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Sample records for 2-methylpropane

  1. A comparative study of two polymorphs of bis(1-hydroxy-2-methylpropan-2-aminium) carbonate.

    Ben Nasr, Mahjouba; Aubert, Emmanuel; Espinosa, Enrique

    2016-03-01

    Alkanolamines have been known for their high CO2 absorption for over 60 years and are used widely in the natural gas industry for reversible CO2 capture. In an attempt to crystallize a salt of (RS)-2-(3-benzoylphenyl)propionic acid with 2-amino-2-methylpropan-1-ol, we obtained instead a polymorph (denoted polymorph II) of bis(1-hydroxy-2-methylpropan-2-aminium) carbonate, 2C4H12NO(+)·CO3(2-), (I), suggesting that the amine group of the former compound captured CO2 from the atmosphere forming the aminium carbonate salt. This new polymorph was characterized by single-crystal X-ray diffraction analysis at low temperature (100 K). The salt crystallizes in the monoclinic system (space group C2/c, Z = 4), while a previously reported form of the same salt (denoted polymorph I) crystallizes in the triclinic system (space group P-1, Z = 2) [Barzagli et al. (2012). ChemSusChem, 5, 1724-1731]. The asymmetric unit of polymorph II contains one 1-hydroxy-2-methylpropan-2-aminium cation and half a carbonate anion, located on a twofold axis, while the asymmetric unit of polymorph I contains two cations and one anion. These polymorphs exhibit similar structural features in their three-dimensional packing. Indeed, similar layers of an alternating cation-anion-cation neutral structure are observed in their molecular arrangements. Within each layer, carbonate anions and 1-hydroxy-2-methylpropan-2-aminium cations form planes bound to each other through N-H...O and O-H...O hydrogen bonds. In both polymorphs, the layers are linked to each other via van der Waals interactions and C-H...O contacts. In polymorph II, a highly directional C-H...O contact (C-H...O = 156°) shows as a hydrogen-bonding interaction. Periodic theoretical density functional theory (DFT) calculations indicate that both polymorphs present very similar stabilities. PMID:26942432

  2. 2-[(5-Chloro-2-oxidobenzylideneazaniumyl]-2-methylpropane-1,3-diol

    Dong-Yue Wang

    2012-02-01

    Full Text Available The title compound, C11H14ClNO3, was prepared by the condensation of equimolar quantities of 5-chlorosalicylaldehyde and 2-amino-2-methylpropane-1,3-diol in methanol. In the crystal, it exists in the zwitterionic form, with nominal proton transfer from the phenol group to the imine N atom. This results in the formation of an intramolecular N—H...O hydrogen bond, which generates an S(6 ring. Intermolecular O—H...O hydrogen bonds arise from the hydroxy groups, forming (001 sheets.

  3. Measurements and thermodynamic modeling of liquid-liquid equilibria in ternary system 2-methoxy-2-methylpropane+p-cresol+water☆

    Liejin Luo; Dong Liu; Libo Li; Yun Chen

    2016-01-01

    Liquid–liquid equilibrium (LLE) data for the ternary system 2-methoxy-2-methylpropane (methyl tert-butyl ether)+p-cresol+water was measured at atmospheric pressure and temperatures of 298.15 K and 313.15 K. From the distribution coefficients and selectivity, it was found that 2-methoxy-2-methylpropane is an efficient solvent to extract p-cresol from wastewater. The consistency of the experimental tie-line data was verified with the Hand and Bachman equations. These data were also correlated with the non-random two liquid (NRTL) and universal quasi-chemical correlation activity coefficient (UNIQUAC) models to yield binary interac-tion parameters for p-cresol extraction process evaluation. Both models agreed with experiments very well, yet the NRTL model showed even smal er average deviation than the UNIQUAC model.

  4. Contribution to study of the thermodynamics properties of mixtures containing 2-methoxy-2-methylpropane, alkanol, alkane

    Graphical abstract: - Highlights: • Experimental enthalpies for the mixtures MTBE + pentanol + hexane and pentanol + hexane were measured. • No experimental ternary values were found in the currently available literature. • Excess molar enthalpies are positive over the whole range of composition. • The ternary contribution is also positive with the exception of a range located around the rich compositions of 1-pentanol. - Abstract: Excess molar enthalpies for the ternary system {x1 2-methoxy-2-methylpropane (MTBE) + x2 1-pentanol + (1 − x1 − x2) hexane} and the involved binary mixture {x 1-pentanol + (1 − x) hexane}, have been measured at T = 298.15 K and atmospheric pressure over the whole composition range. We are not aware of the existence of previous experimental measurement of the excess enthalpy for the ternary mixture under study in the literature currently available. Values of the excess molar enthalpies were measured using a Calvet microcalorimeter. The results were fitted by means of different variable degree polynomials. The ternary contribution to the excess enthalpy was correlated with the equation due to Verdes et al. (2004), and the equation proposed by Myers–Scott (1963) was used to fit the experimental binary mixture measured in this work. Smooth representations of the results are presented and used to construct constant excess molar enthalpy contours on Roozeboom diagrams. The excess molar enthalpies for the binary and ternary system are positive over the whole range of composition. The binary mixture {x 1-pentanol + (1 − x) hexane} is asymmetric, with its maximum displace toward a high mole fraction of decane. The ternary contribution is also positive with the exception of a range located around the rich compositions of 1-pentanol, and the representation is asymmetric. Additionally, the group contribution model of the UNIFAC model, in the versions of Larsen et al. (1987) [18] and Gmehling et al. (1993) [19] was used to estimate

  5. Experimental and theoretical excess molar enthalpies of ternary and binary mixtures containing 2-Methoxy-2-Methylpropane, 1-propanol, heptane

    Highlights: • Experimental enthalpies for the ternary system MTBE + propanol + heptane were measured. • No experimental ternary values were found in the currently available literature. • Experimental enthalpies for the binary system propanol + heptane were measured. • Excess molar enthalpies are positive over the whole range of composition. • The ternary contribution is also positive, and the representation is asymmetric. -- Abstract: Excess molar enthalpies, at the temperature of 298.15 K and atmospheric pressure, have been measured for the ternary system {x1 2-Methoxy-2-Methylpropane (MTBE) + x2 1-propanol + (1 − x1 − x2) heptane}, over the whole composition range. Also, experimental data of excess molar enthalpy for the involved binary mixture {x 1-propanol + (1 − x) heptane} at the 298.15 K and atmospheric pressure, are reported. We are not aware of any previous experimental measurement of excess enthalpy in the literature for the ternary system presented in this study. Values of the excess molar enthalpies were measured using a Calvet microcalorimeter. The ternary contribution to the excess enthalpy was correlated with the equation due to Morris et al. (1975) [15], and the equation proposed by Myers–Scott (1963) [14] was used to fitted the experimental binary mixture measured in this work. Additionally, the experimental results are compared with the estimations obtained by applying the group contribution model of UNIFAC, in the versions of Larsen et al. (1987) [16] and Gmehling et al. (1993) [17]. Several empirical expressions for estimating ternary properties from binary results were also tested

  6. Heat of Mixing and Solution of 2-Methylpropan-2-ol C4H10O + C16H34 Hexadecane (HMSD1111, LB3996_H)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Heat of Mixing and Solution of 2-Methylpropan-2-ol C4H10O + C16H34 Hexadecane (HMSD1111, LB3996_H)' providing data from direct low-pressure calorimetric measurement of molar excess enthalpy at variable mole fraction and constant temperature.

  7. Synthesis and evaluation of poly(Sodium 2-Acrylamido-2-Methylpropane Sulfonate-co-Styrene)/magnetite nanoparticle composites as corrosion inhibitors for steel.

    El-Mahdy, Gamal A; Atta, Ayman M; Al-Lohedan, Hamad A

    2014-01-01

    Self-stabilized magnetic polymeric composite nanoparticles of coated poly-(sodium 2-acrylamido-2-methylpropane sulfonate-co-styrene)/magnetite (PAMPS-Na-co-St/Fe3O4) were prepared by emulsifier-free miniemulsion polymerization using styrene (St) as a monomer, 2-acrylamido-2-methylpropane sulfonic acid sodium salt (AMPS-Na) as an ionic comonomer, N,N-methylenebisacrylamide (MBA) as crosslinker, hexadecane (HD) as a hydrophobic solvent, and 2,2-azodiisobutyronitrile (AIBN) as an initiator in the presence of hydrophobic oleic acid coated magnetite particles. Hydrophobic oleic acid coated magnetite particles with an average size of about 7-10 nm were prepared with the new modified water-based magnetite ferrofluid, synthesized by a chemical modified coprecipitation method. The morphology and the particle size distributions of the crosslinked PAMPS-Na-co-St/Fe3O4 composite were observed and analyzed by transmission electron microscopy (TEM). The average Fe3O4 content of PAMPS-Na-co-St/Fe3O4 was determined by thermogravimetric analysis (TGA). The inhibitory action of PAMPS-Na-co-St/Fe3O4 towards steel corrosion in 1 M HCl solutions has been investigated by polarization and electrochemical impedance spectroscopy (EIS) methods. Polarization measurements indicate that PAMPS-Na-co-St/Fe3O4 acts as a mixed type-inhibitor and the inhibition efficiency increases with inhibitor concentration. The results of potentiodynamic polarization and EIS measurements clearly showed that the inhibition mechanism involves blocking of the steel surface by inhibitor molecules via adsorption. PMID:24487568

  8. Synthesis and Evaluation of Poly(Sodium 2-Acrylamido-2-Methylpropane Sulfonate-co-Styrene/Magnetite Nanoparticle Composites as Corrosion Inhibitors for Steel

    Gamal A. El-Mahdy

    2014-01-01

    Full Text Available Self-stabilized magnetic polymeric composite nanoparticles of coated poly-(sodium 2-acrylamido-2-methylpropane sulfonate-co-styrene/magnetite (PAMPS-Na-co-St/Fe3O4 were prepared by emulsifier-free miniemulsion polymerization using styrene (St as a monomer, 2-acrylamido-2-methylpropane sulfonic acid sodium salt (AMPS-Na as an ionic comonomer, N,N-methylenebisacrylamide (MBA as crosslinker, hexadecane (HD as a hydrophobic solvent, and 2,2-azodiisobutyronitrile (AIBN as an initiator in the presence of hydrophobic oleic acid coated magnetite particles. Hydrophobic oleic acid coated magnetite particles with an average size of about 7-10 nm were prepared with the new modified water-based magnetite ferrofluid, synthesized by a chemical modified coprecipitation method. The morphology and the particle size distributions of the crosslinked PAMPS-Na-co-St/Fe3O4 composite were observed and analyzed by transmission electron microscopy (TEM. The average Fe3O4 content of PAMPS-Na-co-St/Fe3O4 was determined by thermogravimetric analysis (TGA. The inhibitory action of PAMPS-Na-co-St/Fe3O4 towards steel corrosion in 1 M HCl solutions has been investigated by polarization and electrochemical impedance spectroscopy (EIS methods. Polarization measurements indicate that PAMPS-Na-co-St/Fe3O4 acts as a mixed type-inhibitor and the inhibition efficiency increases with inhibitor concentration. The results of potentiodynamic polarization and EIS measurements clearly showed that the inhibition mechanism involves blocking of the steel surface by inhibitor molecules via adsorption.

  9. C4H9I 2-Iodo-2-methylpropane

    Demaison, J.

    This document is part of Subvolume C 'Symmetric Top Molecules' of Volume 29 'Molecular Constants Mostly from Microwave, Molecular Beam, and Sub-Doppler Laser Spectroscopy' of Landolt-Börnstein - Group II 'Molecules and Radicals'.

  10. Synthesis and Characterization of Graft Copolymer of Dextran and 2-Acrylamido-2-methylpropane Sulphonic Acid

    Venkanna Azmeera

    2012-01-01

    Full Text Available A novel biodegradable graft copolymer of dextran (Dx and 2-acrylamido-2-methyl-1-propane sulphonic acid (AMPS was synthesized by grafting poly-AMPS chains onto dextran backbone by free radical polymerization using ceric ammonium nitrate (CAN as an initiator. Different amounts of AMPS were used to synthesize four different grades of graft copolymers with different side chain lengths. These grafted polymers were characterized by elemental analysis, FTIR, 1HNMR, rheological technique, scanning electron microscopy (SEM, thermogravimetric analysis (TGA, and X-ray diffractometry (XRD. They exhibited efficient flocculation performance in kaolin suspension.

  11. (SS,2S,3S-2-(2-Methylpropan-2-sulfinamido-3-phenylbutyronitrile

    Klaus Harms

    2009-11-01

    Full Text Available The absolute configuration has been determined for the title compound, C14H20N2OS. There are two independent molecules in the asymmetric unit. Intermolecular N—H...O hydrogen bonds are observed in the crystal packing, forming infinite chains with the base vectors [100] and [010]. Each chain contains only one of the two independent molecules.

  12. Bis{(R-N-[(R-2-benzyloxy-1-(4-tert-butylphenylethyl]-2-methylpropane-2-sulfinamide} monohydrate

    Charlotte L. Humes

    2014-04-01

    Full Text Available The asymmetric unit of the title compound, 2C23H33NO2S·H2O, contains one organic molecule in a general position and one co-crystallized water molecule on a crystallographic twofold axis. Each water molecule serves as a hydrogen-bond donor to a pair of S=O acceptors on symmetry-related molecules. Thus, each trio of molecules forms one title formula unit. These groupings are further connected along [010] via weak non-classical C—H...O hydrogen bonds.

  13. Preparation and characterization of poly(2-acrylamido-2-methylpropane-sulfonic acid)/Chitosan hydrogel using gamma irradiation and its application in wastewater treatment

    Gad, Y. H.

    2008-09-01

    Radiation grafting of chitosan with 2-acrylamido-2-methyl propane sulfonic acid (AMPS) has been successfully performed. The effect of absorbed dose (kGy) and the chitosan:AMPS ratio on graft hydrogelization was studied. The structure of the prepared hydrogel was confirmed using infrared spectroscopy (IR). Thermal properties were simultaneously studied by thermogravimetric analysis (TGA). The effect of the polymerization variables on the swelling % of the prepared hydrogel was investigated. The highest equilibrium degree of swelling (38.6 g/g) and gel % (94.7%) of the prepared chitosan-AMPS hydrogel was at 40% AMPS and absorbed dose of 10 kGy. The removal of methylene blue, acid red dye, Cd (II) and Cr (III) from composed wastewater was also investigated. The effect of pH, the chitosan:AMPS ratio and the concentration of the pollutant on the adsorption process were studied.

  14. THERMODYNAMIC PROPERTIES HF 298, S 298, AND CP(T) FOR 2-FLUORO-2-METHYLPROPANE, HF 298 OF FLUORINATED ETHANES, AND GROUP ADDITIVITY FOR FLUOROALKANES. (R824970)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  15. Protection of Petroleum Pipeline Carbon Steel Alloys with New Modified Core-Shell Magnetite Nanogel against Corrosion in Acidic Medium

    El Mahdy, Gamal A.; Atta, Ayman M.; Dyab, Amro K. F.; Hamad A. Al-Lohedan

    2013-01-01

    New method was used to prepare magnetite nanoparticle based on reduction of Fe(III) ions with potassium iodide to produce Fe3O4 nanoparticle. The prepared magnetite was stabilized with cross-linked polymer based on 2-acrylamido-2-methylpropane sulfonic acid (AMPS to prepare novel core-shell nanogel. In this respect, Fe3O4/poly(2-acrylamido-2-methylpropane sulfonic acid) (PAMPS) magnetic nanogels with controllable particle size produced via free aqueous polymerization at 65°C have been develop...

  16. Rate of Hydrolysis of Tertiary Halogeno Alkanes

    Pritchard, D. R.

    1978-01-01

    Describes an experiment to measure the relative rate of hydrolysis of the 2-x-2 methylpropanes, where x is bromo, chloro or iodo. The results are plotted on a graph from which the relative rate of hydrolysis can be deduced. (Author/GA)

  17. Gas-chromatographic analysis of some volatile congeners in different types of strong alcoholic fruit spirits

    Kostik, Vesna; Memeti, Shaban; Bauer, Biljana

    2013-01-01

    Beside ethyl alcohol, the major active component of alcoholic beverages, almost all alcoholic drinks contain volatile and non-volatile substances called congeners. They are present in different concentrations depending on beverage type and manufacturing methods. In the current study, the major volatile compounds besides ethanol as: methanol, ethyl acetate, 1-propanol (n-propanol), 2-propanol (i-propanol), 1-butanol(n-butanol), i-butanol (2-methylpropan-1-ol), n-amyl alcohol (n-pentanol), i-am...

  18. The use of deuterium N.m.r. spectroscopy in mechanistic studies of alkane-exchange reactions on supported platinum and rhodium catalysts

    2D N.m.r. spectra (55.28 MHz) have been obtained for samples of ethane, propane, 2-methylpropane, and 2,2-dimethylpropane produced during the exchange of the hydrocarbons with deuterium over silica-supported platinum and rhodium catalysts. The results provide new evidence about the mechanism of the exchange reactions of these metals and about the isotopic shifts associated with deuterium atoms in different positions in the molecules. (author)

  19. Determination of some volatile compounds in fruit spirits produced from grapes (Vitis Vinifera L.) and plums (Prunus domestica L.) cultivars

    Kostik, Vesna; Gjorgjeska, Biljana; Angelovska, Bistra; Kovacevska, Ivona

    2014-01-01

    Fruit spirits contain a large array of volatile compounds among which the important role from toxicological aspect besides ethanol has methanol, aliphatic esters and fusel alcohols. This study evaluates the content of ethanol, ethyl acetate, methanol, isopropyl alcohol (2-propanol), n-propyl alcohol (propan-l-ol), isobutyl alcohol (2-methylpropan-1-ol), n-butyl alcohol (1-butanol), isoamyl alcohol (3-methyl-1-butanol) and n-amyl alcohol (pentan-1-ol) in different grapes and plum brandies i...

  20. Novel negatively-charged membrane adsorbers made using combination of photopolymerization and immersion precipitation

    Tomković Tanja

    2016-01-01

    Full Text Available A novel method combining a traditional immersion precipitation process for making membranes with photopolymerization and crosslinking of functional monomers included in the casting solution was used to prepare asymmetric polyethersulfone membranes with submicron particles incorporating glycidyl methacrylate copolymer. In order to introduce sulfonic groups epoxide rings of glycidyl methacrylate were opened using two methods. The first method was functionalization with sodium sulfite, and the second method was functionalization with sulfuric acid and then grafting with 2-acrylamido-2-methylpropane sulfonic acid. Obtained membranes were characterized using infrared spectroscopy, conductometric titration and water permeability measurements. Scanning electron microscopy and atomic force microscopy were used to investigate the surface morphology and topology of membrane. Dynamic adsorption of Rhodamine B as a model dye was used to demonstrate suitability of these novel membranes for membrane adsorption since the adsorption capacity for dye cations was much better for both functionalized membrane with sodium sulfite and grafted membrane with 2-acrylamido-2-methylpropane sulfonic acid compared to the nonfunctionalized membrane. [Projekat Ministarstva nauke Republike Srbije, br. TR32008 and III 43009

  1. Structure-guided engineering of Lactococcus lactis alcohol dehydrogenase LlAdhA for improved conversion of isobutyraldehyde to isobutanol

    Liu, Xiang

    2013-03-01

    We have determined the X-ray crystal structures of the NADH-dependent alcohol dehydrogenase LlAdhA from Lactococcus lactis and its laboratory-evolved variant LlAdhA(RE1) at 1.9Å and 2.5Å resolution, respectively. LlAdhA(RE1), which contains three amino acid mutations (Y50F, I212T, and L264V), was engineered to increase the microbial production of isobutanol (2-methylpropan-1-ol) from isobutyraldehyde (2-methylpropanal). Structural comparison of LlAdhA and LlAdhA(RE1) indicates that the enhanced activity on isobutyraldehyde stems from increases in the protein\\'s active site size, hydrophobicity, and substrate access. Further structure-guided mutagenesis generated a quadruple mutant (Y50F/N110S/I212T/L264V), whose KM for isobutyraldehyde is ∼17-fold lower and catalytic efficiency (kcat/KM) is ∼160-fold higher than wild-type LlAdhA. Combining detailed structural information and directed evolution, we have achieved significant improvements in non-native alcohol dehydrogenase activity that will facilitate the production of next-generation fuels such as isobutanol from renewable resources.

  2. Identification and characterization of the aroma-impact components of Thai fish sauce.

    Lapsongphon, Nawaporn; Yongsawatdigul, Jirawat; Cadwallader, Keith R

    2015-03-18

    Comprehensive analysis of the potent odorants in Thai premium fish sauce samples was accomplished by use of complementary volatile isolation methods combined with gas chromatography-olfactometry (GC-O) and GC-mass spectrometry. Odorants of intermediate and low volatility were determined by direct solvent extraction/solvent-assisted flavor evaporation (DSE-SAFE) and aroma extract dilution analysis (AEDA). Meanwhile, static headspace dilution analysis (SHDA) and headspace solid-phase microextraction (H-SPME) were used to determine the highly volatile odorants. Results of AEDA indicated the importance (log3FD factor≥6) of five acidic odorants (butanoic acid, 3-methylbutanoic acid, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, 4-hydroxy-2-ethyl-5-methyl-3(2H)-furanone, and 2-phenylacetic acid) and four neutral/basic odorants (3-methylbutanal, (Z)-1,5-octadien-3-one, phenylacetaldehyde, and o-aminoacetophone). Results of SHDA indicated the predominant (log3FD factors≥5) headspace odorants were methanethiol, 2-methylpropanal, 2-methylbutanal, 3-methylbutanal, dimethyl trisulfide, 3-(methylthio)propanal, and butanoic acid. Concentrations for 21 odorants were determined by stable isotope dilution analysis (SIDA), and their odor-activity values (OAVs) were calculated. Among these, methanethiol, 2-methylpropanal, 3-methylbutanal, dimethyl trisulfide, 3-(methylthio)propanal, and butanoic acid had the highest OAVs (>500). Results of aroma recombination and omission studies revealed the importance of acids, aldehydes, and sulfur-containing compounds to the overall aroma of the Thai fish sauce. PMID:25730550

  3. Amino-functionalized (meth)acryl polymers by use of a solvent-polarity sensitive protecting group (Br-t-BOC).

    Ritter, Helmut; Tabatabai, Monir; Herrmann, Markus

    2016-01-01

    We describe the synthesis of bromo-tert-butyloxycarbonyl (Br-t-BOC)-amino-protected monomers 2-((1-bromo-2-methylpropan-2-yl)oxycarbonylamino)ethyl (meth)acrylate 3a,b. For this purpose, 2-isocyanatoethyl (meth)acrylate 1a,b was reacted with 1-bromo-2-methylpropan-2-ol (2a). The free radical polymerization of (Br-t-BOC)-aminoethyl (meth)acrylates 3a,b yielded poly((Br-t-BOC)-aminoethyl (meth)acrylate) 6a,b bearing protected amino side groups. The subsequent solvolysis of the Br-t-BOC function led to the new polymers poly(2-aminoethyl (meth)acrylate) 8a,b with protonated free amino groups. The monomers and the resulting polymers were thoroughly characterized by (1)H NMR, IR, GPC and DSC methods. The kinetics of the deprotection step was followed by (1)H NMR spectroscopy. The solvent polarity and neighboring group effects on the kinetics of deprotection are discussed. PMID:26977183

  4. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 08, Revision 4 (FGE.08Rev4): Aliphatic and alicyclic mono-, di-, tri-, and polysulphides with or without additional oxygenated functional groups from chemical

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister; Lund, Pia; Binderup, Mona-Lise; Frandsen, Henrik Lauritz

    publication of the last revision of this FGE, the EFSA has been requested to evaluate 10 additional substances, which have been included in the present revision of FGE.08. For the substances methyl methanethiosulphonate [FL-no: 12.159], 2-methylbutane-2-thiol [FL-no: 12.172], 2-methylpropane-2- thiol [FL......The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 80 flavouring substances in the Flavouring Group Evaluation 08, Revision 4, using the Procedure in Commission Regulation (EC) No 1565/2000. Since the.......112, 12.116, 12.120, 12.164, 12.167, 12.199, 15.007, 15.102 and 15.125 and 15.134], evaluated through the Procedure, no appropriate NOAEL was available and additional data are required. Besides the safety assessment of the flavouring substances, the specifications for the materials of commerce have also...

  5. Solubility of anthracene in binary alkane + methyl tert-butyl ether solvent mixtures at 298.15 K

    McHale, M.E.R.; Kauppila, A.S.M.; Acree, W.E. Jr. [Univ. of North Texas, Denton, TX (United States). Dept. of Chemistry

    1996-09-01

    Experimental solubilities are reported for anthracene dissolved in seven binary mixtures containing methyl tert-butyl ether (also called 2-methoxy-2-methylpropane) with hexane, heptane, octane, cyclohexane, methylcyclohexane, 2,2,4-trimethylpentane, and tert-butylcyclohexane (also called (1,1-dimethylethyl)-cyclohexane) at 25 C. Results of these measurements are used to test two mathematical representations based upon the combined nearly ideal binary solvent (NIBS)/Redlich-Kister equation and modified Wilson model. For the seven systems studied, both equations were found to provide an accurate mathematical representation of the experimental data, with an overall average absolute deviation between measured and calculated values being on the order of 0.5%.

  6. Thermodynamic and acoustical properties of mixtures p-anisaldehyde—alkanols (C1-C4)—2-methyl-1-propanol at 303.15 K

    Saini, Balwinder; Kumar, Ashwani; Rani, Ruby; Bamezai, Rajinder K.

    2016-07-01

    The density, viscosity and speed of sound of pure p-anisaldehyde and some alkanols, for example, methanol, ethanol, propan-1-ol, propan-2-ol, butan-1-ol, butan-2-ol, 2-methylpropan-1-ol, and the binary mixtures of p-anisaldehyde with these alkanols were measured over the entire composition range at 303.15 K. From the experimental data, various thermodynamic parameters such as excess molar volume ( V E), excess Gibbs free energy of activation (Δ G*E), and deviation parameters like viscosity (Δη), speed of sound (Δ u), isentropic compressibility (Δκs), are calculated. The excess as well as deviation parameters are fitted to Redlich—Kister equation. Additionally, the viscosity data for the systems has been used to correlate the application of empirical relation given by Grunberg and Nissan, Katti and Chaudhari, and Hind et al. The results are discussed in terms of specific interactions present in the mixtures.

  7. Producing Radical-Free Hyperpolarized Perfusion Agents for In Vivo Magnetic Resonance Using Spin-Labeled Thermoresponsive Hydrogel.

    Cheng, Tian; Mishkovsky, Mor; Junk, Matthias J N; Münnemann, Kerstin; Comment, Arnaud

    2016-07-01

    Dissolution dynamic nuclear polarization (DNP) provides a way to tremendously improve the sensitivity of nuclear magnetic resonance experiments. Once the spins are hyperpolarized by dissolution DNP, the radicals used as polarizing agents become undesirable since their presence is an additional source of nuclear spin relaxation and their toxicity might be an issue. This study demonstrates the feasibility of preparing a hyperpolarized [1-(13) C]2-methylpropan-2-ol (tert-butanol) solution free of persistent radicals by using spin-labeled thermoresponsive hydrophilic polymer networks as polarizing agents. The hyperpolarized (13) C signal can be detected for up to 5 min before the spins fully relax to their thermal equilibrium. This approach extends the applicability of spin-labeled thermoresponsive hydrogel to the dissolution DNP field and highlights its potential as polarizing agent for preparing neat slowly relaxing contrast agents. The hydrogels are especially suited to hyperpolarize deuterated alcohols which can be used for in vivo perfusion imaging. PMID:27184565

  8. Polymerization of novel methacrylated anthraquinone dyes

    Christian Dollendorf

    2013-02-01

    Full Text Available A new series of polymerizable methacrylated anthraquinone dyes has been synthesized by nucleophilic aromatic substitution reactions and subsequent methacrylation. Thereby, green 5,8-bis(4-(2-methacryloxyethylphenylamino-1,4-dihydroxyanthraquinone (2, blue 1,4-bis(4-((2-methacryloxyethyloxyphenylaminoanthraquinone (6 and red 1-((2-methacryloxy-1,1-dimethylethylaminoanthraquinone (12, as well as 1-((1,3-dimethacryloxy-2-methylpropan-2-ylaminoanthraquinone (15 were obtained. By mixing of these brilliant dyes in different ratios and concentrations, a broad color spectrum can be generated. After methacrylation, the monomeric dyes can be covalently emplaced into several copolymers. Due to two polymerizable functionalities, they can act as cross-linking agents. Thus, diffusion out of the polymer can be avoided, which increases the physiological compatibility and makes the dyes promising compounds for medical applications, such as iris implants.

  9. Separation of PCR-ready DNA from dairy products using magnetic hydrophilic microspheres and poly(ethylene glycol)-NaCl water solutions

    Carboxyl group-containing magnetic nonporous poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) (P(HEMA-co-GMA)) and magnetic glass microspheres were used for the isolation of bacterial DNA. P(HEMA-co-GMA) microspheres were prepared by the dispersion polymerization in toluene/2-methylpropan-1-ol mixture in the presence of magnetite nanoparticles obtained by coprecipitation of Fe(II) and Fe(III) salts with ammonium hydroxide. Carboxyl groups were then introduced by oxidation of the microspheres with potassium permanganate. The most extensive DNA recovery was achieved at PEG 6000 concentrations of 12% or 16% and 2 M NaCl. The method proposed was used for bacterial DNA isolation from different dairy products containing Bifidobacterium and Lactobacillus cells. The presence of target DNA and the quality of isolated DNA were checked by polymerase chain reaction (PCR) amplification with specific primers.

  10. Scientific Opinion on the safety and efficacy of branched-chain primary aliphatic alcohols/aldehydes/acids, acetals and esters with esters containing branched-chain alcohols and acetals containing branched-chain aldehydes (chemical group 2 when used as flavourings for all animal species

    EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP

    2012-10-01

    Full Text Available

    Chemical group 2 consists of branched-chain primary aliphatic alcohols/aldehydes/acids, acetals and esters with esters containing branched-chain alcohols and acetals containing branched-chain aldehydes, of which 34 are currently authorised for use as flavours in food. The use of 2-methylpropionic acid, isopentyl acetate, 3-methylbutyl butyrate and 2-methylbutyl acetate is safe at the proposed use level of 25 mg/kg complete feed for cattle, salmonids and non food producing animals and at 5 mg/kg complete feed for pigs and poultry. 2-Methylpropan-1-ol, isopentanol, 2-ethylhexan-1-ol, 2-methylpropanal, 3-methylbutanal, 2-methylbutyraldehyde, 3-methylbutyric acid, 2-methylvaleric acid, 2-ethylbutyric acid, 2-methylbutyric acid, 2-methylheptanoic acid, 4-methyloctanoic acid, isobutyl acetate, isobutyl butyrate, 3-methylbutyl propionate, 3-methylbutyl formate, glyceryl tributyrate, isobutyl isobutyrate, isopentyl isobutyrate, isobutyl isovalerate, isopentyl 2-methylbutyrate, 2-methylbutyl isovalerate and 2-methylbutyl butyrate are safe at the proposed use level of 5 mg/kg complete feed for all animal species. 3,7-Dimethyloctan-1-ol, 2-methylundecanal, 4-methylnonanoic acid, 3-methylbutyl hexanoate, 3-methylbutyl dodecanoate, 3-methylbutyl octanoate and 3-methylbutyl 3-methylbutyrate are safe at a maximum of 1.5 mg/kg complete feed for cattle, salmonids and non food-producing animals and of 1.0 mg/kg complete feed for pigs and poultry. No safety concern was identified for the consumer from the use of these compounds up to the highest safe level in feedingstuffs for all animal species. All compounds should be considered as irritants to skin, eyes and respiratory tract, and as skin sensitisers. The compounds do not pose a risk to the environment when used at concentrations considered safe for the target species. Since all compounds are used in food as flavourings, no further demonstration of efficacy is necessary.

  11. Scientific Opinion on the safety and efficacy of aliphatic and aromatic mono- and di-thiols and mono-, di-, tri-, and polysulphides with or without additional oxygenated functional groups (chemical group 20 when used as flavourings for all animal species

    EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP

    2013-05-01

    Full Text Available Chemical group 20 consists of aliphatic and aromatic mono- and di-thiols and mono-, di-, tri-, and polysulphides with or without additional oxygenated functional groups, of which 31 are currently authorised for use as flavours in food. The FEEDAP Panel was unable to perform an assessment of six compounds (methanethiol, methyl propyl disulphide, dipropyl trisulphide, 3-mercaptobutan-2-one, 3-(methylthiobutanal and 3-methyl-1,2,4-trithiane because of issues related to the purity of the compounds. The FEEDAP Panel concludes that the following 25 compounds are safe for the target species at the proposed maximum dose level (0.05 mg/kg complete feed: 3-(methylthiopropionaldehyde, methyl 3-(methylthiopropionate, allylthiol, dimethyl sulphide, dibutyl sulphide, diallyl disulphide, diallyl trisulphide, dimethyl trisulphide, dipropyl disulphide, allyl isothiocyanate, dimethyl disulphide, 2-methylbenzene-1-thiol, S-methyl butanethioate, allyl methyl disulphide, 3-(methylthiopropan-1-ol, 3-(methylthiohexan-1-ol, 1-propane-1-thiol, diallyl sulphide, 2,4-dithiapentane, 2-methyl-2-(methyldithiopropanal, 2-methylpropane-1-thiol, methylsulfinylmethane, propane-2-thiol, 3,5-dimethyl-1,2,4-trithiolane and 2-methyl-4-propyl-1,3-oxathiane. No safety concern for the consumer would arise from the use of these 25 compounds of CG 20 up to the highest safe level in feedingstuffs for all animal species, with the exception of allyl isothiocyanate. Although additional exposure to this substance through its low use level in animal feeds would not substantially increase consumer exposure, the FEEDAP Panel notes that the estimated exposure of consumers is already higher than the acceptable daily intake (ADI. All compounds should be considered irritant to skin, eyes and respiratory tract and as skin sensitisers. The proposed concentration of 0.05 mg flavour/kg feed is not expected to cause detrimental effects to the environment, except for 2-methylpropane-1-thiol, for which 0

  12. Experimental and modeling study of the oxidation of n- and iso-butanal

    Veloo, Peter S.

    2013-09-01

    Understanding the kinetics of large molecular weight aldehydes is essential in the context of both conventional and alternative fuels. For example, they are key intermediates formed during the low-temperature oxidation of hydrocarbons as well as during the high-temperature oxidation of oxygenated fuels such as alcohols. In this study, an experimental and kinetic modeling investigation of n-butanal (. n-butyraldehyde) and iso-butanal (. iso-butyraldehyde or 2-methylpropanal) oxidation kinetics was performed. Experiments were performed in a jet stirred reactor and in counterflow flames over a wide range of equivalence ratios, temperatures, and pressures. The jet stirred reactor was utilized to observe the evolution of stable intermediates and products for the oxidation of n- and iso-butanal at elevated pressures and low to intermediate temperatures. The counterflow configuration was utilized for the determination of laminar flame speeds. A detailed chemical kinetic interpretative model was developed and validated consisting of 244 species and 1198 reactions derived from a previous study of the oxidation of propanal (propionaldehyde). Extensive reaction pathway and sensitivity analysis was performed to provide detailed insight into the mechanisms governing low-, intermediate-, and high-temperature reactivity. The simulation results using the present model are in good agreement with the experimental laminar flame speeds and well within a factor of two of the speciation data obtained in the jet stirred reactor. © 2013 The Combustion Institute.

  13. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 08, Revision 5 (FGE.08Rev5): Aliphatic and alicyclic mono-, di-, tri-, and polysulphides with or without additional oxygenated functional groups from chemical

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister; Lund, Pia; Binderup, Mona-Lise; Frandsen, Henrik Lauritz

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 80 flavouring substances in the Flavouring Group Evaluation 08, Revision 4, using the Procedure in Commission Regulation (EC) No 1565/2000. Since the...... publication of the last revision of this FGE, the EFSA has been requested to evaluate additional toxicological data submitted for two flavouring substances, one on supporting substance 2,5-dihydroxy-2,5-dimethyl-1,4-dithiane [FL-no: 15.006], which support the evaluation of the candidate substance 2...... present revision of FGE.08. For the substances methyl methanethiosulphonate [FL-no: 12.159], 2-methylbutane-2-thiol [FL-no: 12.172], 2-methylpropane-2-thiol [FL-no: 12.174], ethyl-2-mercapto-2-methyl propanoate [FL-no: 12.304] and 2,4,4-trimethyl-1,3-oxathiane [FL-no: 16.057] there is an indication of a...

  14. A chemical assessment of the suitability of allyl- iso-propyltelluride as a Te precursor for metal organic vapour phase epitaxy

    Hails, Janet E.; Cole-Hamilton, David J.; Stevenson, John; Bell, William; Foster, Douglas F.; Ellis, David

    2001-04-01

    The chemical studies, which led to the testing of allyl- iso-propyltelluride (allylTePr i) as a Te precursor in metal organic vapour phase epitaxy are presented. The pyrolysis in hydrogen of allylTePr i gave products including 1,5-hexadiene, propane and propene. Co-pyrolysis of dimethylcadmium (Me 2Cd) and allylTePr i gave the hydrocarbons expected from the pyrolysis of the individual precursors plus additional hydrocarbons including 2-methylpropane and 1-butene. Plots of percentage decomposition versus temperature, which proved extremely useful in determining the likely growth temperatures for both CdTe and HgTe, showed that allylTePr i is less stable than both Pr 2iTe (di- iso-propyltelluride) and Me 2Cd. The possible role of Hg in the growth of CdTe is also discussed. The chemistry of allylTePr i is well suited for use as an efficient precursor for epitaxial growth of tellurium containing semiconductors since there is very little formation of other organotellurium compounds on pyrolysis.

  15. Mid-infrared surface transmitting and detecting quantum cascade device for gas-sensing

    Harrer, Andreas; Szedlak, Rolf; Schwarz, Benedikt; Moser, Harald; Zederbauer, Tobias; Macfarland, Donald; Detz, Hermann; Andrews, Aaron Maxwell; Schrenk, Werner; Lendl, Bernhard; Strasser, Gottfried

    2016-02-01

    We present a bi-functional surface emitting and surface detecting mid-infrared device applicable for gas-sensing. A distributed feedback ring quantum cascade laser is monolithically integrated with a detector structured from a bi-functional material for same frequency lasing and detection. The emitted single mode radiation is collimated, back reflected by a flat mirror and detected by the detector element of the sensor. The surface operation mode combined with the low divergence emission of the ring quantum cascade laser enables for long analyte interaction regions spatially separated from the sample surface. The device enables for sensing of gaseous analytes which requires a relatively long interaction region. Our design is suitable for 2D array integration with multiple emission and detection frequencies. Proof of principle measurements with isobutane (2-methylpropane) and propane as gaseous analytes were conducted. Detectable concentration values of 0-70% for propane and 0-90% for isobutane were reached at a laser operation wavelength of 6.5 μm utilizing a 10 cm gas cell in double pass configuration.

  16. A flow reactor study of neopentane oxidation at 8 atmospheres: Experiments and modeling

    Wang, S.; Miller, D.L.; Cernansky, N.P. [Drexel Univ., Philadelphia, PA (United States). Dept. of Mechanical Engineering and Mechanics; Curran, H.J.; Pitz, W.J.; Westbrook, C.K. [Lawrence Livermore National Lab., CA (United States)

    1999-08-01

    An existing detailed chemical kinetic reaction mechanism for neopentane oxidation is applied to new experimental measurements, taken in a flow reactor operating at a pressure of 8 atm. The reactor temperature ranged from 620 K to 810 K and flow rates of the reactant gases neopentane, oxygen, and nitrogen were 0.285, 7.6, and 137.1 standard liter per minute (SLM), respectively, producing an equivalence ratio of 0.3. Initial simulations identified some deficiencies in the existing model and the paper presents modifications which included upgrading the thermodynamic parameters of alkyl radical and alkylperoxy radical species, adding an alternative isomerization reaction of hydroperoxy-neopentyl-peroxy, and a multistep reaction sequence for 2-methylpropan-2-yl radical with molecular oxygen. These changes improved the calculation for the overall reactivity and the concentration profiles of the following primary products: formaldehyde, acetone, isobutene; 3,3-dimethyloxetane, methacrolein, carbon monoxide, carbon dioxide, and water. Experiments indicate that neopentane shows negative temperature coefficient behavior similar to other alkanes, though it is not as pronounced as that shown by n-pentane for example. Modeling results indicate that this behavior is caused by the {beta}-scission of the neopentyl radical and the chain propagation reactions of the hydroperoxyl-neopentyl radical.

  17. Optimal Design for Reactivity Ratio Estimation: A Comparison of Techniques for AMPS/Acrylamide and AMPS/Acrylic Acid Copolymerizations

    Alison J. Scott

    2015-11-01

    Full Text Available Water-soluble polymers of acrylamide (AAm and acrylic acid (AAc have significant potential in enhanced oil recovery, as well as in other specialty applications. To improve the shear strength of the polymer, a third comonomer, 2-acrylamido-2-methylpropane sulfonic acid (AMPS, can be added to the pre-polymerization mixture. Copolymerization kinetics of AAm/AAc are well studied, but little is known about the other comonomer pairs (AMPS/AAm and AMPS/AAc. Hence, reactivity ratios for AMPS/AAm and AMPS/AAc copolymerization must be established first. A key aspect in the estimation of reliable reactivity ratios is design of experiments, which minimizes the number of experiments and provides increased information content (resulting in more precise parameter estimates. However, design of experiments is hardly ever used during copolymerization parameter estimation schemes. In the current work, copolymerization experiments for both AMPS/AAm and AMPS/AAc are designed using two optimal techniques (Tidwell-Mortimer and the error-in-variables-model (EVM. From these optimally designed experiments, accurate reactivity ratio estimates are determined for AMPS/AAm (rAMPS = 0.18, rAAm = 0.85 and AMPS/AAc (rAMPS = 0.19, rAAc = 0.86.

  18. Proteinase-producing halophilic lactic acid bacteria isolated from fish sauce fermentation and their ability to produce volatile compounds.

    Udomsil, Natteewan; Rodtong, Sureelak; Tanasupawat, Somboon; Yongsawatdigul, Jirawat

    2010-07-15

    Halophilic lactic acid bacteria were isolated from fish sauce mashes fermented at 1 to 12 months. Seven out of sixty-four isolates were selected according to their proteolytic activity and growth at 25% NaCl for characterization and investigation of volatile compound production. All selected isolates were Gram-positive cocci with pairs/tetrads and grew at 0-25% NaCl, pH 4.5-9.0. Results of 16S rRNA gene sequence analysis showed 99% homology to Tetragenococcus halophilus ATCC 33315. The restriction fragment length polymorphism (RFLP) patterns of all isolates were also similar to those of T. halophilus ATCC 33315. These isolates were, thus, identified as T. halophilus. All isolates hydrolyzed fish protein in the medium containing 25% NaCl. Intracellular aminopeptidase of 7 isolates exhibited the highest activity of 2.85-3.67 U/ml toward Ala-p-nitroanilide (Ala-pNA). T.halophilus strains MS33 and M11 showed the highest alanyl aminopeptidase activity (Phalophilus MS33 and MRC5-5-2 were 1-propanol, 2-methylpropanal, and benzaldehyde, corresponding to major volatile compounds in fish sauce. T.halophilus appeared to play an important role in volatile compound formation during fish sauce fermentation. PMID:20541276

  19. Use of Tetragenococcus halophilus as a starter culture for flavor improvement in fish sauce fermentation.

    Udomsil, Natteewan; Rodtong, Sureelak; Choi, Yeung Joon; Hua, Yanglin; Yongsawatdigul, Jirawat

    2011-08-10

    The potential of Tetragenococcus halophilus as a starter culture for flavor improvement in fish sauce fermentation was elucidated. Four strains of T. halophilus isolated from fish sauce mashes were inoculated to anchovy mixed with 25% NaCl with an approximate cell count of 10(6) CFU/mL. The α-amino content of 6-month-old fish sauce samples inoculated with T. halophilus was 780-784 mM. The addition of T. halophilus MRC10-1-3 and T. halophilus MCD10-5-10 resulted in a reduction of histamine (P halophilus showed high contents of total amino acids with predominantly high glutamic acid. Major volatile compounds in fish sauce were 2-methylpropanal, 2-methylbutanal, 3-methylbutanal, and benzaldehyde. T. halophilus-inoculated fish sauce samples demonstrated the ability to reduce dimethyl disulfide, a compound contributing to a fecal note. The use of T. halophilus for fish sauce fermentation improves amino acid profiles and volatile compounds as well as reduces biogenic amine content of a fish sauce product. PMID:21710980

  20. Transferable force field for alcohols and polyalcohols.

    Ferrando, Nicolas; Lachet, Véronique; Teuler, Jean-Marie; Boutin, Anne

    2009-04-30

    A new force field has been developed for alcohol and polyalcohol molecules. Based on the anisotropic united-atom force field AUA4 developed for hydrocarbons, it only introduces one new anisotropic united atom corresponding to the hydroxyl group OH. In the case of polyalcohols and complex molecules, the calculation of the intramolecular electrostatic energy is revisited. These interactions are calculated between charges belonging to the different local dipoles of the molecule, one dipole being defined as a group of consecutive charges globally neutral. This new method allows avoiding the use of empirical scaling parameters commonly introduced to calculate 1-4 electrostatic interactions. The transferability of the proposed potential is demonstrated through the simulation of a wide variety of alcohol families: primary alcohols (methanol, ethanol, propan-1-ol, hexan-1-ol, octan-1-ol), secondary alcohols (propan-2-ol), tertiary alcohols (2-methylpropan-2-ol), phenol, and diols (1,2-ethanediol, 1,3-propanediol, 1,5-pentanediol). Monte Carlo simulations carried out in the Gibbs ensemble lead to a good agreement between calculated and experimental data for the thermodynamic properties along the liquid/vapor saturation curve, for the critical point coordinates and for the liquid structure at room temperature. Additional simulations were performed on the methanol + n-butane system showing the capability of the proposed potential to reproduce the azeotropic behavior of such mixtures with a good agreement. PMID:19344171

  1. Determination of direct photolysis rate constants and OH radical reactivity of representative odour compounds in brewery broth using a continuous flow-stirred photoreactor

    Jürgens, Marion; Jacob, Fritz; Ekici, Perihan; Friess, Albrecht; Parlar, Harun

    A method based on photolysis was developed for the appropriate treatment of organic pollutants in air exhausting from breweries upon wort decoction, and thereby causing smell nuisance. A continuous flow stirred photoreactor was built-up exclusively, allowing OH radicals to react with selected odorous compounds contained in exhaust vapours, such as: 2-methylpropanal, 3-methylbutanal, 2-methylbutanal, 3-methyl-1-butanol, n-hexanal, 2-methylbutyl isobutyrate, 2-undecanone, phenyl acetaldehyde, myrcene, limonene, linalool, humulene, dimethylsulphide, and dimethyltrisulphide. These substances were quantified in brewery broth before and after UV irradiation using high-resolution gas chromatography-mass spectrometry (HRGC-MS). For odour analysis, high-resolution gas chromatography-flame ionisation detection (HRGC-FID) coupled with sensory methods was used. Determined quantum yields of about 10 -3 for phenyl acetaldehyde, myrcene, and humulene pointed out that direct photolysis contributed to their decay. Quantum yields of below 10 -4 for the other substances indicated that UV irradiation did not contribute significantly to their degradation processes. Hydroxyl radical reaction rate constants and Henry constants of organic compounds were also measured. Substances accompanied with low Henry constants converted rapidly, whereas those with higher ones, relatively slowly. Determined aroma values concluded that after UV-H 2O 2 treatment, only dimethylsulphide and myrcene remained as important odorous compounds, but in significantly reduced concentrations. The UV-H 2O 2 treatment of brewery broth has been proved effective to reduce smell-irritating substances formed upon wort decoction.

  2. Synthesis and Application of Hybrid Polymer Composites Based on Silver Nanoparticles as Corrosion Protection for Line Pipe Steel

    Ayman M. Atta

    2014-05-01

    Full Text Available A facile method was developed to synthesize in high yield dispersed silver nanoparticles (AgNPs with small particle sizes of less than 10 nm. Silver nitrate was reduced to silver nanoparticles by p-chloroaniline in the presence of polyoxyethylene maleate 4-nonyl-2-propylene-phenol (NMA as a stabilizer. The produced AgNPs were used to prepare hybrid polymer based on N-isopropylacrylamide (NIPAm, 2-acrylamido-2-methylpropane sulfonic acid (AMPS, N,N-methylenebisacrylamide (MBA and potassium persulfate (KPS using a semi-batch solution polymerization method. The prepared AgNPs and hybrid polymer were characterized by Fourier transform infrared (FTIR spectroscopy, X-ray diffraction (XRD patterns and transmission electron microscopy (TEM. The corrosion inhibition activity of the AgNPs and hybrid polymer towards steel corrosion in the presence of hydrochloric acid has been investigated by polarization and electrochemical impedance spectroscopy (EIS methods. Polarization measurements indicate that the AgNPs and hybrid polymer acts as a mixed type-inhibitor and the inhibition efficiency increases with inhibitor concentration. The results of potentiodynamic polarization and EIS measurements clearly showed that the inhibition mechanism involves blocking of the steel surface by inhibitor molecules via adsorption.

  3. Development and characterization of a novel, antimicrobial, sterile hydrogel dressing for burn wounds: single-step production with gamma irradiation creates silver nanoparticles and radical polymerization.

    Boonkaew, Benjawan; Barber, Philip M; Rengpipat, Sirirat; Supaphol, Pitt; Kempf, Margit; He, Jibao; John, Vijay T; Cuttle, Leila

    2014-10-01

    Patients with burn wounds are susceptible to wound infection and sepsis. This research introduces a novel burn wound dressing that contains silver nanoparticles (SNPs) to treat infection in a 2-acrylamido-2-methylpropane sulfonic acid sodium salt (AMPS-Na(+) ) hydrogel. Silver nitrate was dissolved in AMPS-Na(+) solution and then exposed to gamma irradiation to form SNP-infused hydrogels. The gamma irradiation results in a cross-linked polymeric network of sterile hydrogel dressing and a reduction of silver ions to form SNPs infused in the hydrogel in a one-step process. About 80% of the total silver was released from the hydrogels after 72 h immersion in simulated body fluid solution; therefore, they could be used on wounds for up to 3 days. All the hydrogels were found to be nontoxic to normal human dermal fibroblast cells. The silver-loaded hydrogels had good inhibitory action against Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus. Results from a pilot study on a porcine burn model showed that the 5-mM silver hydrogel was efficient at preventing bacterial colonization of wounds, and the results were comparable to the commercially available silver dressings (Acticoat(TM) , PolyMem Silver(®) ). These results support its use as a potential burn wound dressing. PMID:25079080

  4. Comparison of Aroma-Active Volatiles in Oolong Tea Infusions Using GC-Olfactometry, GC-FPD, and GC-MS.

    Zhu, JianCai; Chen, Feng; Wang, LingYing; Niu, YunWei; Yu, Dan; Shu, Chang; Chen, HeXing; Wang, HongLin; Xiao, ZuoBing

    2015-09-01

    The aroma profile of oolong tea infusions (Dongdingwulong, DDWL; Tieguanyin, TGY; Dahongpao, DHP) were investigated in this study. Gas chromatography-olfactometry (GC-O) with the method of aroma intensity (AI) was employed to investigate the aroma-active compounds in tea infusions. The results presented forty-three, forty-five, and forty-eight aroma-active compounds in the TGY, DHP, and DDWL infusions, including six, seven, and five sulfur compounds, respectively. In addition, the concentration of volatile compounds in the tea infusions was further quantitated by solid phase microextraction-gas chromatography (SPME)-GC-MS and SPME-GC-flame photometric detection (FPD). Totally, seventy-six and thirteen volatile and sulfur compounds were detected in three types of tea infusions, respectively. Quantitative results showed that forty-seven aroma compounds were at concentrations higher than their corresponding odor thresholds. On the basis of the odor activity values (OAVs), 2-methylpropanal (OAV: 230-455), 3-methylbutanal (1-353), 2-methylbutanal (34-68), nerolidol (108-184), (E)-2-heptenal (148-294), hexanal (134-230), octanal (28-131), β-damascenone (29-59), indole (96-138), 6-methyl-5-hepten-2-one (34-67), (R)-(-)-linalool (63-87), and dimethyl sulfide (7-1320) presented relatively higher OAVs than those of other compounds, indicating the importance of these compounds in the overall aroma of tea infusions. PMID:26257073

  5. Scale-up of the Reversible Addition-Fragmentation Chain Transfer (RAFT Polymerization Using Continuous Flow Processing

    Nenad Micic

    2014-01-01

    Full Text Available A controlled radical polymerization process using the Reversible Addition-Fragmentation Chain Transfer (RAFT approach was scaled up by a factor of 100 from a small laboratory scale of 5 mL to a preparative scale of 500 mL, using batch and continuous flow processing. The batch polymerizations were carried out in a series of different glass vessels, using either magnetic or overhead stirring, and different modes of heating: Microwave irradiation or conductive heating in an oil bath. The continuous process was conducted in a prototype tubular flow reactor, consisting of 6 mm ID stainless steel tubing, fitted with static mixers. Both reactor types were tested for polymerizations of the acid functional monomers acrylic acid and 2-acrylamido-2-methylpropane-1-sulfonic acid in water at 80 °C with reaction times of 30 to 40 min. By monitoring the temperature during the exothermic polymerization process, it was observed that the type and size of reactor had a significant influence on the temperature profile of the reaction.

  6. Immobilization of yeast cells with ionic hydrogel produced by radiation polymerization

    The mixture of an ionic monomer of 2-acrylamido 2-methylpropane-sulfonic acid and a series of polyethylene glycol dimethacrylate monomer were polymerized at-78 deg C with 60Co γ-rays and were used for immobilization of yeast cells. The immobilized yeast cells with these carriers had higher ethanol productivity than that without any carriers. The yield of ethanol with poly TBAS-14G carrier was the highest, and increased by 3.5 times compared with the free yeast cells. It was found that the ethanol yield increased with the increase of the glycol number in polyethylene glycol dimethacrylate. The state of the immobilized cells was observed with microscope and it was found that the difference in the ethanol productivity was mainly due to the difference in the internal structure and the properties of polymer carrier. It was considered that the polymer carrier had a proper hydrophilicity, swelling ability, cation in the surface and porousity in the internal structure for immobilizing yeast cells

  7. Novel and conventional working fluid mixtures for solar Rankine cycles: Performance assessment and multi-criteria selection

    This work investigates the performance of working fluid mixtures for use in solar ORC (Organic Rankine Cycle systems) with heat storage employing FPC (Flat Plate Collectors). Several mixtures are considered including conventional choices often utilized in ORC as well as novel mixtures previously designed using advanced computer aided molecular design methods (Papadopoulos et al., 2013). The impact of heat source variability on the ORC performance is assessed for different working fluid mixtures. Solar radiation is represented in detail through actual, hourly averaged data for an entire year. A multi-criteria mixture selection methodology unveils important trade-offs among several important system operating parameters and efficiently highlights optimum operating ranges. Such parameters include the ORC thermal efficiency, the net generated power, the volume ratio across the turbine, the mass flow rate of the ORC working fluid, the evaporator temperature glide, the temperature drop in the storage tank, the ORC total yearly operating duration, the required collector aperture area to generate 1 kW of power and the irreversibility. A mixture of neopentane – 2-fluoromethoxy-2-methylpropane at 70% neopentane is found to be the most efficient in all the considered criteria simultaneously. - Highlights: • Investigation of novel and conventional working fluid mixtures for solar ORCs. • Systematic, multi-criteria assessment methodology for mixture selection. • Simultaneous consideration of multiple important mixture performance criteria. • Effects of year-round solar variability in a solar ORC with heat storage tank

  8. Direct nuclear magnetic resonance observation of odorant binding to mouse odorant receptor MOR244-3.

    Burger, Jessica L; Jeerage, Kavita M; Bruno, Thomas J

    2016-06-01

    Mammals are able to perceive and differentiate a great number of structurally diverse odorants through the odorant's interaction with odorant receptors (ORs), proteins found within the cell membrane of olfactory sensory neurons. The natural gas industry has used human olfactory sensitivity to sulfur compounds (thiols, sulfides, etc.) to increase the safety of fuel gas transport, storage, and use through the odorization of this product. In the United States, mixtures of sulfur compounds are used, but the major constituent of odorant packages is 2-methylpropane-2-thiol, also known as tert-butyl mercaptan. It has been fundamentally challenging to understand olfaction and odorization due to the low affinity of odorous ligands to the ORs and the difficulty in expressing a sufficient number of OR proteins. Here, we directly observed the binding of tert-butyl mercaptan and another odiferous compound, cis-cyclooctene, to mouse OR MOR244-3 on living cells by saturation transfer difference (STD) nuclear magnetic resonance (NMR) spectroscopy. This effort lays the groundwork for resolving molecular mechanisms responsible for ligand binding and resulting signaling, which in turn will lead to a clearer understanding of odorant recognition and competition. PMID:27019154

  9. γ-Unsaturated aldehydes as potential Lilial replacers.

    Schroeder, Martin; Mathys, Marion; Ehrensperger, Nadja; Büchel, Michelle

    2014-10-01

    A series of Claisen rearrangements was undertaken in order to find a replacement for Lilial (=3-(4-(tert-butyl)phenyl)-2-methylpropanal), a high-tonnage perfumery ingredient with a lily-of-the-valley odour, which is a CMR2 material [1]. 5,7,7-Trimethyl-4-methyleneoctanal (10), the synthesis of which is described, became the main lead. It possesses an odour which is very close to that of Lilial but lacks its substantivity. Aldehydes with higher molecular weights than that of 10 were, therefore, synthesised in order to boost substantivity and to understand the structural requirements for a 'Lilial' odour. The aldehydes were obtained via Claisen rearrangements of 'exo-methylidene' vinyl ethers, allenyl vinyl ethers, or allenyl allyl ethers. Alternatively, coupling of terminal alkynes with allyl alcohols led to the desired aldehydes. Derivatives of 10 and their sila analogues were also synthesised. The olfactory properties of all synthesised molecules were evaluated for possible structure-odour relationships (SOR). PMID:25329790

  10. Intermolecular Hydrogen Transfer in Isobutane Hydrate

    Takeshi Sugahara

    2012-05-01

    Full Text Available Electron spin resonance (ESR spectra of butyl radicals induced with γ-ray irradiation in the simple isobutane (2-methylpropane hydrate (prepared with deuterated water were investigated. Isothermal annealing results of the γ-ray-irradiated isobutane hydrate reveal that the isobutyl radical in a large cage withdraws a hydrogen atom from the isobutane molecule through shared hexagonal-faces of adjacent large cages. During this “hydrogen picking” process, the isobutyl radical is apparently transformed into a tert-butyl radical, while the sum of isobutyl and tert-butyl radicals remains constant. The apparent transformation from isobutyl to tert-butyl radicals is an irreversible first-order reaction and the activation energy was estimated to be 35 ± 3 kJ/mol, which was in agreement with the activation energy (39 ± 5 kJ/mol of hydrogen picking in the γ-ray-irradiated propane hydrate with deuterated water.

  11. Identification of the degradation pathways of alkanolamines with TiO{sub 2} photocatalysis

    Lu, Chung-Shin, E-mail: cslu6@ntcnc.edu.tw [Department of General Education, National Taichung Nursing College, Taichung 403, Taiwan (China); Chen, Chiing-Chang [Department of Science Application and Dissemination, National Taichung University, Taichung 403, Taiwan (China); Mai, Fu-Der [Department of Biochemistry, School of Medicine, Taipei Medical University, Taipei 110, Taiwan (China); Li, Hua-Kuang [Department of General Education, National Taichung Nursing College, Taichung 403, Taiwan (China)

    2009-06-15

    The present study deals with the photocatalytic degradation of the alkanolamine, 2-dimethylamino-2-methyl-1-propanol (DMAMP), in the presence of TiO{sub 2} particles and UV-A ({lambda} = 365 nm) radiation. The obtained results show complete oxidation of DMAMP after 20 h, and a little over 90% of DMAMP was mineralization after 64-h of treatment. The effects of the solution pH, catalyst loading, and anions on the photocatalytic degradation of DMAMP were investigated, as well as the reaction intermediates that were formed during treatment. To the best of our knowledge, this is the first time that reports the degradation pathways of DMAMP. A number of intermediates were identified by GC/MS techniques during the treatment of DMAMP, following three tentative degradation routes. The first one is based on the oxidation of the primary alcohol group leading to the formation of corresponding aldehyde and carboxylic acid. The second route is based on the rupture of the N-C bond to form 2-methylpropanal and acetone. The last degradation route is based on the cyclization of the {beta}-amino alcohol group to form the oxazolidine derivatives.

  12. Identification of the degradation pathways of alkanolamines with TiO2 photocatalysis

    The present study deals with the photocatalytic degradation of the alkanolamine, 2-dimethylamino-2-methyl-1-propanol (DMAMP), in the presence of TiO2 particles and UV-A (λ = 365 nm) radiation. The obtained results show complete oxidation of DMAMP after 20 h, and a little over 90% of DMAMP was mineralization after 64-h of treatment. The effects of the solution pH, catalyst loading, and anions on the photocatalytic degradation of DMAMP were investigated, as well as the reaction intermediates that were formed during treatment. To the best of our knowledge, this is the first time that reports the degradation pathways of DMAMP. A number of intermediates were identified by GC/MS techniques during the treatment of DMAMP, following three tentative degradation routes. The first one is based on the oxidation of the primary alcohol group leading to the formation of corresponding aldehyde and carboxylic acid. The second route is based on the rupture of the N-C bond to form 2-methylpropanal and acetone. The last degradation route is based on the cyclization of the β-amino alcohol group to form the oxazolidine derivatives.

  13. Fabrication, modeling and optimization of an ionic polymer gel actuator

    The modeling of the electro-active behavior of ionic polymer gel is studied and the optimum conditions that maximize the deflection of the gel are investigated. The bending deformation of polymer gel under an electric field is formulated by using chemo-electro-mechanical parameters. In the modeling, swelling and shrinking phenomena due to the differences in ion concentration at the boundary between the gel and solution are considered prior to the application of an electric field, and then bending actuation is applied. As the driving force of swelling, shrinking and bending deformation, differential osmotic pressure at the boundary of the gel and solution is considered. From this behavior, the strain or deflection of the gel is calculated. To find the optimum design parameter settings (electric voltage, thickness of gel, concentration of polyion in the gel, ion concentration in the solution, and degree of cross-linking in the gel) for bending deformation, a nonlinear constrained optimization model is formulated. In the optimization model, a bending deflection equation of the gel is used as an objective function, and a range of decision variables and their relationships are used as constraint equations. Also, actuation experiments are conducted using poly(2-acrylamido-2-methylpropane sulfonic acid) (PAMPS) gel and the optimum conditions predicted by the proposed model have been verified by the experiments

  14. Configuration control on the shape memory stiffness of molecularly imprinted polymer for specific uptake of creatinine

    Ang, Qian Yee; Zolkeflay, Muhammad Helmi; Low, Siew Chun

    2016-04-01

    In this study, sol-gel processing was proposed to prepare a creatinine (Cre)-imprinted molecularly imprinted polymer (MIP). The intermolecular interaction constituted by the cross-linkers, i.e., 2-acrylamido-2-methylpropane-sulfonic acid (AMPS) and aluminium ion (Al3+), was studied and compared in order to form a confined matrix that promises the effectiveness of molecular imprinting. In view of the shape recognition, the hydrogen bonded Cre-AMPS did not demonstrate good recognition of Cre, with Cre binding found only at 5.70 ± 0.15 mg g-1 of MIP. Whilst, MIP cross-linked using Al3+ was able to attain an excellent Cre adsorption capacity of 19.48 ± 0.64 mg g-1 of MIP via the stronger ionic interaction of Cre-Al3+. Based on the Scatchard analysis, a higher Cre concentration in testing solution required greater driving force to resolve the binding resistance of Cre molecules, so as to have a precise Cre binding with shape factor. The molecular recognition ability of Cre-MIP in present work was shape-specific for Cre as compared to its structural analogue, 2-pyrrolidinone (2-pyr), by an ideal selectivity coefficient of 6.57 ± 0.10. In overall, this study has come up with a practical approach on the preparation of MIP for the detection of renal dysfunction by point-of-care Cre testing.

  15. Metabolism and Disposition of Hepatitis C Polymerase Inhibitor Dasabuvir in Humans.

    Shen, Jianwei; Serby, Michael; Reed, Aimee; Lee, Anthony J; Menon, Rajeev; Zhang, Xiaomei; Marsh, Kennan; Wan, Xia; Kavetskaia, Olga; Fischer, Volker

    2016-08-01

    Dasabuvir [also known as ABT-333 or N-(6-(3-(tert-butyl)-5-(2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)-2-methoxyphenyl)naphthalen-2-yl)methanesulfonamide] is a potent non-nucleoside NS protein 5B polymerase inhibitor of the hepatitis C virus (HCV) and is being developed in combination with paritaprevir/ritonavir and ombitasvir in an oral regimen with three direct-acting antivirals for the treatment of patients infected with HCV genotype 1. This article describes the mass balance, metabolism, and disposition of dasabuvir in humans. After administration of a single oral dose of 400-mg [(14)C]dasabuvir (without coadministration of paritaprevir/ritonavir and ombitasvir) to four healthy male volunteers, the mean total percentage of the administered radioactive dose recovered was 96.6%. The recovery from the individual subjects ranged from 90.8% to 103%. Dasabuvir and corresponding metabolites were predominantly eliminated in feces (94.4% of the dose) and minimally through renal excretion (2.2% of the dose). The biotransformation of dasabuvir primarily involves hydroxylation of the tert-butyl group to form active metabolite M1 [N-(6-(5-(2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)-3-(1-hydroxy-2-methylpropan-2-yl)-2-methoxyphenyl)naphthalen-2-yl)methanesulfonamide], followed by glucuronidation and sulfation of M1 and subsequent secondary oxidation. Dasabuvir was the major circulating component (58% of total radioactivity) in plasma, followed by metabolite M1 (21%). Other minor metabolites represented secondary role in elimination. Cytochrome P450 profiling indicated that dasabuvir was mainly metabolized by CYP2C8, followed by CYP3A4. In summary, the biotransformation pathway and clearance routes of dasabuvir were characterized, and the structures of metabolites in circulation and excreta were elucidated. PMID:27179126

  16. Isobutane as a probe of the structure of 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquids

    Highlights: • The solubility of isobutane was determined in [CnC1Im][NTf2] (n = 2, 4, 6, 8 and 10). • Iso-C4H10 solubility decreases with T and increases with n to reach x = 0.1 (n = 10, T = 303 K). • Isobutane is, on average, 1.6 times less soluble than n-butane in this family of ionic liquids. • Solubility increase with n is due to a more negative enthalpy of dissolution (n ⩾ 6). - Abstract: An experimental study of the solubility and of the thermodynamic properties of solvation, between temperatures (303 and 343) K and at pressures close to atmospheric, of 2-methylpropane (isobutane) in several ionic liquids based on the bis(trifluoromethylsulfonyl)imide anion and on 1-alkyl-3-methylimidazolium cations, [CnC1Im][NTf2], with alkyl side-chains varying from two to ten carbon atoms is presented. The isobutane solubility increases with increasing size of the alkyl side-chain of the cation in the ionic liquid and decreases with increasing temperature (as typical of an exothermal dissolution process). The mole fraction solubility of isobutane varies from 0.904 · 10−2 in [C2C1Im][NTf2] at T = 343 K to 1.002 · 10−1 in [C10C1Im][NTf2] at T = 303 K. The values measured in this work are compared to the behaviour of n-butane in the same ionic liquids published in a previous study (Costa Gomes et al., 2012). Isobutane was found to be significantly less soluble than n-butane in all the ionic liquids. The differences found are interpreted in relation to the molecular structures obtained by molecular dynamics simulations for the solutions of n-butane and isobutane in the studied [CnC1Im][NTf2] ionic liquids

  17. Novel dispersed magnetite core-shell nanogel polymers as corrosion inhibitors for carbon steel in acidic medium

    Graphical abstract: Display Omitted Research highlights: → Through a one-step thermal reaction, magnetite nanoparticles were synthesized, and self-assembled mixed films of modified cross-linked ionic polymer magnetite nanoparticles were prepared on iron surface. → The size distribution and shape of magnetite nanoparticles were examined using transmission electron microscopy (TEM). → The corrosion inhibition efficiency of carbon steel in 1 M HCl by the synthesized Fe3O4 nanogel polymers has been studied using potentiodynamic polarization and EIS. → Scanning electron microscopy (SEM) measurements were applied to study the morphology of the carbon steel surface. - Abstract: Novel core-shell preparing poly(2-acrylamido-2-methylpropane sulfonic acid) (PAMPS) and copolymers with acrylic acid (AA) or acrylamide (AM) magnetic nanogels with controllable particle size produced via free aqueous polymerization at room temperature have been developed for the first time. The crosslinking polymerization was carried out in the presence of N,N'-methylenebisacrylamide (MBA) as a crosslinker, N,N,N',N'-tetramethylethylenediamine (TEMED) and potassium peroxydisulfate (KPS) as redox initiator system. The structure and morphology of the magnetic nanogels were characterized by Fourier transform infrared spectroscopy (FTIR), transmission and scanning electron microscopy (TEM and SEM). The effectiveness of the synthesized compounds as corrosion inhibitors for carbon steel in 1 M HCl was investigated by various electrochemical techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed enhancement in inhibition efficiencies with increasing the inhibitor concentrations and temperatures. The results showed the nanogel particles act as mixed inhibitors. Adsorption of nanogel particles was found to fit the Langmuir isotherm and was chemisorption.

  18. Metal organic framework–organic polymer monolith stationary phases for capillary electrochromatography and nano-liquid chromatography

    Graphical abstract: -- Highlights: •Microwave-assisted synthesis of hybrid metal organic framework (MOF)–polymer monolith. •MOF–polymer monolith was applied to CEC, nano-UHPLC and nano-LC–MS2. •Excellent separation for isomers, aromatic acids and PAHs were achieved. •High sequence coverage for the nano-LC separation tryptic digested BSA peptides. -- Abstract: In this study, metal organic framework (MOF)–organic polymer monoliths prepared via a 5-min microwave-assisted polymerization of ethylene dimethacrylate (EDMA), butyl methacrylate (BMA), and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) with the addition of various weight percentages (30–60%) of porous MOF (MIL-101(Cr)) were developed as stationary phases for capillary electrochromatography (CEC) and nano-liquid chromatography (nano-LC). Powder X-ray diffraction (PXRD) patterns and nitrogen adsorption/desorption isotherms of these MOF–organic polymer monoliths showed the presence of the inherent characteristic peaks and the nano-sized pores of MIL-101(Cr), which confirmed an unaltered crystalline MIL-101(Cr) skeleton after synthesis; while energy dispersive spectrometer (EDS) and micro-FT-IR spectra suggested homogenous distribution of MIL-101(Cr) in the MIL-101(Cr)–poly(BMA–EDMA) monoliths. This hybrid MOF–polymer column demonstrated high permeability, with almost 800-fold increase compared to MOF packed column, and efficient separation of various analytes (xylene, chlorotoluene, cymene, aromatic acids, polycyclic aromatic hydrocarbons and trypsin digested BSA peptides) either in CEC or nano-LC. This work demonstrated high potentials for MOF–organic polymer monolith as stationary phase in miniaturized chromatography for the first time

  19. Metal organic framework–organic polymer monolith stationary phases for capillary electrochromatography and nano-liquid chromatography

    Huang, Hsi-Ya, E-mail: hyhuang@cycu.edu.tw; Lin, Cheng-Lan; Wu, Cheng-You; Cheng, Yi-Jie; Lin, Chia-Her, E-mail: chiaher@cycu.edu.tw

    2013-05-24

    Graphical abstract: -- Highlights: •Microwave-assisted synthesis of hybrid metal organic framework (MOF)–polymer monolith. •MOF–polymer monolith was applied to CEC, nano-UHPLC and nano-LC–MS{sup 2}. •Excellent separation for isomers, aromatic acids and PAHs were achieved. •High sequence coverage for the nano-LC separation tryptic digested BSA peptides. -- Abstract: In this study, metal organic framework (MOF)–organic polymer monoliths prepared via a 5-min microwave-assisted polymerization of ethylene dimethacrylate (EDMA), butyl methacrylate (BMA), and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) with the addition of various weight percentages (30–60%) of porous MOF (MIL-101(Cr)) were developed as stationary phases for capillary electrochromatography (CEC) and nano-liquid chromatography (nano-LC). Powder X-ray diffraction (PXRD) patterns and nitrogen adsorption/desorption isotherms of these MOF–organic polymer monoliths showed the presence of the inherent characteristic peaks and the nano-sized pores of MIL-101(Cr), which confirmed an unaltered crystalline MIL-101(Cr) skeleton after synthesis; while energy dispersive spectrometer (EDS) and micro-FT-IR spectra suggested homogenous distribution of MIL-101(Cr) in the MIL-101(Cr)–poly(BMA–EDMA) monoliths. This hybrid MOF–polymer column demonstrated high permeability, with almost 800-fold increase compared to MOF packed column, and efficient separation of various analytes (xylene, chlorotoluene, cymene, aromatic acids, polycyclic aromatic hydrocarbons and trypsin digested BSA peptides) either in CEC or nano-LC. This work demonstrated high potentials for MOF–organic polymer monolith as stationary phase in miniaturized chromatography for the first time.

  20. TAME5OX, abiotic siderophore analogue to enterobactin involving 8-hydroxyquinoline subunits: Thermodynamic and photophysical studies

    Akbar, Rifat; Baral, Minati; Kanungo, B. K.

    2015-05-01

    The synthesis, thermodynamic and photophysical properties of trivalent metal complexes of biomimetic nonadentate analogue, 5,5‧-(2-(((8-hydroxyquinolin-5-yl)methylamino)methyl)-2-methylpropane-1,3-diyl)bis(azanediyl)bis(methylene)diquinolin-8-ol (TAME5OX), have been described. Combination of absorption and emission spectrophotometry, potentiometry, electrospray mass spectrometry, IR, and theoretical investigation were used to fully characterize metal (Fe+3, Al+3 and Cr+3) chelates of TAME5OX. In solution, TAME5OX forms protonated complexes [M(H3L)]3+ below pH 3.4, which consecutively deprotonates through one to three-proton processes with rise of pH. The formation constants (Log β11n) of neutral complexes formed at or above physiological pH, have been determined to be 30.18, 23.27 and 22.02 with pM values of 31.16, 18.07 and 18.12 for Fe+3, Al+3 and Cr+3 ions, respectively, calculated at pH 7.4, indicating TAME5OX is a powerful among synthetic metal chelator. The results clearly demonstrate that the ligand in a tripodal orchestration firmly binds these ions over wide pH range and forms distorted octahedral complexes. The binding and the coordination event could be monitored from absorption and fluorescence spectroscopy. The high thermodynamic stability in water at physiological pH of ferric complex of TAME5OX indicates that these complexes are resistant to hydrolysis and therefore are well suited for the development of device for applications as probes. The ligand displays high sensitive fluorescence enhancement to Al3+ at pH 7.4, in water. Moreover, TAME5OX can distinguish Al3+ from Fe3+ and Cr3+ via two different sensing mechanisms: photoinduced electron transfer (PET) for Al3+ and internal charge transfer (ICT) for Fe3+ and Cr3+. Density functional theory was employed for optimization and evaluation of vibrational modes, NBO analysis, excitation and emission properties of the different species of metal complexes observed by solution studies.

  1. Singlet molecular oxygen generated in dark biological process.

    Di Mascio, Paolo; Medeiros, Marisa H G

    2014-10-01

    Ultraweak chemiluminescence arising from biomolecules oxidation has been attributed to the radiative deactivation of singlet molecular oxygen [(1)O2] and electronically excited triplet carbonyl products involving dioxetane intermediates. As examples, we will discuss the generation of (1)O2 from lipid hydroperoxides, which involves a cyclic mechanism from a linear tetraoxide intermediate. The generation of (1)O2 in aqueous solution via energy transfer from the excited triplet acetone arising from the thermodecomposition of dioxetane a chemical source, and horseradish peroxidase-catalyzed oxidation of 2-methylpropanal, as an enzymatic source, will also be discussed. The approach used to unequivocally demonstrate the generation of (1)O2 in these reactions is the use of (18)O-labeled hydroperoxide / triplet dioxygen ((18)[(3)O2]), the detection of labeled compounds by HPLC coupled to tandem mass spectrometry (HPLC-MS/MS) and the direct spectroscopic detection and characterization of (1)O2 light emission. Characteristic light emission at 1,270nm, corresponding to the singlet delta state monomolecular decay was observed. Using(18)[(3)O2], we observed the formation of (18)O-labeled (1)O2 ((18)[(1)O2]) by the chemical trapping of (18)[(1)O2]with the anthracene-9,10-diyldiethane-2,1-diyl disulfate disodium salt (EAS) and detected the corresponding (18)O-labeled EAS endoperoxide usingHPLC-MS/MS. The combined use of the thermolysis of a water-soluble naphthalene endoperoxide as a generator of (18)O labeled (1)O2 and the sensitivity of HPLC-MS/MS allowed the study of (1)O2reactivity toward biomolecules. Photoemission properties and chemical trapping clearly demonstrate that the production of hydroperoxide and excited carbonyls generates (18)[(1)O2], and points to the involvement of (1)O2 in physiological and pathophysiological mechanism. Supported by FAPESP (2012/12663-1), CAPES, INCT Redoxoma (FAPESP/CNPq/CAPES; 573530/2008-4), NAP Redoxoma (PRPUSP; 2011.1.9352.1.8), CEPID

  2. Oxidation of dimethyl-ether and ethylene in the atmosphere and combustion environment and thermodynamic studies on hydrofluorocarbons usingab initio calculation methods

    Yamada, Takahiro

    1999-08-01

    Reaction pathways and kinetics are analyzed on CH3OC.H2 unimolecular decay and on the complete CH3OC.H2 + O2 reaction system using thermodynamic properties DHdegf 298,Sdeg 298, and Cp(T) 300 CHEMKIN II is used for numerical integration. Overall agreement of the model data with experimental data is very good. Reaction pathways are analyzed and kinetics are determined on formation and reactions of the adduct resulting from OH addition to ethylene using the above ab initio methods. Hydrogen atom tunneling is included by use of Eckart formalism. Rate constants are compared with experimentally determined product branching ratios (C.H2CH 2OH stabilization: CH2O + CH3: CH3CHO + H). ab initio calculations are performed to estimate thermodynamic properties of nine fluorinated ethane compounds (fluoroethane to hexafluoroethane), eight fluoropropane (1-fluoropropane, 1,1- and 1,2- difluoropropane, 1,1,1- and 1,1,2-trifluoropropane, 1,1,1,2- and 1,1,2,2-tetrafluoropropane and 1,1,1,2,2- pentafluoropropane), and 2-fluoro,2-methylpropane. Standard entropies and heat capacities are calculated using the rigid-rotor-harmonic-oscillator approximation with direct integration over energy levels of the intramolecular rotation potential energy curve. Enthalpies of formation are estimated using G2MP2 total energies and isodesmic reactions. Thermodynamic properties for fluorinated carbon groups C/C/F/H2, C/C/F2/H, C/C/F3, C/C2/F/H, C/C2/F2 and C/C3/F for fluorinated alkane compounds, CD/F/H and CD/F2 for fluorinated alkene compounds and CT/F for fluorinated alkyne compounds are estimated. Fluorine-fluorine interaction terms F/F, 2F/F, 3F/F, 2F/2F, 3F/2F and 3F/3F for alkane compounds, F//F, 2F//F and 2F/2F for alkene compounds, and F///F for alkyne compound are also estimated.

  3. Comparison of different real time VOC measurement techniques in a ponderosa pine forest

    L. Kaser

    2012-10-01

    Full Text Available Volatile organic compound (VOC mixing ratios measured by five independent instruments are compared at a forested site dominated by ponderosa pine (Pinus Ponderosa during the BEACHON-ROCS field study in summer 2010. The instruments included a Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-TOF-MS, a Proton Transfer Reaction Quadrupole Mass Spectrometer (PTR-MS, a Fast Online Gas-Chromatograph coupled to a Mass Spectrometer (GC/MS; TOGA, a Thermal Dissociation Chemical Ionization Mass Spectrometer (PAN-CIMS and a Fiber Laser-Induced Fluorescence Instrument (FILIF. The species discussed in this comparison include the most important biogenic VOCs and a selected suite of oxygenated VOCs that are thought to dominate the VOC reactivity at this particular site as well as typical anthropogenic VOCs that showed low mixing ratios at this site. Good agreement was observed for methanol, the sum of the oxygenated hemiterpene 2-methyl-3-buten-2-ol (MBO and the hemiterpene isoprene, acetaldehyde, the sum of acetone and propanal, benzene and the sum of methyl ethyl ketone (MEK and butanal. Measurements of the above VOCs conducted by different instruments agree within 20%. The ability to differentiate the presence of toluene and cymene by PTR-TOF-MS is tested based on a comparison with GC-MS measurements, suggesting a study-average relative contribution of 74% for toluene and 26% for cymene. Similarly, 2-hydroxy-2-methylpropanal (HMPR is found to interfere with the sum of methyl vinyl ketone and methacrolein (MVK+MAC using PTR-(TOF-MS at this site. A study-average relative contribution of 85% for MVK+MAC and 15% for HMPR was determined. The sum of monoterpenes measured by PTR-MS and PTR-TOF-MS was generally 20–25% higher than the sum of speciated monoterpenes measured by TOGA, which included α-pinene, β-pinene, camphene, carene, myrcene, limonene, cineole as well as other terpenes. However, this difference is consistent throughout the

  4. Comparison of different real time VOC measurement techniques in a ponderosa pine forest

    L. Kaser

    2013-03-01

    Full Text Available Volatile organic compound (VOC mixing ratios measured by five independent instruments are compared at a forested site dominated by ponderosa pine (Pinus Ponderosa during the BEACHON-ROCS field study in summer 2010. The instruments included a Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-TOF-MS, a Proton Transfer Reaction Quadrupole Mass Spectrometer (PTR-MS, a Fast Online Gas-Chromatograph coupled to a Mass Spectrometer (GC/MS; TOGA, a Thermal Dissociation Chemical Ionization Mass Spectrometer (PAN-CIMS and a Fiber Laser-Induced Fluorescence Instrument (FILIF. The species discussed in this comparison include the most important biogenic VOCs and a selected suite of oxygenated VOCs that are thought to dominate the VOC reactivity at this particular site as well as typical anthropogenic VOCs that showed low mixing ratios at this site. Good agreement was observed for methanol, the sum of the oxygenated hemiterpene 2-methyl-3-buten-2-ol (MBO and the hemiterpene isoprene, acetaldehyde, the sum of acetone and propanal, benzene and the sum of methyl ethyl ketone (MEK and butanal. Measurements of the above VOCs conducted by different instruments agree within 20%. The ability to differentiate the presence of toluene and cymene by PTR-TOF-MS is tested based on a comparison with GC-MS measurements, suggesting a study-average relative contribution of 74% for toluene and 26% for cymene. Similarly, 2-hydroxy-2-methylpropanal (HMPR is found to interfere with the sum of methyl vinyl ketone and methacrolein (MVK + MAC using PTR-(TOF-MS at this site. A study-average relative contribution of 85% for MVK + MAC and 15% for HMPR was determined. The sum of monoterpenes measured by PTR-MS and PTR-TOF-MS was generally 20–25% higher than the sum of speciated monoterpenes measured by TOGA, which included α-pinene, β-pinene, camphene, carene, myrcene, limonene, cineole as well as other terpenes. However, this difference is consistent throughout the study

  5. Computer aided screening and evaluation of herbal therapeutics against MRSA infections.

    Skariyachan, Sinosh; Krishnan, Rao Shruti; Siddapa, Snehapriya Bangalore; Salian, Chithra; Bora, Prerana; Sebastian, Denoj

    2011-01-01

    Methicillin resistant Staphylococcus aureus (MRSA), a pathogenic bacterium that causes life threatening outbreaks such as community-onset and nosocomial infections has emerged as 'superbug'. The organism developed resistance to all classes of antibiotics including the best known Vancomycin (VRSA). Hence, there is a need to develop new therapeutic agents. This study mainly evaluates the potential use of botanicals against MRSA infections. Computer aided design is an initial platform to screen novel inhibitors and the data finds applications in drug development. The drug-likeness and efficiency of various herbal compounds were screened by ADMET and docking studies. The virulent factor of most of the MRSA associated infections are Penicillin Binding Protein 2A (PBP2A) and Panton-Valentine Leukocidin (PVL). Hence, native structures of these proteins (PDB: 1VQQ and 1T5R) were used as the drug targets. The docking studies revealed that the active component of Aloe vera, β-sitosterol (3S, 8S, 9S, 10R, 13R, 14S, 17R) -17- [(2R, 5R)-5-ethyl-6-methylheptan-2-yl] -10, 13-dimethyl 2, 3, 4, 7, 8, 9, 11, 12, 14, 15, 16, 17- dodecahydro-1H-cyclopenta [a] phenanthren-3-ol) showed best binding energies of -7.40 kcal/mol and -6.34 kcal/mol for PBP2A and PVL toxin, respectively. Similarly, Meliantriol (1S-1-[ (2R, 3R, 5R)-5-hydroxy-3-[(3S, 5R, 9R, 10R, 13S, 14S, 17S)-3-hydroxy 4, 4, 10, 13, 14-pentamethyl-2, 3, 5, 6, 9, 11, 12, 15, 16, 17-decahydro-1H-cyclopenta[a] phenanthren-17-yl] oxolan-2-yl] -2- methylpropane-1, 2 diol), active compound in Azadirachta indica (Neem) showed the binding energies of -6.02 kcal/mol for PBP2A and -8.94 for PVL toxin. Similar studies were conducted with selected herbal compound based on pharmacokinetic properties. All in silico data tested in vitro concluded that herbal extracts of Aloe-vera, Neem, Guava (Psidium guajava), Pomegranate (Punica granatum) and tea (Camellia sinensis) can be used as therapeutics against MRSA infections. PMID:22125390

  6. Indigenous Georgian wine-associated yeasts and grape cultivars to edit the wine quality in a precision oenology perspective

    Ileana eVigentini

    2016-03-01

    Full Text Available In Georgia, one of the most ancient vine-growing environment, the homemade production of wine is still very popular in every rural family and spontaneous fermentation of must, without addition of chemical preservatives, is the norm. The present work investigated the yeast biodiversity in five Georgian areas (Guria, Imereti, Kakheti, Kartli, Ratcha-Lechkhumi sampling grapes and wines from 22 different native cultivars, in 26 vineyards and 19 family cellars. One hundred and eighty-two isolates were ascribed to 15 different species by PCR-ITS and RFLP, and partial sequencing of D1/D2 domain 26S rDNA gene. Metschnikowia pulcherrima (F’ = 0.56, I’ = 0.32, Hanseniaspora gulliermondii (F’ = 0.49, I’ = 0.27 and Cryptococcus flavescens (F’ = 0.31, I’ = 0.11 were the dominant yeasts found on grapes, whereas Saccharomyces cerevisiae showed the highest prevalence into wine samples. Seventy four isolates with fermentative potential were screened for oenological traits such as ethanol production, resistance to SO2, and acetic acid, glycerol and H2S production. Three yeast strains (Kluyveromyces marxianus UMY207, S. cerevisiae UMY255, Torulaspora delbrueckii UMY196 were selected and separately inoculated in vinifications experiments at a Georgian cellar. Musts were prepared from healthy grapes of local varieties, Goruli Mtsvane (white berry cultivar and Saperavi (black berry cultivar. Physical (°Brix and microbial analyses (plate counts were performed to monitor the fermentative process. The isolation of indigenous S. cerevisiae yeasts beyond the inoculated strains indicated that a co-presence occurred during the vinification tests. Results from quantitative GC-FID analysis of volatile compounds revealed that the highest amount of fermentation flavours, such as 4-ethoxy-4-oxobutanoic acid (monoethyl succinate, 2-methylpropan-1-ol, ethyl 2-hydroxypropanoate and 2-phenylethanol, were significantly more produced in fermentation conducted in Saperavi

  7. Indigenous Georgian Wine-Associated Yeasts and Grape Cultivars to Edit the Wine Quality in a Precision Oenology Perspective.

    Vigentini, Ileana; Maghradze, David; Petrozziello, Maurizio; Bonello, Federica; Mezzapelle, Vito; Valdetara, Federica; Failla, Osvaldo; Foschino, Roberto

    2016-01-01

    In Georgia, one of the most ancient vine-growing environment, the homemade production of wine is still very popular in every rural family and spontaneous fermentation of must, without addition of chemical preservatives, is the norm. The present work investigated the yeast biodiversity in five Georgian areas (Guria, Imereti, Kakheti, Kartli, Ratcha-Lechkhumi) sampling grapes and wines from 22 different native cultivars, in 26 vineyards and 19 family cellars. One hundred and eighty-two isolates were ascribed to 15 different species by PCR-ITS and RFLP, and partial sequencing of D1/D2 domain 26S rDNA gene. Metschnikowia pulcherrima (F' = 0.56, I' = 0.32), Hanseniaspora guilliermondii (F' = 0.49, I' = 0.27), and Cryptococcus flavescens (F' = 0.31, I' = 0.11) were the dominant yeasts found on grapes, whereas Saccharomyces cerevisiae showed the highest prevalence into wine samples. Seventy four isolates with fermentative potential were screened for oenological traits such as ethanol production, resistance to SO2, and acetic acid, glycerol and H2S production. Three yeast strains (Kluyveromyces marxianus UMY207, S. cerevisiae UMY255, Torulaspora delbrueckii UMY196) were selected and separately inoculated in vinifications experiments at a Georgian cellar. Musts were prepared from healthy grapes of local varieties, Goruli Mtsvane (white berry cultivar) and Saperavi (black berry cultivar). Physical (°Brix) and microbial analyses (plate counts) were performed to monitor the fermentative process. The isolation of indigenous S. cerevisiae yeasts beyond the inoculated strains indicated that a co-presence occurred during the vinification tests. Results from quantitative GC-FID analysis of volatile compounds revealed that the highest amount of fermentation flavors, such as 4-ethoxy-4-oxobutanoic acid (monoethyl succinate), 2-methylpropan-1-ol, ethyl 2-hydroxypropanoate, and 2-phenylethanol, were significantly more produced in fermentation conducted in Saperavi variety inoculated

  8. Optimisation and validation of a HS-SPME-GC-IT/MS method for analysis of carbonyl volatile compounds as biomarkers in human urine: Application in a pilot study to discriminate individuals with smoking habits.

    Calejo, Isabel; Moreira, Nathalie; Araújo, Ana Margarida; Carvalho, Márcia; Bastos, Maria de Lourdes; de Pinho, Paula Guedes

    2016-02-01

    A new and simple analytical approach consisting of an automated headspace solid-phase microextraction (HS-SPME) sampler coupled to gas chromatography-ion trap/mass spectrometry detection (GC-IT/MS) with a prior derivatization step with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) was developed to detect volatile carbonyl metabolites with low molecular weights in human urine. A central composite design (CCD) was used to optimise the PFBHA concentration and extraction conditions that affect the efficiency of the SPME procedure. With a sample volume of 1 mL, optimal conditions were achieved by adding 300 mg/L of PFBHA and allowing the sample to equilibrate for 6 min at 62°C and then extracting the samples for 51 min at the same temperature, using a divinylbenzene/polydimethylsiloxane (DVB/PDMS) fibre. The method allowed the simultaneous identification and quantification of 44 carbonyl compounds consisting of aldehydes, dialdehydes, heterocyclic aldehydes and ketones. The method was validated with regards to the linearity, inter- and intra-day precision and accuracy. The detection limits ranged from 0.009 to 0.942 ng/mL, except for 4-hydroxy-2-nonenal (15 ng/mL), and the quantification limits varied from 0.029 to 1.66 ng/mL, except for butanal (2.78 ng/mL), 2-butanone (2.67 ng/mL), 4-heptanone (3.14 ng/mL) and 4-hydroxy-2-nonenal (50.0 ng/mL). The method accuracy was satisfactory, with recoveries ranging from 90 to 107%. The proof of applicability of the methodology was performed in a pilot target analysis of urine samples obtained from 18 healthy smokers and 18 healthy non-smokers (control group). Chemometric supervised analysis was performed using the volatile patterns acquired for these samples and clearly showed the potential of the volatile carbonyl profiles to discriminate urine from smoker and non-smoker subjects. 5-Methyl-2-furfural (p<0.0001), 2-methylpropanal, nonanal and 2-methylbutanal (p<0.05) were identified as potentially useful

  9. Volatile compounds of Domiati cheese made from buffaloe's milk with different fat content.

    El-Mageed, Magda A. Abd

    1997-12-01

    Full Text Available Buffaloe's milk was manufactured to Domiati cheese with different fat content in the cheese milk (1%, 3.5% and 7%. Results obtained during the ripening period revealed that the low fat cheese (Karish is not able to long period storage, while half cream cheese had a good quality and flavour along the ripening period. The full cream cheese did not exceed the first month of ripening, then it deteriorated. The main components found were acrolein (propenal, heptanal, acetone, butan-2 one, ethanol, butan-2 ol, 2-methylpropan- 1-ol, 3-methyl butan-1-ol, ethyl propionate, propyl propionate, pentane and octane. Methyl mercaptan, methyl thiopropionate, and dimethyl trisulfide together with propyl butyrate, were existed in the samples which are characterized as bad cheese samples. Most of the previous compounds were developed after 1 month of ripening period.

    La leche de búfalo fue procesada para obtener queso Domiati con diferente contenido graso en la cuajada (1%, 3.5% y 7%. Los resultados obtenidos durante el período de maduración revelaron que el queso con bajo contenido en grasa (Karish no permite un largo período de almacenamiento, mientras que el queso con un contenido medio en grasa tuvo una buena calidad y flavor durante el período de maduración. El queso con alto contenido graso no duró más que el primer mes de maduración, deteriorándose posteriormente. Los principales componentes encontrados fueron acroleína (propenal, heptanal, acetona, butan-2-ona, etanol, butan-2-ol, 2- metil-propan-1-ol, 3 metil butan-1-ol, propionato de etilo, propionate de propilo, pentano y octano. Metil mercaptol, tiopropionato de metilo y trisulfuro de dimetilo Junto con butirato de propilo se encontraron en muestras que fueron caracterizadas como muestras de quesos malos. La mayoría de los compuestos anteriores se produjeron después de un mes de período de maduración.

  10. Indigenous Georgian Wine-Associated Yeasts and Grape Cultivars to Edit the Wine Quality in a Precision Oenology Perspective

    Vigentini, Ileana; Maghradze, David; Petrozziello, Maurizio; Bonello, Federica; Mezzapelle, Vito; Valdetara, Federica; Failla, Osvaldo; Foschino, Roberto

    2016-01-01

    In Georgia, one of the most ancient vine-growing environment, the homemade production of wine is still very popular in every rural family and spontaneous fermentation of must, without addition of chemical preservatives, is the norm. The present work investigated the yeast biodiversity in five Georgian areas (Guria, Imereti, Kakheti, Kartli, Ratcha-Lechkhumi) sampling grapes and wines from 22 different native cultivars, in 26 vineyards and 19 family cellars. One hundred and eighty-two isolates were ascribed to 15 different species by PCR-ITS and RFLP, and partial sequencing of D1/D2 domain 26S rDNA gene. Metschnikowia pulcherrima (F’ = 0.56, I’ = 0.32), Hanseniaspora guilliermondii (F’ = 0.49, I’ = 0.27), and Cryptococcus flavescens (F’ = 0.31, I’ = 0.11) were the dominant yeasts found on grapes, whereas Saccharomyces cerevisiae showed the highest prevalence into wine samples. Seventy four isolates with fermentative potential were screened for oenological traits such as ethanol production, resistance to SO2, and acetic acid, glycerol and H2S production. Three yeast strains (Kluyveromyces marxianus UMY207, S. cerevisiae UMY255, Torulaspora delbrueckii UMY196) were selected and separately inoculated in vinifications experiments at a Georgian cellar. Musts were prepared from healthy grapes of local varieties, Goruli Mtsvane (white berry cultivar) and Saperavi (black berry cultivar). Physical (°Brix) and microbial analyses (plate counts) were performed to monitor the fermentative process. The isolation of indigenous S. cerevisiae yeasts beyond the inoculated strains indicated that a co-presence occurred during the vinification tests. Results from quantitative GC-FID analysis of volatile compounds revealed that the highest amount of fermentation flavors, such as 4-ethoxy-4-oxobutanoic acid (monoethyl succinate), 2-methylpropan-1-ol, ethyl 2-hydroxypropanoate, and 2-phenylethanol, were significantly more produced in fermentation conducted in Saperavi variety

  11. pH dependent photophysical studies of new europium and terbium complexes of tripodal ligand: Experimental and semiempirical approach

    Akbar, Rifat [Department of Chemistry, Sant Longowal Institute of Engineering & Technology, Longowal, Punjab 148106 (India); Baral, Minati [Department of Chemistry, National Institute of Technology Kurukshetra, Haryana 136119 (India); Kanungo, B K, E-mail: b.kanungo@gmail.com [Department of Chemistry, Sant Longowal Institute of Engineering & Technology, Longowal, Punjab 148106 (India)

    2015-11-15

    The photophysical properties of adduct of a novel nonadentate tripodal ligand, 5,5′-(2-(((8-hydroxyquinolin-5-yl)methylamino)methyl)-2-methylpropane-1, 3-diyl)bis(azanediyl)bis(methylene diquinolin-8-ol, (TAME5OX), with Eu{sup 3+} and Tb{sup 3+} metal ions have been probed for photonics applications. The absorption spectroscopy of these complexes show remarkable spectral changes due to characteristic lanthanide transitions, which support the use of TAME5OX as a sensitive optical pH based sensor to detect Ln{sup 3+} metal ions in biological systems. In addition, these complexes have also been shown to exhibit strong green fluorescence allowing simultaneous sensing within the visible region under physiological pH in competitive medium for both Eu{sup 3+} and Tb{sup 3+} ions. The intense fluorescence from these compounds were revealed to intermittently get quenched under acidic as well as basic conditions due to the photoinduced intramolecular electron transfer from excited 8-hydroxyquinoline (8-HQ) moiety to metal ion, just an opposite process. This renders these compounds the OFF–ON–OFF type of pH-dependent fluorescent sensor. The thermodynamic stability and aqueous coordination chemistry of the chelator with the said lanthanide ions have also been probed by potentiometric, UV–visible and fluorescence spectrophotometric method. TAME5OX has been found to form two protonated complexes [Ln(H{sub 5}L)]{sup 5+} and [Ln(H{sub 4}L)]{sup 4+} below pH 2.5 with both metal ions, which consecutively deprotonates through one proton process with rise of pH. The formation constants (log β{sub 11n}) of neutral complexes have been determined to be 33.51 and 32.16 with pLn (pLn=−log[Ln{sup 3+}]) values of 16.14 and 19.48 for Eu{sup 3+} and Tb{sup 3+} ions, respectively, calculated at pH 7.4, indicating TAME5OX is a good lanthanide synthetic chelator. The emission lifetimes of the Eu{sup 3+} and Tb{sup 3+} complexes recorded in D{sub 2}O and H{sub 2}O suggest the presence

  12. pH dependent photophysical studies of new europium and terbium complexes of tripodal ligand: Experimental and semiempirical approach

    The photophysical properties of adduct of a novel nonadentate tripodal ligand, 5,5′-(2-(((8-hydroxyquinolin-5-yl)methylamino)methyl)-2-methylpropane-1, 3-diyl)bis(azanediyl)bis(methylene diquinolin-8-ol, (TAME5OX), with Eu3+ and Tb3+ metal ions have been probed for photonics applications. The absorption spectroscopy of these complexes show remarkable spectral changes due to characteristic lanthanide transitions, which support the use of TAME5OX as a sensitive optical pH based sensor to detect Ln3+ metal ions in biological systems. In addition, these complexes have also been shown to exhibit strong green fluorescence allowing simultaneous sensing within the visible region under physiological pH in competitive medium for both Eu3+ and Tb3+ ions. The intense fluorescence from these compounds were revealed to intermittently get quenched under acidic as well as basic conditions due to the photoinduced intramolecular electron transfer from excited 8-hydroxyquinoline (8-HQ) moiety to metal ion, just an opposite process. This renders these compounds the OFF–ON–OFF type of pH-dependent fluorescent sensor. The thermodynamic stability and aqueous coordination chemistry of the chelator with the said lanthanide ions have also been probed by potentiometric, UV–visible and fluorescence spectrophotometric method. TAME5OX has been found to form two protonated complexes [Ln(H5L)]5+ and [Ln(H4L)]4+ below pH 2.5 with both metal ions, which consecutively deprotonates through one proton process with rise of pH. The formation constants (log β11n) of neutral complexes have been determined to be 33.51 and 32.16 with pLn (pLn=−log[Ln3+]) values of 16.14 and 19.48 for Eu3+ and Tb3+ ions, respectively, calculated at pH 7.4, indicating TAME5OX is a good lanthanide synthetic chelator. The emission lifetimes of the Eu3+ and Tb3+ complexes recorded in D2O and H2O suggest the presence of water molecules in the first coordination sphere of the metal ions. NMR titrations were carried out

  13. Synthesis of High Molecular Weight Inverse Emulsion Polymer Resistant to Temperature and Salt%高相对分子质量反相乳液耐温抗盐聚合物合成研究

    雷齐玲

    2015-01-01

    在概述反相乳液聚合物合成进展的基础上,对提高其相对分子质量和改进耐温性进行了研究.通过优选耐温单体提高产物耐温性,通过优选合成条件提高产物相对分子质量.选用丙烯酸(AA)、丙烯酰胺(AM) 和2-丙烯酰氨基-2-甲基丙磺酸(AMPS) 为水溶性单体,以液体石蜡为油相,以过硫酸盐为引发剂,采用反相乳液共聚法合成了AA/AM/AMPS反相乳液耐温抗盐聚合物.试验发现,乳化剂最佳用量为8%,最佳油水比为1:1,最佳引发温度为20℃,在此条件下合成的反相乳液耐温抗盐聚合物相对分子质量可达1500×104.在90℃矿化度为32868mg/L的水中,7天内产物黏度保留率较常规聚丙烯酰胺高出59%; 溶解时间仅为常规聚丙烯酰胺的1/7,具有较好的耐温抗盐性能和溶解性.研究结果对现阶段反相乳液聚合物性能的提高具有借鉴作用.%Summing up the progress of inverse emulsion polymer synthesis, enhancing molecular weight and high temperature resistance was probed into in this paper. Temperature resistance of product was enhanced by selecting temperature resistant monomer, and molecular weight of product by optimizing synthesis conditions. Selecting acrylic acid (AA), acrylamide (AM), 2- acrylamido-2-methylpropane sulfonic acid (AMPS) as water-soluble monomer, liquid paraffin as oil phase, the persulfate as initiator, inverse emulsion copolymerization was used for synthesizing AA / AM / AMPS inverse emulsion poly-mer resistant to temperature and salt. Test showed that the optimum amount of emulsifier was 8%, the best oil-water ratio was 1. 1:1, the best initiation temperature was 20℃, and the molecular weight of inverse emulsion polymer resistant to tem-perature and salt could reach 1500×104. In water of 90℃and 32868mg/L salinity, the product viscosity retention rate was 59% higher than conventional polyacrylamide within 7 days, but dissolution time was only 1/7 of conventional polyacrylam

  14. 抗盐降失水剂HTF-110L的研制及性能评价%Synthesis and Properties Evaluation of Salt Resistant Fluid Loss Additive HTF-110L

    郭锦棠; 骆成; 余前峰; 刘硕琼; 靳建州; 于永金

    2015-01-01

    针对目前固井降失水剂所存在的抗高温抗盐能力差、温度适应范围窄的问题,以2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、丙烯酰胺(AM)、丙烯酸(AA)为主要单体,并引入新型多羟基羧酸化合物,采用自由基水溶液共聚合成了抗温、抗盐、温度适应范围广的降失水剂 HTF-110L.采用正交实验法,优选出了最佳合成工艺条件.采用红外光谱、核磁共振和热失重分析对共聚物进行了表征.结果表明:各单体成功参与聚合,聚合产物为目标产物,降失水剂耐温性能良好;由于在共聚物分子链中引入了多种功能性基团,合成的降失水剂在淡水、盐水水泥浆中具有良好的降失水性能;降失水剂分散性弱,在高温条件下对水泥浆的稳定性影响较小,低温条件下缓凝性弱,对水泥石强度发展无不良影响,具有较宽的温度适用范围;降失水剂与其他油井水泥外加剂配伍性好,以 HTF-110L 为主剂的低密度、高密度水泥浆体系具有失水量小、流变性好、稳定性佳、过渡时间短、抗压强度高等特点,综合性能优异.%The currently used cement fluid loss additive has the problems of weak salt tolerance,poor thermal stabil-ity and narrow range of temperature adaptation. To solve the problems,a novel high temperature-resistant,salt-tolerant and wide-range-of-temperature-applied fluid loss additive HTF-110L was synthesized by using the monomers of 2-acrylamido-2-methylpropane sulfonic acid(AMPS),acrylamide(AM),acrylic acid(AA)and poly-hydroxyls carboxylic acid with the method of aqueous solution polymerization. Optimal synthesizing process conditions of HTF-110L were extracted by orthogonal experiment. The synthetic fluid loss additive was characterized by Fourier trans-form infrared spectroscopy,proton nuclear magnetic resonance spectroscopy and thermogravimetric analysis. The analysis results reveal that the polymer is the target