil and ethylene prices in the last 3 – 4 years contribute to the healthy demand growth for basic oleochemicals: fatty acids and fatty alcohols. Oleochemicals are starting to replace crude oil derived products in various applications. As widely practiced in petrochemical industry, catalyst plays a very important role in the production of basic oleochemicals. Catalytic reactions are abound in the production of oleochemicals: Nickel based catalysts are used in the hydrogenation of unsaturated fatty acids; sodium methylate catalyst in the transesterification of triglycerides; sulfonic based polystyrene resin catalyst in esterification of fatty acids; and copper chromite/copper zinc catalyst in the high pressure hydrogenation of methyl esters or fatty acids to produce fatty alcohols. To maintain long catalyst life, it is crucial to ensure the absence of catalyst poisons and inhibitors in the feed. The preparation methods of nickel and copper chromite catalysts are as follows: precipitation, filtration, drying, and calcinations. Sodium methylate is derived from direct reaction of sodium metal and methanol under inert gas. The sulfonic based polystyrene resin is derived from sulfonation of polystyrene crosslinked with di-vinyl-benzene. © 2007 BCREC UNDIP. All rights reserved.[Presented at Symposium and Congress of MKICS 2007, 18-19 April 2007, Semarang, Indonesia][How to Cite: E. Suyenty, H. Sentosa, M. Agustine, S. Anwar, A. Lie, E. Sutanto. (2007. Catalyst in Basic Oleochemicals. Bulletin of Chemical Reaction Engineering and Catalysis, 2 (2-3: 22-31.  doi:10.9767/bcrec.2.2-3.6.22-31][How to Link/DOI: http://dx.doi.org/10.9767/bcrec.2.2-3.6.22-31 || or local: http://ejournal.undip.ac.id/index.php/bcrec/article/view/6

  8. High-effective approach from amino acid esters to chiral amino alcohols over Cu/ZnO/Al2O3 catalyst and its catalytic reaction mechanism

    Science.gov (United States)

    Zhang, Shuangshuang; Yu, Jun; Li, Huiying; Mao, Dongsen; Lu, Guanzhong

    2016-01-01

    Developing the high-efficient and green synthetic method for chiral amino alcohols is an intriguing target. We have developed the Mg2+-doped Cu/ZnO/Al2O3 catalyst for hydrogenation of L-phenylalanine methyl ester to chiral L-phenylalaninol without racemization. The effect of different L-phenylalanine esters on this title reaction was studied, verifying that Cu/ZnO/Al2O3 is an excellent catalyst for the hydrogenation of amino acid esters to chiral amino alcohols. DFT calculation was used to study the adsorption of substrate on the catalyst, and showed that the substrate adsorbs on the surface active sites mainly by amino group (-NH2) absorbed on Al2O3, and carbonyl (C=O) and alkoxy (RO-) group oxygen absorbed on the boundary of Cu and Al2O3. This catalytic hydrogenation undergoes the formation of a hemiacetal intermediate and the cleavage of the C–O bond (rate-determining step) by reacting with dissociated H to obtain amino aldehyde and methanol ad-species. The former is further hydrogenated to amino alcohols, and the latter desorbs from the catalyst surface. PMID:27619990

  9. Synthesis of Metal-organic Frameworks Based on Zr4+ and Benzene 1,3,5-Tricarboxylate Linker as Heterogeneous Catalyst in the Esterification Reaction of Palmitic Acid

    Science.gov (United States)

    Larasati, I.; Winarni, D.; Putri, F. R.; Hanif, Q. A.; Lestari, W. W.

    2017-07-01

    The conversion of the biomass into biodiesels via catalytic esterification and trans-esterification became an interesting topic due to the depletion of fossil-based energy. Homogenous catalysts such as HCl, H2SO4 and NaOH commonly used as catalyst, however, the use of this kind of catalyst causes more problems, such as the difficulties on the separation from the product and the pollution effect on the environment. Heterogeneous catalysts, such as Metal-Organic Frameworks (MOFs) give an alternative promising way to substitute these limitations due to their strong catalytic site, porosity, high specific surface area, and easy-separation and reusable properties. Herein, we reported the synthesis of MOFs based on zirconium(IV) and H3BTC linker (H3BTC = benzene-1,3,5-tricarboxylic acid) by solvothermal and reflux method. Solvothermal reaction at 120 °C was found to be the optimum method, that was indicated by most crystalline product compared to the simulated pattern in XRD analysis. The formation of the framework was characterized by FTIR analysis, which showed a significant shift from 1722 cm-1 to 1620 cm-1. The synthesized Zr(IV)-BTC was thermally stable up to 322°C as shown by TG/DTA analysis. This high thermal stability was related to the high oxidation state of Zr(IV), which give a significant covalent character to the Zr-O bond.

  10. High-effective approach from amino acid esters to chiral amino alcohols over Cu/ZnO/Al2O3 catalyst and its catalytic reaction mechanism

    Science.gov (United States)

    Zhang, Shuangshuang; Yu, Jun; Li, Huiying; Mao, Dongsen; Lu, Guanzhong

    2016-09-01

    Developing the high-efficient and green synthetic method for chiral amino alcohols is an intriguing target. We have developed the Mg2+-doped Cu/ZnO/Al2O3 catalyst for hydrogenation of L-phenylalanine methyl ester to chiral L-phenylalaninol without racemization. The effect of different L-phenylalanine esters on this title reaction was studied, verifying that Cu/ZnO/Al2O3 is an excellent catalyst for the hydrogenation of amino acid esters to chiral amino alcohols. DFT calculation was used to study the adsorption of substrate on the catalyst, and showed that the substrate adsorbs on the surface active sites mainly by amino group (-NH2) absorbed on Al2O3, and carbonyl (C=O) and alkoxy (RO-) group oxygen absorbed on the boundary of Cu and Al2O3. This catalytic hydrogenation undergoes the formation of a hemiacetal intermediate and the cleavage of the C-O bond (rate-determining step) by reacting with dissociated H to obtain amino aldehyde and methanol ad-species. The former is further hydrogenated to amino alcohols, and the latter desorbs from the catalyst surface.

  11. A highly efficient nano-Fe{sub 3}O{sub 4} encapsulated-silica particles bearing sulfonic acid groups as a solid acid catalyst for synthesis of 1,8-dioxo-octahydroxanthene derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Naeimi, Hossein, E-mail: naeimi@kashanu.ac.ir; Nazifi, Zahra Sadat [University of Kashan, Department of Organic Chemistry, Faculty of Chemistry (Iran, Islamic Republic of)

    2013-11-15

    The functionalization of silica-coated Fe{sub 3}O{sub 4} magnetic nanoparticles (Fe{sub 3}O{sub 4}@SiO{sub 2}) using chlorosulfonic acid were afforded sulfonic acid-functionalized magnetic Fe{sub 3}O{sub 4} nanoparticles (Fe{sub 3}O{sub 4}@SiO{sub 2}–SO{sub 3}H) that can be applied as an organic–inorganic hybrid heterogeneous catalyst. The used Fe{sub 3}O{sub 4} magnetic nanoparticles are 18–30 nm sized that was rapidly functionalized and can be used as catalyst in organic synthesis. The prepared nanoparticles were characterized by X-ray diffraction analysis, magnetization curve, scanning electron microscope, dynamic laser scattering, and FT-IR measurements. The resulting immobilized catalysts have been successfully used in the synthesis of 1,8‐dioxo-octahydroxanthene derivatives under solvent free condition. This procedure has many advantages such as; a much milder method, a shorter reaction time, a wide range of functional group tolerance, and absence of any tedious workup or purification. Other remarkable features include the catalyst can be reused at least five times without any obvious change in its catalytic activity. This procedure also avoids hazardous reagents/solvents, and thus can be an eco-friendly alternative to the existing methods.Graphical AbstractA highly efficient nano-Fe{sub 3}O{sub 4} encapsulated-silica particles bearing sulfonic acid groups as a solid acid catalyst for synthesis of 1,8-dioxo-octahydroxanthene derivatives.

  12. 3-[(3-(Trimethoxysilylpropylthio]propane-1-oxy-sulfonic acid: An efficient recyclable heterogeneous catalyst for the synthesis of 3,4-dihydropyrimidin-2(1H-ones/thiones

    Directory of Open Access Journals (Sweden)

    Srinivasa Rao Jetti

    2017-05-01

    Full Text Available An efficient method for the synthesis of 3,4-dihydropyrimidin-2(1H-ones and thiones through one-pot three-component reaction of ethyl acetoacetate, aryl aldehyde and urea or thiourea in ethanol using 3-[(3-(trimethoxysilylpropylthio]propane-1-oxy-sulfonic acid as catalyst is described. The use of 3-[(3-(trimethoxysilylpropylthio]propane-1-oxy-sulfonic acid as a catalyst offers several advantages such as high yields, short reaction times, mild reaction condition and a recyclable catalyst with a very easy work up.

  13. The Effect of Acidic and Redox Properties of V2O5/CeO2-ZrO2 Catalysts in Selective Catalytic Reduction of NO by NH3

    DEFF Research Database (Denmark)

    Putluru, Siva Sankar Reddy; Riisager, Anders; Fehrmann, Rasmus

    2009-01-01

    V2O5 supported ZrO2 and CeO2–ZrO2 catalysts were prepared and characterized by N2 physisorption, XRPD, TPR, and NH3-TPD methods. The influence of calcination temperature from 400 to 600 °C on crystallinity, acidic and redox properties were studied and compared with the catalytic activity...... on acidic and redox properties of the catalyst. The V2O5/CeO2–ZrO2 catalysts showed high activity and selectivity for reduction of NO with NH3....

  14. Formic Acid Dehydrogenation on Au-Based Catalysts at Near-Ambient Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Ojeda, Manuel; Iglesia, Enrique

    2008-11-24

    Formic acid (HCOOH) is a convenient hydrogen carrier in fuel cells designed for portable use. Recent studies have shown that HCOOH decomposition is catalyzed with Ru-based complexes in the aqueous phase at near-ambient temperatures. HCOOH decomposition reactions are used frequently to probe the effects of alloying and cluster size and of geometric and electronic factors in catalysis. These studies have concluded that Pt is the most active metal for HCOOH decomposition, at least as large crystallites and extended surfaces. The identity and oxidation state of surface metal atoms influence the relative rates of dehydrogenation (HCOOH {yields} H{sub 2} + CO{sub 2}) and dehydration (HCOOH {yields} H{sub 2}O + CO) routes, a selectivity requirement for the synthesis of CO-free H{sub 2} streams for low-temperature fuel cells. Group Ib and Group VIII noble metals catalyze dehydrogenation selectively, while base metals and metal oxides catalyze both routes, either directly or indirectly via subsequent water-gas shift (WGS) reactions.

  15. Changes of Lignin Molecular Structures in a Modification of Kraft Lignin Using Acid Catalyst

    Directory of Open Access Journals (Sweden)

    Sunghoon Kim

    2016-08-01

    Full Text Available The purpose of this study is to modify lignin for better blending with general purpose synthetic polymers. The possible advantages by using this modification would be cost reduction, better physical properties, and biodegradability. In this study, butyrolactone-modified lignin (BLL and tetrahydrofuran-modified lignin (THFL were used for aliphatic chain modification of lignin using an acid-catalyzed esterification method in order to mimic the relation of lignin-carbohydrate-complex (LCC and cellulose. The results of several analyses indicated that lignin was well modified. It was confirmed that the lignin was modified as expected and the reaction sites of the modification, as well as the reaction behaviors, were varied by the reagent types. The result of X-ray diffraction analysis (XRD analysis indicated that modified lignin/polymer blends increased the crystallinity due to their good compatibility. It can be confirmed that the type of alkyl chain and the miscibility gap between the alkyl chain-matrix affected the mechanical properties enormously in the fungi-degradable environment. From this study, a new method of lignin modification is proposed, and it is found that modified lignin retains the property of the substituted aliphatic chain well. This method could be a proper lignin modification method.

  16. Effect of metal ratio and calcination temperature of chromium based mixed oxides catalyst on FAME density from palm fatty acid distillate

    Science.gov (United States)

    Wan, Z.; Fatimah, S.; Shahar, S.; Noor, A. C.

    2017-09-01

    Mixed oxides chromium based catalysts were synthesized via sol-gel method for the esterification of palm fatty acid distillate (PFAD) to produce fatty acid methyl ester (FAME). The reactions were conducted in a batch reactor at reaction temperature of 160 °C for 4 h and methanol to PFAD molar ratio of 3:1. The effects of catalyst preparation conditions which are the mixed metal ratio and calcination temperature were studied. The various metal ratio of Cr:Mn (1:0, 0:1, 1:1, 1:2 and 2:1) and Cr:Ti (0:1, 1:1, 1:2 and 2:1) resulted in FAME density ranges from 1.041 g/cm3 to 0.853 g/cm3 and 1.107 g/cm3 to 0.836 g/cm3, respectively. The best condition catalyst was found to be Cr:Ti metal ratio of 1:2 and Cr:Mn metal ratio of 1:1. The calcination temperature of the mixed oxides between 300 °C to 700°C shows effect on the FAME density obtained in the reaction. The calcination at 500°C gave the lowest FAME density of 0.836 g/cm3 and 0.853 g/cm3 for Cr:Ti and Cr:Mn mixed oxides, respectively. The density of FAME is within the value range of the biodiesel fuel property. Thus, mixed oxides of Cr-Ti and Cr-Mn have good potentials as heterogeneous catalyst for FAME synthesis from high acid value oils such as PFAD.

  17. Catalysts and methods of using the same

    Science.gov (United States)

    Slowing, Igor Ivan; Kandel, Kapil

    2017-02-14

    The present invention provides a catalyst including a mesoporous silica nanoparticle and a catalytic material comprising iron. In various embodiments, the present invention provides methods of using and making the catalyst. In some examples, the catalyst can be used to hydrotreat fatty acids or to selectively remove fatty acids from feedstocks.

  18. Catalyst Deactivation 2001

    Energy Technology Data Exchange (ETDEWEB)

    Spivey, J.J. (ed.); Roberts, G.W. (ed.) [Department of Chemical Engineering, 2401 Stinson Avenue, Riddick Engineering Labs, NC State University, Box 7905, Raleigh, NC 27695 (United States); Davis, B.H. (ed.) [University of Kentucky, Centre for Applied Energy Research, 2540 Research Park Drive, Lexington, KY 40511-8433 (United States)

    2001-10-01

    Selected Papers: Maxted Award Lecture. Whisker carbon revisited (J.R. Rostrup-Nielsen, J Sehested). Carbon Deposition. Various forms of the carbonaceous deposit on the model cobalt catalyst studied in hydrogenation of ethylene (J. Lojewska). Hydrodechlorination of 1,2-dichloropropane over Pt-Cu/C catalysts: coke formation determined by a novel technique-TEOM (Weidung. Zhu et al.). Characterization of structure and combustion behavior of the coke formed on a hydroisomerization catalyst (Jin-an Wang et al.). The effects of pore structure on catalyst deactivation by coke formation (L.D.T. Camara et al.). Coke deactivation of acid sites on ZSM-5 zeolite (G.V. Echevsky et al.). Characterization of the Working Catalyst. Deactivation of a zirconia supported chromia aromatization catalyst investigated by in-situ H-D tracer experiments (H. Ehwald et al.). Deactivation/Regeneration in Environmental Processes. Study of the sintering of a DeNOx commercial catalyst (I. Nova et al.). Deactivation of chromium oxide catalyst for the removal of perchloroethylene (PCE) (Sung Dae Yim et al.). Deactivation/Regeneration in Industrial Processes. Deactivation of Pd-based combustion catalysts supported on modified alumina (P.O. Thevenin et al.). Selective acid-base poisoning on bifunctional alkylation reaction (A. Borgna et al.). Processes occurring during deactivation/regeneration of a vanadia/alumina catalyst under propane dehydrogenation conditions (S David Jackson et al.). Regeneration of supported palladium catalyst for selective hydrogenation of acetylene (L.O. Almanza, O.I. Martinez). Quinone mediated stabilization of a palladium catalyst for the synthesis of hydrogen peroxide from carbon monoxide, water and oxygen (D. Bianchi et al.). Metals on a novel USY zeolite after hydrothermal aging (Huiping Tian et al.). General Papers. Partial oxidation of toluene to benzaldehyde over vanadium antimonate catalysts doped with titanium: The influence (S. Larrondo et al.). Deactivation and

  19. Taurine as a green bio-organic catalyst for the preparation of bio-active barbituric and thiobarbituric acid derivatives in water media.

    Science.gov (United States)

    Daneshvar, Nader; Shirini, Farhad; Langarudi, Mohaddeseh Safarpoor Nikoo; Karimi-Chayjani, Reyhaneh

    2017-12-21

    Taurine, a β-amino acid that is abundantly available in the tissues of human and animals, is efficiently used as a green bio-organic catalyst in the preparation of some of the biologically active barbituric and thiobarbituric acid derivatives. In the presence of taurine, 5-Arylidene (thio) barbituric acid derivatives were prepared via Knovenagel reaction between aldehydes and (thio)barbituric acid. Using this reagent also pyrano[2,3-d]pyrimidinone(thione) derivatives were synthesized through a three-component reaction between aldehydes, (thio)barbituric and malononitrile. Both reactions are performed in water with good to excellent yields during acceptable reaction times. No organic solvent was used during reaction or separation steps and no extra-purification was exerted. Meanwhile, reusability of taurine was easy and noticeably high. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Production of Bio-Hydrogenated Diesel by Hydrotreatment of High-Acid-Value Waste Cooking Oil over Ruthenium Catalyst Supported on Al-Polyoxocation-Pillared Montmorillonite

    Directory of Open Access Journals (Sweden)

    Kinya Sakanishi

    2012-02-01

    Full Text Available Waste cooking oil with a high-acid-value (28.7 mg-KOH/g-oil was converted to bio-hydrogenated diesel by a hydrotreatment process over supported Ru catalysts. The standard reaction temperature, H2 pressure, liquid hourly space velocity (LHSV, and H2/oil ratio were 350 °C, 2 MPa, 15.2 h–1, and 400 mL/mL, respectively. Both the free fatty acids and the triglycerides in the waste cooking oil were deoxygenated at the same time to form hydrocarbons in the hydrotreatment process. The predominant liquid hydrocarbon products (98.9 wt% were n-C18H38, n-C17H36, n-C16H34, and n-C15H32 when a Ru/SiO2 catalyst was used. These long chain normal hydrocarbons had high melting points and gave the liquid hydrocarbon product over Ru/SiO2 a high pour point of 20 °C. Ru/H-Y was not suitable for producing diesel from waste cooking oil because it formed a large amount of C5–C10 gasoline-ranged paraffins on the strong acid sites of HY. When Al-polyoxocation-pillared montmorillonite (Al13-Mont was used as a support for the Ru catalyst, the pour point of the liquid hydrocarbon product decreased to −15 °C with the conversion of a significant amount of C15–C18 n-paraffins to iso-paraffins and light paraffins on the weak acid sites of Al13-Mont. The liquid product over Ru/Al13-Mont can be expected to give a green diesel for current diesel engines because its chemical composition and physical properties are similar to those of commercial petro-diesel. A relatively large amount of H2 was consumed in the hydrogenation of unsaturated C=C bonds and the deoxygenation of C=O bonds in the hydrotreatment process. A sulfided Ni-Mo/Al13-Mont catalyst also produced bio-hydrogenated diesel by the hydrotreatment process but it showed slow deactivation during the reaction due to loss of sulfur. In contrast, Ru/Al13-Mont did not show catalyst deactivation in the hydrotreatment of waste cooking oil after 72 h on-stream because the waste cooking oil was not found to contain sulfur

  1. ALKALI RESISTANT CATALYST

    DEFF Research Database (Denmark)

    2008-01-01

    The present invention concerns the selective removal of nitrogen oxides (NOx) from gasses. In particular, the invention concerns a process, a catalyst and the use of a catalyst for the selective removal of nitrogen oxides in the presence of ammonia from gases containing a significant amount...... of alkali metal and/or alkali-earth compounds which process comprises using a catalyst combined of (i) a formed porous superacidic support, said superacidic support having an Hammett acidity stronger than Ho=-12, and (ii) a metal oxide catalytic component deposited on said superacidic support selected from...

  2. A highly efficient nano-Fe3O4 encapsulated-silica particles bearing sulfonic acid groups as a solid acid catalyst for synthesis of 1,8-dioxo-octahydroxanthene derivatives

    Science.gov (United States)

    Naeimi, Hossein; Nazifi, Zahra Sadat

    2013-11-01

    The functionalization of silica-coated Fe3O4 magnetic nanoparticles (Fe3O4@SiO2) using chlorosulfonic acid were afforded sulfonic acid-functionalized magnetic Fe3O4 nanoparticles (Fe3O4@SiO2-SO3H) that can be applied as an organic-inorganic hybrid heterogeneous catalyst. The used Fe3O4 magnetic nanoparticles are 18-30 nm sized that was rapidly functionalized and can be used as catalyst in organic synthesis. The prepared nanoparticles were characterized by X-ray diffraction analysis, magnetization curve, scanning electron microscope, dynamic laser scattering, and FT-IR measurements. The resulting immobilized catalysts have been successfully used in the synthesis of 1,8-dioxo-octahydroxanthene derivatives under solvent free condition. This procedure has many advantages such as; a much milder method, a shorter reaction time, a wide range of functional group tolerance, and absence of any tedious workup or purification. Other remarkable features include the catalyst can be reused at least five times without any obvious change in its catalytic activity. This procedure also avoids hazardous reagents/solvents, and thus can be an eco-friendly alternative to the existing methods.

  3. Paraffin Alkylation Using Zeolite Catalysts in a slurry reactor: Chemical Engineering Principles to Extend Catalyst Lifetime

    NARCIS (Netherlands)

    Jong, K.P. de; Mesters, C.M.A.M.; Peferoen, D.G.R.; Brugge, P.T.M. van; Groot, C. de

    1996-01-01

    The alkylation of isobutane with 2-butene is carried out using a zeolitic catalyst in a well stirred slurry reactor. Whereas application of fixed bed technology using a solid acid alkylation catalyst has in the led to catalysts lifetimes in the range of minutes, in this work we report catalyst

  4. Acetic acid effects on enhancement of growth rate and reduction of amorphous carbon deposition on CNT arrays along a growth window in a floating catalyst reactor

    Science.gov (United States)

    Maghrebi, Morteza; Khodadadi, Abbas Ali; Mortazavi, Yadollah; Sane, Ali; Rahimi, Mohsen; Shirazi, Yaser; Tsakadze, Zviad; Mhaisalkar, Subodh

    2009-11-01

    The mm-long carbon nanotube (CNT) arrays were grown in a floating catalyst reactor, using xylene-ferrocene and a small amount of acetic acid as the feed. The CNT arrays deposited on a quartz substrate at several positions along the reactor were extensively characterized using Raman spectroscopy, scanning electron microscopy, X-ray diffraction, high-resolution transmission electron microscopy, and optical microscopy. Various characterization methods consistently reveal that the acetic acid additive to the feed alleviates deposition of amorphous carbon layer, which gradually thickens CNTs along the reactor. The acetic acid also resulted in a higher growth rate along the so-called growth window, where CNT arrays are deposited on the quartz substrate. High-performance liquid chromatography of extracted byproducts (PAHs) confirmed the presence of some polycyclic aromatic hydrocarbons. The solid weight of PAHs decreased upon addition of ferrocene as the catalyst precursor, as well as of acetic acid to xylene feed. The results suggest that primary light products of xylene pyrolysis can be competitive reactants for both catalytic and subsequent pyrolytic reactions. They may also be more efficient feeds for CNT growth than xylene itself.

  5. A new Keggin-type polyoxometalate catalyst for degradation of aqueous organic contaminants

    Science.gov (United States)

    Olgun, Asim; Çolak, Alper Tolga; Gübbük, İ. Hilal; Şahin, Onur; Kanar, Ebru

    2017-04-01

    In this study, a new polyoxometalate, K16[Ni(H2O)6]2[BW12O40]4·48H2O (1) was synthesized at room temperature and characterized by X-ray single crystal diffractions, elemental analyses, IR spectra, and thermo gravimetric analyses (TGA). Crystal structure analysis reveals that compound 1 exhibits a supramolecular structure containing one Keggin-type [BW12O40]4 heteropoly anion. The catalytic properties of this molecule for the degradation of Methyl red (MR), Rhodamine B (RhB), Methyl orange (MO) and Congo red (CR) were investigated. The results show that the compound 1 is a promising catalyst candidate for dye degradation.

  6. Improved molecular weight control in ring-opening metathesis polymerization (ROMP) reactions with ru-based olefin metathesis catalysts using N donors and acid: a kinetic and mechanistic investigation.

    Science.gov (United States)

    Dunbar, Miles A; Balof, Shawna L; LaBeaud, Lawrence J; Yu, Bing; Lowe, Andrew B; Valente, Edward J; Schanz, Hans-Jörg

    2009-11-16

    The effect of the addition of H(3)PO(4) on the ROMP activity of cyclooctene (COE) with first- [Cl(2)(PCy(3))(2)Ru=CHPh] and second-generation [(H(2)IMes)Cl(2)(PCy(3))Ru=CHPh] Grubbs' catalysts 1 and 4 (Cy=cyclohexyl, Ph=phenyl, Mes=2,4,6-trimethylphenyl (mesityl)), their inhibited mixtures with 1-methylimidazole (MIM), as well as their isolated bis-N,N'-dimethylaminopyridine (DMAP) derivatives [Cl(2)(PCy(3))(DMAP)(2)Ru=CHPh)] (5 b) and [Cl(2)(H(2)IMes)(DMAP)(2)Ru=CHPh] (7 b) (DMAP=dimethylaminopyridine), a novel catalyst, has been investigated. The studies include the determination of their initiation rates, as well as a determination of the molecular weights and molecular weight distributions of the polymers obtained with these catalysts and catalyst mixtures from the exo-7-oxanorbornene derivative 11. The structure of catalyst 7 b was confirmed by means of X-ray diffraction. All N-donor-bearing catalysts or N-donor-containing catalyst mixtures not only exhibited elevated activity in the presence of acid, but also increased initiation rates. Using the reversible inhibition/activation protocol with MIM and H(3)PO(4) enabled us to conduct controlled ROMP with catalyst 4 producing the isolated exo-7-oxanorbornene-based polymer 12 with predetermined molecular weights and narrow molecular weight distributions. This effect was based on fast and efficient catalyst initiation in contrast to the parent catalyst 4. Hexacoordinate complex 5 b also experienced a dramatic increase in initiation rates upon acid-addition and the ROMP reactions became well-controlled in contrast to the acid-free reaction. In contrast, complex 7 b performs well-controlled ROMP in the absence of acid, whereas the polymerization of the same monomer becomes less controlled in the presence of H(3)PO(4). The closer evaluation of catalysts 5 b and 7 b demonstrated that their initiation rates exhibit a linear dependency on the substrate concentration in contrast to catalysts 1 and 4. As a consequence

  7. Reuse of sewage sludge as a catalyst in ozonation - Efficiency for the removal of oxalic acid and the control of bromate formation

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Gang [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Pan, Zhi-Hui [School Of Civil Engineering, Guangzhou University, Guangzhou 510006 (China); Ma, Jun, E-mail: majun@hit.edu.cn [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Liu, Zheng-Qian, E-mail: liuzhengqian@gmail.com [School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhao, Lei [School of Civil Engineering, Harbin Institute of Technology, Harbin 150090 (China); Li, Jun-Jing [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer Sewage sludge was converted into catalyst (SBC) and characterized. Black-Right-Pointing-Pointer SBC can enhance oxalic acid degradation in ozonation. Black-Right-Pointing-Pointer Surface reaction mechanism is responsible for enhancement of ozonation by SBC. Black-Right-Pointing-Pointer SBC can control the formation of bromate in ozonation. Black-Right-Pointing-Pointer Several combined reasons for the control of bromate formation are proposed. - Abstract: Sewage derived sludge is produced with an annual amount increase of 2% all over the world and it is an urgent issue to be addressed by human being. In the present study, sludge was converted into sludge-based catalyst (SBC) with ZnCl{sub 2} as activation agent and characterized by several methods (e.g., scanning electron microscope, X-ray photoelectron spectroscope and Fourier transform infrared spectroscope). Then it was used as a catalyst to enhance the removal of refractory organic matter, oxalic acid, and to control the formation of bromate (BrO{sub 3}{sup -}) in bench semi-continuous ozonation experiments. The effects of various operating parameters on the control of BrO{sub 3}{sup -} formation were investigated. Furthermore, the mechanism for the enhancement of organic matter removal and the control of BrO{sub 3}{sup -} formation was discussed as well. Results indicate that the combination of SBC with ozone shows a strong synergistic effect, resulting in a notable improvement on oxalic acid removal. A crucial surface reaction mechanism for the enhancement of organic matter removal is proposed on the basis of negative effect of higher pH and no inhibition effect of tert-butanol. The control for BrO{sub 3}{sup -} formation was demonstrated and the reason for its control in the process of O{sub 3}/SBC is the combined effect of SBC reductive properties, ozone exposure decrease and hydrogen peroxide concentration increase.

  8. One-Pot 2-Methyltetrahydrofuran Production from Levulinic Acid in Green Solvents Using Ni-Cu/Al2 O3 Catalysts.

    Science.gov (United States)

    Obregón, Iker; Gandarias, Iñaki; Miletić, Nemanja; Ocio, Ainhoa; Arias, Pedro L

    2015-10-26

    The one-pot hydrogenation of levulinic acid to 2-methyltetrahydrofuran (MTHF) was performed using a series of Ni-Cu/Al2 O3 catalysts in green solvents, such as water and biomass-derived alcohols. Ni/Al2 O3 provided the highest activity, whereas Cu/Al2 O3 was the most selective, reaching a 75 % MTHF yield at 250 °C after 24 h reaction time. Synergetic effects were observed when bimetallic Ni-Cu/Al2 O3 catalysts were used, reaching a 56 % MTHF yield in 5 h at 250 °C for the optimum Ni/Cu ratio. Remarkably, these high yields were obtained using non-noble metal-based catalysts and 2-propanol as the solvent. The catalytic activity and selectivity results are correlated to temperature programmed reduction (TPR), XRD, and STEM characterization data, identifying the role associated with mixed Ni-Cu particles in addition to monometallic Cu and Ni. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Ultrasound-assisted oxidative desulfurization process of liquid fuel by phosphotungstic acid encapsulated in a interpenetrating amine-functionalized Zn(II)-based MOF as catalyst.

    Science.gov (United States)

    Afzalinia, Ahmad; Mirzaie, Abbas; Nikseresht, Ahmad; Musabeygi, Tahereh

    2017-01-01

    In this work, ultrasound-assisted oxidative desulfurization (UAOD) of liquid fuels performed with a novel heterogeneous highly dispersed Keggin-type phosphotungstic acid (H3PW12O40, PTA) catalyst that encapsulated into an amino-functionalized MOF (TMU-17-NH2). The prepared composite exhibits high catalytic activity and reusability in oxidative desulfurization of model fuel. Ultrasound-assisted oxidative desulfurization (UAOD) is a new way to performed oxidation reaction of sulfur-contain compounds rapidly, economically, environment-friendly and safely, under mild conditions. Ultrasound waves can be apply as an efficient tool to decrease the reaction time and improves oxidative desulfurization system performance. PTA@TMU-17-NH2 could be completely performed desulfurization of the model oil by 20mg of catalyst, O/S molar ratio of 1:1 in presence of MeCN as extraction solvent. The obtained results indicated that the conversions of DBT to DBTO2 achieve 98% after 15min in ambient temperature. In this work, we prepared TMU-17-NH2 and PTA/TMU-17-NH2 composite by ultrasound irradiation for first time and employed in UAOD process. Prepared catalyst exhibit an excellent reusability without PTA leaching and loss of activity. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  10. Reducing-Agent-Free Instant Synthesis of Carbon-Supported Pd Catalysts in a Green Leidenfrost Droplet Reactor and Catalytic Activity in Formic Acid Dehydrogenation

    Science.gov (United States)

    Lee, Dong-Wook; Jin, Min-Ho; Lee, Young-Joo; Park, Ju-Hyoung; Lee, Chun-Boo; Park, Jong-Soo

    2016-05-01

    The development of green synthesis methods for supported noble metal catalysts remains important challenges to improve their sustainability. Here we first synthesized carbon-supported Pd catalysts in a green Leidenfrost droplet reactor without reducing agents, high-temperature calcination and reduction procedures. When the aqueous solution containing Pd nitrate precursor, carbon support, and water is dripped on a hot plate, vapor layer is formed between a solution droplet and hot surface, which allow the solution droplet to be levitated on the hot surface (Leidenfrost phenomena). Subsequently, Pd nanoparticles can be prepared without reducing agents in a weakly basic droplet reactor created by the Leidenfrost phenomena, and then the as-prepared Pd nanoparticles are loaded on carbon supports during boiling down the droplet on hot surface. Compared to conventional incipient wetness and chemical synthetic methods, the Leidenfrost droplet reactor does not need energy-consuming, time-consuming, and environmentally unfriendly procedures, which leads to much shorter synthesis time, lower carbon dioxide emission, and more ecofriendly process in comparison with conventional synthesis methods. Moreover, the catalysts synthesized in the Leidenfrost droplet reactor provided much better catalytic activity for room-temperature formic acid decomposition than those prepared by the incipient wetness method.

  11. ACETAL OBTAINED FROM ETHANOL AND ACID-ACTIVATED BENTONITE AS A CATALYST: AN ALTERNATIVE FOR THE SUGAR-ALCOHOL AGROINDUSTRY

    Directory of Open Access Journals (Sweden)

    Oscar Yecid Buitrago Suescún

    2010-05-01

    Full Text Available This study discusses the results of characterizing and activating a bentonite from the Valle del Cauca region. The betonite is used as a catalyst in the reaction to obtain 1,1-Diethoxyethane from ethanol, which can be extracted from sugar cane. Important factors are analyzed such as: the activation of the bentonite; the percentage of bentonite; the reaction temperature; and the ethanol/acetaldehyde feed ratio. In addition, comparison tests are performed against the CaCl2 catalyst which is commonly used in previous literature. Physical and spectrometric constants are measured for the obtained product confirming that it is 1,1-Diethoxyethane.

  12. Modified montmorillonite as a heterogeneous catalyst in (m)ethyl esterification reaction of lauric acid; Montmorilonita modificada como catalisador heterogeneo em reacoes de esterificacao (M)etilica de acido laurico

    Energy Technology Data Exchange (ETDEWEB)

    Zatta, Leandro; Nepel, Angelita; Barison, Andersson; Wypych, Fernando, E-mail: wypych@ufpr.br [Departamento de Quimica, Universidade Federal do Parana (UFPR), Curitiba , PR (Brazil)

    2012-07-01

    Montmorillonite was modified with zirconium polyoxycations in the presence of ammonium sulphate. The material was characterized and used as a catalyst in the esterification of lauric acid, the reactions being accompanied by 2{sup 3} factorial design. Conversions of up to 95.33 and 83.35% were observed for the methyl and ethyl esterification reactions respectively, proving superior to results obtained by thermal conversion. The material was submitted to three reaction cycles and similar conversions were observed, indicating the catalyst is not significantly deactivated after reuse. The catalyst was also tested under reflux conditions, yielding a maximum conversion of 36.86%. (author)

  13. Microwave assisted chemistry: A rapid and regioselective route for direct ortho-acylation of phenols and naphthols by methanesulfonic acid as catalyst

    Directory of Open Access Journals (Sweden)

    Hossein Naeimi

    2017-05-01

    Full Text Available Direct ortho-acylation of phenols and naphthols with methanesulfonic acid (MSA as the catalyst has been studied under microwave stimulation. The microwave assisted reaction was environmentally benign in terms of faster reaction, useful conditions and higher yield of the desired products. However, after 3–4 min reaction time at 200–300 Watt, selectivity to over 98% ortho-acylation products was obtained. These reactions have some advantages in competition with other methods such as; short reaction times, high yield and regioselectivity of products, mild reaction conditions and easy workup of the reactions.

  14. Succinimide-N-sulfonic acid: An efficient and recyclable catalyst for the one-pot synthesis of tetrahydrobenzo[c]acridine-8(7H-one derivatives

    Directory of Open Access Journals (Sweden)

    M. Ghashang

    2017-01-01

    Full Text Available Synthesis of substituted 10,10-dimethyl-7-phenyl-9,10,11,12-tetrahydrobenzo[c]acridin-8(7H-one derivatives proceeded by the one-pot reaction of aromatic aldehydes, 5,5-dimethylcyclohexane-1,3-dione (dimedone and 1-naphthylamine, in the presence of Succinimide-N-sulfonic acid (SuSA has been reported. Simplicity of operation, high yields, easy work-up and a wide range of substrate applicabilities are the key advantages of this methodology. Furthermore, the catalyst can be recovered conveniently and reused efficiently.

  15. Superior performance of metal-organic frameworks over zeolites as solid acid catalysts in the Prins reaction: green synthesis of nopol.

    Science.gov (United States)

    Opanasenko, Maksym; Dhakshinamoorthy, Amarajothi; Hwang, Young Kyu; Chang, Jong-San; Garcia, Hermenegildo; Čejka, Jiří

    2013-05-01

    The catalytic performance of a set of metal-organic frameworks [CuBTC, FeBTC, MIL-100(Fe), MIL-100(Cr), ZIF-8, MIL-53(Al)] was investigated in the Prins condensation of β-pinene with formaldehyde and compared with the catalytic behavior of conventional aluminosilicate zeolites BEA and FAU and titanosilicate zeolite MFI (TS-1). The activity of the investigated metal-organic frameworks (MOFs) increased with the increasing concentration of accessible Lewis acid sites in the order ZIF-8acid sites of zeolites BEA and FAU, which showed significantly lower selectivity to the target nopol than the MOFs. Its high activity, the preservation of its structure and active sites, and the possibility to use it in at least three catalytic cycles without loss of activity make MIL-100 (Fe) the best performing catalyst of the series for the Prins condensation of β-pinene and paraformaldehyde. Our report exemplifies the advantages of MOFs over zeolites as solid catalysts in liquid-phase reactions for the production of fine chemicals. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Mesoporous molecular sieve catalysts

    DEFF Research Database (Denmark)

    Højholt, Karen Thrane

    This thesis deals with a very specific class of molecular sieves known as zeolites. Zeolites are a class of crystalline aluminosilicates characterised by pores or cavities of molecular dimensions as part of their crystal structure. In this work zeolites were modified for the use and understanding...... of different catalytic applications. Primarily the zeolites were modified regarding the porosity and the introduction of metals to the framework. The obtained materials were used as solid acid catalysts, as an inert matrix for stabilising metal nanoparticles and as an anchoring material for molecular metal...... be used as solid acid catalysts but can also be used as a size-selective matrix. It was shown that it is possible to encapsulate 1-2 nm sized gold nanoparticles by silicalite-1 or ZSM-5 zeolite crystals thereby forming a sintering-stable and substrate size-selective oxidation catalyst. After carrying out...

  17. Effects of Lewis acidity of metal oxide promoters on the activity and selectivity of Co-based Fischer–Tropsch synthesis catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Gregory R.; Bell, Alexis T. (LBNL); (UCB)

    2016-06-17

    Metal oxides of Ce, Gd, La, Mn, and Zr were investigated as promoters for improving the activity and selectivity of Co-based FTS catalysts. The extent to which these promoters decrease the selectivity toward CH4 and increase the selectivity toward C5+ hydrocarbons was found to depend on both the loading and the composition of the oxide promoter. Elemental mapping by STEM–EDS revealed that the propensity for a given metal oxide to associate with Co affects the sensitivity of the product distribution to changes in promoter loading. For all promoters, a sufficiently high loading resulted in the product distributions becoming insensitive to further increases in promoter loading, very likely due to the formation of a half monolayer of promoter oxide over the Co surface. Simulations suggest that the fraction of Co active sites that are adjacent to the promoter moieties approaches unity at this degree of coverage. The oxidation state of the promoter metal cation under reaction conditions, determined by in situ XANES measurements, was used to calculate relative Lewis acidity of the promoter metal cation. A strong positive correlation was found between the C5+ product selectivity and the Lewis acidity of the promoter metal cations, suggesting that the promotional effects are a consequence of Lewis acid–base interactions between the reaction intermediates and the promoter metal cations. Rate data obtained at different pressures were used to estimate the apparent rate coefficient and the CO adsorption constant appearing in the Langmuir–Hinshelwood expression that describes the CO consumption kinetics for both unpromoted and the metal oxide-promoted catalysts. Both parameters exhibited positive correlations with the promoter Lewis acidity. In conclusion, these results are consistent with the hypothesis that the metal cations of the promoter act as Lewis acids that interact with the O atom of adsorbed CO to facilitate CO adsorption and

  18. A combined experimental and computational study of the mechanism of fructose dehydration to 5-hydroxymethylfurfural in dimethylsulfoxide using Amberlyst 70, PO43-/niobic acid, or sulfuric acid catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jing [Northwestern Univ., Evanston, IL (United States); Das, Anirban [Northwestern Univ., Evanston, IL (United States); Assary, Rajeev S. [Argonne National Lab. (ANL), Argonne, IL (United States); Curtiss, Larry A. [Argonne National Lab. (ANL), Argonne, IL (United States); Weitz, Eric [Northwestern Univ., Evanston, IL (United States)

    2016-02-01

    We report on a combined experimental and theoretical study of the acid catalyzed dehydration of d-fructose in dimethylsulfoxide (DMSO) using; Amberlyst 70, PO43-/niobic acid, and sulfuric acid as catalysts. The reaction has been studied and intermediates characterized using; 13C, 1H, and 17O NMR, and high resolution electrospray ionization mass spectrometry (HR ESI–MS). High level G4MP2 theory calculations are used to understand the thermodynamic landscape for the reaction mechanism in DMSO. We have experimentally identified two key intermediates in the dehydration of fructose to form HMF that were also identified, using theory, as local minima on the potential surface for reaction. A third intermediate, a species capable of undergoing keto–enol tautomerism, was also experimentally detected. However, it was not possible to experimentally distinguish between the keto and the enol forms. These data with different catalysts are consistent with common intermediates along the reaction pathway from fructose to HMF in DMSO. The role of oxygen in producing acidic species in reactions carried out in DMSO in presence of air is also discussed.

  19. New heterogeneous acid catalysts in the synthesis of biodiesel; Estudo de novos catalisadores heterogeneous acidos na sintese de biodiesel

    Energy Technology Data Exchange (ETDEWEB)

    Soldi, Rafael A.; Cesar-Oliveira, Maria Aparecida F. [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Quimica. Lab. de Polimeros Sinteticos], e-mail: mafco@quimica.ufpr.br; Oliveira, Angelo R.S.; Ramos, Luiz P. [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Quimica. Centro de Pesquisa em Quimica Aplicada (CEPESQ)

    2007-07-01

    In this work, sulfonated polystyrene compounds (PSS) were synthesized from linear polystyrene (PS). Several methods and experimental conditions were investigated for the sulfonation of PS, producing catalytically active polymeric materials with sulfonation degrees in the range of 5.0-6.2 mmol -SO{sub 3}H/g of dry polymer. The performance of these catalysts was evaluated in transesterification reactions of beef tallow and vegetable oils with ethanol and methanol. For the sake of comparison, the same reaction conditions employed for the PSS catalysts were also used for an Amberlyst 15 (3,7 mmol SO{sub 3}H/g - Aldrich). The PSS samples were shown to be insoluble in the reaction media, leading to conversion rates of 85%, 75% and 80% of the refined soybean oil, beef tallow and crude corn oil in to ethyl esters, respectively, and 94% of the refined soybean oil methyl esters. Amberlyst 15 was studied as an alternative to the process, but its conversion rate to alkyl esters was very low in the employed conditions. These results demonstrated that our synthetic PSS materials have a great potential to act as heterogeneous catalysts for transesterification. (author)

  20. Formic acid oxidation on Pt-Au nanoparticles: Relation between the catalyst activity and the poisoning rate

    Science.gov (United States)

    Obradović, M. D.; Rogan, J. R.; Babić, B. M.; Tripković, A. V.; Gautam, A. R. S.; Radmilović, V. R.; Gojković, S. Lj.

    2012-01-01

    Pt-Au nanoparticles supported on high area carbon were prepared by simultaneous reduction of Au and Pt precursors and by reduction of Pt precursor on already prepared Au nanoparticles. The first method produced a solid solution of Pt in Au containing ∼5% Pt with the remaining Pt on the nanoparticles' surface. For the Pt:Au precursor ratio of 1:4 and 1:9, the surface ratio was found to be 0.70:0.30 and 0.55:0.45, respectively. By the second method with the Pt:Au precursors ratio of 1:12, the surface ratio was 0.30:0.70. The voltammetric peaks of Pt-oxide reduction and COads oxidation demonstrated electronic modification of Pt by Au in all catalysts. With decreasing Pt:Au surface ratio the activity for HCOOH oxidation increases and surface coverage by COads decreases. The highest activity under potentiodynamic and quasi steady-state conditions without poisoning by COads was observed for the catalyst with the lowest Pt:Au surface ratio. Chronoamperometic test showed that its high catalytic activity is associated with a high deactivation rate. It was postulated that too strong adsorption of a reactive or non-reactive intermediate caused by electron modification of Pt by underlying Au, is responsible for the deactivation. This result stresses that high Pt dispersion, necessary for promotion of the dehydrogenation path in HCOOH oxidation, can produce too strong adsorption of intermediates causing deactivation of the catalyst.

  1. Reaction catalysts of urea-formaldehyde resin, as related to strength properties of southern pine particleboard

    Science.gov (United States)

    C. -Y. Hse

    1974-01-01

    Twelve resins were formulated with factorial combinations of three alkaline catalysts (i.e., somdium hydroxide, hexamethylenetetramine, and triethanolamine) and four acidic catalysts (i.e., acetic acid, hydrochloric acid, ammonium chloride, and phosphoric acid). The resins were replicated.

  2. Natural DNA-modified graphene/Pd nanoparticles as highly active catalyst for formic acid electro-oxidation and for the Suzuki reaction.

    Science.gov (United States)

    Qu, Konggang; Wu, Li; Ren, Jinsong; Qu, Xiaogang

    2012-09-26

    Natural DNA has been considered as a building block for developing novel functional materials. It is abundant, renewable, and biodegradable and has a well-defined structure and conformation with many unique features, which are difficult to find in other polymers. Herein, calf thymus DNA modified graphene/Pd nanoparticle (DNA-G-Pd) hybrid materials are constructed for the first time using DNA as a mediator, and the prepared DNA-G-Pd hybrid shows high catalytic activity for fuel cell formic acid electro-oxidation and for organic Suzuki reaction. The main advantages of using DNA are not only because the aromatic nucleobases in DNA can interact through π-π stacking with graphene basal surface but also because they can chelate Pd via dative bonding in such defined sites along the DNA lattice. Our results indicate that isolated, homogeneous, and ultrafine spherical Pd nanoparticles are densely in situ decorated on DNA-modified graphene surfaces with high stability and dispersibility. The prepared DNA-G-Pd hybrid has much greater activity and durability for formic acid electro-oxidation than the commercial Pd/C catalyst and polyvinylpyrrolidone-mediated graphene/Pd nanoparticle (PVP-G-Pd) hybrid used for direct formic acid fuel cells (DFAFCs). Besides, the DNA-G-Pd hybrid can also be an efficient and recyclable catalyst for the organic Suzuki reaction in aqueous solution under aerobic conditions without any preactivation. Since DNA can chelate various transition metal cations, this proof-of-concept protocol provides the possibility for the tailored design of other novel catalytic materials based on graphene with full exploitation of their properties.

  3. Investigation of the behaviour of solid acid catalysts for acylations and cyanisations of aromatics. Final report; Untersuchungen zur Wirkungsweise von festen sauren Katalysatoren bei Acylierungen und Cyanierungen von Aromaten. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Kemnitz, E.

    2002-01-01

    The present state of the art in the field of FRIEDEL-CRAFTS-ACYLATIONS is characterized by the application of homogenous catalysts (at least stochiometric amounts) like AlCl{sub 3} or FeCl{sub 3}. Problems arising from this application are corrosions, difficult product separations from the catalyst and the origin of acid waste water. Hence, the aim of this project was the development of suitable solid catalysts which overcome the problems ascribed above. Sulfated zirconia (SZ) was found to be an excellent solid Br.o/nsted-acid to be used especially in their aerogel or cryogel form. Thus with this catalyst system, in the benzoylation of anisol nearly 100% conversion may be achieved. In this way it could be proved, that with SZ a solid Br.o/nsted-acid might be available which gives reasonable hope to substitute in a near future, at least for some reactions, the classical homogeneous catalysts and to overcome their problems in use. (orig.)

  4. A novel method for enhancing on-stream stability of fluid catalytic cracking (FCC) gasoline hydro-upgrading catalyst. Post-treatment of HZSM-5 zeolite by combined steaming and citric acid leaching

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Xiuying [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249 (China); Fan, Yu.; Shi, Gang; Liu, Haiyan [The Key Laboratory of Catalysis, China National Petroleum Co., China University of Petroleum, Beijing 102249 (China); Liu, Zhihong [Science and Technology Management Department, PetroChina Company, Ltd., World Tower, 16 Andelu, Dongcheng District, Beijing 100011 (China); Bao, Xiaojun [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249 (China); The Key Laboratory of Catalysis, China National Petroleum Co., China University of Petroleum, Beijing 102249 (China)

    2007-07-30

    This article describes a novel modification method consisting of steaming and subsequent citric acid leaching to finely tune acidity and pore structure of HZSM-5 zeolite and thereby to enhance the on-stream stability of the zeolite derived fluid catalytic cracking (FCC) gasoline hydro-upgrading catalyst. A series of dealuminated HZSM-5 zeolites and their derived catalysts were prepared and characterized by X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), {sup 27}Al MAS NMR, nitrogen adsorption, temperature programmed desorption of ammonium (NH{sub 3}-TPD) and infrared (IR) spectroscopy of chemisorbed pyridine. The results showed that the citric acid leaching could preferentially remove the extra-framework Al (EFAl) species formed by steaming treatment and thus reopen the EFAl-blocked pore channels of the steamed zeolite. The steaming treatment at a suitable temperature and subsequent citric acid leaching not only decreased the strength of acid sites to a desirable degree but also increased the ratio of medium and strong Lewis acidity to medium and strong Broensted acidity, both of which conferred the resulting catalyst with superior selectivity to aromatics, good hydroisomerization activity and gasoline research octane number (RON) preservability, as well as enhanced on-stream stability. The results fully demonstrated that the treatments by steaming and followed citric acid leaching can serve as an important method for adjusting the physicochemical properties of HZSM-5 zeolite. (author)

  5. H{sub 3}PW{sub 12}O{sub 40} (HPA), an efficient and reusable catalyst for biodiesel production related reactions. Esterification of oleic acid and etherification of glycerol

    Energy Technology Data Exchange (ETDEWEB)

    Sepulveda, Jorge H.; Vera, Carlos R.; Yori, Juan C.; Badano, Juan M., E-mail: jsepulve@fiq.unl.edu.a [Instituto de Investigaciones en Catalisis y Petroquimica, Santiago del Estero Santa Fe (Argentina); Santarosa, Daniel; Mandelli, Dalmo [Pontificia Universidade Catolica de Campinas, SP (Brazil). Faculdade Quimica

    2011-07-01

    In esterification of oleic acid with methanol at 25 deg C HPA displayed the highest activity. Moreover the HPA could be reused after being transformed into its cesium salt. In the reaction of etherification of glycerol HPA and Amberlyst 35W showed similar initial activity levels. The results of acid properties demonstrate that HPA is a strong protonic acid and that both surface and bulk protons contribute to the acidity. Because of its strong affinity for polar compounds, HPA is also seemingly dissolved in both oleic acid and methanol. The reaction in this case proceeds with the catalyst in the homogenous phase. (author)

  6. Electronically tailoring 3D flower-like graphene via alumina doping and incorporating Co as an efficient oxygen electrode catalyst in both alkaline and acid media

    Science.gov (United States)

    Ma, Xiu-Xiu; He, Xing-Quan

    2017-06-01

    3D graphene-based electrode catalysts have intrigued tremendous research in energy conversion and storage systems not only for the intrinsic properties of graphene, but also due to its high active density for the oxygen electrode reaction with efficient mass and electron transports. In this work, we try to electronically tailor 3D nitrogen-doped graphene (NG) using alumina (Al), and obtain the flower-like structure with a high Brunauer-Emmett-Teller (BET) surface area and abundant active sites, as a result, pure cobalt nanoparticles are easily confined. Physical characterizations confirm that this natural tuning of graphene by Al causes the increasing of surface defects, as a result, the physicochemical stability of Al and graphene is improved, and vice versa, consequently, the co-modification of Al and Co induce outstanding oxygen reduction reaction (ORR) performance including distinct onset potential, large diffusion limiting current density, kinetic current density and good stability, which are comparable with those of 20 wt% Pt/C in both alkaline and acidic media; in addition, the fabricated composite also delivers prior oxygen evolution reaction activity, superior to the benchmark RuO2. This hybrid herein exhibits a combined ORR and OER potential gap of 0.745 V, rivaling state-of-the-art bifunctional oxygen electrode catalysts.

  7. Metal chloride hydrates as Lewis acid catalysts in multicomponent synthesis of 2,4,5-triarylimidazoles or 2,4,5-triaryloxazoles

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Marcelo V. [Departamento de Engenharia de Processos, Fundacao de Ciencia e Tecnologia, Cachoeirinha, RS (Brazil); Russowsky, Dennis, E-mail: dennis@iq.ufrgs.br [Laboratorio de Sinteses Organicas, Instituto de Quimica, Universidade Federal do Rio Grande do Sul, Porto Alegre-RS (Brazil); Ruthner, Marcelo M.; Fontoura, Luiz A.M. [Curso de Quimica, Universidade Luterana do Brasil, Canoas, RS (Brazil)

    2012-07-01

    A series of nine metal chloride hydrates (ZnCl{sub 2}.2H{sub 2}O, SnCl{sub 2}.2H{sub 2}O, CdCl{sub 2}.2H{sub 2}O, MnCl{sub 2}.4H{sub 2}O, CoCl{sub 2}.6H{sub 2}O, SrCl{sub 2}.6H{sub 2}O, NiCl{sub 2}.6H{sub 2}O, CrCl{sub 3}.6H{sub 2}O and CeCl{sub 3}.7H{sub 2}O) was investigated as mild and inexpensive Lewis acid catalysts to promote the multicomponent synthesis of triarylimidazoles. Reactions starting from benzil showed the best results when SnCl{sub 2}.2H{sub 2}O was used, while for benzoin as the starting material, CeCl{sub 3}.7H{sub 2}O was more efficient. All reactions were performed in EtOH as solvent. These catalysts were also successfully employed in the synthesis of triaryloxazoles. (author)

  8. Hierarchical structured ZnFe2O4@RGO@TiO2 composite as powerful visible light catalyst for degradation of fulvic acid

    Science.gov (United States)

    Feng, Jiantao; Wang, Yechen; Hou, Yanhui; Li, Liangchao

    2017-05-01

    Hierarchical structured ZnFe2O4@reduced graphite oxide@TiO2 (ZnFe2O4@RGO@TiO2) nanocomposite was prepared by an electrostatic layer-by-layer route, which played a synthetic effect of Fenton oxidation of ZnFe2O4 and photocatalytic oxidation of TiO2 to degrade fulvic acid (FA) solution under visible-light irradiation. In this method, RGO, as the middle layer, can effectively promote the photo-induced electron flow between the ZnFe2O4 and TiO2 and further improve the efficiency of the photo-Fenton oxidation. The influencing factors on photo-Fenton oxidation, including solution pH, catalyst, and H2O2 dosage, have also been investigated. The results illustrated that the ternary composite presented the enhanced catalytic performance. Under visible light irradiation, the degradation efficiency of the sample on the FA solution can reach 95.4% within 3 h. In addition, the catalyst exhibited superior stability and reusability, and its degradation efficiency was still up to 90% after 5 cycles. Therefore, the composite will be a kind of efficient photocatalyst and had a promising application for visible-light driven destruction of organic pollutants.

  9. Laser-induced removal of a dye C.I. Acid Red 87 using n-type WO{sub 3} semiconductor catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Qamar, M. [Center of Excellence in Nanotechnology, King Fahd University of Petroleum and Minerals, KFUPM Box 741, Dhahran 31261 (Saudi Arabia); Gondal, M.A., E-mail: magondal@kfupm.edu.sa [Center of Excellence in Nanotechnology, King Fahd University of Petroleum and Minerals, KFUPM Box 741, Dhahran 31261 (Saudi Arabia); Laser Research Laboratory, Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Hayat, K. [Chemistry Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Yamani, Z.H. [Center of Excellence in Nanotechnology, King Fahd University of Petroleum and Minerals, KFUPM Box 741, Dhahran 31261 (Saudi Arabia); Laser Research Laboratory, Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Al-Hooshani, K. [Center of Excellence in Nanotechnology, King Fahd University of Petroleum and Minerals, KFUPM Box 741, Dhahran 31261 (Saudi Arabia); Chemistry Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

    2009-10-30

    Water contamination by organic substances such as dyes is of great concern worldwide due to their utilization in many industrial processes and environmental concerns. To cater the needs for waste water treatment polluted with organic dyes, laser-induced photocatalytic process was investigated for removal of a dye derivative namely Acid Red 87 using n-type WO{sub 3} semiconductor catalyst. The degradation was investigated in aqueous suspensions of tungsten oxide under different experimental conditions using laser instead of conventional UV lamp as an irradiation source. The degradation process was monitored by measuring the change in dye concentration as a function of laser irradiation time by employing UV spectroscopic analysis. The degradation of dye was studied by varying different parameters such as laser energy, reaction pH, substrate concentration, catalyst concentration, and in the presence of electron acceptors such as hydrogen peroxide (H{sub 2}O{sub 2}), and potassium bromate (KBrO{sub 3}). The degradation rates were found to be strongly dependent on all the above-mentioned parameters. Our experimental results revealed that the dye degradation process was very fast (within few minutes) under laser irradiation as compared to conventional setups using broad spectral lamps (hours or days) and this laser-induced photocatalytic degradation method could be an effective means to eliminate the pollutants present in liquid phase. The experience gained through this study could be beneficial for treatment of waste water contaminated with organic dyes and other organic pollutants.

  10. Nano Silica Phosphoric Acid: An Efficient Catalyst for the One- Pot Synthesis of 1, 2, 4, 5-Tetrasubstituted Imidazoles

    Directory of Open Access Journals (Sweden)

    A. Bamoniri

    2012-03-01

    Full Text Available Two  simple  protocols  for  the  synthesis  of  1,  2,  4,  5-   tetrasubstitutedimidazoles  using  nano-SPA  as  a  reusable,  eco-   friendly,  inexpensive,  and  efficient  catalyst  are  reported.  Short   reaction  times,  high  yields,  scale-up  and  easy  workup  are  the   advantages of these protocols.

  11. Polyphosphoric acid supported on Ni0.5Zn0.5Fe2O4 nanoparticles as a magnetically-recoverable green catalyst for the synthesis of pyranopyrazoles

    Directory of Open Access Journals (Sweden)

    Farid Moeinpour

    2017-05-01

    Full Text Available Polyphosphoric acid supported on silica coated Ni0.5Zn0.5Fe2O4 nanoparticles was found to be magnetically separable, highly efficient, eco-friendly, green and recyclable heterogeneous catalyst. This new catalyst at first was fully characterized by TEM, SEM, FTIR and XRD techniques and then catalytic activity of this catalyst was investigated in the synthesis of 5-cyano-1,4-dihydropyrano[2,3-c]pyrazoles. Also the Ni0.5Zn0.5Fe2O4 magnetic nanoparticle-supported polyphosphoric acid could be reused at least six times without significant loss of activity. It could be recovered easily by applying an external magnet.

  12. Preparation of fibrous titania oxynitride - carbon catalyst and oxygen reduction reaction analysis in both acidic and alkaline media

    Science.gov (United States)

    Kinumoto, Taro; Sou, Yoshinori; Ono, Kohei; Matsuoka, Miki; Arai, Yasuhiko; Tsumura, Tomoki; Toyoda, Masahiro

    2015-01-01

    A fibrous catalyst of titania oxynitride and carbon is prepared and its catalytic behavior in the oxygen reduction reaction (ORR) are investigated in both HClO4 and KOH aqueous solutions. TiO2 particles are successfully deposited on activated carbon fibers by a liquid phase deposition technique using (NH4)2TiF6 and H3BO3. The catalyst obtained after subsequent ammonia nitridation at 1273 K had a fibrous structure with TiOxNy and TiN components. Interestingly, the product demonstrates catalytic activity for the ORR in not only HClO4 but also KOH aqueous solution. The onset potential in HClO4 solution is assumed to be moderate, at 0.85 V; on the other hand, that in KOH solution is relatively high at 0.95 V. Furthermore, it is considered from the Tafel plot analysis of the KOH solution result that the ORR mechanism follows a peroxide intermediate pathway and the rate-determining step would be a one-electron-transfer reaction to oxygen molecules adsorbed on the active site.

  13. Catalytic Transformation of Ethylbenzene over Y-Zeolite-based Catalysts

    KAUST Repository

    Al-Khattaf, Sulaiman

    2008-11-19

    Catalytic transformation of ethylbenzene (EB) has been investigated over ultrastable Y (USY)-zeolite-based catalysts in a novel riser simulator at different operating conditions. The effect of reaction conditions on EB conversion is reported. The USY catalyst (FCC-Y) was modified by steaming to form a significantly lower acidity catalyst (FCC-SY). The current study shows that the FCC-SY catalyst favors EB disproportionation more than cracking. A comparison has been made between the results of EB conversion over the lowly acidic catalyst (FCC-SY) and the highly acidic catalyst (FCC-Y) under identical conditions. It was observed that increase in catalyst acidity favored cracking of EB at the expense of disproportionation. Kinetic parameters for EB disappearance during disproportionation reaction over the FCC-SY catalyst were calculated using the catalyst activity decay function based on time on stream (TOS). © 2008 American Chemical Society.

  14. New Role of Flavin as a General Acid-Base Catalyst with No Redox Function in Type 2 Isopentenyl-diphosphate Isomerase*S⃞

    Science.gov (United States)

    Unno, Hideaki; Yamashita, Satoshi; Ikeda, Yosuke; Sekiguchi, Shin-ya; Yoshida, Norie; Yoshimura, Tohru; Kusunoki, Masami; Nakayama, Toru; Nishino, Tokuzo; Hemmi, Hisashi

    2009-01-01

    Using FMN and a reducing agent such as NAD(P)H, type 2 isopentenyl-diphosphate isomerase catalyzes isomerization between isopentenyl diphosphate and dimethylallyl diphosphate, both of which are elemental units for the biosynthesis of highly diverse isoprenoid compounds. Although the flavin cofactor is expected to be integrally involved in catalysis, its exact role remains controversial. Here we report the crystal structures of the substrate-free and complex forms of type 2 isopentenyl-diphosphate isomerase from the thermoacidophilic archaeon Sulfolobus shibatae, not only in the oxidized state but also in the reduced state. Based on the active-site structures of the reduced FMN-substrate-enzyme ternary complexes, which are in the active state, and on the data from site-directed mutagenesis at highly conserved charged or polar amino acid residues around the active site, we demonstrate that only reduced FMN, not amino acid residues, can catalyze proton addition/elimination required for the isomerase reaction. This discovery is the first evidence for this long suspected, but previously unobserved, role of flavins just as a general acid-base catalyst without playing any redox roles, and thereby expands the known functions of these versatile coenzymes. PMID:19158086

  15. The conversion of CO2 and CH4 to acetic acid over the Au-exchanged ZSM-5 catalyst: a density functional theory study.

    Science.gov (United States)

    Panjan, Wasinee; Sirijaraensre, Jakkapan; Warakulwit, Chompunuch; Pantu, Piboon; Limtrakul, Jumras

    2012-12-28

    The direct conversion of methane and carbon dioxide to acetic acid is one of the most challenging research topics. Using the density functional theory (M06-L) the study reveals the catalytic activity of the Au(I)-ZSM-5 zeolite in this reaction. The Au(I)-ZSM-5 is represented by a 34T quantum cluster model. The activation of the C-H bond over the Au-ZSM-5 zeolite would readily take place via the homolytic σ-bond activation with an energy barrier of 10.5 kcal mol(-1), and subsequent proton transfer from the Au cation to the zeolitic oxygen, yielding the stable methyl-gold complex adsorbed on the zeolite Brønsted acid. The conversion of CO(2) on this bi-functional catalyst involves the Brønsted acid site playing a role in the protonation of CO(2) and the methyl-gold complex acting as a methylating agent. The activation energy of 52.9 kcal mol(-1) is predicted.

  16. Carbon nitride frameworks padded with graphene as efficient metal-free catalyst for HER in acidic and alkali electrolytes

    Science.gov (United States)

    Meng, Shiming; Li, Bin; Li, Songmei; Yang, Shubin

    2017-05-01

    Although hydrogen evolution reaction (HER) is one of the most promising pathways to generate hydrogen in large-scale for future fuels, it is still lacking efficient and low-cost electrocatalysts. Here, carbon nitride frameworks padded with graphene (CNF-G) are explored as efficient metal-free catalysts with low-cost and good durability via a directly annealing commercial melamine sponge with graphene oxide. Owing to the high electrical conductivity of graphene, CNF-G exhibits outstanding catalytic activity during HER process in wide pH ranges. The overpotentials and Tafel slopes of CNF-G were 149 mV and 116 mV dec-1 in 0.5 M H2SO4, as well as 319 mV and 160 mV dec-1 in 1 M KOH, respectively. More importantly, CNF-G shows a high and stable catalytic activity demonstrated by a multiple cyclic voltammetry and long potentiostatic polarization.

  17. Method of performing sugar dehydration and catalyst treatment

    Science.gov (United States)

    Hu, Jianli [Kennewick, WA; Holladay, Johnathan E [Kennewick, WA; Zhang, Xinjie [Burlington, MA; Wang, Yong [Richland, WA

    2010-06-01

    The invention includes a method of treating a solid acid catalyst. After exposing the catalyst to a mixture containing a sugar alcohol, the catalyst is washed with an organic solvent and is then exposed to a second reaction mixture. The invention includes a process for production of anhydrosugar alcohol. A solid acid catalyst is provided to convert sugar alcohol in a first sample to an anhydrosugar alcohol. The catalyst is then washed with an organic solvent and is subsequently utilized to expose a second sample. The invention includes a method for selective production of an anhydrosugar. A solid acid catalyst is provided within a reactor and anhydrosugar alcohol is formed by flowing a starting sugar alcohol into the reactor. The acid catalyst is then exposed to an organic solvent which allows a greater amount of additional anhydrosugar to be produced than would occur without exposing the acid catalyst to the organic solvent.

  18. Combined use of titration calorimetry and spectrofluorimetry for the screening of the acidity of solid catalysts in different liquids

    Energy Technology Data Exchange (ETDEWEB)

    Gervasini, Antonella, E-mail: antonella.gervasini@unimi.it [Dipartimento di Chimica, Università degli Studi di Milano, via Camillo Golgi, 19, 20133 Milano (Italy); Auroux, Aline, E-mail: aline.auroux@ircelyon.univ-lyon1.fr [Université Lyon 1, CNRS, UMR 5256, Institut de Recherches sur la Catalyse et l‘Environnement de Lyon (IRCELYON), 2 Avenue A. Einstein, 69626 Villeurbanne (France)

    2013-09-10

    Graphical abstract: Measurements of acidity of oxides of catalytic importance in various liquids open the possibility to know their effective acidity, which is related with their activity in liquid-heterogeneous catalysis. Titration-calorimetry alone or in connection with spectrofluorimetry is efficient for this scope. - Highlights: • Measurements of acidity of oxides of catalytic importance in various liquids. • Titration-calorimetry alone or in connection with spectrofluorimetry is efficient for this scope. • Effective acidities are expressed by given sample in various liquids. • Nb-containing samples are able to maintain acidity in protic liquids. - Abstract: The effective acid and base surface properties of selected acidic and basic samples of catalytic interest (alumina, titania, zirconia, silica–alumina, niobium oxide, niobium phosphate, boron nitride, and hydrotalcite) were measured by titration with basic and acidic molecular probes (aniline, 2-phenylethylamine, and phenol) in various liquids (cyclohexane, 1,4-dioxane, isopropanol, n-decane, and toluene) with different polar and protic characteristics. The combined use of a reaction calorimeter and a spectrofluorimeter has been performed. The set-up of the coupled technique and the most interesting results are shown here. The study confirmed that the acid–base properties of solids are deeply affected by the nature and properties of the liquid surrounding the samples. Few oxides are able to maintain their surface acidity in highly polar and protic solvents, in particular whose containing niobium. In general, the solvating and coordinative ability of the most polar and protic liquids caused remarkable loss of acidity/basicity of the oxide surfaces.

  19. Trimetallic naphtha reforming catalysts II. Properties of the acid function and influence of the order of addition of the metallic precursors on Pt-Re-Sn/ -Al2O3-Cl

    OpenAIRE

    Carvalho, Luiz Souza; Pieck, C. L.; Varela, Maria do Carmo Rangel Santos; Fígoli, N. S.; Vera, C. R.; Parera, José Miguel

    2004-01-01

    p. 105-116 Mono, bi- and trimetallic catalysts were prepared by successive impregnation of -Al2O3 with Pt, Re and Sn precursors, with intermediate drying, calcination and reduction steps. The catalysts were tested in the reactions of n-pentane (500 ◦C, WHSV = 4.5, H2:n-C5 = 6) and n-octane (500 ◦C, WHSV = 1.8, H2:n-C8 = 10). Concerning the preparation parameters it was found that the addition of Sn first favorably affects the catalytic acid function, increasing the activity for alkane ...

  20. A new sol-gel synthesis of 45S5 bioactive glass using an organic acid as catalyst.

    Science.gov (United States)

    Faure, J; Drevet, R; Lemelle, A; Ben Jaber, N; Tara, A; El Btaouri, H; Benhayoune, H

    2015-02-01

    In this paper a new sol-gel approach was explored for the synthesis of the 45S5 bioactive glass. We demonstrate that citric acid can be used instead of the usual nitric acid to catalyze the sol-gel reactions. The substitution of nitric acid by citric acid allows to reduce strongly the concentration of the acid solution necessary to catalyze the hydrolysis of silicon and phosphorus alkoxides. Two sol-gel powders with chemical compositions very close to that of the 45S5 were obtained by using either a 2M nitric acid solution or either a 5mM citric acid solution. These powders were characterized and compared to the commercial Bioglass®. The surface properties of the two bioglass powders were assessed by scanning electron microscopy (SEM) and by Brunauer-Emmett-Teller method (BET). The Fourier transformed infrared spectroscopy (FTIR) and the X-ray diffraction (XRD) revealed a partial crystallization associated to the formation of crystalline phases on the two sol-gel powders. The in vitro bioactivity was then studied at the key times during the first hours of immersion into acellular Simulated Body Fluid (SBF). After 4h immersion into SBF we clearly demonstrate that the bioactivity level of the two sol-gel powders is similar and much higher than that of the commercial Bioglass®. This bioactivity improvement is associated to the increase of the porosity and the specific surface area of the powders synthesized by the sol-gel process. Moreover, the nitric acid is efficiently substituted by the citric acid to catalyze the sol-gel reactions without alteration of the bioactivity of the 45S5 bioactive glass. Copyright © 2014 Elsevier B.V. All rights reserved.