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Sample records for electron-deficient olefins scope

  1. Reactions of Fischer carbene complexes with Electron-deficient olefins: Scope and limitations of this route to donor-acceptor-substituted cyclopropanes

    Energy Technology Data Exchange (ETDEWEB)

    Wienand, A.; Reissig, H.U. (Inst. fuer Organische Chemie der Technischen Hochschule Darmstadt (West Germany))

    1990-12-01

    The Fischer carbene complex ((CO){sub 5}Cr{double bond}C(OMe)Ph) (1) is able to transfer its carbene ligand to a variety of electron-deficient olefins and provides donor-acceptor-substituted cyclopropanes in good yields. Apt activating groups with respect to the alkene are ester, amide, nitrile, sulfone, and dialkyl phosphonate functions. Methyl vinyl ketone (19) affords products in low yield that may arise from an intermediate cyclopropane derivative. Phenyl vinyl sulfoxide (24) mainly acts as an oxidizing agent, transforming 1 into methyl benzoate. for olefin 24 and {alpha}-(N-methylanilino)acrylonitrile the authors found products that should be formed on an olefin metathesis pathway. The methyl-substituted carbene complex 48 also affords the expected donor-acceptor-substituted cyclopropanes; however, acyclic isomers are formed in higher amounts. The molybdenum and tungsten complexes 55 and 56, respectively, also furnish cyclopropane derivatives, but the yields are lower than with the chromium compound 1. Disubstituted olefins and complex 1 still give the cyclopropanes in moderate yields, while all trisubstituted and most of the difunctionalized alkenes do not react with this Fischer carbene complex. The cyclopropanes synthesized can be deprotonated and alkylated or transformed into ring-opened products. These model reactions demonstrate the synthetic potentials of donor-acceptor-substituted cyclopropanes prepared via Fischer carbene complexes.

  2. Pd(II)-Catalyzed Olefination of Electron-Deficient Arenes Using 2,6-Dialkylpyridine Ligands

    Science.gov (United States)

    Zhang, Yang-Hui; Shi, Bing-Feng; Yu, Jin-Quan

    2009-01-01

    Pd(II)-catalyzed meta-olefination of highly electron deficient arenes is achieved through the use of a rationally designed mutually repulsive ligand. The combination of directed and non-directed C–H functionalization of arenes provides a versatile route for the synthesis of highly sought-after 1,2,4-trisubstituted arenes. PMID:19296661

  3. Olefination of Electron-Deficient Alkenes with Allyl Acetate: Stereo- and Regioselective Access to (2Z,4E)-Dienamides.

    Science.gov (United States)

    Li, Feifei; Yu, Chunbing; Zhang, Jian; Zhong, Guofu

    2016-09-16

    A Ru-catalyzed direct olefination of electron-deficient alkenes with allyl acetate via C-H bond activation is disclosed. By using N,N-disubstituted aminocarbonyl as the directing group, this external oxidant-free protocol resulted in high reaction efficiency and good stereo- and regioselectivities, which opens a novel synthetic passway for access to (Z,E)-butadiene skeletons.

  4. Photochemical reactions of electron-deficient olefins with N,N,N',N'-tetramethylbenzidine via photoinduced electron-transfer

    International Nuclear Information System (INIS)

    Pan Yang; Zhao Junshu; Ji Yuanyuan; Yan Lei; Yu Shuqin

    2006-01-01

    Photoinduced electron transfer reactions of several electron-deficient olefins with N,N,N',N'-tetramethylbenzidine (TMB) in acetonitrile solution have been studied by using laser flash photolysis technique and steady-state fluorescence quenching method. Laser pulse excitation of TMB yields 3 TMB* after rapid intersystem crossing from 1 TMB*. The triplet which located at 480 nm is found to undergo fast quenching with the electron acceptors fumaronitrile (FN), dimethyl fumarate (DMF), diethyl fumarate (DEF), cinnamonitrile (CN), α-acetoxyacrylonitrile (AAN), crotononitrile (CrN) and 3-methoxyacrylonitrile (MAN). Substituents binding to olefin molecule own different electron-donating/withdrawing powers, which determine the electron-deficient property (π-cloud density) of olefin molecule as well as control the electron transfer rate constant directly. The detection of ion radical intermediates in the photolysis reactions confirms the proposed electron transfer mechanism, as expected from thermodynamics. The quenching rate constants of triplet TMB by these olefins have been determined at 510 nm to avoid the disturbance of formed TMB cation radical around 475 nm. All the k q T values approach or reach to the diffusion-controlled limit. In addition, fluorescence quenching rate constants k q S have been also obtained by calculating with Stern-Volmer equation. A correlation between experimental electron transfer rate constants and free energy changes has been explained by Marcus theory of adiabatic outer-sphere electron transfer. Disharmonic k q values for CN and CrN in endergonic region may be the disturbance of exciplexs formation. e of exciplex formation

  5. Oxidative Olefination of Anilides with Unactivated Alkenes Catalyzed by an (Electron-Deficient η(5) -Cyclopentadienyl)Rhodium(III) Complex Under Ambient Conditions.

    Science.gov (United States)

    Takahama, Yuji; Shibata, Yu; Tanaka, Ken

    2015-06-15

    The oxidative olefination of sp(2) C-H bonds of anilides with both activated and unactivated alkenes using an (electron-deficient η(5) -cyclopentadienyl)rhodium(III) complex is reported. In contrast to reactions using this electron-deficient rhodium(III) catalyst, [Cp*RhCl2 ]2 showed no activity against olefination with unactivated alkenes. In addition, the deuterium kinetic isotope effect (DKIE) study revealed that the C-H bond cleavage step is thought to be the turnover-limiting step. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Facile Preparation of (2Z,4E)-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate.

    Science.gov (United States)

    Ding, Liyuan; Yu, Chunbing; Zhao, Zhenqiang; Li, Feifei; Zhang, Jian; Zhong, Guofu

    2017-06-21

    Direct cross-coupling between two alkenes via vinylic C-H bond activation represents an efficient strategy for the synthesis of butadienes with high atomic and step economy. However, this functionality-directed cross-coupling reaction has not been developed, as there are still limited directing groups in practical use. In particular, a stoichiometric amount of oxidant is usually required, producing a large amount of waste. Due to our interest in novel 1,3-butadiene synthesis, we describe the ruthenium-catalyzed olefination of electron-deficient alkenes using allyl acetate and without external oxidant. The reaction of 2-phenyl acrylamide and allyl acetate was chosen as a model reaction, and the desired diene product was obtained in 80% isolated yield with good stereoselectivity (Z,E/Z,Z = 88:12) under optimal conditions: [Ru(p-cymene) Cl2]2 (3 mol %) and AgSbF6 (20 mol %) in DCE at 110 ºC for 16 h. With the optimized catalytic conditions in hand, representative α- and/or β-substituted acrylamides were investigated, and all reacted smoothly, regardless of aliphatic or aromatic groups. Also, differently N-substituted acrylamides have proven to be good substrates. Moreover, we examined the reactivity of different allyl derivatives, suggesting that the chelation of acetate oxygen to the metal is crucial for the catalytic process. Deuterium-labeled experiments were also conducted to investigate the reaction mechanism. Only Z-selective H/D exchanges on acrylamide were observed, indicating a reversible cyclometalation event. In addition, a kinetic isotope effect (KIE) of 3.2 was observed in the intermolecular isotopic study, suggesting that the olefinic C-H metalation step is probably involved in the rate-determining step.

  7. Photochemical reactions of electron-deficient olefins with N,N,N',N'-tetramethylbenzidine via photoinduced electron-transfer

    Energy Technology Data Exchange (ETDEWEB)

    Pan Yang [Laboratory of Bond-selective Chemistry, Department of Chemical Physics, University of Science and Technology of China, No. 96 of Jinzhai Road, Hefei, Anhui 230026 (China); Zhao Junshu [Laboratory of Bond-selective Chemistry, Department of Chemical Physics, University of Science and Technology of China, No. 96 of Jinzhai Road, Hefei, Anhui 230026 (China); Ji Yuanyuan [Laboratory of Bond-selective Chemistry, Department of Chemical Physics, University of Science and Technology of China, No. 96 of Jinzhai Road, Hefei, Anhui 230026 (China); Yan Lei [Laboratory of Bond-selective Chemistry, Department of Chemical Physics, University of Science and Technology of China, No. 96 of Jinzhai Road, Hefei, Anhui 230026 (China); Yu Shuqin [Laboratory of Bond-selective Chemistry, Department of Chemical Physics, University of Science and Technology of China, No. 96 of Jinzhai Road, Hefei, Anhui 230026 (China)], E-mail: sqyu@ustc.edu.cn

    2006-01-05

    Photoinduced electron transfer reactions of several electron-deficient olefins with N,N,N',N'-tetramethylbenzidine (TMB) in acetonitrile solution have been studied by using laser flash photolysis technique and steady-state fluorescence quenching method. Laser pulse excitation of TMB yields {sup 3}TMB* after rapid intersystem crossing from {sup 1}TMB*. The triplet which located at 480 nm is found to undergo fast quenching with the electron acceptors fumaronitrile (FN), dimethyl fumarate (DMF), diethyl fumarate (DEF), cinnamonitrile (CN), {alpha}-acetoxyacrylonitrile (AAN), crotononitrile (CrN) and 3-methoxyacrylonitrile (MAN). Substituents binding to olefin molecule own different electron-donating/withdrawing powers, which determine the electron-deficient property ({pi}-cloud density) of olefin molecule as well as control the electron transfer rate constant directly. The detection of ion radical intermediates in the photolysis reactions confirms the proposed electron transfer mechanism, as expected from thermodynamics. The quenching rate constants of triplet TMB by these olefins have been determined at 510 nm to avoid the disturbance of formed TMB cation radical around 475 nm. All the k{sub q}{sup T} values approach or reach to the diffusion-controlled limit. In addition, fluorescence quenching rate constants k{sub q}{sup S} have been also obtained by calculating with Stern-Volmer equation. A correlation between experimental electron transfer rate constants and free energy changes has been explained by Marcus theory of adiabatic outer-sphere electron transfer. Disharmonic k{sub q} values for CN and CrN in endergonic region may be the disturbance of exciplexs formation. e of exciplex formation.

  8. Visible-Light Photoredox-Catalyzed Giese Reaction: Decarboxylative Addition of Amino Acid Derived α-Amino Radicals to Electron-Deficient Olefins

    KAUST Repository

    Millet, Anthony; Lefebvre, Quentin; Rueping, Magnus

    2016-01-01

    A tin- and halide-free, visible-light photoredox-catalyzed Giese reaction was developed. Primary and secondary α-amino radicals were generated readily from amino acids in the presence of catalytic amounts of an iridium photocatalyst. The reactivity of the α-amino radicals has been evaluated for the functionalization of a variety of activated olefins. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  9. Visible-Light Photoredox-Catalyzed Giese Reaction: Decarboxylative Addition of Amino Acid Derived α-Amino Radicals to Electron-Deficient Olefins

    KAUST Repository

    Millet, Anthony

    2016-06-20

    A tin- and halide-free, visible-light photoredox-catalyzed Giese reaction was developed. Primary and secondary α-amino radicals were generated readily from amino acids in the presence of catalytic amounts of an iridium photocatalyst. The reactivity of the α-amino radicals has been evaluated for the functionalization of a variety of activated olefins. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  10. 1-acetylvinyl acrylates: new captodative olefins bearing an internal probe for the evaluation of the relative reactivity of captodative against electron-deficient double bonds in Diels-Alder and Friedel-Crafts reactions

    International Nuclear Information System (INIS)

    Herrera, Rafael; Universidad Michoacana de San Nicolas de Hidalgo, Morelia, Mich.; Jimenez-Vazquez, Hugo A.; Delgado, Francisco; Tamariz, Joaquin; Soederberg, Bjoern C.G.

    2005-01-01

    The captodative olefins 1-acetylvinyl esters of methacrylic and trans-crotonic acids, 3a and 3b, have been prepared. The presence of a second double bond in the molecule, acting as an internal probe, allowed us to compare their relative reactivity in Diels-Alder and Friedel-Crafts reactions. The reactivity was evaluated with cyclopentadiene (6) as diene in Diels-Alder cycloadditions, and with furan (9) and thiophene (10) as heteroaromatic Friedel-Crafts substrates. In both processes, the captodative enone double bond proved to be more reactive than that in the acrylic moiety. FMO theory accounted for this chemo selectivity as a consequence of the major π contribution of the enone to the LUMO of these molecules. The slight exo stereoselectivity observed in the cycloaddition to 6 parallels the higher stability of the corresponding transition state, according to the results of B3LYP/6-311G(d,p) calculations. (author)

  11. Synthesis of o-Alkenylated 2-Arylbenzoxazoles via Rh-Catalyzed Oxidative Olefination of 2-Arylbenzoxazoles: Scope Investigation, Structural Features, and Mechanism Studies.

    Science.gov (United States)

    Zhou, Quan; Zhang, Jing-Fan; Cao, Hui; Zhong, Rui; Hou, Xiu-Feng

    2016-12-16

    2-Arylbenzazoles are promising molecules for potential applications in medicine and material areas. Efficient protocols for direct regioselective functionalization of 2-arylbenzoxazoles are in high demand. Herein, we disclose a general method for selective ortho-olefination of 2-arylbenzo[d]oxazoles with alkenes enabled by versatile Cp*Rh(III) in high yields. This protocol features broad functional group tolerance and high regioselectivity. Intermolecular competition studies and kinetic isotope effect experiments imply that the oxidative olefination process occurs via an electrophilic C-H activation pathway. The molecular structure of the m-fluoro-substituted olefination product confirms regioselective C-H activation/olefination at the more hindered site in cases where the meta F atom or heteroatom substituent existed. Apparent torsion angles were observed in the structures of mono- and bis-olefination products, which resulted in distinct different chemical shifts of olefinic protons. Additionally, two gram-scale reactions and further transformation experiments demonstrate that this method is practical for synthesis of ortho-alkenylated 2-arylbenzoxazole derivatives.

  12. Production of olefins from bioethanol. Catalysts, mechanism

    Directory of Open Access Journals (Sweden)

    Kusman Dossumov

    2012-12-01

    Full Text Available This review describes methods of catalytic obtaining from bioethanol of valuable industrial products – olefins, particularly ethylene. Аmong olefins, ethylene is the most popular key raw material of petrochemical synthesis. The scope of appllication of ethylene is almost unlimited in petrochemical products: polyethylene, ethylbenzene, styrene, ethylene dichloride, vinyl chloride etc. It also examines catalysts for the production of olefins and their properties. The most promising and commercially advantageous process of ethylene production by catalytic dehydration of ethanol on catalysts based on modified alumina. And this review discusses the mechanisms of catalytic conversion of ethanol to ethylene.

  13. Enantioselective 1,3-dipolar cycloadditions of diazoacetates with electron-deficient olefins.

    Science.gov (United States)

    Sibi, Mukund P; Stanley, Levi M; Soeta, Takahiro

    2007-04-12

    [reaction: see text] A general strategy for highly enantioselective 1,3-dipolar cycloaddition of diazoesters to beta-substituted, alpha-substituted, and alpha,beta-disubstituted alpha,beta-unsaturated pyrazolidinone imides is described. Cycloadditions utilizing less reactive alpha,beta-disubstituted dipolarophiles require elevated reaction temperatures, but still provide the corresponding pyrazolines with excellent enantioselectivities. Finally, an efficient synthesis of (-)-manzacidin A employing this cycloaddition methodology as a key step is illustrated.

  14. Pd(II)-Catalyzed Hydroxyl-Directed C–H Olefination Enabled by Mono-Protected Amino Acid Ligands

    Science.gov (United States)

    Lu, Yi; Wang, Dong-Hui; Engle, Keary M.

    2010-01-01

    A novel Pd(II)-catalyzed ortho-C–H olefination protocol has been developed using spatially remote, unprotected tertiary, secondary, and primary alcohols as the directing groups. Mono-N-protected amino acid ligands were found to promote the reaction, and an array of olefin coupling partners could be used. When electron-deficient alkenes were used, the resulting olefinated intermediates underwent subsequent Pd(II)-catalyzed oxidative intramolecular cyclization to give the corresponding pyran products, which could be converted into ortho-alkylated alcohols under hydrogenolysis conditions. The mechanistic details of the oxidative cyclization step are discussed and situated in the context of the overall catalytic cycle. PMID:20359184

  15. Catalytic asymmetric dihydroxylation of olefins with reusable OsO(4)(2-) on ion-exchangers: the scope and reactivity using various cooxidants.

    Science.gov (United States)

    Choudary, Boyapati M; Chowdari, Naidu S; Jyothi, Karangula; Kantam, Mannepalli L

    2002-05-15

    Exchanger-OsO(4) catalysts are prepared by an ion-exchange technique using layered double hydroxides and quaternary ammonium salts covalently bound to resin and silica as ion-exchangers. The ion-exchangers with different characteristics and opposite ion selectivities are specially chosen to produce the best heterogeneous catalyst that can operate using the various cooxidants in the asymmetric dihydroxylation reaction. LDH-OsO(4) catalysts composed of different compositions are evaluated for the asymmetric dihydroxylation of trans-stilbene. Resin-OsO(4) and SiO(2)-OsO(4) designed to overcome the problems associated with LDH-OsO(4) indeed show consistent activity and enantioselectivity in asymmetric dihydroxylation of olefins using K(3)Fe(CN)(6) and molecular oxygen as cooxidants. Compared to the Kobayashi heterogeneous systems, resin-OsO(4) is a very efficient catalyst for the dihydroxylation of a wide variety of aromatic, aliphatic, acyclic, cyclic, mono-, di-, and trisubstituted olefins to afford chiral vicinal diols with high yields and enantioselectivities irrespective of the cooxidant used. Resin-OsO(4) is recovered quantitatively by a simple filtration and reused for a number of cycles with consistent activity. The high binding ability of the heterogeneous osmium catalyst enables the use of an equimolar ratio of ligand to osmium to give excellent enantioselectives in asymmetric dihydroxylation in contrast to the homogeneous osmium system in which excess molar quantities of the expensive chiral ligand to osmium are invariably used. The complexation of the chiral ligand (DHQD)(2)PHAL, having very large dimension, a prerequisite to obtain higher ee, is possible only with the OsO(4)(2-) located on the surface of the supports.

  16. Rhodium-Catalyzed Regioselective C7-Olefination of Indazoles Using an N-Amide Directing Group.

    Science.gov (United States)

    Guo, Lei; Chen, Yanyu; Zhang, Rong; Peng, Qiujun; Xu, Lanting; Pan, Xianhua

    2017-02-01

    A rhodium-catalyzed regioselective C-H olefination of indazole is described. This protocol relies on the use of an efficient and removable N,N-diisopropylcarbamoyl directing group, which offers facile access to C7-olefinated indazoles with high regioselectivity, ample substrate scope and broad functional group tolerance. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Olefin Autoxidation in Flow

    OpenAIRE

    Neuenschwander Ulrich; Jensen Klavs F.

    2014-01-01

    Handling hazardous multiphase reactions in flow brings not only safety advantages but also significantly improved performance due to better mass transfer characteristics. In this paper we present a continuous microreactor setup capable of performing olefin autoxidations with O2 under solvent free and catalyst free conditions. Owing to the transparent reactor design consumption of O2 can be visually followed and exhaustion of the gas bubbles marks a clear end point along the channel length coo...

  18. Base-catalyzed tandem Michael/dehydro-Diels-Alder reaction of α,α-dicyanoolefins with electron-deficient 1,3-conjugated enynes: a facile entry to angularly fused polycycles.

    Science.gov (United States)

    Zhang, Mingrui; Zhang, Junliang

    2014-01-07

    Angularly fused carbocyclic frameworks and their heteroatom-substituted analogues exist in many natural products that display a broad and interesting range of biological activities. Preparation of polycyclic products by cycloaddition reactions have been the long-standing hot topic in the synthetic community. Dehydro-Diels-Alder (DDA) reactions are one class of dehydropericyclic reactions that are derived conceptually by systematic removal of hydrogen atom pairs. A base-promoted tandem Michael addition and DDA reaction of α,α-dicyanoolefins with electron-deficient 1,3-conjugated enynes was realized in which a DDA reaction takes place between the arylalkynes and electron-deficient tetrasubstituted olefin. The control experiments support the stepwise anionic reaction pathway rather than the concerted reaction pathway. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Synthetic and mechanistic aspects of titanium-mediated carbonyl olefinations

    Energy Technology Data Exchange (ETDEWEB)

    Petasis, N.A.; Staszewski, J.P.; Hu, Yong-Han; Lu, Shao-Po [Univ. of Southern California, Los Angeles, CA (United States)

    1995-12-31

    A new method for the olefination of carbonyl compounds with dimethyl titanocene, and other related bishydrocarbyl titanocene derivatives has been recently developed in the author`s laboratories. This process is experimentally convenient and works with various types of carbonyl compounds, including aldehydes, ketones, esters, lactones, carbonates, anhydrides, amides, imides, lactams, thioesters, selenoesters, and acylsilanes. More recent studies have focused on the scope and utility of this reaction, including mechanistic studies and synthetic applications. In addition to varying the reaction conditions, the authors have examined several mixed titanocene derivatives and have found ways for carrying out this type of olefination at room temperature, such as the use of tris(trimethylsilyl) titanacyclobutene. The authors have also employed this reaction in the modification of carbohydrates and cyclobutenediones. This olefination was also followed-up with subsequent transformations to produce carbocycles and heterocycles, including tetrahydrofurans and tetrahydropyrans.

  20. Olefin metathesis in air

    Directory of Open Access Journals (Sweden)

    Lorenzo Piola

    2015-10-01

    Full Text Available Since the discovery and now widespread use of olefin metathesis, the evolution of metathesis catalysts towards air stability has become an area of significant interest. In this fascinating area of study, beginning with early systems making use of high oxidation state early transition metal centers that required strict exclusion of water and air, advances have been made to render catalysts more stable and yet more functional group tolerant. This review summarizes the major developments concerning catalytic systems directed towards water and air tolerance.

  1. Atmosphere-Controlled Chemoselectivity: Rhodium-Catalyzed Alkylation and Olefination of Alkylnitriles with Alcohols.

    Science.gov (United States)

    Li, Junjun; Liu, Yuxuan; Tang, Weijun; Xue, Dong; Li, Chaoqun; Xiao, Jianliang; Wang, Chao

    2017-10-17

    The chemoselective alkylation and olefination of alkylnitriles with alcohols have been developed by simply controlling the reaction atmosphere. A binuclear rhodium complex catalyzes the alkylation reaction under argon through a hydrogen-borrowing pathway and the olefination reaction under oxygen through aerobic dehydrogenation. Broad substrate scope is demonstrated, permitting the synthesis of some important organic building blocks. Mechanistic studies suggest that the alkylation product may be formed through conjugate reduction of an alkene intermediate by a rhodium hydride, whereas the formation of olefin product may be due to the oxidation of the rhodium hydride complex with molecular oxygen. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Palladium catalyzed selective distal C-H olefination of biaryl systems.

    Science.gov (United States)

    Maity, Soham; Hoque, Ehtasimul; Dhawa, Uttam; Maiti, Debabrata

    2016-11-29

    Palladium catalyzed selective distal C-H activation with nitrile based templates has been of significant research interest in recent times. In this report, we disclose the distal C-H olefination of biphenyl systems with high regio- and stereo-selectivity and useful synthetic yields. The utility of this method has been demonstrated through its wide olefin scope, its operation at the gram scale and the easy removal/recovery of the directing group.

  3. Isobutane/olefin-alkylation

    Energy Technology Data Exchange (ETDEWEB)

    Waitkamp, J.; Maixner, S.

    1983-11-01

    Isobutane/olefin-alkylation - technology and reaction mechanism of a refinery process for production of high octane gasoline components: The alkylation of i-butane with olefins, especially with butenes, is a process for the conversion of light byproducts of a catalytic cracker to high quality gasoline components. Alkylate is a complex mixture of i-paraffins containing 5 to ca. 12 carbon atoms. Due to their octane numbers the four trimethylpentane isomers are the most desirable product components. Indeed, under optimum process conditions these isomers are the main products. Presently, alkylation capacity in the western world amounts to more than 40x10/sup 6/ t/a. Most units are located in the USA. Two liquid-phase processes using sulfuric acid and hydrofluoric acid, respectively, are of commercial importance. At present, there is a definite trend towards HF-alkylation. The reaction mechanism which proceeds via carbocations, is extremely complex. It is composed of a great variety of individual steps. Modern mechanistic concepts are discussed.

  4. Olefin metathesis and metathesis polymerization

    CERN Document Server

    Ivin, K J

    1997-01-01

    This book is a follow-up to Ivins Olefin Metathesis, (Academic Press, 1983). Bringing the standard text in the field up to date, this Second Edition is a result of rapid growth in the field, sparked by the discovery of numerous well-defined metal carbene complexes that can act as very efficient initiators of all types of olefin metathesis reaction, including ring-closing metathesis of acyclic dienes, enynes, and dienynes; ring-opening metathesis polymerizationof cycloalkenes, acyclic diene metathesis polymerization; and polymerization of alkynes, as well as simple olefin metathesis. Olefin Metathesis and Metathesis Polymerization provides a broad, up-to-date account of the subject from its beginnings in 1957 to the latest applications in organic synthesis. The book follows the same format as the original, making it useful toteachers and to researchers, and will be of particular interest to those working in the fields of organic chemistry, polymer chemistry, organometallic chemistry, catalysis, materials scien...

  5. Metylcyclohexane conversion to light olefins

    Directory of Open Access Journals (Sweden)

    SCOFIELD C.F.

    1998-01-01

    Full Text Available This study consists in the evaluation of the catalytic properties of zeolites with different structures in the conversion of methylcyclohexane to light olefins. Results obtained suggest that the steric constrictions of the catalysts used play an important role in hydrogen transfer reactions. Higher selectivities for light olefins (C3= and C4= were observed for zeolites having more closed structures, like MFI and ferrerite, when compared to those having more open ones, like beta, omega and faujasite.

  6. Metylcyclohexane conversion to light olefins

    OpenAIRE

    SCOFIELD, C.F.; BENAZZI, E.; CAUFFRIEZ, H.; MARCILLY, C.

    1998-01-01

    This study consists in the evaluation of the catalytic properties of zeolites with different structures in the conversion of methylcyclohexane to light olefins. Results obtained suggest that the steric constrictions of the catalysts used play an important role in hydrogen transfer reactions. Higher selectivities for light olefins (C3= and C4=) were observed for zeolites having more closed structures, like MFI and ferrerite, when compared to those having more open ones, like beta, omega and fa...

  7. Palladium-catalyzed aryl C-H olefination with unactivated, aliphatic alkenes.

    Science.gov (United States)

    Deb, Arghya; Bag, Sukdev; Kancherla, Rajesh; Maiti, Debabrata

    2014-10-01

    Palladium-catalyzed coupling between aryl halides and alkenes (Mizoroki-Heck reaction) is one of the most popular reactions for synthesizing complex organic molecules. The limited availability, problematic synthesis, and higher cost of aryl halide precursors (or their equivalents) have encouraged exploration of direct olefination of aryl carbon-hydrogen (C-H) bonds (Fujiwara-Moritani reaction). Despite significant progress, the restricted substrate scope, in particular noncompliance of unactivated aliphatic olefins, has discouraged the use of this greener alternative. Overcoming this serious limitation, we report here a palladium-catalyzed chelation-assisted ortho C-H bond olefination of phenylacetic acid derivatives with unactivated, aliphatic alkenes in good to excellent yields with high regio- and stereoselectivities. The versatility of this operationally simple method has been demonstrated through drug diversification and sequential C-H olefination for synthesizing divinylbenzene derivatives.

  8. A protocol for amide bond formation with electron deficient amines and sterically hindered substrates

    DEFF Research Database (Denmark)

    Due-Hansen, Maria E; Pandey, Sunil K; Christiansen, Elisabeth

    2016-01-01

    A protocol for amide coupling by in situ formation of acyl fluorides and reaction with amines at elevated temperature has been developed and found to be efficient for coupling of sterically hindered substrates and electron deficient amines where standard methods failed.......A protocol for amide coupling by in situ formation of acyl fluorides and reaction with amines at elevated temperature has been developed and found to be efficient for coupling of sterically hindered substrates and electron deficient amines where standard methods failed....

  9. Hydride Olefin complexes of tantalum and niobium

    NARCIS (Netherlands)

    Klazinga, Aan Hendrik

    1979-01-01

    This thesis describes investigations on low-valent tantalum and niobium hydride and alkyl complexes, particularly the dicyclopentadienyl tantalum hydride olefin complexes Cp2Ta(H)L (L=olefin). ... Zie: Summary

  10. Direct Wittig Olefination of Alcohols.

    Science.gov (United States)

    Li, Qiang-Qiang; Shah, Zaher; Qu, Jian-Ping; Kang, Yan-Biao

    2018-01-05

    A base-promoted transition metal-free approach to substituted alkenes using alcohols under aerobic conditions using air as the inexpensive and clean oxidant is described. Aldehydes are relatively difficult to handle compared to corresponding alcohols due to their volatility and penchant to polymerize and autoxidize. Wittig ylides are easily oxidized to aldehydes and consequently form homo-olefination products. By the strategy of simultaneously in situ generation of ylides and aldehydes, for the first time, alcohols are directly transferred to olefins with no need of prepreparation of either aldehydes or ylides. Thus, the di/monocontrollable olefination of diols is accomplished. This synthetically practical method has been applied in the gram-scale synthesis of pharmaceuticals, such as DMU-212 and resveratrol from alcohols.

  11. Experimental evidence for interactions between anions and electron-deficient aromatic rings.

    Science.gov (United States)

    Berryman, Orion B; Johnson, Darren W

    2009-06-14

    This feature article summarizes our research aimed at using electron-deficient aromatic rings to bind anions in the context of complementary research in this active field. Particular attention is paid to the different types of interactions exhibited between anions and electron-deficient arenes in solution. The 120+ references cited in this article underscore the flurry of recent activity by numerous researchers in this field, which was relatively nascent when our efforts began in 2005. While the interaction of anions with electron-deficient aromatic rings has recently garnered much attention by supramolecular chemists, the observation of these interactions is not a recent discovery. Therefore, we begin with a historical perspective on early examples of anions interacting with electron-deficient arenes. An introduction to recent (and not so recent) computational investigations concerning anions and electron-deficient aromatic rings as well as a brief structural survey of crystalline examples of this interaction are provided. Finally, the limited solution-based observations of anions interacting with electron-deficient aromatic rings are summarized to introduce our current investigations in this area. We highlight three different systems from our lab where anion-arene interactions have been investigated. First, we show that tandem hydrogen bonds and anion-arene interactions augment halide binding in solution. Second, a crystallographic and computational study highlights the multiple types of interactions possible between anions and electron-deficient arenes. Third, we summarize the first example of a class of designed receptors that emphasize the different types of anion-arene interactions possible in solution.

  12. Practical and General Palladium-Catalyzed Synthesis of Ketones from Internal Olefins

    KAUST Repository

    Morandi, Bill; Wickens, Zachary K.; Grubbs, Robert H.

    2013-01-01

    Make it simple! A convenient and general palladium-catalyzed oxidation of internal olefins to ketones is reported. The transformation occurs at room temperature and shows wide substrate scope. Applications to the oxidation of seed-oil derivatives and a bioactive natural product (see scheme) are described, as well as intriguing mechanistic features.

  13. Practical and General Palladium-Catalyzed Synthesis of Ketones from Internal Olefins

    KAUST Repository

    Morandi, Bill

    2013-01-16

    Make it simple! A convenient and general palladium-catalyzed oxidation of internal olefins to ketones is reported. The transformation occurs at room temperature and shows wide substrate scope. Applications to the oxidation of seed-oil derivatives and a bioactive natural product (see scheme) are described, as well as intriguing mechanistic features.

  14. BF3·Et2O promoted conjugate addition of ethanethiol to electron-deficient alkynes

    Institute of Scientific and Technical Information of China (English)

    Qing Fa Zhou; Xue Ping Chu; Shen Zhao; Tao Lu; Wei Fang Tang

    2012-01-01

    An effective method for the synthesis of vinyl thioethers through the conjugate addition of ethanethiol to electron-deficient alkynes promoted by BF3·Et2O has been developed.Electron-deficient internal alkynes react with ethanethiol in this system to yield mainly Z-isomer of vinyl thioether adducts,while electron-deficient terminal alkynes afford mainly E-isomer of vinyl thioether adducts.

  15. Rh(III)-catalyzed olefination of N-sulfonyl imines: synthesis of ortho-olefinated benzaldehydes.

    Science.gov (United States)

    Zhang, Tao; Wu, Lamei; Li, Xingwei

    2013-12-20

    Rh(III)-catalyzed olefination of N-sulfonyl imines using acrylates and styrenes has been achieved for the synthesis of ortho-olefinated benaldehydes. This reaction proceeds via a chelation assisted C-H olefination/in situ hydrolysis process.

  16. Manganese catalyzed cis-dihydroxylation of electron deficient alkenes with H2O2

    NARCIS (Netherlands)

    Saisaha, Pattama; Pijper, Dirk; van Summeren, Ruben P.; Hoen, Robert; Smit, Christian; de Boer, Johannes W.; Hage, Ronald; Alsters, Paul L.; Feringa, Bernard; Browne, Wesley R.

    2010-01-01

    A practical method for the multigram scale selective cis-dihydroxylation of electron deficient alkenes such as diethyl fumarate and N-alkyl and N-aryl-maleimides using H2O2 is described. High turnovers (>1000) can be achieved with this efficient manganese based catalyst system, prepared in situ from

  17. Ligand-Enabled Reactivity and Selectivity in a Synthetically Versatile Aryl C–H Olefination*

    Science.gov (United States)

    Wang, Dong-Hui; Engle, Keary M.; Shi, Bing-Feng; Yu, Jin-Quan

    2010-01-01

    The Mizoroki–Heck reaction, which couples aryl halides with olefins, has been widely used to stitch together the carbogenic cores of numerous complex organic molecules. Given that the position-selective introduction of a halide onto an arene is not always straightforward, direct olefination of aryl C–H bonds would obviate the inefficiencies associated with generating halide precursors or their equivalents; however, methods for carrying out such a reaction have suffered from narrow substrate scope and low positional selectivity. Here we report an operationally simple, atom-economical, carboxylate-directed Pd(II)-catalyzed C–H olefination reaction with phenylacetic acid and 3-phenylpropionic acid substrates, using oxygen at atmospheric pressure as the oxidant. The positional selectivity can be tuned by introducing amino acid derivatives as ligands. We demonstrate the versatility of the method through direct elaboration of commercial drug scaffolds and efficient synthesis of 2-tetralone and naphthoic acid natural product cores. PMID:19965380

  18. Direct Olefination of Alcohols with Sulfones by Using Heterogeneous Platinum Catalysts.

    Science.gov (United States)

    Siddiki, S M A Hakim; Touchy, Abeda Sultana; Kon, Kenichi; Shimizu, Ken-Ichi

    2016-04-18

    Carbon-supported Pt nanoparticles (Pt/C) were found to be effective heterogeneous catalysts for the direct Julia olefination of alcohols in the presence of sulfones and KOtBu under oxidant-free conditions. Primary alcohols, including aryl, aliphatic, allyl, and heterocyclic alcohols, underwent olefination with dimethyl sulfone and aryl alkyl sulfones to give terminal and internal olefins, respectively. Secondary alcohols underwent methylenation with dimethyl sulfone. Under 2.5 bar H2, the same reaction system was effective for the transformation of alcohol OH groups to alkyl groups. Structural and mechanistic studies of the terminal olefination system suggested that Pt(0) sites on the Pt metal particles are responsible for the rate-limiting dehydrogenation of alcohols and that KOtBu may deprotonate the sulfone reagent. The Pt/C catalyst was reusable after the olefination, and this method showed a higher turnover number (TON) and a wider substrate scope than previously reported methods, which demonstrates the high catalytic efficiency of the present method. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Nanographenes as electron-deficient cores of donor-acceptor systems.

    Science.gov (United States)

    Liu, Yu-Min; Hou, Hao; Zhou, Yan-Zhen; Zhao, Xin-Jing; Tang, Chun; Tan, Yuan-Zhi; Müllen, Klaus

    2018-05-15

    Conjugation of nanographenes (NGs) with electro-active molecules can establish donor-acceptor π-systems in which the former generally serve as the electron-donating moieties due to their electronic-rich nature. In contrast, here we report a series of reversed donor-acceptor structures are obtained by C-N coupling of electron-deficient perchlorinated NGs with electron-rich anilines. Selective amination at the vertexes of the NGs is unambiguously shown through X-ray crystallography. By varying the donating ability of the anilino groups, the optical and assembly properties of donor-acceptor NGs can be finely modulated. The electron-deficient concave core of the resulting conjugates can host electron-rich guest molecules by intermolecular donor-acceptor interactions and gives rise to charge-transfer supramolecular architectures.

  20. Biomimetic Aerobic C–H Olefination of Cyclic Enaminones at Room Temperature: Development toward the Synthesis of 1,3,5-Trisubstituted Benzenes

    Science.gov (United States)

    Yu, Yi-Yun

    2014-01-01

    A green and mild protocol for the dehydrogenative olefination of cyclic enaminones was devised via palladium catalysis at room temperature using oxygen as the terminal oxidant. The synthetic utility of the olefinated cyclic enaminones afforded a series of unique 1,3,5-trisubstituted benzenes via an unanticipated Diels-Alder tandem reaction. The broad substrate scope and good yields achieved with this new protocol provide an alternative pathway for arene functionalization. PMID:25071423

  1. Biomimetic Aerobic C-H Olefination of Cyclic Enaminones at Room Temperature: Development toward the Synthesis of 1,3,5-Trisubstituted Benzenes.

    Science.gov (United States)

    Yu, Yi-Yun; Georg, Gunda I

    2014-04-14

    A green and mild protocol for the dehydrogenative olefination of cyclic enaminones was devised via palladium catalysis at room temperature using oxygen as the terminal oxidant. The synthetic utility of the olefinated cyclic enaminones afforded a series of unique 1,3,5-trisubstituted benzenes via an unanticipated Diels-Alder tandem reaction. The broad substrate scope and good yields achieved with this new protocol provide an alternative pathway for arene functionalization.

  2. New Trends in Olefin Production

    Directory of Open Access Journals (Sweden)

    Ismaël Amghizar

    2017-04-01

    Full Text Available Most olefins (e.g., ethylene and propylene will continue to be produced through steam cracking (SC of hydrocarbons in the coming decade. In an uncertain commodity market, the chemical industry is investing very little in alternative technologies and feedstocks because of their current lack of economic viability, despite decreasing crude oil reserves and the recognition of global warming. In this perspective, some of the most promising alternatives are compared with the conventional SC process, and the major bottlenecks of each of the competing processes are highlighted. These technologies emerge especially from the abundance of cheap propane, ethane, and methane from shale gas and stranded gas. From an economic point of view, methane is an interesting starting material, if chemicals can be produced from it. The huge availability of crude oil and the expected substantial decline in the demand for fuels imply that the future for proven technologies such as Fischer-Tropsch synthesis (FTS or methanol to gasoline is not bright. The abundance of cheap ethane and the large availability of crude oil, on the other hand, have caused the SC industry to shift to these two extremes, making room for the on-purpose production of light olefins, such as by the catalytic dehydrogenation of propane.

  3. Alkylation of isobutane with light olefins: Yields of alkylates for different olefins

    Energy Technology Data Exchange (ETDEWEB)

    Albright, L.F. [Purdue Univ., West Lafayette, IN (United States); Kranz, K.E.; Masters, K.R. [STRATCO, Inc., Leawood, KS (United States)

    1993-12-01

    For alkylation of isobutane with C{sub 3}-C{sub 5} olefins using sulfuric acid as the catalyst, the yields of alkylates with different olefins are compared as the operating conditions are changed. The results of recent pilot plant experiments with propylene, C{sub 4} olefins, and C{sub 5} olefins permit such comparisons. The yields expressed as weight of alkylate produced per 100 wt of olefin consumed varied from about 201:100 to 220:100. Weight ratios of the isobutane consumed per olefin consumed vary from about 101:100 to 120:100. differences of yield values are explained by the changes in the overall chemistry. The procedure employed to calculate yields with good accuracy is based on the analysis of the alkylate and the amount of conjunct polymers produced. Based on literature data, yields are also reported for alkylations using HF as the catalyst.

  4. Alternative Test Method for Olefins in Gasoline

    Science.gov (United States)

    This action proposes to allow for an additional alternative test method for olefins in gasoline, ASTM D6550-05. The allowance of this additional alternative test method will provide more flexibility to the regulated industry.

  5. Myoglobin-Catalyzed Olefination of Aldehydes.

    Science.gov (United States)

    Tyagi, Vikas; Fasan, Rudi

    2016-02-12

    The olefination of aldehydes constitutes a most valuable and widely adopted strategy for constructing carbon-carbon double bonds in organic chemistry. While various synthetic methods have been made available for this purpose, no biocatalysts are known to mediate this transformation. Reported herein is that engineered myoglobin variants can catalyze the olefination of aldehydes in the presence of α-diazoesters with high catalytic efficiency (up to 4,900 turnovers) and excellent E diastereoselectivity (92-99.9 % de). This transformation could be applied to the olefination of a variety of substituted benzaldehydes and heteroaromatic aldehydes, also in combination with different alkyl α-diazoacetate reagents. This work provides a first example of biocatalytic aldehyde olefination and extends the spectrum of synthetically valuable chemical transformations accessible using metalloprotein-based catalysts. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. (Z)-Selective Takai olefination of salicylaldehydes.

    Science.gov (United States)

    Geddis, Stephen M; Hagerman, Caroline E; Galloway, Warren R J D; Sore, Hannah F; Goodman, Jonathan M; Spring, David R

    2017-01-01

    The Takai olefination (or Takai reaction) is a method for the conversion of aldehydes to vinyl iodides, and has seen widespread implementation in organic synthesis. The reaction is usually noted for its high ( E )-selectivity; however, herein we report the highly ( Z )-selective Takai olefination of salicylaldehyde derivatives. Systematic screening of related substrates led to the identification of key factors responsible for this surprising inversion of selectivity, and enabled the development of a modified mechanistic model to rationalise these observations.

  7. Direct catalytic olefination of alcohols with sulfones.

    Science.gov (United States)

    Srimani, Dipankar; Leitus, Gregory; Ben-David, Yehoshoa; Milstein, David

    2014-10-06

    The synthesis of terminal, as well as internal, olefins was achieved by the one-step olefination of alcohols with sulfones catalyzed by a ruthenium pincer complex. Furthermore, performing the reaction with dimethyl sulfone under mild hydrogen pressure provides a direct route for the replacement of alcohol hydroxy groups by methyl groups in one step. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Palladium(II-catalyzed Heck reaction of aryl halides and arylboronic acids with olefins under mild conditions

    Directory of Open Access Journals (Sweden)

    Tanveer Mahamadali Shaikh

    2013-08-01

    Full Text Available A series of general and selective Pd(II-catalyzed Heck reactions were investigated under mild reaction conditions. The first protocol has been developed employing an imidazole-based secondary phosphine oxide (SPO ligated palladium complex (6 as a precatalyst. The catalytic coupling of aryl halides and olefins led to the formation of the corresponding coupled products in excellent yields. A variety of substrates, both electron-rich and electron-poor olefins, were converted smoothly to the targeted products in high yields. Compared with the existing approaches employing SPO–Pd complexes in a Heck reaction, the current strategy features mild reaction conditions and broad substrate scope. Furthermore, we described the coupling of arylboronic acids with olefins, which were catalyzed by Pd(OAc2 and employed N-bromosuccinimide as an additive under ambient conditions. The resulted biaryls have been obtained in moderate to good yields.

  9. Synthesis of Fluoroolefins via Julia-Kocienski Olefination

    OpenAIRE

    Zajc, Barbara; Kumar, Rakesh

    2010-01-01

    The Julia-Kocienski olefination provides a versatile platform for the synthesis of fluorovinyl compounds. This review describes our efforts as well as those of others in the synthesis of various fluorinated aryl and heteroaryl sulfones and their utility as olefination reagents for the modular assembly of fluoroalkenes. Where data is available, the influence of the fluorine atom on the reactivity of the olefination reagents and the stereochemical outcome of the olefination are described.

  10. Synthesis of Fluoroolefins via Julia-Kocienski Olefination.

    Science.gov (United States)

    Zajc, Barbara; Kumar, Rakesh

    2010-01-01

    The Julia-Kocienski olefination provides a versatile platform for the synthesis of fluorovinyl compounds. This review describes our efforts as well as those of others in the synthesis of various fluorinated aryl and heteroaryl sulfones and their utility as olefination reagents for the modular assembly of fluoroalkenes. Where data is available, the influence of the fluorine atom on the reactivity of the olefination reagents and the stereochemical outcome of the olefination are described.

  11. Catalytic olefin polymerization with early transition metal compounds

    NARCIS (Netherlands)

    Eshuis, Johan Jan Willem

    1991-01-01

    The catalysis of organic reactions by soluble metal complexes has become a major tool in synthesis, both in the laboratory and in the chemical industry. Processes catalyzed by transition metal complexes include carbonylation, olefin polymerization, olefin addition, olefin oxidation and alkane and

  12. Olefin copolymerization using atom transfer radical polymerization (ATRP)

    NARCIS (Netherlands)

    Venkatesh, R.; Klumperman, B.

    2003-01-01

    Olefin copolymers of alpha-olefins with polar monomers with various architectures remain an ultimate goal in polyolefin engineering. The present paper is a more detailed study on the copolymn. of alpha-olefins (1-octene) with acrylates (Me acrylate). Comparison of reaction kinetics between free

  13. Gamma radiolysis of 3-methylpentane. Effect of added olefins on the formation of C12-olefins

    International Nuclear Information System (INIS)

    Laet, M. de; Tilquin, B.

    1991-01-01

    Contributions of congruent (parent derived) olefins to the formation of unsaturated heavy products (C 12 H 24 ) are investigated. Effects of dose or of olefinic additives on the G yield values are studied by capillary gas chromatography. The dose dependence is explained by transfer of positive charge to congruent olefins (C 6 H 12 ) even though their concentrations build up linearly with dose. γ Irradiation of 3-methylpentane containing pentenes or butenes (0.2-2 mol %) provides good examples of transfer of energy, however the results are unexpected. C-H scission in the radiolysis of solid 3-methylpentane is also reviewed. (author)

  14. Manganese catalyzed cis-dihydroxylation of electron deficient alkenes with H(2)O(2).

    Science.gov (United States)

    Saisaha, Pattama; Pijper, Dirk; van Summeren, Ruben P; Hoen, Rob; Smit, Christian; de Boer, Johannes W; Hage, Ronald; Alsters, Paul L; Feringa, Ben L; Browne, Wesley R

    2010-10-07

    A practical method for the multigram scale selective cis-dihydroxylation of electron deficient alkenes such as diethyl fumarate and N-alkyl and N-aryl-maleimides using H(2)O(2) is described. High turnovers (>1000) can be achieved with this efficient manganese based catalyst system, prepared in situ from a manganese salt, pyridine-2-carboxylic acid, a ketone and a base, under ambient conditions. Under optimized conditions, for diethyl fumarate at least 1000 turnovers could be achieved with only 1.5 equiv. of H(2)O(2) with d/l-diethyl tartrate (cis-diol product) as the sole product. For electron rich alkenes, such as cis-cyclooctene, this catalyst provides for efficient epoxidation.

  15. Electron-deficient anthraquinone derivatives as cathodic material for lithium ion batteries

    Science.gov (United States)

    Takeda, Takashi; Taniki, Ryosuke; Masuda, Asuna; Honma, Itaru; Akutagawa, Tomoyuki

    2016-10-01

    We studied the electronic and structural properties of electron-deficient anthraquinone (AQ) derivatives, Me4N4AQ and TCNAQ, and investigated their charge-discharge properties in lithium ion batteries along with those of AQ. Cyclic voltammogram, X-ray structure analysis and theoretical calculations revealed that these three acceptors have different features, such as different electron-accepting properties with different reduction processes and lithium coordination abilities, and different packing arrangements with different intermolecular interactions. These differences greatly affect the charge-discharge properties of lithium ion batteries that use these compounds as cathode materials. Among these compounds, Me4N4AQ showed a high charge/discharge voltage (2.9-2.5 V) with high cyclability (>65% of the theoretical capacity after 30 cycles; no decrease after 15 cycles). These results provide insight into more in-depth design principles for lithium ion batteries using AQ derivatives as cathodic materials.

  16. π-Extended Isoindigo-Based Derivative: A Promising Electron-Deficient Building Block for Polymer Semiconductors.

    Science.gov (United States)

    Xu, Long; Zhao, Zhiyuan; Xiao, Mingchao; Yang, Jie; Xiao, Jian; Yi, Zhengran; Wang, Shuai; Liu, Yunqi

    2017-11-22

    The exploration of novel electron-deficient building blocks is a key task for developing high-performance polymer semiconductors in organic thin-film transistors. In view of the situation of the lack of strong electron-deficient building blocks, we designed two novel π-extended isoindigo-based electron-deficient building blocks, IVI and F 4 IVI. Owing to the strong electron-deficient nature and the extended π-conjugated system of the two acceptor units, their copolymers, PIVI2T and PF 4 IVI2T, containing 2,2'-bithiophene donor units, are endowed with deep-lying highest occupied molecular orbital (HOMO)/lowest unoccupied molecular orbital (LUMO) energy levels and strong intermolecular interactions. In comparison to PIVI2T, the fluorinated PF 4 IVI2T exhibits stronger intra- and intermolecular interactions, lower HOMO/LUMO energy levels up to -5.74/-4.17 eV, and more ordered molecular packing with a smaller π-π stacking distance of up to 3.53 Å, resulting in an excellent ambipolar transporting behavior and a promising application in logic circuits for PF 4 IVI2T in ambient with hole and electron mobilities of up to 1.03 and 1.82 cm 2 V -1 s -1 , respectively. The results reveal that F 4 IVI is a promising and strong electron-deficient building unit to construct high-performance semiconducting polymers, which provides an insight into the structure-property relationships for the exploration and molecular engineering of excellent electron-deficient building blocks in the field of organic electronics.

  17. Olefin metathesis in nano-sized systems

    Directory of Open Access Journals (Sweden)

    Denise Méry

    2011-01-01

    Full Text Available The interplay between olefin metathesis and dendrimers and other nano systems is addressed in this mini review mostly based on the authors’ own contributions over the last decade. Two subjects are presented and discussed: (i The catalysis of olefin metathesis by dendritic nano-catalysts via either covalent attachment (ROMP or, more usefully, dendrimer encapsulation – ring closing metathesis (RCM, cross metathesis (CM, enyne metathesis reactions (EYM – for reactions in water without a co-solvent and (ii construction and functionalization of dendrimers by CM reactions.

  18. (Z-Selective Takai olefination of salicylaldehydes

    Directory of Open Access Journals (Sweden)

    Stephen M. Geddis

    2017-02-01

    Full Text Available The Takai olefination (or Takai reaction is a method for the conversion of aldehydes to vinyl iodides, and has seen widespread implementation in organic synthesis. The reaction is usually noted for its high (E-selectivity; however, herein we report the highly (Z-selective Takai olefination of salicylaldehyde derivatives. Systematic screening of related substrates led to the identification of key factors responsible for this surprising inversion of selectivity, and enabled the development of a modified mechanistic model to rationalise these observations.

  19. Olefin Recovery from Chemical Industry Waste Streams

    Energy Technology Data Exchange (ETDEWEB)

    A.R. Da Costa; R. Daniels; A. Jariwala; Z. He; A. Morisato; I. Pinnau; J.G. Wijmans

    2003-11-21

    The objective of this project was to develop a membrane process to separate olefins from paraffins in waste gas streams as an alternative to flaring or distillation. Flaring these streams wastes their chemical feedstock value; distillation is energy and capital cost intensive, particularly for small waste streams.

  20. Cyclic olefin copolymer-silica nanocomposites foams

    Czech Academy of Sciences Publication Activity Database

    Pegoretti, A.; Dorigato, A.; Biani, A.; Šlouf, Miroslav

    2016-01-01

    Roč. 51, č. 8 (2016), s. 3907-3916 ISSN 0022-2461 R&D Projects: GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : cyclic olefin copolymer * nanocomposites * silica Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.599, year: 2016

  1. Synthesis of pterostilbene by Julie Olefination

    Science.gov (United States)

    A simple, stereoselective route for the synthesis of the biologically active compounds trans-pterostilbene and tetramethoxy stilbene from the readily available starting materials 3,5-dimethoxy benzyl alcohol and 4-hydroxy benzaldehyde was developed using Julia olefination as a key reaction....

  2. Techno-economic analysis of the coal-to-olefins process in comparison with the oil-to-olefins process

    International Nuclear Information System (INIS)

    Xiang, Dong; Qian, Yu; Man, Yi; Yang, Siyu

    2014-01-01

    Highlights: • Present the opportunities and challenges of coal-to-olefins (CTO) development. • Conduct a techno-economic analysis on CTO compared with oil-to-olefins (OTO). • Suggest approaches for improving energy efficiency and economic performance of CTO. • Analyze effects of plant scale, feedstock price, CO 2 tax on CTO and OTO. - Abstract: Olefins are one of the most important oil derivatives widely used in industry. To reduce the dependence of olefins industry on oil, China is increasing the production of olefins from alternative energy resources, especially from coal. This study is concerned with the opportunities and obstacles of coal-to-olefins development, and focuses on making an overall techno-economic analysis of a coal-to-olefins plant with the capacity of 0.7 Mt/a olefins. Comparison is made with a 1.5 Mt/a oil-to-olefins plant based on three criteria including energy efficiency, capital investment, and product cost. It was found that the coal-based olefins process show prominent advantage in product cost because of the low price of its feedstock. However, it suffers from the limitations of higher capital investment, lower energy efficiency, and higher emissions. The effects of production scale, raw material price, and carbon tax were varied for the two production routes, and thus the operational regions were found for the coal-to-olefins process to be competitive

  3. Palladium-catalyzed aerobic regio- and stereo-selective olefination reactions of phenols and acrylates via direct dehydrogenative C(sp2)-O cross-coupling.

    Science.gov (United States)

    Wu, Yun-Bin; Xie, Dan; Zang, Zhong-Lin; Zhou, Cheng-He; Cai, Gui-Xin

    2018-04-26

    An efficient olefination protocol for the oxidative dehydrogenation of phenols and acrylates has been achieved using a palladium catalyst and O2 as the sole oxidant. This reaction exhibits high regio- and stereo-selectivity (E-isomers) with moderate to excellent isolated yields and a wide substrate scope (32 examples) including ethyl vinyl ketone and endofolliculina.

  4. Regioselective C2 Oxidative Olefination of Indoles and Pyrroles through Cationic Rhodium(III)-Catalyzed C-H Bond Activation.

    Science.gov (United States)

    Li, Bin; Ma, Jianfeng; Xie, Weijia; Song, Haibin; Xu, Shansheng; Wang, Baiquan

    2013-09-02

    Be economic with your atoms! An efficient Rh-catalyzed oxidative olefination of indoles and pyrroles with broad substrate scope and tolerance is reported. The catalytic reaction proceeds with excellent regio- and stereoselectivity. The directing group N,N-dimethylcarbamoyl was crucial for the reaction and could be removed easily. Copyright © 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. 1-O-vinyl glycosides via Tebbe olefination, their use as chiral auxiliaries and monomers.

    Science.gov (United States)

    Yuan, Jialong; Lindner, Kristof; Frauenrath, Holger

    2006-07-21

    A series of anomerically pure 1-O-formyl glycosides 1 was prepared and converted into the corresponding 1-O-vinyl glycosides 2 by Tebbe olefination. The unsubstituted vinyl glycosides were obtained as anomerically pure compounds in good yields, and the method of preparation was compatible with the presence of a variety of functional groups. Remarkably, the anomeric formate group was regioselectively converted into the corresponding olefin in the presence of acetate and benzoate protecting groups. With the perspective to use the 1-O-vinyl glycosides as monomers for the preparation of glycosylated poly(vinyl alcohol) derivatives with controlled tacticity, their scope as chiral auxiliaries for a stereodifferentiation in addition reactions to the olefin function was investigated by using the [2+2] cycloaddition to dichloroketene as a model reaction. In particular, vinyl 2,3,4,6-tetra-O-benzoyl-alpha-d-mannopyranoside (2i) exhibited excellent diastereoselectivity. Finally, the 1-O-vinyl glycosides were successfully subjected to radical homopolymerization in bulk or used as electron-rich comonomers in radical copolymerizations with maleic anhydride, yielding alternating, glycosylated poly(vinyl alcohol-alt-maleic anhydride).

  6. Catalytic olefin polymerization with early transition metal compounds

    OpenAIRE

    Eshuis, Johan Jan Willem

    1991-01-01

    The catalysis of organic reactions by soluble metal complexes has become a major tool in synthesis, both in the laboratory and in the chemical industry. Processes catalyzed by transition metal complexes include carbonylation, olefin polymerization, olefin addition, olefin oxidation and alkane and arene oxidation. Traditionally, heterogeneous catalysts have been used for the production of large-scale commodity chemicals such as methanol and ammonia and in the production of high octane gasoline...

  7. Conversion of olefins to liquid motor fuels

    Science.gov (United States)

    Rabo, Jule A.; Coughlin, Peter K.

    1988-01-01

    Linear and/or branched claim C.sub.2 to C.sub.12 olefins are converted to hydrocarbon mixtures suitable for use as liquid motor fuels by contact with a catalyst capable of ensuring the production of desirable products with only a relatively minor amount of heavy products boiling beyond the diesel oil range. The catalyst having desirable stability during continuous production operations, comprises a steam stabilized zeolite Y catalyst of hydrophobic character, desirably in aluminum-extracted form. The olefins such as propylene, may be diluted with inerts, such as paraffins or with water, the latter serving to moderate the acidity of the catalyst, or to further moderate the activity of the aluminum-extracted catalyst, so as to increase the effective life of the catalyst.

  8. Thermal 18F atom addition to olefins

    International Nuclear Information System (INIS)

    Rogers, P.J.M.

    1986-01-01

    The addition of thermal 18 F atoms to olefins was investigated using various substrate molecules. The 18 F atoms were produced by the 19 F(n,2n) 18 F nuclear reaction with >10 5 eV of energy which is removed by multiple collisions with SF 6 molecules before reaction occurs with an olefin. By varying the SF 6 /substrate mole ratio it was demonstrated that the fraction of non-thermal reactions is dependent upon the frequency of non-reactive energy reducing collisions with SF 6 . The rate constants for addition and abstraction reactions with propene, cis-1-chloropropene and trans-1-chloropropene were determined. The substitution of a C1 atom for the olefinic H atom in the C 1 position does not affect the rate of 18 F bond formation but it changes the orientation of attack. The 18 F atom prefers the terminal carbon-in propene and propene-d 6 by a factor of 1.35 while the preference is less than 0.5 for the terminal carbon in cis-1-chloropropene and trans-1-chloropropene. The addition of 18 F atoms to olefins creates vibrationally excited fluoroalkyl radicals which can either decompose or stabilize by collision with another molecule. The rate constants for decomposition of excited CH 3 CHCHC1F radicals formed by 18 F addition to cis-1-chloropropene and trans-1-chloropropene are competitive with C 1 -C 2 bond rotation. The 18 F atoms add to the parent molecule with retention of geometry and a memory of the geometry persists as demonstrated by the cis-1-fluoropropene/trans-1-fluoropropene decomposition product ratio

  9. Olefin recovery from FCC off-gas can pay off

    International Nuclear Information System (INIS)

    Brahn, M.G.

    1992-01-01

    This paper reports on olefins recovery from refinery FCC offgas streams which offers an attractive cash flow from olefins from a tail-gas stream that has typically been consumed as refinery fuel. Such recovery schemes can be employed in refineries or olefins plants, and can be tailored to fit individual requirements. Mobil Chemical Co. has operated such a dephlegmator-based off-gas recovery unit at its Beaumont, Tex., olefin plant since 1987. It reported that the project was paid out within 11 months of initial start-up

  10. Rhodium-catalyzed regioselective olefination directed by a carboxylic group.

    Science.gov (United States)

    Mochida, Satoshi; Hirano, Koji; Satoh, Tetsuya; Miura, Masahiro

    2011-05-06

    The ortho-olefination of benzoic acids can be achieved effectively through rhodium-catalyzed oxidative coupling with alkenes. The carboxylic group is readily removable to allow ortho-olefination/decarboxylation in one pot. α,β-Unsaturated carboxylic acids such as methacrylic acid also undergo the olefination at the β-position. Under the rhodium catalysis, the cine-olefination of heteroarene carboxylic acids such as thiophene-2-carboxylic acid proceeds smoothly accompanied by decarboxylation to selectively produce the corresponding vinylheteroarene derivatives. © 2011 American Chemical Society

  11. The olefin metathesis reaction: reorganization and cyclization of organic compounds

    International Nuclear Information System (INIS)

    Frederico, Daniel; Brocksom, Ursula; Brocksom, Timothy John

    2005-01-01

    The olefin metathesis reaction allows the exchange of complex alkyl units between two olefins, with the formation of a new olefinic link and a sub-product olefin usually ethylene. This reaction has found extensive application in the last ten years with the development of the Grubbs and Schrock catalysts, in total synthesis of complex organic molecules, as opposed to the very important use in the petrochemical industry with relatively simple molecules. This review intends to trace a historical and mechanistic pathway from industry to academy, before illustrating the more recent advances. (author)

  12. Alternative routes to olefins. Chances and challenges

    Energy Technology Data Exchange (ETDEWEB)

    Meiswinkel, A.; Delhomme, C.; Ponceau, M. [Linde AG, Pullach (Germany)

    2013-11-01

    In the future, conventional raw materials which are used for the production of olefins will get shorter and more expensive and alternative raw materials and production routes will gain importance. Natural gas, coal, shale oil or bio-mass are potential sources for the production of olefins, especially ethylene and propylene, as major base chemicals. Several potential production routes were already developed in the past, but cost, energy and environmental considerations might make these unattractive or unfeasible in comparison to traditional processes (e.g. steam cracking). Other processes such as methanol to olefins processes were successfully developed and first commercial units are running. In addition, combination of traditional processes (e.g. coal/biomass gasification, Fischer-Tropsch and steam cracking) might enable new pathways. Besides, dehydration of ethanol is opening direct routes from biomass to 'green' ethylene. However, for these 'bio-routes', feedstock availability and potential land use conflict with food production (sugar cane, wheat,..) still need to be evaluated. finally, new oxidative routes, including processes such as oxidative coupling of methane or oxidative dehydrogenation, are still at an early development stage but present potential for future industrial applications. (orig.) (Published in summary form only)

  13. Columnar Self-Assembly of Electron-Deficient Dendronized Bay-Annulated Perylene Bisimides.

    Science.gov (United States)

    Gupta, Ravindra Kumar; Shankar Rao, Doddamane S; Prasad, S Krishna; Achalkumar, Ammathnadu S

    2018-03-07

    Three new heteroatom bay-annulated perylene bisimides (PBIs) have been synthesized by microwave-assisted synthesis in excellent yield. N-annulated and S-annulated perylene bisimides exhibited columnar hexagonal phase, whereas Se-annulated perylene bisimide exhibited low temperature columnar oblique phase in addition to the high temperature columnar hexagonal phase. The cup shaped bay-annulated PBIs pack into columns with enhanced intermolecular interactions. In comparison to PBI, these molecules exhibited lower melting and clearing temperature, with good solubility. A small red shift in the absorption was seen in the case of N-annulated PBI, whereas S- and Se-annulated PBIs exhibited blue-shifted absorption spectra. Bay-annulation increased the HOMO and LUMO levels of the N-annulated perylene bisimide, whereas a slight increase in the LUMO level and a decrease in the HOMO levels were observed in the case of S- and Se-annulated perylene bisimides, in comparison to the simple perylene bisimide. The band gaps of PBI and PBI-N were almost same, whereas an increase in the band gaps were observed in the case of S- and Se-annulated PBIs. The tendency to freeze in the ordered glassy columnar phase for PBI-N and PBI-S will help to overcome the charge traps due to crystallization, which are detrimental to one-dimensional charge carrier mobility. These solution processable electron deficient columnar semiconductors possessing good thermal stability may form an easily accessible promising class of n-type materials. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Surface-enhanced light olefin yields during steam cracking

    NARCIS (Netherlands)

    Golombok, M.; Kornegoor, M.; Brink, van den P.; Dierickx, J.; Grotenbreg, R.

    2000-01-01

    Various papers have shown enhanced olefin yields during steam cracking when a catalytic surface is introduced. Our studies reveal that increased light olefin yields during catalytic steam cracking are mainly due to a surface volume effect and not to a traditional catalytic effect. Augmentation of

  15. Alkylation of isobutane with light olefins catalyzed by zeolite beta

    NARCIS (Netherlands)

    Nivarthy, G.S.; Feller, A.P.; Seshan, Kulathuiyer; Lercher, J.A.

    2000-01-01

    Alkylation of isobutane with ethene and propene was studied over an H-BEA catalyst in a well-stirred reactor. Under similar conditions of space velocity and paraffin-to-olefin feed ratio, lower initial olefin conversions were observed with ethene or propene than those reported earlier for butene.

  16. Rhodium(iii)-catalyzed ortho-olefination of aryl phosphonates.

    Science.gov (United States)

    Chary, Bathoju Chandra; Kim, Sunggak

    2013-09-25

    Rhodium(iii)-catalyzed C-H olefination of aryl phosphonic esters is reported for the first time. In this mild and efficient process, the phosphonic ester group is utilized successfully as a new directing group. In addition, mono-olefination for aryl phosphonates is observed using a phosphonic diamide directing group.

  17. Carbonyl-Olefin Exchange Reaction: Present State and Outlook

    Science.gov (United States)

    Kalinova, Radostina; Jossifov, Christo

    The carbonyl-olefin exchange reaction (COER) is a new reaction between carbonyl group and olefin double bond, which has a formal similarity with the olefin metathesis (OM) - one carbon atom in the latter is replaced with an oxygen atom. Till now the new reaction is performed successfully only when the two functional groups (carbonyl group and olefin double bond) are in one molecule and are conjugated. The α, β-unsaturated carbonyl compounds (substituted propenones) are the compounds with such a structure. They polymerize giving substituted polyacetylenes. The chain propagation step of this polymerization is in fact the COER. The question arises: is it possible the COER to take place when the two functional groups are not in one molecule and are not conjugated, and could this reaction became an alternative of the existing carbonyl olefination reactions?

  18. Rhodium(I) catalysis in olefin photoreactions

    International Nuclear Information System (INIS)

    Salomon, R.G.; El Sanadi, N.

    1975-01-01

    The photorearrangement (254 nm) of 1,5-cyclooctadiene (1) in the presence of rhodium(I) chloride to give 1,4-cyclooctadiene (4) was found by deuterium labeling to involve an intramolecular [1,3] shift of hydrogen. A rate-determining cleavage of an allylic C--H bond is indicated by a deuterium isotope effect, k/sub H//k/sub D/ = 1.55 +- 0.03 for the 1 → 4 rearrangement. The acyclic 1,5-diene, 3,3-dimethyl-1,5-hexadiene (8), rearranges in the presence of rhodium(I) chloride upon uv irradiation (254 nm) to give cis-3,3-dimethyl-1,4-hexadiene (10) and the trans isomer 11 in a 1:4 ratio, respectively. This observation supports a mechanism for the photorearrangement of olefins catalyzed by rhodium(I) involving an initial photodissociation of one of two rhodium(I) coordinated carbon-carbon double bonds. This results in an increase in the coordinative unsaturation of rhodium(I) and enhances the proclivity of this d/sub s/ metal atom toward oxidative addition of an allylic C--H bond. A eta 3 -allylrhodium hydride intermediate then gives rearranged olefin by reductive elimination. Lastly, a novel photochemical, rhodium(I) catalyzed hydrogen transfer is reported which gives cyclooctene (7) from cyclooctadienes under unprecedentedly mild conditions. (auth)

  19. A method for producing lower olefins

    Energy Technology Data Exchange (ETDEWEB)

    Lemayev, N.V.; Grigorovich, V.A.; Isayev, V.A.; Liakumovich, A.G.; Mitrofanov, A.I.; Orekhov, A.I.; Trifonov, S.V.; Vernov, P.A.

    1983-01-01

    In the known method for producing lower olefins by pyrolysis of a hydrocarbon raw material in the presence of an initiator which contains ammonia, in order to increase the output of the target products, morpholine or piperidine are additionally introduced into the initiator in a volume of 0.00001 to 0.1 percent each, converted for the raw material. The compounds to be added may be introduced into the pyrolysis zone by dissolving them in the hydrocarbon raw material or in water, which forms vapors with dilution of the raw material being subjected to pyrolysis. The increase in the outputs of the lower olefins in the process through the use of additives may be explained by the synergistic effect of the mixture of ammonia, morpholine and piperidine used. With benzine pyrolysis without the additives the output of ethylene is 24.1 percent; in comparable conditions with additives of ammonia or morpholine alone, or of piperidine alone, the outputs are 24.0, 26.2 and 25.8 percent, respectively. With the joint presence of ammonia and piperidine, the output of ethylene reaches 27.2 percent and with the addition of ammonia and morpholine, it reaches 27.4 percent.

  20. Production and use of light olefins. Preprints of the conference

    Energy Technology Data Exchange (ETDEWEB)

    Ernst, S.; Buzzoni, R.; Leitner, W.; Lercher, J.A.; Lichtscheidl, J.; Nees, F.; Santacesaria, E. (eds.)

    2009-07-01

    Within the conference of the German Society for Petroleum and Coal Science and Technology e.V. (Hamburg, Federal Republic of Germany) in Berlin (Federal Republic of Germany) at 28th to 30th September, 2009, the following lectures were held: (1) Steamcracking - State of the Art (H. Zimmermann); (2) Diversify Feedstock Options to Olefin Production (Q. Ling et al.); (3) Syngas to lower olefins (E. Schwab et al.); (4) STAR process registered for the on-purpose production of propylene (K. Bueker); (5) The catalytic activity of zinc oxide supported on aerosil for C-H activation of light alkanes (S. Arndt et al.); (6) Novel catalytic approaches for the oxidative dehydrogenation of ethane (D. Hartmann); (7) A comparison of the active sites structures of homogeneous and heterogeneous olefin polymerisation catalysts (A. Zecchina); (8) Catalytic strategies in metathesis (C. Coperet); (9) Multi-technology integrated production and consumption of olefins (J. Popp et al.); (10) Olefin oligomerization for the production of fuels and petrochemicals (H. Olivier-Bourbigou et al.); (11) Dieselization of the world - How to increase diesel yield in a refinery (A. Dueker); (12) Isomerization of butenes: LyondellBasell's Isomplus technology development (T. Zak et al.); (13) Valuable products from butadiene, carbon dioxide and further base chemicals (A. Behr); (14) The partial oxidation of propene to propylene oxide using N{sub 2}O as an oxidant (T. Thoemmes); (15) Alternative feedstocks for olefin production: What role will ethanol play? (B.R. Maughon); (16) Production of light olefins from renewable resources - The effect of deoxygenation degree on yields of light olefins (D. Kubicka et al.); (17) Recovery of low olefins from refinery offgases (M. Bender).

  1. SAXS observation of structural evolution of heated olefin

    International Nuclear Information System (INIS)

    Sun Minhua; Mou Hongchen; Wang Yuxi; Li Demin; Wang Aiping; Ma Congxiao; Cheng Weidong; Wang Dan; Liu Jia

    2007-01-01

    Structural evolution of olefin during its heating process was observed with SAXS method at Beijing Synchrotron Radiation Facility. The mean square fluctuation of electron density increased from 468.5 nm -2 at 22 degree C to 2416 nm -2 at 100 degree C, while the electronic gyration radius decreased from 11.61 nm at 22 degree C to 11.16 nm at 100 degree C. Therefore, the olefin softens as a result of the increased thermal motion of the molecules, rather than the shrinking size of fundamental structural units of olefin. (authors)

  2. Reactions of dihydridotetrakis(triphenylphosphine)ruthenium(II) with olefins and isolation of new ruthenium-olefin complexes

    International Nuclear Information System (INIS)

    Komiya, Sanshiro; Yamamoto, Akio

    1976-01-01

    Dihydridotetrakis(triphenylphosphine)ruthenium (II), RuH 2 (PPh 3 ) 4 , reacts with olefins (ethylene, propylene, stylene and butadiene) to give olefin-coordinated complexes of the type, Ru(olefin)(PPh 3 ) 3 and equimolar amounts of their hydrogenation products per mol of the dihydride complex. The olefin coordinated with ruthenium can be exchanged with other olefins. Olefin-coordinated complexes easily react with molecular hydrogen to afford tetrahydridotris(triphenylphosphine)ruthenium, RuH 4 (PPh 3 ) 3 , releasing alkane at room temperature, Under hydrogen atmosphere catalytic hydrogenation of the olefins smoothly takes place with RuH 2 (PPh 3 ) 4 . (Ethylene)tris(triphenylphosphine)ruthenium(0) reacts with methyl iodide to give propylene and a trace of butadiene along with methane, ethylene, and small amounts of ethane and butenes. The formation of propylene suggests that oxidative addition involving cleavage of the C-H bond of ethylene to ruthenium giving a hydridovinyl complex may be taking place. Reactions of Ru(C 2 H 4 )(PPh 3 ) 3 with methyl-d 3 iodide and ethyl iodide, and of Ru(C 3 H 6 )(PPh 3 ) 3 with methyl iodide were examined to test the generality of this type of reaction. The reaction of Ru(C 2 H 4 )(PPh 3 ) 3 with CD 3 I released CD 4 and CD 2 H 2 together with CD 3 H suggesting the involvement of α-hydrogen abstraction. (auth.)

  3. Ru(II)-Catalyzed Oxidative Heck-Type Olefination of Aromatic Carboxylic Acids with Styrenes through Carboxylate-Assisted C-H Bond Activation.

    Science.gov (United States)

    Dana, Suman; Mandal, Anup; Sahoo, Harekrishna; Mallik, Sumitava; Grandhi, Gowri Sankar; Baidya, Mahiuddin

    2018-02-02

    A straightforward synthesis of 2-styrylbenzoic acids from aryl carboxylic acids is disclosed through a carboxylate-assisted coupling under Ru(II) catalysis. This protocol is simple and exhibits broad scope with high tolerance of common organic functional groups, providing good to excellent yields of diverse olefinated products. The efficacy of this protocol has been showcased through sequential syntheses of isochromanone, isocoumarin, and formal synthesis of anacardic acid derivative in good yields.

  4. Cobalt catalyzed hydroesterification of a wide range of olefins

    Energy Technology Data Exchange (ETDEWEB)

    Van Rensburg, H.; Hanton, M.; Tooze, R.P.; Foster, D.F. [Sasol Technology UK, St Andrews (United Kingdom)

    2011-07-01

    Petrochemical raw materials are an essential raw material for the production of detergents with a substantial portion of synthetic fatty alcohols being produced via hydroformylation of oil or coal derived olefins. Carbonylation processes other than hydroformylation have to date not been commercially employed for the production of fatty esters or alcohols. In this document we highlight the opportunities of converting olefins to esters using cobalt catalyzed alkoxycarbonylation. This process is highly versatile and applicable to a wide range of olefins, linear or branched, alpha or internal in combination with virtually any chain length primary or secondary alcohol allowing the synthesis of a diverse array of compounds such as ester ethoxylated surfactants, methyl branched detergents, lubricants and alkyl propanoates. Furthermore, alkoxycarbonylation of a broad olefin/paraffin hydrocarbon range could be used to produce the corresponding broad cut detergent alcohols. (orig.)

  5. Olefin Metathesis in Peptidomimetics, Dynamic Combinatorial Chemistry, and Molecular Imprinting

    National Research Council Canada - National Science Library

    Low, Tammy K

    2006-01-01

    .... Our research goals consisted of employing olefin metathesis in the synthesis of peptidomimetics, and studying the feasibility of this method in dynamic combinatorial chemistry and molecular imprinting of nerve agents...

  6. Olefin copolymerization via reversible addition-fragmentation chain transfer

    NARCIS (Netherlands)

    Venkatesh, R.; Staal, B.B.P.; Klumperman, B.

    2004-01-01

    Successful statistical copolymn. of an a-olefin (1-octene) with an acrylate (Bu acrylate, BA) and with a methacrylate (Me methacrylate, MMA), employing reversible addn.-fragmentation chain transfer (RAFT) mediated polymn. has been accomplished

  7. Direct observation of OH production from the ozonolysis of olefins

    Science.gov (United States)

    Donahue, Neil M.; Kroll, Jesse H.; Anderson, James G.; Demerjian, Kenneth L.

    Ozone olefin reactions may be a significant source of OH in the urban atmosphere, but current evidence for OH production is indirect and contested. We report the first direct observation of OH radicals from the reaction of ozone with a series of olefins (ethene, isoprene, trans-2-butene and 2,3 dimethyl-2-butene) in 4-6 torr of nitrogen. Using LIF to directly observe the steady-state of OH produced by the initial ozone-olefin reaction and subsequently destroyed by the OH-olefin reaction, we are able to establish OH yields broadly consistent with indirect values. The identification of the OH is unequivocal, and there is no indication that it is produced by a secondary process. To support these observations, we present a complete ab-initio potential energy surface for the O3-ethene reaction, extending from the reactants to available products.

  8. Olefins and chemical regulation in Europe: REACH.

    Science.gov (United States)

    Penman, Mike; Banton, Marcy; Erler, Steffen; Moore, Nigel; Semmler, Klaus

    2015-11-05

    REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) is the European Union's chemical regulation for the management of risk to human health and the environment (European Chemicals Agency, 2006). This regulation entered into force in June 2007 and required manufacturers and importers to register substances produced in annual quantities of 1000 tonnes or more by December 2010, with further deadlines for lower tonnages in 2013 and 2018. Depending on the type of registration, required information included the substance's identification, the hazards of the substance, the potential exposure arising from the manufacture or import, the identified uses of the substance, and the operational conditions and risk management measures applied or recommended to downstream users. Among the content developed to support this information were Derived No-Effect Levels or Derived Minimal Effect Levels (DNELs/DMELs) for human health hazard assessment, Predicted No Effect Concentrations (PNECs) for environmental hazard assessment, and exposure scenarios for exposure and risk assessment. Once registered, substances may undergo evaluation by the European Chemicals Agency (ECHA) or Member State authorities and be subject to requests for additional information or testing as well as additional risk reduction measures. To manage the REACH registration and related activities for the European olefins and aromatics industry, the Lower Olefins and Aromatics REACH Consortium was formed in 2008 with administrative and technical support provided by Penman Consulting. A total of 135 substances are managed by this group including 26 individual chemical registrations (e.g. benzene, 1,3-butadiene) and 13 categories consisting of 5-26 substances. This presentation will describe the content of selected registrations prepared for 2010 in addition to the significant post-2010 activities. Beyond REACH, content of the registrations may also be relevant to other European activities, for

  9. Total Synthesis and Stereochemical Assignment of Delavatine A: Rh-Catalyzed Asymmetric Hydrogenation of Indene-Type Tetrasubstituted Olefins and Kinetic Resolution through Pd-Catalyzed Triflamide-Directed C-H Olefination.

    Science.gov (United States)

    Zhang, Zhongyin; Wang, Jinxin; Li, Jian; Yang, Fan; Liu, Guodu; Tang, Wenjun; He, Weiwei; Fu, Jian-Jun; Shen, Yun-Heng; Li, Ang; Zhang, Wei-Dong

    2017-04-19

    Delavatine A (1) is a structurally unusual isoquinoline alkaloid isolated from Incarvillea delavayi. The first and gram-scale total synthesis of 1 was accomplished in 13 steps (the longest linear sequence) from commercially available starting materials. We exploited an isoquinoline construction strategy and developed two reactions, namely Rh-catalyzed asymmetric hydrogenation of indene-type tetrasubstituted olefins and kinetic resolution of β-alkyl phenylethylamine derivatives through Pd-catalyzed triflamide-directed C-H olefination. The substrate scope of the first reaction covered unfunctionalized olefins and those containing polar functionalities such as sulfonamides. The kinetic resolution provided a collection of enantioenriched indane- and tetralin-based triflamides, including those bearing quaternary chiral centers. The selectivity factor (s) exceeded 100 for a number of substrates. These reactions enabled two different yet related approaches to a key intermediate 28 in excellent enantiopurity. In the synthesis, the triflamide served as not only an effective directing group for C-H bond activation but also a versatile functional group for further elaborations. The relative and absolute configurations of delavatine A were unambiguously assigned by the syntheses of the natural product and its three stereoisomers. Their cytotoxicity against a series of cancer cell lines was evaluated.

  10. Olefin Metathesis in Peptidomimetics, Dynamic Combinatorial Chemistry, and Molecular Imprinting

    Science.gov (United States)

    2006-08-01

    organic, and biochemistry, lectured in chemistry of weapons, and researched on ionic liquids and nucleic acid derivatives. She discovered her joy of...Products from oligomerization of the dimer scaffold or olefin isomerization are excluded from these projected numbers.97,98 The number of...Figure 3-8). This is excluding any olefin isomerization products or oligomerization of the cyclic scaffold. If stereoisomers are considered, then

  11. Rh(III)-catalyzed oxidative olefination of N-(1-naphthyl)sulfonamides using activated and unactivated alkenes.

    Science.gov (United States)

    Li, Xuting; Gong, Xue; Zhao, Miao; Song, Guoyong; Deng, Jian; Li, Xingwei

    2011-11-04

    Rhodium(III)-catalyzed oxidative olefination of N-(1-naphthyl)sulfonamides has been achieved at the peri position. Three categories of olefins have been successfully applied. Activated olefins reacted to afford five-membered azacycles as a result of oxidative olefination-hydroamination. Unactivated olefins reacted to give the olefination product. 2-fold oxidative C-C and C-N coupling was achieved for allylbenzenes. © 2011 American Chemical Society

  12. Synthesis of interlocked molecules by olefin metathesis

    Science.gov (United States)

    Clark, Paul Gregory

    A large body of work in the Grubbs group has focused on the development of functional-group tolerant ruthenium alkylidene catalysts that perform a number of olefin metathesis reactions. These catalysts have seen application in a wide range of fields, including classic total synthesis as well as polymer and materials chemistry. One particular family of compounds, interlocked molecules, has benefitted greatly from these advances in catalyst stability and activity. This thesis describes several elusive and challenging interlocked architectures whose syntheses have been realized through the utilization of different types of ruthenium-catalyzed olefin metathesis reactions. Ring-closing olefin metathesis has enabled the synthesis of a [c2]daisy-chain dimer with the ammonium binding site near the cap of the dimer. A deprotonated DCD possessing such a structural attribute will more forcefully seek to restore coordinating interactions upon reprotonation, enhancing its utility as a synthetic molecular actuator. Dimer functionalization facilitated incorporation into linear polymers, with a 48% size increase of an unbound, extended analogue of the polymer demonstrating slippage of the dimer units. Ongoing work is directed at further materials studies, in particular, exploring the synthesis of macroscopic networks containing the DCD units and analyzing the correlation between molecular-scale extension-contraction manipulations and resulting macro-scale changes. A "clipping" approach to a polycatenated cyclic polymer, a structure that resembles a molecular "charm bracelet", has been described. The use of ring-opening metathesis polymerization of a carbamate monomer in the presence of a chain transfer agent allowed for the synthesis of a linear polymer that was subsequently functionalized and cyclized to the corresponding cyclic analogue. This cyclic polymer was characterized through a variety of techniques, and subjected to further functionalization reactions, affording a cyclic

  13. A method for producing light olefines

    Energy Technology Data Exchange (ETDEWEB)

    Kavada, N.; Katsuno, K.

    1982-11-04

    A method is proposed for producing light olefins from MeOH in the presence of a catalyst (Kt), a crystalline silicate which includes silicon, an alkaline and or alkaline earth metal, titanium(4+) and phosphorus(5+), whose composition is described by the formula p(019 plus or minus 0.3)M2/mO with pZ4/nO2 with SiO2, where M is the alkaline or alkaline earth metal, Z = titanium(4+) or phosphorus(5+), m is the valency of the metal, n is the valency of Z and O is less than p is less than or equal to 0.1. A high selectivity of MeOH to C2 to C4 olefins is achieved in the presence of the catalyst. Silicon powder, silica gel, colloidal silicon, liquid glass or silicates of alkaline metals in a ratio of SiO2 to M2O of 1 to 5 is used as the source of the first component. Hydroxides or silicates of potassium and sodium (best sodium) and nitrates or chlorides of alkaline earth metals (best calcium) are used as the source of the second component. Water soluble compounds of titanium(4+) (best Ti(SO4)2, TiBr4 and TiI4) and phosphorus(5+) (best H3PO4, Na3PO4) are used as the source of the third component. Heterocyclic compounds (best morpholine, oxazolidine and their derivatives, which are taken in a molar ratio of crystallization agent to SiO2 of 0.01 to 50 (best at 0.1 to 10), are used as the crystallization agent (ArK). The catalyst is prepared through heating in an autoclave at a temperature of 80 to 300 degrees (best at 120 to 200 degrees) at atmospheric pressure for 10 to 50 hours with mixing of the mixture of the three components, water and the crystallization agent. The forming crystalline product is cooled, poured off, washed with water, dried for several hours at a temperature of at least 100 degrees and roasted in air for 2 to 48 hours at 300 to 700 degrees.

  14. Proceedings of the DGMK-Conference 'Creating value from light olefins - production and conversion'. Authors' manuscripts

    Energy Technology Data Exchange (ETDEWEB)

    Emig, G; Kraemer, H J; Weitkamp, J [eds.

    2001-07-01

    Main topics of the conference were: production of light olefin by steamcracking and catalytic cracking processes, catalysts, methanol to olefin processes, oxidative dehydrogenation, partial oxidation, selective oxidation of alkanes with various catalysts. (uke)

  15. Primary Alcohols from Terminal Olefins: Formal Anti-Markovnikov Hydration via Triple Relay Catalysis

    KAUST Repository

    Dong, G.; Teo, P.; Wickens, Z. K.; Grubbs, R. H.

    2011-01-01

    Alcohol synthesis is critical to the chemical and pharmaceutical industries. The addition of water across olefins to form primary alcohols (anti-Markovnikov olefin hydration) would be a broadly useful reaction but has largely proven elusive

  16. Reactivity of olefin and allyl ligands in π-complexes of metals

    International Nuclear Information System (INIS)

    Kukushkin, Yu.N.

    1987-01-01

    The data on reactivity of olefin and allyl ligands in transition metal (Ru, W) π-complexes, published up to 1984 are presented. Metal ion coordination of olefins causes their appreciable reactivity change. Transformations of π-olefin ligands into σ-alkyl ones, interaction of π-complexes with oxygen nucleophilic reagents, amines, halogenides and pseudohalogenides are considered

  17. Palladium(II)-catalyzed ortho-olefination of arenes applying sulfoxides as remote directing groups.

    Science.gov (United States)

    Wang, Binjie; Shen, Chuang; Yao, Jinzhong; Yin, Hong; Zhang, Yuhong

    2014-01-03

    A novel palladium-catalyzed ortho-C(sp(2))-H olefination protocol has been developed by the use of sulfoxide as the directing group. Importantly, relatively remote coordination can be accessed to achieve the ortho olefination of benzyl, 2-arylethyl, and 3-arylpropenyl sulfoxide substrates, and the olefinated sulfoxide can be easily transformed to other functionalities.

  18. Kinetically based NMR method of measuring blending octane number of olefins

    NARCIS (Netherlands)

    Golombok, M.; Bruijn, J.; Morley, C.

    1995-01-01

    Olefins are highly nonlinear octane blenders so that standard GC analyses are poor predictors of blend quality. Engine rating is the only way of measuring olefin octane number nonlinearity. It is thus not possible to rapidly assess the quality of the product obtained from an olefin-producing

  19. Rapid synthesis of an electron-deficient t-BuPHOX ligand: cross-coupling of aryl bromides with secondary phosphine oxides

    KAUST Repository

    McDougal, Nolan T.

    2010-10-01

    Herein an efficient and direct copper-catalyzed coupling of oxazoline-containing aryl bromides with electron-deficient secondary phosphine oxides is reported. The resulting tertiary phosphine oxides can be reduced to prepare a range of PHOX ligands. The presented strategy is a useful alternative to known methods for constructing PHOX derivatives.

  20. Rapid synthesis of an electron-deficient t-BuPHOX ligand: cross-coupling of aryl bromides with secondary phosphine oxides

    KAUST Repository

    McDougal, Nolan T.; Streuff, Jan; Mukherjee, Herschel; Virgil, Scott C.; Stoltz, Brian M.

    2010-01-01

    Herein an efficient and direct copper-catalyzed coupling of oxazoline-containing aryl bromides with electron-deficient secondary phosphine oxides is reported. The resulting tertiary phosphine oxides can be reduced to prepare a range of PHOX ligands. The presented strategy is a useful alternative to known methods for constructing PHOX derivatives.

  1. Ionic liquids for separation of olefin-paraffin mixtures

    Science.gov (United States)

    Dai, Sheng; Luo, Huimin; Huang, Jing-Fang

    2013-09-17

    The invention is directed to an ionic liquid comprising (i) a cationic portion containing a complex of a silver (I) ion and one or more neutral ligands selected from organoamides, organoamines, olefins, and organonitriles, and (ii) an anionic portion having the chemical formula ##STR00001## wherein m and n are independently 0 or an integer of 1 or above, and p is 0 or 1, provided that when p is 0, the group --N--SO.sub.2--(CF.sub.2).sub.nCF.sub.3 subtended by p is replaced with an oxide atom connected to the shown sulfur atom. The invention is also directed to a method for separating an olefin from an olefin-paraffin mixture by passing the mixture through a layer of the ionic liquid described above.

  2. Allene or alkyne treatment of olefin conversion catalysts

    International Nuclear Information System (INIS)

    Banks, R.L.

    1986-01-01

    This patent describes a disproportionation process which comprises contacting at least one olefin from the group consisting of: acyclic mono- and polyenes having at least 3 up to 10 carbon atoms per molecule, and cycloalkyl and aryl derivatives thereof; cyclic mono- and polyenes having at least 4 to 10 carbon atoms per molecule, and alkyl and aryl derivatives thereof; mixtures of two or more of the above olefins; and mixtures of ethylene with one or more of the above olefins capable of undergoing disproportionation with a tungsten oxide on silica disproportionation catalyst system under disproportionation conditions, the improvement comprising contacting the catalyst with an activating amount of at least one alkyne conforming to the formula: R-C=C-R wherein each R is independently H or a C/sub 1/-C/sub 6/ carbon radical per mole of tungsten oxide

  3. Olefination reactions of phosphorus-stabilized carbon nucleophiles.

    Science.gov (United States)

    Gu, Yonghong; Tian, Shi-Kai

    2012-01-01

    A range of phosphorus-stabilized carbon nucleophiles have been employed for alkene synthesis with high chemo-, regio-, and stereoselectivity. The Wittig, Horner-Wadsworth-Emmons, Horner-Wittig, and Evans-Akiba reactions utilize phosphonium-, phosphonate-, phosphine oxide-, and pentacoordinated phosphorane-stabilized carbanions as nucleophiles, respectively, to undergo olefination with aldehydes or ketones, and each of these transformations has its own advantages and limitations. Modifying the structures of these nucleophiles along with optimizing reaction conditions results in the formation of a wide variety of polysubstituted alkenes in a highly stereoselective manner. The olefination of imines with phosphonium ylides has recently emerged as a useful approach to tune the stereoselectivity for alkene synthesis. This review focuses on recent advances in the stereoselective olefination of phosphorus-stabilized carbon nucleophiles.

  4. Comparing Ru and Fe-catalyzed olefin metathesis

    KAUST Repository

    Poater, Albert; Chaitanya Vummaleti, Sai Vikrama; Pump, Eva; Cavallo, Luigi

    2014-01-01

    Density functional theory calculations have been used to explore the potential of Fe-based complexes with an N-heterocyclic carbene ligand, as olefin metathesis catalysts. Apart from a less endothermic reaction energy profile, a small reduction in the predicted upper energy barriers (≈ 2 kcal mol -1) is calculated in the Fe catalyzed profile with respect to the Ru catalysed profile. Overall, this study indicates that Fe-based catalysts have the potential to be very effective olefin metathesis catalysts. This journal is © the Partner Organisations 2014.

  5. Methylenation of perfluoroalkyl ketones using a Peterson olefination approach.

    Science.gov (United States)

    Hamlin, Trevor A; Kelly, Christopher B; Cywar, Robin M; Leadbeater, Nicholas E

    2014-02-07

    An operationally simple, inexpensive, and rapid route for the olefination of a wide array of trifluoromethyl ketones to yield 3,3,3-trifluoromethylpropenes is reported. Using a Peterson olefination approach, the reaction gives good to excellent yields of the alkene products and can be performed without purification of the β-hydroxysilyl intermediate. The reaction can be extended to other perfluoroalkyl substituents and is easily scaled up. The alkenes prepared can be readily transformed into a variety of other perfluoroalkyl-containing compounds.

  6. Silver-Catalyzed Aldehyde Olefination Using Siloxy Alkynes.

    Science.gov (United States)

    Sun, Jianwei; Keller, Valerie A; Meyer, S Todd; Kozmin, Sergey A

    2010-03-20

    We describe the development of a silver-catalyzed carbonyl olefination employing electron rich siloxy alkynes. This process constitutes an efficient synthesis of trisubstituted unsaturated esters, and represents an alternative to the widely utilized Horner-Wadsworth-Emmons reaction. Excellent diastereoselectivities are observed for a range of aldehydes using either 1-siloxy-1-propyne or 1-siloxy-1-hexyne. This mild catalytic process also enables chemoselective olefination of aldehydes in the presence of either ester or ketone functionality. Furthermore, since no by-products are generated, this catalytic process is perfectly suited for development of sequential reactions that can be carried out in a single flask.

  7. Electrochemistry for biofuel generation: transformation of fatty acids and triglycerides to diesel-like olefin/ether mixtures and olefins.

    Science.gov (United States)

    dos Santos, Tatiane R; Harnisch, Falk; Nilges, Peter; Schröder, Uwe

    2015-03-01

    Electroorganic synthesis can be exploited for the production of biofuels from fatty acids and triglycerides. With Coulomb efficiencies (CE) of up to 50 %, the electrochemical decarboxylation of fatty acids in methanolic and ethanolic solutions leads to the formation of diesel-like olefin/ether mixtures. Triglycerides can be directly converted in aqueous solutions by using sonoelectrochemistry, with olefins as the main products (with a CE of more than 20 %). The latter reaction, however, is terminated at around 50 % substrate conversion by the produced side-product glycerol. An energy analysis shows that the electrochemical olefin synthesis can be an energetically competitive, sustainable, and--in comparison with established processes--economically feasible alternative for the exploitation of fats and oils for biofuel production. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. P(O)R2-Directed Enantioselective C-H Olefination toward Chiral Atropoisomeric Phosphine-Olefin Compounds.

    Science.gov (United States)

    Li, Shi-Xia; Ma, Yan-Na; Yang, Shang-Dong

    2017-04-07

    An effective synthesis of chiral atropoisomeric biaryl phosphine-olefin compounds via palladium-catalyzed enantioselective C-H olefination has been developed for the first time. The reactions are operationally simple, tolerate wide functional groups, and have a good ee value. Notably, P(O)R 2 not only acts as the directing group to direct C-H activation in order to make a useful ligand but also serves to facilitate composition of the product in a useful manner in this transformation.

  9. Capturing of the monoterpene olefin limonene produced in Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Jongedijk, E.J.; Cankar, K.; Ranzijn, J.; Krol, van der A.R.; Bouwmeester, H.J.; Beekwilder, M.J.

    2015-01-01

    Monoterpene olefins such as limonene are plant compounds with applications as flavouring and fragrance agents, as solvents and potentially also in polymer and fuel chemistry. We engineered baker's yeast Saccharomyces cerevisiae to express a (-)-limonene synthase from Perilla frutescens and a

  10. Methanol conversion to lower olefins over RHO type zeolite

    KAUST Repository

    Masih, Dilshad; Imai, Hiroyuki; Yokoi, Toshiyuki; Kondo, Junkonomura; Tatsumi, Takashi

    2013-01-01

    Eight-membered ring small-pore zeolite of RHO-type topology has been synthesized, characterized and tested for methanol-to-olefin (MTO) reaction. The zeolite was hydrothermally crystallized from the gel with Si/Al ratio of 5.0. It showed a high BET

  11. Ozonolysis of Model Olefins-Efficiency of Antiozonants

    NARCIS (Netherlands)

    Huntink, N.M.; Datta, Rabin; Talma, Auke; Noordermeer, Jacobus W.M.

    2006-01-01

    In this study, the efficiency of several potential long lasting antiozonants was studied by ozonolysis of model olefins. 2-Methyl-2-pentene was selected as a model for natural rubber (NR) and 5-phenyl-2-hexene as a model for styrene butadiene rubber (SBR). A comparison was made between the

  12. The asymmetric Schrock olefin metathesis catalysts. A computational study

    NARCIS (Netherlands)

    Goumans, T.P.M.; Ehlers, A.W.; Lammertsma, K.

    2005-01-01

    The mechanism of the transition metal catalyzed olefin metathesis reaction with the Schrock catalyst is investigated with pure (BP86) and hybrid (B3LYP) density functional theory. On the free-energy surface there is no adduct between ethylene and model catalyst (MeO)

  13. Mesoporous molecular sieves as advanced supports for olefin metathesis catalysts

    Czech Academy of Sciences Publication Activity Database

    Balcar, Hynek; Čejka, Jiří

    2013-01-01

    Roč. 257, 21-22 (2013), s. 3107-3124 ISSN 0010-8545 R&D Projects: GA AV ČR IAA400400805; GA ČR GBP106/12/G015 Institutional support: RVO:61388955 Keywords : Olefin metathesis * mesoporous molecular sieves * Heterogeneous catalysts Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 12.098, year: 2013

  14. Catalytic polymerization of olefins in supercritical carbon dioxide

    NARCIS (Netherlands)

    Kemmere, M.F.; Vries, de T.J.; Keurentjes, J.T.F.

    2004-01-01

    A novel process is being developed for the catalytic polymerization of olefins in supercritical carbon dioxide (sc CO2), for which potential applications will mainly be in the production of EPDM and other elastomers. For this purpose, the Brookhart catalyst has been tested for the homopolymerization

  15. Radiation-induced copolymerization of hexafluoroacetone with α-olefins

    International Nuclear Information System (INIS)

    Matsuda, O.; Watanabe, S.; Okamoto, J.; Machi, S.; Tabata, Y.

    1977-01-01

    The copolymerization of hexafluoroacetone with higher α-olefins above butene, such as 1-pentene (I), 1-hexene (II), 1-octene (III), 2-methyl-1-butene (IV), 2-methyl-1-pentene (V), 3-methyl-1-butene (VI), and 4-methyl-1-pentene (VII) was studied at relatively low temperatures by γ-ray irradiation. Copolymerization of II, IV, V, and VII with hexafluoroacetone was found to scarcely take place at -78 0 C in bulk, but the addition of trichlorotrifluoroethane in amounts to yield equimolar mixtures resulted in conversion of 15.7 percent for IV and of 2.1 to 4.0 percent for the other α-olefins. Higher conversion of V at -78 0 C than at 0 0 C suggest that copolymerization may take place via an ionic mechanism. The effects of various additives on the copolymerization are reported. Infrared spectral studies indicated that the double bond of the α-olefins is opened to form a polymer. The C--O double bond of the hexafluoroacetone and the α-olefin double bond are opened to form the copolymer

  16. Optical fibre Bragg grating recorded in TOPAS cyclic olefin copolymer

    DEFF Research Database (Denmark)

    Johnson, I.P.; Yuan, Scott Wu; Stefani, Alessio

    2011-01-01

    A report is presented on the inscription of a fibre Bragg grating into a microstructured polymer optical fibre fabricated from TOPAS cyclic olefin copolymer. This material offers two important advantages over poly (methyl methacrylate), which up to now has formed the basis for polymer fibre Bragg...

  17. Olefination of carbonyl compounds: modern and classical methods

    Energy Technology Data Exchange (ETDEWEB)

    Korotchenko, V N; Nenajdenko, Valentine G; Balenkova, Elizabeth S [Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow (Russian Federation); Shastin, Aleksey V [Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow Region (Russian Federation)

    2004-10-31

    The published data on the methods for alkene synthesis by olefination of carbonyl compounds are generalised and systematised. The main attention is given to the use of transition metals and organoelement compounds. The review covers the data on both classical and newly developed methods that are little known to chemists at large.

  18. Manganese Catalyzed α-Olefination of Nitriles by Primary Alcohols.

    Science.gov (United States)

    Chakraborty, Subrata; Das, Uttam Kumar; Ben-David, Yehoshoa; Milstein, David

    2017-08-30

    Catalytic α-olefination of nitriles using primary alcohols, via dehydrogenative coupling of alcohols with nitriles, is presented. The reaction is catalyzed by a pincer complex of an earth-abundant metal (manganese), in the absence of any additives, base, or hydrogen acceptor, liberating dihydrogen and water as the only byproducts.

  19. Olefination of carbonyl compounds: modern and classical methods

    Science.gov (United States)

    Korotchenko, V. N.; Nenajdenko, Valentine G.; Balenkova, Elizabeth S.; Shastin, Aleksey V.

    2004-10-01

    The published data on the methods for alkene synthesis by olefination of carbonyl compounds are generalised and systematised. The main attention is given to the use of transition metals and organoelement compounds. The review covers the data on both classical and newly developed methods that are little known to chemists at large.

  20. Access to Functionalized Steroid Side Chains via Modified Julia Olefination

    Science.gov (United States)

    Izgu, Enver Cagri; Burns, Aaron C.; Hoye, Thomas R.

    2011-01-01

    Various functionalized steroidal side chains were conveniently accessed by a modified Julia olefination strategy using a common sulfone donor and an appropriate α-branched aldehyde acceptor. For the coupling of these hindered classes of reaction partners (and in contrast to typically observed trends), the benzothiazolyl(BT)-sulfone anion gave superior outcomes compared to the phenyltetrazolyl(PT)-sulfone anion. PMID:21244047

  1. Characterization of electron-deficient chemical bonding of diborane with attosecond electron wavepacket dynamics and laser response

    International Nuclear Information System (INIS)

    Yonehara, Takehiro; Takatsuka, Kazuo

    2009-01-01

    We report a theoretical study of non-adiabatic electrons-nuclei coupled dynamics of diborane H 2 BH 2 BH 2 under several types of short pulse lasers. This molecule is known to have particularly interesting geometrical and electronic structures, which originate from the electron-deficient chemical bondings. We revisit the chemical bonding of diborane from the view point of electron wavepacket dynamics coupled with nuclear motions, and attempt to probe the characteristics of it by examining its response to intense laser fields. We study in the following three aspects, (i) bond formation of diborane by collision between two monoboranes, (ii) attosecond electron wavepacket dynamics in the ground state and first excited state by circularly polarized laser pulse, and (iii) induced fragmentation back to monoborane molecules by linearly polarized laser. The wave lengths of two types of laser field employed are 200 nm (in UV range) and 800 nm (in IR range), and we track the dynamics from hundreds of attoseconds up to few tens of femtoseconds. To this end, we apply the ab initio semiclassical Ehrenfest theory, into which the classical vector potential of a laser field is introduced. Basic features of the non-adiabatic response of electrons to the laser fields is elucidated in this scheme. To analyze the electronic wavepackets thus obtained, we figure out bond order density that is a spatial distribution of the bond order and bond order flux density arising only from the bonding regions, and so on. Main findings in this work are: (i) dimerization of monoboranes to diborane is so efficient that even intense laser is hard to prevent it; (ii) collective motions of electron flux emerge in the central BHHB bonding area in response to the circularly polarized laser fields; (iii) laser polarization with the direction of central two BH bonding vector is efficient for the cleavage of BH 3 -BH 3 ; and (iv) nuclear derivative coupling plays a critical role in the field induced

  2. Solution-phase parallel synthesis of aryloxyimino amides via a novel multicomponent reaction among aromatic (Z)-chlorooximes, isocyanides, and electron-deficient phenols.

    Science.gov (United States)

    Mercalli, Valentina; Giustiniano, Mariateresa; Del Grosso, Erika; Varese, Monica; Cassese, Hilde; Massarotti, Alberto; Novellino, Ettore; Tron, Gian Cesare

    2014-11-10

    A library of 41 aryloxyimino amides was prepared via solution phase parallel synthesis by extending the multicomponent reaction of (Z)-chlorooximes and isocyanides to the use of electron-deficient phenols. The resulting aryloxyiminoamide derivatives can be used as intermediates for the synthesis of benzo[d]isoxazole-3-carboxamides, dramatically reducing the number of synthetic steps required by other methods reported in literature.

  3. Reactions of rhodium(I) carbonyl chloride with olefins

    International Nuclear Information System (INIS)

    Varshavskii, Yu.S.; Kiseleva, N.V.; Cherkasova, T.G.; Buzina, N.A.; Bresler, L.S.

    1987-01-01

    The reactions of [Rh(CO) 2 Cl] 2 (Y 0 ) with cyclooctene and several other olefins (1-heptene, 1-hexene, ethylene, and cyclohexene) have been studied by IR and 13 C NMR spectroscopy. The main reaction products are the binuclear complexes Rh 2 L(CO) 3 Cl 2 (Y 1 ) and [RhL(CO)Cl] 2 (Y 2 ), where L denotes the olefin. The extent of replacement of the carbonyl groups depends on the nature of the olefin and the conditions under which the reaction is carried out (the L:Rh ratio and the removal of CO from the reaction sphere). The liquid olefins form the following series according to their ability to replace the carbonyl groups: C 8 H 14 > C 7 H 14 , C 6 H 12 > C 6 H 10 . In the presence of an excess of C 8 H 14 , Y 2 disproportionates with the formation of a dicarbonyl product, which presumably corresponds to the formula Rh(C 8 H 14 ) 2 (CO) 2 Cl (a pentacoordinate complex with a trigonal-bipyramidal structure). The 13 C signal in the NMR spectrum of a solution of Y 2 in C 8 H 14 is a singlet with σ( 13 C) 180.3 ppm, which is an indication of the rapid exchange of the carbonyl groups. Rapid exchange of the CO ligands is also observed in solutions of Y 0 in the olefins (with the exception of C 6 H 10 ). For example, the 13 C signal in the spectrum of a solution of Y 0 in C 8 H 14 is a singlet with σ( 13 C) 179.8 ppm. The spectrum of Y 0 in C 6 H 10 is a doublet with σ( 13 C) = 178.5 ppm and 1 J(CRh) = 76.3 Hz. A scheme for the interaction of Y 0 with olefins based on the conception of the trans antagonism of π-acceptor ligands has been proposed

  4. Prenylcoumarins in One or Two Steps by a Microwave-Promoted Tandem Claisen Rearrangement/Wittig Olefination/Cyclization Sequence.

    Science.gov (United States)

    Schultze, Christiane; Schmidt, Bernd

    2018-05-04

    The one-pot synthesis of 8-prenylcoumarins from 1,1-dimethylallylated salicylaldehydes and the stabilized ylide [(ethoxycarbonyl)methylene]triphenylphosphorane under microwave conditions was found to have a limited scope. The sequence suffers from a difficult and sometimes low-yielding synthesis of the precursors and from a competing deprenylation upon microwave irradiation. This side reaction occurs in particular with electron rich arenes with two or more alkoxy groups at adjacent positions, a prominent substitution pattern in naturally occurring 8-prenylcoumarins. Both limitations of this one-step sequence were overcome by a two-step synthesis consisting of a microwave-promoted tandem allyl ether Claisen rearrangement/Wittig olefination and a subsequent olefin cross metathesis with 2-methyl-2-butene. The cross metathesis step proceeds with a high selectivity and yields exclusively the desired prenyl, rather than the alternative crotyl substituent. Several naturally occurring 8-prenylcoumarins that were previously inaccessible have been synthesized in good overall yields along this route.

  5. Scope Definition

    DEFF Research Database (Denmark)

    Bjørn, Anders; Owsianiak, Mikołaj; Laurent, Alexis

    2018-01-01

    The scope definition is the second phase of an LCA. It determines what product systems are to be assessed and how this assessment should take place. This chapter teaches how to perform a scope definition. First, important terminology and key concepts of LCA are introduced. Then, the nine items...... making up a scope definition are elaborately explained: (1) Deliverables. (2) Object of assessment, (3) LCI modelling framework and handling of multifunctional processes, (4) System boundaries and completeness requirements, (5) Representativeness of LCI data, (6) Preparing the basis for the impact...... assessment, (7) Special requirements for system comparisons, (8) Critical review needs and (9) Planning reporting of results. The instructions relate both to the performance and reporting of a scope definition and are largely based on ILCD....

  6. Synthesis of terminal alkenes from internal alkenes and ethylene via olefin metathesis

    Science.gov (United States)

    Schrodi, Yann [Agoura Hills, CA

    2011-11-29

    This invention relates generally to olefin metathesis, and more particularly relates to the synthesis of terminal alkenes from internal alkenes using a cross-metathesis reaction catalyzed by a selected olefin metathesis catalyst. In one embodiment of the invention, for example, a method is provided for synthesizing a terminal olefin, the method comprising contacting an olefinic substrate comprised of at least one internal olefin with ethylene, in the presence of a metathesis catalyst, wherein the catalyst is present in an amount that is less than about 1000 ppm relative to the olefinic substrate, and wherein the metathesis catalyst has the structure of formula (II) ##STR00001## wherein the various substituents are as defined herein. The invention has utility, for example, in the fields of catalysis, organic synthesis, and industrial chemistry.

  7. Ternary catalyst-olefin-hydroperoxide complexes and their contribution to epoxidation

    International Nuclear Information System (INIS)

    Svitych, R.B.; Rzhevskaya, N.N.; Buchachenko, A.L.; Yablonskij, O.P.; Petukhov, A.A.; Belyaev, V.A.

    1976-01-01

    Electron and NMR spectroscopy have been used for studying the complex formation of catalysts (Mo 5+ , Mn 2+ , Co 2+ ) in double and triple systems: metal-olefin and metal-olefin-hydroperoxide. It has been established that ions of metals form complexes with olefins in the first sphere. The formation has been proved of ternary complexes metal-olefin-hydroperoxide. The structure of the complexes has been proposed with olefins in the first and hydroperoxide in the second sphere of the metal ion. The structure explains known kinetic regularities of epoxydation and the mechanism of the formation of final products, oxide and alcohol. It has been shown that the best catalysts for epoxydation of olefins with hydroperoxides must be the compounds of the metals with an electron state of ion d 0 [ru

  8. A latent ruthenium based olefin metathesis catalyst with a sterically demanding NHC ligand

    KAUST Repository

    Leitgeb, Anita; Abbas, Mudassar E.; Fischer, Roland C.; Poater, Albert; Cavallo, Luigi; Slugovc, Christian

    2012-01-01

    An olefin metathesis catalyst featuring a SIPr NHC and an ester chelating carbene ligand is introduced. In contrast to its previously published SIMes analogue, only the trans dichloro configurated isomer was obtained. The two counterparts are tested in various olefin metathesis reactions, revealing a striking superiority of the new complex in the cross metathesis of olefins with methyl vinyl ketone allowing for full conversion with only 500 ppm catalyst loading. © 2012 The Royal Society of Chemistry.

  9. Pd(II)-Catalyzed Olefination of sp3 C–H Bonds

    Science.gov (United States)

    Wasa, Masayuki; Engle, Keary M.; Yu, Jin-Quan

    2010-01-01

    The first Pd(II)-catalyzed sp3 C–H olefination reaction has been developed using N-arylamide directing groups. Following olefination, the resulting intermediates were found to undergo rapid 1,4-addition to give the corresponding γ lactams. Notably, this method was effective with substrates containing α-hydrogen atoms and could be applied to effect methylene C–H olefination of cyclopropane substrates. PMID:20187642

  10. Direct olefination of fluorinated benzothiadiazoles: a new entry to optoelectronic materials.

    Science.gov (United States)

    Xiao, Yu-Lan; Zhang, Bo; He, Chun-Yang; Zhang, Xingang

    2014-04-14

    Fluorinated olefin-containing benzothiadiazoles have important applications in optoelectronic materials. Herein, we reported the direct olefination of fluorinated benzothiadiazoles, as catalyzed by palladium. The reaction proceeds under mild reaction conditions and shows high functional-group compatibility. A preliminary study of the properties of the resulting symmetrical and unsymmetrical olefin-containing fluorinated benzothiadiazoles in red-light-emitting dyes has also been conducted. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. The activation mechanism of Fe-based olefin metathesis catalysts

    KAUST Repository

    Poater, Albert

    2014-08-01

    Density functional theory calculations have been used to describe the first turnover for olefin metathesis reaction of a homogenous Fe-based catalyst bearing a N-heterocyclic carbene ligand with methoxyethene as a substrate. Equal to conventional Ru-based catalysts, the activation of its Fe congener occurs through a dissociative mechanism, however with a more exothermic reaction energy profile. Predicted upper energy barriers were calculated to be on average ∼2 kcal/mol more beneficial for Fe catalyzed metathesis. Overall, this present computational study emphasises on advantages of Fe-based metathesis and gives a potential recipe for the design of an efficient Fe-based olefin metathesis catalysts. © 2014 Elsevier B.V.

  12. The activation mechanism of Fe-based olefin metathesis catalysts

    KAUST Repository

    Poater, Albert; Pump, Eva; Vummaleti, Sai V. C.; Cavallo, Luigi

    2014-01-01

    Density functional theory calculations have been used to describe the first turnover for olefin metathesis reaction of a homogenous Fe-based catalyst bearing a N-heterocyclic carbene ligand with methoxyethene as a substrate. Equal to conventional Ru-based catalysts, the activation of its Fe congener occurs through a dissociative mechanism, however with a more exothermic reaction energy profile. Predicted upper energy barriers were calculated to be on average ∼2 kcal/mol more beneficial for Fe catalyzed metathesis. Overall, this present computational study emphasises on advantages of Fe-based metathesis and gives a potential recipe for the design of an efficient Fe-based olefin metathesis catalysts. © 2014 Elsevier B.V.

  13. Methanol conversion to lower olefins over RHO type zeolite

    KAUST Repository

    Masih, Dilshad

    2013-07-01

    Eight-membered ring small-pore zeolite of RHO-type topology has been synthesized, characterized and tested for methanol-to-olefin (MTO) reaction. The zeolite was hydrothermally crystallized from the gel with Si/Al ratio of 5.0. It showed a high BET specific surface area (812 m2 g-1), micropore volume (0.429 cm3 g-1), and acid amount (2.53 mmol g-1). Scanning electron microscopy observations showed small crystallites of about 1 μm. The zeolite was active for MTO reaction with 100% methanol conversions at 623-723 K, whereas selectivity to lower olefins changed with time. © 2013 Elsevier B.V.

  14. Methyltrioxorhenium as catalyst of a novel aldehyde olefination

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, W.A. (Technische Univ. Muenchen, Garching (Germany). Anorganisch-Chemisches Inst.); Wang Mei (Academia Sinica, Dalian Inst. of Chemical Physics (China))

    1991-12-01

    From aldehydes or cyclic ketones, diazoalkanes, and teritiary phosphanes, olefins may be prepared with MTO as catalyst. In particular, diazoacetates and -malonates (R{sup 2}, R{sup 3} = H, CO{sub 2}Et, or 2 x CO{sub 2}Me) can be transformed into olefins with aliphatic and aromatic aldehydes (R{sup 1} = iPr, trans-PhCH=CH, Ph, 4-NO{sub 2}C{sub 6}H{sub 4}, etc.). Readily accessible starting materials, easy handling, mild reaction conditions, and good yields characterize the new synthesis method. (R' = Ph, 3-C{sub 6}H{sub 4}SO{sub 3}Na, nBu.) (orig.).

  15. A three-membered ring approach to carbonyl olefination.

    Science.gov (United States)

    Niyomchon, Supaporn; Oppedisano, Alberto; Aillard, Paul; Maulide, Nuno

    2017-10-23

    The carbon-carbon double bond, with its diverse and multifaceted reactivity, occupies a prominent position in organic synthesis. Although a variety of simple alkenes are readily available, the mild and chemoselective introduction of a unit of unsaturation into a functionalized organic molecule remains an ongoing area of research, and the olefination of carbonyl compounds is a cornerstone of such approaches. Here we show the direct olefination of hydrazones via the intermediacy of three-membered ring species generated by addition of sulfoxonium ylides, departing from the general dogma of alkenes synthesis from carbonyls. Moreover, the mild reaction conditions and operational simplicity of the transformation render the methodology appealing from a practical point of view.

  16. Decarbonisation of olefin processes using biomass pyrolysis oil

    International Nuclear Information System (INIS)

    Sharifzadeh, M.; Wang, L.; Shah, N.

    2015-01-01

    Highlights: • Decarbonization of olefin processes using biomass pyrolysis oil was proposed. • The decarbonization is based on integrated catalytic processing of bio-oil. • The retrofitted process features significant economic and environmental advantages. - Abstract: An imperative step toward decarbonisation of current industrial processes is to substitute their petroleum-derived feedstocks with biomass and biomass-derived feedstocks. For decarbonisation of the petrochemical industry, integrated catalytic processing of biomass pyrolysis oil (also known as bio-oil) is an enabling technology. This is because, under certain conditions, the reaction products form a mixture consisting of olefins and aromatics, which are very similar to the products of naphtha hydro-cracking in the conventional olefin processes. These synergies suggest that the catalytic bio-oil upgrading reactors can be seamlessly integrated to the subsequent separation network with minimal retrofitting costs. In addition, the integrated catalytic processing provides a high degree of flexibility for optimization of different products in response to market fluctuations. With the aim of assessing the techno-economic viability of this pathway, five scenarios in which different fractions of bio-oil (water soluble/water insoluble) were processed with different degrees of hydrogenation were studied in the present research. The results showed that such a retrofit is not only economically viable, but also provides a high degree of flexibility to the process, and contributes to decarbonisation of olefin infrastructures. Up to 44% reductions in greenhouse gas emissions were observed in several scenarios. In addition, it was shown that hydrogen prices lower than 6 $/kg will result in bio-based chemicals which are cheaper than equivalent petrochemicals. Alternatively, for higher hydrogen prices, it is possible to reform the water insoluble phase of bio-oil and produce bio-based chemicals, cheaper than

  17. Surface science of single-site heterogeneous olefin polymerization catalysts

    OpenAIRE

    Kim, Seong H.; Somorjai, Gabor A.

    2006-01-01

    This article reviews the surface science of the heterogeneous olefin polymerization catalysts. The specific focus is on how to prepare and characterize stereochemically specific heterogeneous model catalysts for the Ziegler–Natta polymerization. Under clean, ultra-high vacuum conditions, low-energy electron irradiation during the chemical vapor deposition of model Ziegler–Natta catalysts can be used to create a “single-site” catalyst film with a surface structure that produces only isotactic ...

  18. Retrofit with membrane the Paraffin/Olefin separation

    Energy Technology Data Exchange (ETDEWEB)

    Motelica, A.; Bruinsma, O.S.L.; Kreiter, R.; Den Exter, M.J.; Vente, J.F. [ECN Biomass and Energy Efficiency, Petten (Netherlands)

    2012-10-15

    Olefins, such as ethylene, propylene, and butadiene, are among the most produced intermediates in petrochemical industry. They are produced from a wide range of hydrocarbon feedstocks (ethane, propane, butane, naphtha, gas oil) via a cracking process. The last step in this process is the separation of olefins from other hydrocarbons, which is traditionally performed with distillation. As the physicochemical properties, such as volatility and boiling point, of the compounds are very similar, the purification becomes capital and energy intensive. For example, the top of an ethylene/ethane distillation column needs to be chilled to -30C and this requires large amount of electric energy consumption. The separation of butadiene from the C4-fraction is performed with the aid of an additional solvent. This solvent has to be regenerated at the cost of additional high temperature steam. To overcome these separation disadvantages of olefin/paraffin separation, different separation methods have been investigated and proposed in recent years. Suggested options are based on better heat integration of the overall process, or on novel separation systems such as Heat Integrated Distillation Columns, membrane separation, adsorption-desorption systems or on hybrid separation methods, for example, distillation combined with membrane separation.

  19. Life cycle assessment of energy consumption and GHG emissions of olefins production from alternative resources in China

    International Nuclear Information System (INIS)

    Xiang, Dong; Yang, Siyu; Li, Xiuxi; Qian, Yu

    2015-01-01

    Highlights: • Conduct a life cycle energy use and GHG emissions of olefins production processes. • Analyse effects of carbon capture and efficiency on alternative olefins production. • Analyse life cycle performance of Chinese olefins industry in three key periods. • Present the advantages and challenges of alternative olefins routes. - Abstract: Olefins are important platform chemicals widely used in industry. In terms of the short supply of oil resources, natural gas and coal are two significant alternative feedstocks. In this paper, energy consumption and GHG emissions of olefins production are analysed with life cycle assessment methods. Results showed the energy consumption and GHG emissions of natural gas-to-olefins are roughly equivalent to those of oil-to-olefins, while coal-to-olefins suffers from higher energy consumption and serious GHG emissions, including 5793 kg eq. CO 2 /t olefins of direct emissions and 5714 kg eq. CO 2 /t olefins of indirect emissions. To address the problem, the effect of carbon capture on coal-to-olefins is investigated. In comprehensive consideration of energy utilization, environmental impact, and economic benefit, the coal-to-olefins with 80% CO 2 capture of the direct emissions is found to be an appropriate choice. With this carbon capture configuration, the direct emissions of the coal-to-olefins are reduced to 1161 kg eq. CO 2 /t olefins. However, the indirect emissions are still not captured, which should be strictly monitored and significantly reduced. Finally, a scenario analysis is conducted to estimate resource utilization and GHG emissions of olefins production of China in 2020. Several suggestions are also proposed for policy making on the sustainable development of olefins industry

  20. Palladium-Catalyzed ortho-Olefination of Phenyl Acetic and Phenyl Propylacetic Esters via C-H Bond Activation.

    Science.gov (United States)

    Hu, Jundie; Guan, Mingyu; Han, Jian; Huang, Zhi-Bin; Shi, Da-Qing; Zhao, Yingsheng

    2015-08-21

    A highly regioselective palladium-catalyzed ester-directed ortho-olefination of phenyl acetic and propionic esters with olefins via C-H bond activation has been developed. A wide variety of phenyl acetic and propionic esters were tolerated in this transformation, affording the corresponding olefinated aromatic compounds. The ortho-olefination of heterocyclic acetic and propionic esters also took place smoothly giving the products in good yields, thus proving the potential utility of this protocol in synthetic chemistry.

  1. 76 FR 5319 - Regulation of Fuel and Fuel Additives: Alternative Test Method for Olefins in Gasoline

    Science.gov (United States)

    2011-01-31

    ... Regulation of Fuel and Fuel Additives: Alternative Test Method for Olefins in Gasoline AGENCY: Environmental... gasoline. This proposed rule will provide flexibility to the regulated community by allowing an additional... A. Alternative Test Method for Olefins in Gasoline III. Statutory and Executive Order Reviews A...

  2. 76 FR 65382 - Regulation of Fuel and Fuel Additives: Alternative Test Method for Olefins in Gasoline

    Science.gov (United States)

    2011-10-21

    ... Regulation of Fuel and Fuel Additives: Alternative Test Method for Olefins in Gasoline AGENCY: Environmental... gasoline. This final rule will provide flexibility to the regulated community by allowing an additional... Method for Olefins in Gasoline III. Statutory and Executive Order Reviews A. Executive Order 12866...

  3. Oxidative cracking of n-hexane: a catalytic pathway to olefins

    NARCIS (Netherlands)

    Boyadjian, C.A.

    2010-01-01

    Steam cracking, the major, current existing route for light olefin production, is the most energy consuming process in the chemical industry. The need for an energy efficient processes, urged substantial research work for the development of new catalytic technologies for light olefin production.

  4. Pd(II)-Catalyzed Enantioselective C-H Olefination of Diphenylacetic Acids

    Science.gov (United States)

    Shi, Bing-Feng; Zhang, Yang-Hui; Lam, Jonathan K.; Wang, Dong-Hui; Yu, Jin-Quan

    2009-01-01

    Pd(II)-catalyzed enantioselective C-H olefination of diphenylacetic acid substrates has been achieved through the use of mono-protected chiral amino acid ligands. The absolute configuration of the resulting olefinated products is consistent with that of a proposed C-H insertion intermediate. PMID:20017549

  5. Redox-Neutral Rh(III)-Catalyzed Olefination of Carboxamides with Trifluoromethyl Allylic Carbonate.

    Science.gov (United States)

    Park, Jihye; Han, Sangil; Jeon, Mijin; Mishra, Neeraj Kumar; Lee, Seok-Yong; Lee, Jong Suk; Kwak, Jong Hwan; Um, Sung Hee; Kim, In Su

    2016-11-18

    The rhodium(III)-catalyzed olefination of various carboxamides with α-CF 3 -substituted allylic carbonate is described. This reaction provides direct access to linear CF 3 -allyl frameworks with complete trans-selectivity. In particular, a rhodium catalyst provided Heck-type γ-CF 3 -allylation products via the β-O-elimination of rhodacycle intermediate and subsequent olefin migration process.

  6. Adsorption heats of olefins on supported MoO3/Al2O3 catalists

    International Nuclear Information System (INIS)

    Grinev, V.E.; Madden, M.; Khalit, V.A.; Aptekar', E.L.; Aldag, A.; Krylov, O.V.

    1983-01-01

    Adsorption heats of C 2 H 4 , C 3 H 6 and C 4 H 8 on supported MoO 3 /Al 2 O 3 catalysts containing 6, 10 and 15 wt. % of MoO 3 at 25, 77 and 195 deg are determimed. Adsorption heat of an olefin increases with a growing length of its carbonic chain. The number of adsorbed olefin molecules grows with an increase in the MoO 3 concentration, while initial adsorption heats decrease. The number of adsorbed olefins is proportional to mean rate of molybdenum reduction in catalysts. Adsorption heats of oxygen on the surface of the catalysts with preliminarily adsorbed olefins are determined. It is shown that adsorption of oxygen and olefins proceeeds both on the same and on different centres of the surface. Mechanisms of surface interactions are discussed

  7. Synthesis of thermoplastic poly(ester-olefin elastomers

    Directory of Open Access Journals (Sweden)

    Tanasijević Branka

    2004-01-01

    Full Text Available A series of thermoplastic poly(ester-olefin elastomers, based on poly(ethylene-stat-butylene, HO-PEB-OH, as the soft segment and poly (butylene terephthalate, PBT, as the hard segment, were synthesized by a catalyzed transesterification reaction in solution. The incorporation of soft hydrogenated poly(butadiene segments into the copolyester backbone was accomplished by the polycondensation of α, ω-dihydroxyl telechelic HO-PEB-OH, (PEB Mn = 3092 g/mol with 1,4-butanediol (BD and dimethyl terephthalate (DMT in the presence of a 50 wt-% high boiling solvent i.e., 1,2,4-trichlorobenzene. The molar ratio of the starting comonomers was selected to result in a constant hard to soft weight ratio of 60:40. The synthesis was optimized in terms of both the concentration of catalyst, tetra-n-butyl-titanate (Ti(OBu4, and stabilizer, N,N'-diphenyl-p-phenylenediamine (DPPD, as well as the reaction time. It was found that the optimal catalyst concentration (Ti(OBu4 for the synthesis of these thermoplastic elastomers was 1.0 mmol/mol ester and the optimal DPPD concentration was 1.0 wt-%. The extent of the reaction was followed by measuring the inherent viscosity of the reaction mixture. The effectiveness of the incorporation of the soft segments into the copolymer chains was proved by Soxhlet extraction with chloroform. The molecular structures, composition and the size of the synthesized poly(ester-butylenes were verified by 1H NMR spectroscopy, viscometry of dilute solutions and the complex dynamic melt viscosity. The thermal properties of poly(ester-olefins were investigated by differential scanning calorimetry (DSC. The degree of crystallinity was also determined by DSC. The thermal and thermo-oxidative stability were investigated by thermogravimetric analysis (TGA. The rheological properties of poly(ester-olefins were investigated by dynamic mechanical spectroscopy in the melt and solid state.

  8. Transmissive Olefination Route to Putative “Morinol I” Lignans

    Science.gov (United States)

    Yao, Lihua; Pitta, Bhaskar; Ravikumar, P. C.; Purzycki, Matthew; Fleming, Fraser F.

    2012-01-01

    A series of morinol-type lignans were rapidly assembled using a Grignard-based transmissive olefination. In combination with palladium-catalyzed arylations, the strategy provides stereoselective access to (7Z, 7′E), (7E, 7′E), (7E, 7′Z) morinol diastereomers and the (7Z, 8′E) and (7E, 8′E) conjugated analogs. Critical for the E/Z-stereoselectivity is a new, general method for converting alkenenitriles to alkenemethanols that circumvents the enal E/Z isomerization commonly encountered during conventional i-Bu2AlH reduction. PMID:22432777

  9. Radiation chemical addition of dimethylformamide to α-olefins

    International Nuclear Information System (INIS)

    Dederichs, B.; Saus, A.; Lennertz, A.M.

    1977-10-01

    With n-hexene-1, n-octene-1 and n-decene-1 the radiation-initiated addition of demethyl formamide to α-olefins is described for the fist time. N,N-dimethyl alkane carbonic acid amides and N-methyl-N-alkyl formamides are formed in a ratio of about 50:50. The addition reaction is investigated in depencence of a solvent, of the ratio of the reaction, temperature, reaction time and dose rate. Mechanistic considerations are performed by radiolysis experiments of dimethyl formamide. (orig.) [de

  10. Separation of Olefin/Paraffin Mixtures with Carrier Facilitated Membrane Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Merkel, T.C.; Blanc, R.; Zeid, J.; Suwarlim, A.; Firat, B.; Wijmans, H.; Asaro, M. (SRI); Greene, M.(Lummus)

    2007-03-12

    This document describes the results of a DOE funded joint effort of Membrane Technology and Research Inc. (MTR), SRI International (SRI), and ABB Lummus (ABB) to develop facilitated transport membranes for olefin/paraffin separations. Currently, olefin/paraffin separation is done by distillation—an extremely energy-intensive process because of the low relative volatilities of olefins and paraffins. If facilitated transport membranes could be successfully commercialized, the potential energy savings achievable with this membrane technology are estimated to be 48 trillion Btu per year by the year 2020. We discovered in this work that silver salt-based facilitated transport membranes are not stable even in the presence of ideal olefin/paraffin mixtures. This decline in membrane performance appears to be caused by a previously unrecognized phenomenon that we have named olefin conditioning. As the name implies, this mechanism of performance degradation becomes operative once a membrane starts permeating olefins. This project is the first study to identify olefin conditioning as a significant factor impacting the performance of facilitated olefin transport membranes. To date, we have not identified an effective strategy to mitigate the impact of olefin conditioning. other than running at low temperatures or with low olefin feed pressures. In our opinion, this issue must be addressed before further development of facilitated olefin transport membranes can proceed. In addition to olefin conditioning, traditional carrier poisoning challenges must also be overcome. Light, hydrogen, hydrogen sulfide, and acetylene exposure adversely affect membrane performance through unwanted reaction with silver ions. Harsh poisoning tests with these species showed useful membrane lifetimes of only one week. These tests demonstrate a need to improve the stability of the olefin complexing agent to develop membranes with lifetimes satisfactory for commercial application. A successful effort

  11. Hydroxycarbonylation of olefins and alcohols in ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Lapidus, A.L.; Eliseev, O.L.; Bondarenko, T.N.; Stepin, N.N. [Russian Academy of Sciences, Moscow (Russian Federation). N.D. Zelinsky Institute of Organic Chemistry

    2006-07-01

    Palladium-catalysed hydroxycarbonylation of olefins and alcohols proceeds in ionic liquid media. Terminal and internal olefins, cyclohexene, styrene, methanol, ethanol, n-butanol, cyclohexanol, benzyl alcohol and 1-phenylethanol were tested as substrates for the reaction. A number of molten salts were applied as a reaction medium and tetrabutylammonium bromide (m.p. 103 C) seemed to be the best. Carbon monoxide pressure of 2 MPa and reaction temperature of 110 C are suitable conditions to furnish the reaction in 2 hours in the presence of palladium acetate as a precursor. Triphenylphosphine added as a ligand reduces reaction rate. The critical role of counter anion in molten salt was also recognised. Yield of acids decreased in the order: Br{sup -} > Cl{sup -} > BF{sub 4} {approx}PF{sub 6}{sup -}. A two-route reaction scheme is proposed to explain the regularities of styrene and 1-phenylethanol hydroxycarbonylation. The catalytic system can be used repeatedly by simple extraction of products with diethyl ether. Nine cycles were carried out without loss of activity. (orig.)

  12. Direct, enantioselective α-alkylation of aldehydes using simple olefins.

    Science.gov (United States)

    Capacci, Andrew G; Malinowski, Justin T; McAlpine, Neil J; Kuhne, Jerome; MacMillan, David W C

    2017-11-01

    Although the α-alkylation of ketones has already been established, the analogous reaction using aldehyde substrates has proven surprisingly elusive. Despite the structural similarities between the two classes of compounds, the sensitivity and unique reactivity of the aldehyde functionality has typically required activated substrates or specialized additives. Here, we show that the synergistic merger of three catalytic processes-photoredox, enamine and hydrogen-atom transfer (HAT) catalysis-enables an enantioselective α-aldehyde alkylation reaction that employs simple olefins as coupling partners. Chiral imidazolidinones or prolinols, in combination with a thiophenol, iridium photoredox catalyst and visible light, have been successfully used in a triple catalytic process that is temporally sequenced to deliver a new hydrogen and electron-borrowing mechanism. This multicatalytic process enables both intra- and intermolecular aldehyde α-methylene coupling with olefins to construct both cyclic and acyclic products, respectively. With respect to atom and step-economy ideals, this stereoselective process allows the production of high-value molecules from feedstock chemicals in one step while consuming only photons.

  13. Gas phase reactions of nitrogen oxides with olefins

    Energy Technology Data Exchange (ETDEWEB)

    Altshuller, A P; Cohen, I

    1961-01-01

    The nature of the condensation products formed in the gas phase reactions of nitrogen dioxide and nitric oxide with pentene-1, 2-methylbutene-2, and 2-methylbutadiene-1,3 was investigated. The reactants were combined at partial pressures in the range of 0.1 to 2.5 mm with the total pressure at one atmosphere. The products were determined by infrared and ultraviolet spectroscopy and colorimetry. The condensates included primary and secondary nitro compounds and alkyl nitrates. Strong hydroxyl and single bond carbon to oxygen stretching vibrations indicate the presence of either nitroalcohols or simple aliphatic alcohols formed through oxidation reactions. Carbonyl stretching frequencies observable in some of the reactions support the conclusion that a portion of the reactants disappear by oxidation rather than by nitration processes. The available results do not indicate the presence of appreciable amounts of tert.-nitro compounds, conjugated nitro-olefins, or gem-dinitro-alkanes. The reactivities of the olefins with the nitrogen oxides are in the decreasing order: 2-methyl-butadiene-1,3, 2-methylbutene-2, pentene-1. 20 references.

  14. How much life is left in your olefin unit

    International Nuclear Information System (INIS)

    Baas, J.; Warner, R.

    1992-01-01

    Highly attractive economics in the olefin industry has justified increasing capacity via plant expansion and using aging olefin units beyond expected limitations. If these existing units are to operate well beyond their design life, what type of analysis and information is necessary to make this decision? What technologies or methods should be used for continued safe and controlled operation of these not so new units. This paper reports that the plant's mechanical integrity is the focal point of this analysis and decision-making method. Plant life expectancy study (PLES) looks at an operating plant's mechanical integrity from several vantage points. Four basic principles, such as plant history, process upsets and operating records, assessment of plant fires, and how to conduct records, assessment of plant fires, and how to conduct inspection and testing, provide the basis of how well a plant has been operated and maintained. Furthermore, the analysis includes a critical component inventory. These items address additional potential-failure causes, such as creep, fatigue, toughness, corrosion, erosion and carburization/oxidation

  15. Techno-economic analysis and comparison of coal based olefins processes

    International Nuclear Information System (INIS)

    Xiang, Dong; Yang, Siyu; Qian, Yu

    2016-01-01

    Highlights: • The coal based Fischer–Tropsch-to-olefins (CFTO) process is proposed and analyzed. • The CFTO suffers from lower energy efficiency and serious CO 2 emissions. • Approaches for improving techno-economic performance of the CFTO are obtained. - Abstract: Traditional olefins production is heavily dependent on oil. In the background of the scarcity of oil and richness of coal in China, olefins production from coal has been attracting more attention of the chemical process industry. The first coal based methanol-to-olefins (CMTO) plant has been commercialized in China. For shorter process route and lower capital cost, Fischer–Fropsch has been put forward in the last few years. The coal based Fischer–Tropsch-to-olefins (CFTO) process is designed in this paper and then its techno-economic and environmental performance was detailed studied in this paper, in comparison with the CMTO. Results show that at the present olefins selectivity, the CFTO suffers from relative lower energy efficiency and higher CO 2 emissions. In economic aspect, the capital investment and product cost of the CFTO are roughly equivalent to that of the CMTO. Although the conversion route of the CFTO is shorter, its techno-economic performance is still inferior to that of the CMTO. It is also found that increase of olefins selectivity by cracking oil or decrease of CO 2 selectivity by improving catalyst could significantly improve the performance of the CFTO.

  16. In vivo and in vitro olefin cyclopropanation catalyzed by heme enzymes

    Science.gov (United States)

    Coelho, Pedro S; Brustad, Eric M; Arnold, Frances H; Wang, Zhan; Lewis, Jared C

    2015-03-31

    The present invention provides methods for catalyzing the conversion of an olefin to any compound containing one or more cyclopropane functional groups using heme enzymes. In certain aspects, the present invention provides a method for producing a cyclopropanation product comprising providing an olefinic substrate, a diazo reagent, and a heme enzyme; and admixing the components in a reaction for a time sufficient to produce a cyclopropanation product. In other aspects, the present invention provides heme enzymes including variants and fragments thereof that are capable of carrying out in vivo and in vitro olefin cyclopropanation reactions. Expression vectors and host cells expressing the heme enzymes are also provided by the present invention.

  17. Ligand-Enabled γ-C(sp(3))-H Olefination of Amines: En Route to Pyrrolidines.

    Science.gov (United States)

    Jiang, Heng; He, Jian; Liu, Tao; Yu, Jin-Quan

    2016-02-17

    Pd(II)-catalyzed olefination of γ-C(sp(3))-H bonds of triflyl (Tf) and 4-nitrobenzenesulfonyl (Ns) protected amines is achieved. Subsequent aza-Wacker oxidative cyclization or conjugate addition of the olefinated intermediates provides a variety of C-2 alkylated pyrrolidines. Three pyridine- and quinoline-based ligands are developed to match different classes of amine substrates, demonstrating a rare example of ligand-enabled C(sp(3))-H olefination reactions. The use of Ns protecting group to direct C(sp(3))-H activation of alkyl amines is also a significant step toward practical C-H functionalizations of alkyl amines.

  18. Stereoselective synthesis of hydroxy stilbenoids and styrenes by atom-efficient olefination with thiophthalides.

    Science.gov (United States)

    Mitra, Prithiba; Shome, Brateen; De, Saroj Ranjan; Sarkar, Anindya; Mal, Dipakranjan

    2012-04-14

    The synthesis of stilbenoids and styryl carboxylic acids is accomplished with high E-stereoselectivity by olefination of aldehydes with thiophthalides under basic conditions. The olefination is highly atom-efficient as it only loses elemental sulfur during the reaction. This olefination, in conjunction with retro Kolbe-Schmitt reaction, allows facile synthesis of E-hydroxystilbenoids with minimal employment of protecting groups. This study also discloses two important findings: formation of i) 4-methylsulfanyl isocoumarins and ii) an 2-arylindenone. This journal is © The Royal Society of Chemistry 2012

  19. Primary Alcohols from Terminal Olefins: Formal Anti-Markovnikov Hydration via Triple Relay Catalysis

    KAUST Repository

    Dong, G.

    2011-09-15

    Alcohol synthesis is critical to the chemical and pharmaceutical industries. The addition of water across olefins to form primary alcohols (anti-Markovnikov olefin hydration) would be a broadly useful reaction but has largely proven elusive; an indirect hydroboration/oxidation sequence requiring stoichiometric borane and oxidant is currently the most practical methodology. Here, we report a more direct approach with the use of a triple relay catalysis system that couples palladium-catalyzed oxidation, acid-catalyzed hydrolysis, and ruthenium-catalyzed reduction cycles. Aryl-substituted terminal olefins are converted to primary alcohols by net reaction with water in good yield and excellent regioselectivity.

  20. Three-component synthesis of C2F5-substituted pyrazoles from C2F5CH2NH2·HCl, NaNO2 and electron-deficient alkynes

    Directory of Open Access Journals (Sweden)

    Pavel K. Mykhailiuk

    2015-01-01

    Full Text Available A one-pot reaction between C2F5CH2NH2·HCl, NaNO2 and electron-deficient alkynes gives C2F5-substituted pyrazoles in excellent yields. The transformation smoothly proceeds in dichloromethane/water, tolerates the presence of air, and requires no purification of products by column chromatography. Mechanistically, C2F5CH2NH2·HCl and NaNO2 react first in water to generate C2F5CHN2, that participates in a [3 + 2] cycloaddition with electron-deficient alkynes in dichloromethane.

  1. Olefin polymerization from single site catalysts confined within porous media

    Science.gov (United States)

    Kasi, Rajeswari M.

    Single Site Catalysts (SSCs) have been utilized for olefin polymerization. Altering the metal-ligand architecture in the SSCs, polyolefin properties can be enhanced in a rational manner. This influence of the ligands in the SSC on the property of polyolefins prepared can be referred to as the primary ligand influence. Extending this understanding and subsequent control of the metal-ligand framework to the interaction of SSCs within organic and inorganic supports is vital for the synthesis of polyolefins with tailored properties. The motivation behind this thesis was to explore the support influence on the reactivity of the SSC tethered to a support matrix during ethylene homo and copolymerization. In order to address this question of the support influence on the final polyolefin properties, synthetic routes to covalently bind SSCs on different matrices have been explored. Two distinct supported SSCs have been used to prepare branched polyethylenes. Branched polyethylenes can be prepared by either copolymerization (ethylene and alpha-olefin) or oligomerization/copolymerization processes (ethylene and in situ generated alpha-olefin). Synthetic routes to prepare precursor catalysts to Constrained Geometry Catalysts (CGCs) by silyl elimination chemistry have been developed (Chapter 2). Efficient synthetic protocols to assemble CGCs on aminomethylpolysytrene matrices (Chapter 3) and amine-functionalized mesoporous silica (Chapter 4) are also reported. These supported catalysts, with appropriate cocatalysts have been used to prepare ethylene homo and copolymers, the polymer thermal properties and microstructures were analyzed by various analytical techniques. Branched polyethylenes (LLDPE) can be prepared by copolymerization chemistry. It has been observed is that the influence of the support is seen in the production of lower crystalline forms of high density polyethylene (HDPE, 20--50% crystalline), while homogeneous polymerization of analogous soluble CGCs afford HDPE

  2. Production of jet fuel range paraffins by low temperature polymerization of gaseous light olefins using ionic liquid

    International Nuclear Information System (INIS)

    Jiang, Peiwen; Wu, Xiaoping; Zhu, Lijuan; Jin, Feng; Liu, Junxu; Xia, Tongyan; Wang, Tiejun; Li, Quanxin

    2016-01-01

    Graphical abstract: A novel catalytic transformation of light olefins into jet fuel range iso-paraffins by the low-temperature olefin polymerizations under atmospheric conditions. - Highlights: • A novel transformation of light olefins to jet fuel range paraffins was demonstrated. • The synthetic fuels can be produced by atmospheric olefin polymerizations. • C 8 –C 15 iso-paraffins from light olefins was achieved with a selectivity of 80.6%. - Abstract: This work demonstrated a novel catalytic transformation of gaseous olefins into jet fuel range iso-paraffins by the low-temperature olefin polymerizations under atmospheric conditions. The production of the desired C 8 –C 15 iso-paraffins with the selectivity of 80.6 C mol% was achieved by the room-temperature polymerizations of gaseous light olefins using the [BMIM] Al 2 Cl 7 ionic liquid. The influences of the reaction conditions on the olefinic polymerizations were investigated in detail. The properties of hydrocarbons in the synthetic fuels were determined by the GC–MS analyses combined with 1 H NMR, and 13 C NMR analyses. The formation of C 8 –C 15 hydrocarbons from gaseous light olefins was illustrated by the identified products and the functional groups. This transformation potentially provides a useful avenue for the production of the most important components of iso-paraffins required in jet fuels.

  3. Radiation-chemical alkylation of olefines with adamantane

    International Nuclear Information System (INIS)

    Podkhalyuzin, A.T.; Vikulin, V.V.; Morozov, V.A.; Nazarova, M.P.; Vereshchinskii, I.V.

    1977-01-01

    Radiation-chemical alkylation of C 2 to C 4 olefines with adamantane was studied in gas phase at temperatures 270 to 430 0 C. The main reaction product is monoalkyladamantane. The reaction proceeds by a free radical chain mechanism. The effective activation energy is of the order of 8 to 10 kcal/mole. Thermal alkylation was carried out for comparison and the contribution of the thermal component to the radiation-thermal process was estimated. Liquid phase alkylation of hexafluoropropylene with adamantane was studied in the presence of solvents. Under various conditions mono- and di-substituted adamantanes are produced containing fluorine in end groups. These compounds were converted to corresponding fluoroalkenyladamantanes by dehydrofluorination. The kinetic parameters were calculated and physical-chemical data concerning some of the resulting products were determined. (author)

  4. New unit for sulfuric acid alkylation of isobutane by olefins

    Energy Technology Data Exchange (ETDEWEB)

    Khadzhiev, S.N.; Baiburskii, V.L.; Deineko, P.S.; Gruzdev, A.S.; Tagavov, I.T.

    1987-01-01

    The authors describe and illustrate a sulfuric acid alkylation unit with a horizontal contact. As a result of the use of this design solution, the isobutane/olefin ratio is 10/1 in comparison with 4/1 to 5/1 in the other types of units, namely vertical reactors and cascade tank reactors. The unit was designed to process the butane-butylene cut (BBC) and part of the propane-propylene cut (PPC) from the G-43-107 cat cracker. The unit design includes provisions for controlled caustic washing of the feed and dehydration in an electric field. The authors present the basic data obtained in the three months of unit operation after startup, in comparison with the operating indexes of a sulfuric acid alkylation unit.

  5. The FCC process as a producer of light olefins

    International Nuclear Information System (INIS)

    Yung, K.Y.; Yanik, S.; O'Connor, P.; Pouwels, C.

    1992-01-01

    To reduce emissions from the gasoline engine, aromatics content and vapor pressure of the motor gasoline pool will be reduced and a minimum amount of oxygen will be mandated. This reformulation will limit the application of high octane components like benzene, toluene and butanes and will require the use of oxygenates. To compensate for the loss in octane, the use of alkylate and, of course also oxygenates will grow. The Fluid Catalytic Cracking Unit is, as producer of (olefinic) propanes, butanes and pentanes, an important feedstock producer for alkylate and oxygenate producing process. Hence, process adjustments and FCC catalyst formations to increase the yield of above desirable light products are of prime importance and will be dealt with in this paper

  6. Selective Metathesis of α-Olefins from Bio-Sourced Fischer–Tropsch Feeds

    KAUST Repository

    Rouen, Mathieu; Queval, Pierre; Borre, Etienne; Falivene, Laura; Poater, Albert; Berthod, Mikael; Hugues, Francois; Cavallo, Luigi; Basle, Olivier; Olivier-Bourbigou, Helene; Mauduit, Marc

    2016-01-01

    The search for a low-cost process for the valorization of linear alpha-olefins combining high productivity and high selectivity is a longstanding goal for chemists. Herein, we report a soluble ruthenium olefin metathesis catalyst that performs the conversion of linear alpha-olefins to longer internal linear olefins with high selectivity (>99%) under neat conditions at low loadings (50 ppm) and without the need of expensive additives. This robust catalytic process allowed us to efficiently and selectively re-equilibrate the naphtha fraction (C-5-C-8) of a Fischer-Tropsch feed derived from non petroleum resources to a higher-value product range (C-9-C-14), useful as detergent and plasticizer precursors.

  7. Rhodium-Catalyzed Enantioselective Cyclopropanation of Olefins with N-Sulfonyl 1,2,3-Triazoles

    Science.gov (United States)

    Chuprakov, Stepan; Kwok, Sen Wai; Zhang, Li; Lercher, Lukas; Fokin, Valery V.

    2009-01-01

    N-Sulfonyl 1,2,3-triazoles readily form rhodium(II) azavinyl carbenes, which react with olefins to produce cyclopropanes with excellent diastereo- and enantioselectivity and in high yield. PMID:19928917

  8. Gum forming olefinic precursors in motor gasoline: a model compound study

    Energy Technology Data Exchange (ETDEWEB)

    Nagpal, J.M.; Joshi, G.C.; Singh, J.; Rastogi, S.N. (Indian Institute of Petroleum, Dehradun (India))

    1994-01-01

    The source of the cracked components in motor gasoline are generally (Fluid Catalytic Cracking) FCC and thermal cracking naphthas incorporated in the gasoline pool. The FCC olefins are predominant in isostructures, while thermal cracking naphthas obtained from visbreaking and coking operations contain substantial amounts of cyclic structures. The contribution of various olefinic structures present in these naphthas are likely to vary. The gum forming tendencies of different types of olefinic structures have been studied by taking model compounds in a known sample matrix through potential gum measurements under accelerated test conditions. Peroxide number values have also been determined on aged sample. Cyclic and dicyclic structures have been found to contribute maximum, towards gum formation tendencies. Branching generally increases the gum formation. However, position of branching plays an important role besides the double bond. Synergistic effects of dienes with straight chain and branched olefins have also been studied. 11 refs., 10 figs., 2 tabs.

  9. Selective Metathesis of α-Olefins from Bio-Sourced Fischer–Tropsch Feeds

    KAUST Repository

    Rouen, Mathieu

    2016-10-14

    The search for a low-cost process for the valorization of linear alpha-olefins combining high productivity and high selectivity is a longstanding goal for chemists. Herein, we report a soluble ruthenium olefin metathesis catalyst that performs the conversion of linear alpha-olefins to longer internal linear olefins with high selectivity (>99%) under neat conditions at low loadings (50 ppm) and without the need of expensive additives. This robust catalytic process allowed us to efficiently and selectively re-equilibrate the naphtha fraction (C-5-C-8) of a Fischer-Tropsch feed derived from non petroleum resources to a higher-value product range (C-9-C-14), useful as detergent and plasticizer precursors.

  10. Esterase-sensitive sulfur dioxide prodrugs inspired by modified Julia olefination.

    Science.gov (United States)

    Wang, Wenyi; Wang, Binghe

    2017-09-12

    Sulfur dioxide (SO 2 ) is an endogenously produced gaseous molecule, and is emerging as a potential gasotransmitter. Herein, we describe the first series of esterase-sensitive prodrugs inspired by modified Julia olefination as SO 2 donors.

  11. Nickel-catalysed retro-hydroamidocarbonylation of aliphatic amides to olefins

    Science.gov (United States)

    Hu, Jiefeng; Wang, Minyan; Pu, Xinghui; Shi, Zhuangzhi

    2017-05-01

    Amide and olefins are important synthetic intermediates with complementary reactivity which play a key role in the construction of natural products, pharmaceuticals and manmade materials. Converting the normally highly stable aliphatic amides into olefins directly is a challenging task. Here we show that a Ni/NHC-catalytic system has been established for decarbonylative elimination of aliphatic amides to generate various olefins via C-N and C-C bond cleavage. This study not only overcomes the acyl C-N bond activation in aliphatic amides, but also encompasses distinct chemical advances on a new type of elimination reaction called retro-hydroamidocarbonylation. This transformation shows good functional group compatibility and can serve as a powerful synthetic tool for late-stage olefination of amide groups in complex compounds.

  12. Extreme ultraviolet (EUV) degradation of poly(olefin sulfone)s: Towards applications as EUV photoresists

    International Nuclear Information System (INIS)

    Lawrie, Kirsten; Blakey, Idriss; Blinco, James; Gronheid, Roel; Jack, Kevin; Pollentier, Ivan; Leeson, Michael J.; Younkin, Todd R.; Whittaker, Andrew K.

    2011-01-01

    Poly(olefin sulfone)s, formed by the reaction of sulfur dioxide (SO 2 ) and an olefin, are known to be highly susceptible to degradation by radiation and thus have been identified as candidate materials for chain scission-based extreme ultraviolet lithography (EUVL) resist materials. In order to investigate this further, the synthesis and characterisation of two poly(olefin sulfone)s namely poly(1-pentene sulfone) (PPS) and poly(2-methyl-1-pentene sulfone) (PMPS), was achieved and the two materials were evaluated for possible chain scission EUVL resist applications. It was found that both materials possess high sensitivities to EUV photons; however; the rates of outgassing were extremely high. The only observed degradation products were found to be SO 2 and the respective olefin suggesting that depolymerisation takes place under irradiation in a vacuum environment. In addition to depolymerisation, a concurrent conversion of SO 2 moieties to a sulfide phase was observed using XPS.

  13. Structure and dynamics of olefin radical cation aggregates. Time-resolved fluorescence detected magnetic resonance

    International Nuclear Information System (INIS)

    Desrosiers, M.F.; Trifunac, A.D.

    1986-01-01

    The time-resolved EPR spectra and thus the structure and dynamics of transient hydrocarbon radical cations are obtained by the pulse radiolysis-fluorescence detected magnetic resonance (FDMR) technique. Here the authors report the observation of short-lived radical cations from olefins. FDMR-EPR spectra of radical cations from tetramethylethylene and cyclohexadiene are illustrated. The olefin radical cations, FDMR spectra are concentration-dependent, since dimerization with neutral molecules takes place at higher (>10 -2 M) olefin concentration. Rate constants for the dimerization reaction are derived and the effect of solvent viscosity on aggregate formation is demonstrated. By monitoring the further reactions of dimer cations the authors have obtained EPR evidence for previously unobserved higher-order (multimer) radical cation aggregates of olefins. 16 references, 5 figures

  14. Capturing of the monoterpene olefin limonene produced in Saccharomyces cerevisiae.

    Science.gov (United States)

    Jongedijk, Esmer; Cankar, Katarina; Ranzijn, Jorn; van der Krol, Sander; Bouwmeester, Harro; Beekwilder, Jules

    2015-01-01

    Monoterpene olefins such as limonene are plant compounds with applications as flavouring and fragrance agents, as solvents and potentially also in polymer and fuel chemistry. We engineered baker's yeast Saccharomyces cerevisiae to express a (-)-limonene synthase from Perilla frutescens and a (+)-limonene synthase from Citrus limon. Both proteins were expressed either with their native plastid targeting signal or in a truncated form in which the plastidial sorting signal was removed. The yeast host strain for expression was AE9 K197G, which expresses a mutant Erg20 enzyme. This enzyme catalyses the formation of geranyl diphosphate, which is the precursor for monoterpenes. Several methods were tested to capture limonene produced by the yeast. Extraction from the culture medium by pentane, or by the addition of CaCl2 followed by solid-phase micro-extraction, did not lead to detectable limonene, indicating that limonene is rapidly lost from the culture medium. Volatile terpenes such as limonene may also be trapped in a dodecane phase added to the medium during fermentation. This method resulted in recovery of 0.028 mg/l (+)-limonene and 0.060 mg/l (-)-limonene in strains using the truncated Citrus and Perilla synthases, respectively. Trapping the headspace during culture of the limonene synthase-expressing strains resulted in higher titres, at 0.12 mg/l (+)-limonene and 0.49 mg/l (-)-limonene. These results show that the volatile properties of the olefins produced require specific methods for efficient recovery of these molecules from biotechnological production systems. Copyright © 2014 John Wiley & Sons, Ltd.

  15. Pd(II/HPMoV-Catalyzed Direct Oxidative Coupling Reaction of Benzenes with Olefins

    Directory of Open Access Journals (Sweden)

    Yasutaka Ishii

    2010-03-01

    Full Text Available The direct aerobic coupling reaction of arenes with olefins was successfully achieved by the use of Pd(OAc2/molybdovanadophosphoric acid (HPMoV as a key catalyst under 1 atm of dioxygen. This catalytic system could be extended to the coupling reaction of various substituted benzenes with olefins such as acrylates, aclrolein, and ethylene through the direct aromatic C-H bond activation.

  16. An Improved Protocol for the Aldehyde Olefination Reaction Using (bmim ( as Reaction Medium

    Directory of Open Access Journals (Sweden)

    Vivek Srivastava

    2013-01-01

    Full Text Available [Ru(CODCl2]/CuCl2·2H2O/LiCl catalytic system works efficiently in ionic liquid media for aldehyde olefination reaction. It offers good yield and selectivity with the added advantage of 5 times recyclability for [Ru(CODCl2] /CuCl2·2H2O/LiCl catalytic system. We also successfully reduced the reaction time from 12 hours to 9 hours for the aldehyde olefination reaction.

  17. Stereoselective Wittig Olefination as a Macrocyclization Tool. Synthesis of Large Carbazolophanes.

    Science.gov (United States)

    Myśliwiec, Damian; Lis, Tadeusz; Gregoliński, Janusz; Stępień, Marcin

    2015-06-19

    Z-Selective Wittig olefination was applied to the synthesis of large carbazolophanes containing up to eight heteroaromatic subunits. A number of strategies were devised and tested, showing that cyclooligomerization yields can be significantly improved by using one-component schemes involving heterobifunctional reactants. [4]- and [6]Carbazolophanes were characterized in the solid state, revealing compact, highly folded structures. Electronic and steric effects of substitution and chain length on the Wittig olefination rates and Z-selectivities were explored theoretically using DFT calculations.

  18. Ligand-Promoted C(sp(3) )-H Olefination en Route to Multi-functionalized Pyrazoles.

    Science.gov (United States)

    Yang, Weibo; Ye, Shengqing; Schmidt, Yvonne; Stamos, Dean; Yu, Jin-Quan

    2016-05-17

    A Pd-catalyzed/N-heterocycle-directed C(sp(3) )-H olefination has been developed. The monoprotected amino acid ligand (MPAA) is found to significantly promote Pd-catalyzed C(sp(3) )-H olefination for the first time. Cu(OAc)2 instead of Ag(+) salts are used as the terminal oxidant. This reaction provides a useful method for the synthesis of alkylated pyrazoles. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. On the nature of the olefination reaction involving ditungsten hexaalkoxides and aldehydes or ketones

    Energy Technology Data Exchange (ETDEWEB)

    Chisholm, M.H.; Huffman, J.C.; Lucas, E.A.; Sousa, A.; Streib, W.E. [Indiana Univ., Bloomington, IN (United States)

    1992-03-25

    Reductive coupling of aldehydes and ketones to olefins under the action of ditungsten hexaalkoxides was investigated. In these reactions, reductive cleavage of the aldehyde or ketone carbonyl is followed by formation of the olefinic C-C bond and breaking of the carbonyl C-O bond of the second aldehyde or ketone. Observations concerning the initial C-O bond cleavage and subsequent C-C bond formation are presented. 10 refs., 4 figs.

  20. Zeolitic imidazolate frameworks with optimized pore structure for olefin/paraffin-separation

    Energy Technology Data Exchange (ETDEWEB)

    Paula, C.; Boehme, U.; Hartmann, M. [Erlangen-Nuernberg Univ. (Germany). Erlangen Catalysis Resource Center

    2013-11-01

    In the chemical industry, the largest part of energy is spent on separation processes such as the separation of olefin/paraffin mixtures from steam cracker effluents by low-temperature rectification. A suitable alternative to this energy and cost intensive process is separation by selective adsorption with suitable microporous adsorbent. In this work, different ZIFs (Zeolitic Imidazolate Frameworks) have been explored with respect to their separation of olefins and paraffins. The studied materials (e.g. ZIF-8 (SOD-Topology), ZIF-71 (RHO-Topology)) were selected because of their low diameter of the largest pore entrance (0.29 to 4.2 nm) which is close to the kinetic diameter of the C{sub 2} to C{sub 4} olefins and paraffins under study. In contrast to other MOF- or zeolite-based adsorbents, in ZIF-8 and ZIF-71, the paraffin is preferentially adsorbed, which is evident from the single-component adsorption isotherms at different temperature. In the corresponding mixture breakthrough curves, the olefin breaks through first and the alkane even displaces the olefin from the pores. Thus, ZIF-8 and ZIF-71 are interesting candidates for the envisaged paraffin/olefin separation. Whether the observed separation behavior is due to the structural properties of the studied ZIFs or a consequence of peculiar chemical properties is subject to further studies. (orig.) (Published in summary form only)

  1. Olefins-selective asymmetric carbon molecular sieve hollow fiber membranes for hybrid membrane-distillation processes for olefin/paraffin separations

    KAUST Repository

    Xu, Liren

    2012-12-01

    In this paper, the development of asymmetric carbon molecular sieve (CMS) hollow fiber membranes and advanced processes for olefin/paraffin separations based on the CMS membranes are reported. Membrane-based olefin/paraffin separations have been pursued extensively over the past decades. CMS membranes are promising to exceed the performance upper bound of polymer materials and have demonstrated excellent stability for gas separations. Previously, a substructure collapse phenomenon was found in Matrimid ® precursor derived CMS fiber. To overcome the permeance loss due to the increased separation layer thickness, 6FDA-DAM and 6FDA/BPDA-DAM precursors were selected as potential new precursors for carbon membrane formation. Defect-free asymmetric 6FDA-DAM and 6FDA/BPDA-DAM hollow fibers were successfully fabricated from a dry-jet/wet-quench spinning process. Polymer rigidity, glass-rubber transition and asymmetric morphology were correlated. CMS hollow fiber membranes produced from 6FDA-polymer precursors showed significant improvement in permeance for ethylene/ethane and propylene/propane separations. Further studies revealed that the CMS membranes are olefins-selective, which means the membranes are able to effectively separate olefins (ethylene and propylene) from paraffins (ethane and propane). This unique feature of CMS materials enables advanced hybrid membrane-distillation process designs. By using the olefins-selective membranes, these new processes may provide advantages over previously proposed retrofitting concepts. Further applications of the membranes are explored for hydrocarbons processes. Significant energy savings and even reduced footprint may be achieved in olefins production units. © 2012 Elsevier B.V.

  2. Ag1 Pd1 Nanoparticles-Reduced Graphene Oxide as a Highly Efficient and Recyclable Catalyst for Direct Aryl C-H Olefination.

    Science.gov (United States)

    Hu, Qiyan; Liu, Xiaowang; Wang, Guoliang; Wang, Feifan; Li, Qian; Zhang, Wu

    2017-12-14

    The efficient and selective palladium-catalyzed activation of C-H bonds is of great importance for the construction of diverse bioactive molecules. Despite significant progress, the inability to recycle palladium catalysts and the need for additives impedes the practical applications of these reactions. Ag 1 Pd 1 nanoparticles-reduced graphene oxide (Ag 1 Pd 1 -rGO) was used as highly efficient and recyclable catalyst for the chelation-assisted ortho C-H bond olefination of amides with acrylates in good yields with a broad substrate scope. The catalyst can be recovered and reused at least 5 times without losing activity. A synergistic effect between the Ag and Pd atoms on the catalytic activity was found, and a plausible mechanism for the AgPd-rGO catalyzed C-H olefination is proposed. These findings suggest that the search for such Pd-based bimetallic alloy nanoparticles is a new method towards the development of superior recyclable catalysts for direct aryl C-H functionalization under mild conditions. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Sequential meta-C-H olefination of synthetically versatile benzyl silanes: effective synthesis of meta-olefinated toluene, benzaldehyde and benzyl alcohols.

    Science.gov (United States)

    Patra, Tuhin; Watile, Rahul; Agasti, Soumitra; Naveen, Togati; Maiti, Debabrata

    2016-02-04

    Tremendous progress has been made towards ortho-selective C-H functionalization in the last three decades. However, the activation of distal C-H bonds and their functionalization has remained fairly underdeveloped. Herein, we report sequential meta-C-H functionalization by performing selective mono-olefination and bis-olefination with late stage modification of the C-Si as well as Si-O bonds. Temporary silyl connection was found to be advantageous due to its easy installation, easy removal and wide synthetic diversification.

  4. Market scope

    International Nuclear Information System (INIS)

    2002-01-01

    Nova Scotia's Energy Strategy is aimed at opening the electricity market to wholesale competition, allowing eligible wholesale customers (such as municipal distribution utilities) to buy their electricity from competitive sources. The Nova Scotia Electricity Marketplace Governance Committee (EMGC) is concerned that this will not promote long-term competition because these eligible customers form only a very small fraction (1.6 per cent) of the total electricity demand in the province. This report examines the possible extensions of competition beyond the minimum specified in the Energy Strategy. It also identifies approaches that the EMGC may consider, including other potential levels of competition and their associated issues. The report discussed the issue of implementing wholesale competition as it relates to unbundling of the transmission tariff from the cost of energy supply and from the cost of distribution in retail marketing. The stages of expanding the market scope were also described with reference to large industrial customers, medium industrial and large commercial customers, and small commercial and residential customers. The report states that it is unlikely that the transition to an open access transmission market will need to be reversed, as it is likely to be an essential component of any further development. The EMGC feels it could minimize future transition costs and promote future evolution of competition by recommending for an institutional and market structure that is compatible with a broader competitive market

  5. Synthesis of Functionalized Pyrazoles via 1,3-Dipolar Cycloaddition of α-Diazo-β-ketophosphonates, Sufones and Esters with Electron-Deficient Alkenes.

    Science.gov (United States)

    Baiju, T V; Namboothiri, Irishi N N

    2017-10-01

    1,3-Dipolar cycloaddition of diazo compounds with olefinic substrates is a promising atom-economic strategy for the construction of functionalized pyrazoles. Over the last few years, our group has been engaged in the synthesis of phosphonyl/sulfonylpyrazoles and pyrazole esters by employing Bestmann-Ohira Reagent (BOR) and its sulfur and ester analogs as 1,3-dipole precursors with various dipolarophiles. This account describes the novel synthetic methods developed in our laboratory, in the perspective of closely related work by others, for the synthesis of phosphonyl/sulfonylpyrazoles, pyrazole esters and the total synthesis of Withasomnine, a natural product, by using 1,3-dipolar cycloaddition as the key step. © 2017 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Determination of mineral oil aromatic hydrocarbons in edible oils and fats by online liquid chromatography-gas chromatography-flame ionization detection - Evaluation of automated removal strategies for biogenic olefins.

    Science.gov (United States)

    Nestola, Marco; Schmidt, Torsten C

    2017-07-07

    The determination of mineral oil aromatic hydrocarbons (MOAH) in foodstuffs gained in importance over the last years as carcinogenicity cannot be excluded for certain MOAH. The existence of olefins in foodstuffs, such as edible oils and fats, can be problematic for the determination of MOAH by LC-GC-FID. Removal of these interfering substances by HPLC based on polarity differences is not possible. During gas chromatographic separation heavily overloaded peaks are observed rendering the detection of small mineral oil contaminations almost impossible. Therefore, removal of these olefins is necessary before subjection of the sample to LC-GC-FID. Epoxidation of olefins to increase their polarity proved to be a valuable tool in the past. Precision and trueness of the results as shown in a collaborative trial, however, are relying on exact reaction conditions. Additionally, it is known that certain MOAH are oxidized during epoxidation and therefore get lost. In the scope of this work, hydroboration, bromohydrin reaction, and epoxidation were examined for their potential for derivatization of unsaturated hydrocarbons with increased robustness and higher recovery of MOAH. Epoxidation by meta-chloroperoxybenzoic acid (mCPBA) delivered the best removal of olefins. Factors influencing this reaction were enlightened. Adaption of the reaction conditions and time-controlled automation increased the recovery of polycyclic MOAH. Good precision (RSD r oils spiked with a lubricating mineral oil (at 24.5mg/kg of MOAH). The trueness of the method was verified by analyzing collaborative trial samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Determination of thermodynamic affinities of various polar olefins as hydride, hydrogen atom, and electron acceptors in acetonitrile.

    Science.gov (United States)

    Cao, Ying; Zhang, Song-Chen; Zhang, Min; Shen, Guang-Bin; Zhu, Xiao-Qing

    2013-07-19

    A series of 69 polar olefins with various typical structures (X) were synthesized and the thermodynamic affinities (defined in terms of the molar enthalpy changes or the standard redox potentials in this work) of the polar olefins obtaining hydride anions, hydrogen atoms, and electrons, the thermodynamic affinities of the radical anions of the polar olefins (X(•-)) obtaining protons and hydrogen atoms, and the thermodynamic affinities of the hydrogen adducts of the polar olefins (XH(•)) obtaining electrons in acetonitrile were determined using titration calorimetry and electrochemical methods. The pure C═C π-bond heterolytic and homolytic dissociation energies of the polar olefins (X) in acetonitrile and the pure C═C π-bond homolytic dissociation energies of the radical anions of the polar olefins (X(•-)) in acetonitrile were estimated. The remote substituent effects on the six thermodynamic affinities of the polar olefins and their related reaction intermediates were examined using the Hammett linear free-energy relationships; the results show that the Hammett linear free-energy relationships all hold in the six chemical and electrochemical processes. The information disclosed in this work could not only supply a gap of the chemical thermodynamics of olefins as one class of very important organic unsaturated compounds but also strongly promote the fast development of the chemistry and applications of olefins.

  8. hf alkylation in the 1980's: the role of isobutane/olefin ratio

    Energy Technology Data Exchange (ETDEWEB)

    Hutson, T. Jr.

    1978-08-01

    Research devoted to maximizing no-lead octane numbers in motor fuel is reported. Results of the studies are the basis for the following conclusions: 1. Isobutane alkylate made from either propylene, butene-2, or C/sub 3/--C/sub 4/ mixed olefins is a low sensitivity, high motor octane product. Typically, C/sub 3/--C/sub 4/ mixed olefin alkylate has a clear motor octane number of about 92.2 and a clear Research octane number of about 93.5. 2. In separate studies with propylene, butene-2 and C/sub 3/--C/sub 4/ mixed olefins, increasing the isobutane-to-olefin ratio suppressed the formation of high molecular weight residue, indicating a substantial reduction in the role of olefin polymerization to large ions. The overall result of increasing ratio was an improvement in selectivity to high-octane components in the alkylate. 3. When alkylating isobutane with propylene, increasing the ratio resulted in a decrease in the concentration of C/sub 7/-fraction (primary product) and an increase in the C/sub 8/-fraction (from chain initiation and subsequent hydrogen transfer). At the same time, the production of chain-termination-product propane also increased. 4. When alkylating isobutane with C/sub 3/--C/sub 4/ mixed olefins, increasing the ratio showed the same trend obtained in separate alkylation tests with propylene and butene-2. As the ratio increased, the concentration of C/sub 7/-fraction (primary propylene--isobutane product) decreased and the concentration of C/sub 8/-fraction increased markedly. Thus, increasing isobutane-to-olefin ratio exerted a strong effect on alkylate quality in the area of about 5 to 1 to 20 to 1; this effect diminished at ratios 20:1.

  9. Gas Chromatographic-Ion Trap Mass Spectrometric Analysis of Volatile Organic Compounds by Ion-Molecule Reactions Using the Electron-Deficient Reagent Ion CCl{3/+}

    Science.gov (United States)

    Wang, Cheng-Zhong; Su, Yue; Wang, Hao-Yang; Guo, Yin-Long

    2011-10-01

    When using tetrachloromethane as the reagent gas in gas chromatography-ion trap mass spectrometry equipped with hybrid ionization source, the cation CCl{3/+} was generated in high abundance and further gas-phase experiments showed that such an electron-deficient reagent ion CCl{3/+} could undergo interesting ion-molecule reactions with various volatile organic compounds, which not only present some informative gas-phase reactions, but also facilitate qualitative analysis of diverse volatile compounds by providing unique mass spectral data that are characteristic of particular chemical structures. The ion-molecule reactions of the reagent ion CCl{3/+} with different types of compounds were studied, and results showed that such reactions could give rise to structurally diagnostic ions, such as [M + CCl3 - HCl]+ for aromatic hydrocarbons, [M - OH]+ for saturated cyclic ether, ketone, and alcoholic compounds, [M - H]+ ion for monoterpenes, M·+ for sesquiterpenes, [M - CH3CO]+ for esters, as well as the further fragment ions. The mechanisms of ion-molecule reactions of aromatic hydrocarbons, aliphatic ketones and alcoholic compounds with the reagent ion CCl{3/+} were investigated and proposed according to the information provided by MS/MS experiments and theoretical calculations. Then, this method was applied to study volatile organic compounds in Dendranthema indicum var. aromaticum and 20 compounds, including monoterpenes and their oxygen-containing derivatives, aromatic hydrocarbon and sesquiterpenes were identified using such ion-molecule reactions. This study offers a perspective and an alternative tool for the analysis and identification of various volatile compounds.

  10. An electron-deficient small molecule accessible from sustainable synthesis and building blocks for use as a fullerene alternative in organic photovoltaics.

    Science.gov (United States)

    McAfee, Seth M; Topple, Jessica M; Payne, Abby-Jo; Sun, Jon-Paul; Hill, Ian G; Welch, Gregory C

    2015-04-27

    An electron-deficient small molecule accessible from sustainable isoindigo and phthalimide building blocks was synthesized via optimized synthetic procedures that incorporate microwave-assisted synthesis and a heterogeneous catalyst for Suzuki coupling, and direct heteroarylation carbon-carbon bond forming reactions. The material was designed as a non-fullerene acceptor with the help of DFT calculations and characterized by optical, electronic, and thermal analysis. Further investigation of the material revealed a differing solid-state morphology with the use of three well-known processing conditions: thermal annealing, solvent vapor annealing and small volume fractions of 1,8-diiodooctane (DIO) additive. These unique morphologies persist in the active layer blends and have demonstrated a distinct influence on device performance. Organic photovoltaic-bulk heterojunction (OPV-BHJ) devices show an inherently high open circuit voltage (Voc ) with the best power conversion efficiency (PCE) cells reaching 1.0 V with 0.4 v/v % DIO as a processing additive. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Proceedings of the DGMK-Conference 'Creating value from light olefins - production and conversion'. Authors' manuscripts

    Energy Technology Data Exchange (ETDEWEB)

    Emig, G.; Kraemer, H.J.; Weitkamp, J. (eds.)

    2001-07-01

    Main topics of the conference were: production of light olefin by steamcracking and catalytic cracking processes, catalysts, methanol to olefin processes, oxidative dehydrogenation, partial oxidation, selective oxidation of alkanes with various catalysts. (uke)

  12. (Electro)Mechanical Properties of Olefinic Block Copolymers

    Science.gov (United States)

    Spontak, Richard

    2014-03-01

    Conventional styrenic triblock copolymers (SBCs) swollen with a midblock-selective oil have been previously shown to exhibit excellent electromechanical properties as dielectric elastomers. In this class of electroactive polymers, compliant electrodes applied as active areas to opposing surfaces of an elastomer attract each other, and thus compress the elastomer due to the onset of a Maxwell stress, upon application of an external electric field. This isochoric process is accompanied by an increase in lateral area, which yields the electroactuation strain (measuring beyond 300% in SBC systems). Performance parameters such as the Maxwell stress, transverse strain, dielectric breakdown, energy density and electromechanical efficiency are determined directly from the applied electric field and resulting electroactuation strain. In this study, the same principle used to evaluate SBC systems is extended to olefinic block copolymers (OBCs), which can be described as randomly-coupled multiblock copolymers that consist of crystallizable polyethylene hard segments and rubbery poly(ethylene-co-octene) soft segments. Considerations governing the development of a methodology to fabricate electroresponsive OBC systems are first discussed for several OBCs differing in composition and bulk properties. Evidence of electroactuation in selectively-solvated OBC systems is presented and performance metrics measured therefrom are quantitatively compared with dielectric elastomers derived from SBC and related materials.

  13. Separation of products of alkylation of isobutane by olefins

    Energy Technology Data Exchange (ETDEWEB)

    Ward, J.

    1979-03-15

    The alkylation (A1) of isobutane (I) by propylene, butylene and amylenes is carried out at 24-52 degrees, pressure sufficient to maintain the liquid phase, and a molar ratio of I to olefins (O1) 10:1-15:1. The bulk ratio of catalysts to hydrocarbons in the reaction zone was 0.5:1-10:1; when using HF-K-T as the catalysts, it should contain less than 5 percent water and greater than or equal to 65 percent titrated HF. The hydrocarbon products (UP) from the alkylation zone are added after separating the catalyst in a fractionation tower; distillation is carried out at 38-49 degrees and 1.03-1.3 NPa. The head fraction containing I and less than 50 molar percent C3H8 and also fraction I at the point below the input side of the UP which contains less than 8 molar percent C3H8 and fraction n-C4H10 at the point below the point of discharge of fraction I is drained from the tower. The alkylate is discharged at the bottom of the tower. According to the patent the tower operates at low pressure. This improves relative volatility of individual components and reduces heat consumption. The best results are obtained when a head fraction or the concentration C3H8 approximately 25 molar percent is discharged.

  14. Catalyst compositions useful for olefin isomerization and disproportionation

    International Nuclear Information System (INIS)

    Drake, C.A.

    1987-01-01

    A process is described for the double bond isomerization of an aliphatic olefinic hydrocarbon feed which comprises contacting the feed under isomerization conditions with a catalyst prepared by: (a) impregnating an alumina support having a surface area of at least 200 m/sup 2//g and a pore volume of at least 0.45 cm/sup 3//g with: 1 up to 20 wt. % of at least one magnesium compound convertible to the oxide, based on the weight of support and calculated as the metal; 0 up to 5 wt. % of at least one alkali metal compound convertible to the oxide, based on the weight of support and calculated as the metal; and 0 up to 5 wt. % of at least one zirconium compound convertible to the oxide, based on the weight of support and calculated as the metal; and (b) heating the alumina support impregnated in accordance with step (a) in an oxygen-containing atmosphere under conditions suitable to convert at least a portion of the magnesium, alkali metal, and zirconium compounds to the oxide form

  15. Mn-Catalyzed Highly Efficient Aerobic Oxidative Hydroxyazidation of Olefins: A Direct Approach to β-Azido Alcohols.

    Science.gov (United States)

    Sun, Xiang; Li, Xinyao; Song, Song; Zhu, Yuchao; Liang, Yu-Feng; Jiao, Ning

    2015-05-13

    An efficient Mn-catalyzed aerobic oxidative hydroxyazidation of olefins for synthesis of β-azido alcohols has been developed. The aerobic oxidative generation of azido radical employing air as the terminal oxidant is disclosed as the key process for this transformation. The reaction is appreciated by its broad substrate scope, inexpensive Mn-catalyst, high efficiency, easy operation under air, and mild conditions at room temperature. This chemistry provides a novel approach to high value-added β-azido alcohols, which are useful precursors of aziridines, β-amino alcohols, and other important N- and O-containing heterocyclic compounds. This chemistry also provides an unexpected approach to azido substituted cyclic peroxy alcohol esters. A DFT calculation indicates that Mn catalyst plays key dual roles as an efficient catalyst for the generation of azido radical and a stabilizer for peroxyl radical intermediate. Further calculation reasonably explains the proposed mechanism for the control of C-C bond cleavage or for the formation of β-azido alcohols.

  16. Radiation degradation of poly(olefin sulphone)s - Fundamental research to practical applications

    International Nuclear Information System (INIS)

    Bowden, M.J.; O'Donnell, J.H.

    1985-01-01

    The degradation of poly(olefin sulphone)s by high energy radiation, particularly by γ-rays and electron beams, provides an example of the application of fundamental science to high technology industry. Scientific interest in the radiation degradation of these polymers was first aroused by the discovery that they underwent highly specific bond scission in the backbone chain as the primary result of absorption of high energy radiation and in fact they were the first polymers in which such an effect had been demonstrated. This conclusion was initially based mainly on evidence from electron spin resonance spectroscopy and was subsequently verified by studies of molecular weight changes. These studies showed that the poly(olefin sulphone)s not only degraded by main chain scission but were also among the most radiation-sensitive polymers known. The extremely high sensitivity of poly(olefin sulphone)s to radiation-induced main-chain scission has found application in the field of microelectronics. Electron beam writing on poly(olefin sulphone) films is used to produce lithographic masks for the manufacture of integrated circuits on silicon wafers. Poly(1-butene sulphone) (PBS) is currently used in the production of a substantial proportion of the masks for the industry. The fundamental aspects of the radiation degradation of poly(olefin sulphone)s and the practical applications to high technology are reviewed. (author)

  17. Optimization of catalytic glycerol steam reforming to light olefins using Cu/ZSM-5 catalyst

    International Nuclear Information System (INIS)

    Zakaria, Z.Y.; Amin, N.A.S.; Linnekoski, J.

    2014-01-01

    Highlights: • Glycerol steam reforming to light olefin using Cu/ZSM-5 process was optimized. • Response surface methodology and multi-objective genetic algorithm were employed. • Second order polynomial model produced adequately fitted experimental data. • Thermodynamic study inferred high temperature requirement for ethylene formation. • Turn-over-frequency at optimized responses is higher than the non-optimized process. - Abstract: Response surface methodology (RSM) and multi-objective genetic algorithm was employed to optimize the process parameters for catalytic conversion of glycerol, a byproduct from biodiesel production, to light olefins using Cu/ZSM-5 catalyst. The effects of operating temperature, weight hourly space velocity (WHSV) and glycerol concentration on light olefins selectivity and yield were observed. Experimental results revealed the data adequately fitted into a second-order polynomial model. The linear temperature and quadratic WHSV terms gave significant effect on both responses. Optimization of both the responses indicated that temperature favouring high light olefin formation lied beyond the experimental design range. The trend in the temperature profile concurred commensurately with the thermodynamic analysis. Multi-objective genetic algorithm was performed to attain a single set of processing parameters that could produce both the highest light olefin selectivity and yield. The turn-over-frequency (TOF) of the optimized responses demonstrated a slightly higher value than the one which was not optimized. Combination of RSM, multi-objective response and thermodynamic is useful to determine the process optimal operating conditions for industrial applications

  18. Use of water in aiding olefin/paraffin (liquid + liquid) extraction via complexation with a silver bis(trifluoromethylsulfonyl)imide salt

    International Nuclear Information System (INIS)

    Wang, Yu; Thompson, Jillian; Zhou, Jingjing; Goodrich, Peter; Atilhan, Mert; Pensado, Alfonso S.; Kirchner, Barbara; Rooney, David; Jacquemin, Johan; Khraisheh, Majeda

    2014-01-01

    Highlights: • Silver-based ILs used as olefin extracting agents for olefin/paraffin mixtures. • Each extraction process is based on the olefin complexation and solvation. • The presence of water influences positively each extraction process. • Each extraction process was evaluated by DFT calculations, NMR, IR and Raman. • LLE data were then correlated by using the UNIQUAC model. - Abstract: This paper describes the extraction of C 5 –C 8 linear α-olefins from olefin/paraffin mixtures of the same carbon number via a reversible complexation with a silver salt (silver bis(trifluoromethylsulfonyl)imide, Ag[Tf 2 N]) to form room temperature ionic liquids [Ag(olefin) x ][Tf 2 N]. From the experimental (liquid + liquid) equilibrium data for the olefin/paraffin mixtures and Ag[Tf 2 N], 1-pentene showed the best separation performance while C 7 and C 8 olefins could only be separated from the corresponding mixtures on addition of water which also improves the selectivity at lower carbon numbers like the C 5 and C 6 , for example. Using infrared and Raman spectroscopy of the complex and Ag[Tf 2 N] saturated by olefin, the mechanism of the extraction was found to be based on both chemical complexation and the physical solubility of the olefin in the ionic liquid ([Ag(olefin) x ][Tf 2 N]). These experiments further support the use of such extraction techniques for the separation of olefins from paraffins

  19. Rh(iii)-catalyzed C-H olefination of N-pentafluoroaryl benzamides using air as the sole oxidant.

    Science.gov (United States)

    Lu, Yi; Wang, Huai-Wei; Spangler, Jillian E; Chen, Kai; Cui, Pei-Pei; Zhao, Yue; Sun, Wei-Yin; Yu, Jin-Quan

    2015-03-01

    The oxidative olefination of a broad array of arenes and heteroarenes with a variety of activated and unactivated olefins has be achieved via a rhodium(iii)-catalyzed C-H activation reaction. The use of an N -pentafluorophenyl benzamide directing group is crucial for achieving catalytic turnovers in the presence of air as the sole oxidant without using a co-oxidant.

  20. (E)-Specific direct Julia-olefination of aryl alcohols without extra reducing agents promoted by bases.

    Science.gov (United States)

    Yao, Chuan-Zhi; Li, Qiang-Qiang; Wang, Mei-Mei; Ning, Xiao-Shan; Kang, Yan-Biao

    2015-05-04

    An unprecedented base-promoted direct olefination of aryl alcohols with sulfones via a Julia-type reaction has been described. No extra reductants are needed for Julia reaction since alcohols work as double sources of aldehydes and the hydride. Generally high yields were given for both terminal and highly (E)-selective internal olefins.

  1. Comparative toxicity of various ozonized olefins to bacteria suspended in air

    Energy Technology Data Exchange (ETDEWEB)

    Dark, P A; Nash, T

    1970-01-01

    Air containing olefin vapor was treated with known amounts of ozone simulating natural concentrations. The bactericidal effect of the mixture was tested using microthreads sprayed with washed cultures of Escherichia coli var. communis or Micrococcus albus, aerosol strain. With 20 different olefins a wide range of activity was found, those in which the double bond formed part of a ring being the most bactericidal; gasoline vapor was about as active as the average open-chain olefin. The two organisms behaved similarly at the experimental relative humidity of 80%. The estimated amount of bactericidal substance present was only about one hundreth of that required to give the same kill with a 'conventional' air disinfectant; a simple physical explanation is proposed for this enhanced effect.

  2. A comprehensive study of olefin metathesis catalyzed by Ru-based catalysts

    KAUST Repository

    Poater, Albert

    2015-09-29

    During a Ru-catalyzed reaction of an olefin with an alkylidene moiety that leads to a metallacycle intermediate, the cis insertion of the olefin can occur from two different directions, namely side and bottom with respect to the phosphine or N-heterocyclic ligand (NHC), depending on the first or second generation Grubbs catalyst. Here, DFT calculations unravel to which extent the bottom coordination of olefins with respect is favored over the side coordination through screening a wide range of catalysts, including first and second generation Grubbs catalysts as well as the subsequent Hoveyda derivatives. The equilibrium between bottom and side coordination is influenced by sterics, electronics, and polarity of the solvent. The side attack is favored for sterically less demanding NHC and/or alkylidene ligands. Moreover the generation of a 14-electron species is also discussed, with either pyridine or phosphine ligands to dissociate.

  3. A comprehensive study of olefin metathesis catalyzed by Ru-based catalysts

    KAUST Repository

    Poater, Albert; Cavallo, Luigi

    2015-01-01

    During a Ru-catalyzed reaction of an olefin with an alkylidene moiety that leads to a metallacycle intermediate, the cis insertion of the olefin can occur from two different directions, namely side and bottom with respect to the phosphine or N-heterocyclic ligand (NHC), depending on the first or second generation Grubbs catalyst. Here, DFT calculations unravel to which extent the bottom coordination of olefins with respect is favored over the side coordination through screening a wide range of catalysts, including first and second generation Grubbs catalysts as well as the subsequent Hoveyda derivatives. The equilibrium between bottom and side coordination is influenced by sterics, electronics, and polarity of the solvent. The side attack is favored for sterically less demanding NHC and/or alkylidene ligands. Moreover the generation of a 14-electron species is also discussed, with either pyridine or phosphine ligands to dissociate.

  4. Stereoselective Carbonyl Olefination with Fluorosulfoximines: Facile Access to Z or E Terminal Monofluoroalkenes.

    Science.gov (United States)

    Liu, Qinghe; Shen, Xiao; Ni, Chuanfa; Hu, Jinbo

    2017-01-09

    Terminal monofluoroalkenes are important structural motifs in the design of bioactive compounds, such as homeostasis regulators and mechanism-based enzyme inhibitors. However, it is difficult to control the stereoselectivity of known carbonyl olefination reactions, and olefin metathesis is limited to disubstituted terminal monofluoroalkenes. Although sulfoximines have been used extensively in organic synthesis, reports on their use in carbonyl olefination reactions have not appeared to date. Herein, we report highly stereoselective carbonyl monofluoroolefination with a fluorosulfoximine reagent. The potential of this method is demonstrated by the synthesis of MDL 72161 and by the late-stage monofluoromethylenation of complex molecules, such as haloperidol and steroid derivatives. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Ligand-enabled ortho-C-H olefination of phenylacetic amides with unactivated alkenes.

    Science.gov (United States)

    Lu, Ming-Zhu; Chen, Xing-Rong; Xu, Hui; Dai, Hui-Xiong; Yu, Jin-Quan

    2018-02-07

    Although chelation-assisted C-H olefination has been intensely investigated, Pd(ii)-catalyzed C-H olefination reactions are largely restricted to acrylates and styrenes. Here we report a quinoline-derived ligand that enables the Pd(ii)-catalyzed olefination of the C(sp 2 )-H bond with simple aliphatic alkenes using a weakly coordinating monodentate amide auxiliary. Oxygen is used as the terminal oxidant with catalytic copper as the co-oxidant. A variety of functional groups in the aliphatic alkenes are tolerated. Upon hydrogenation, the ortho -alkylated product can be accessed. The utility of this reaction is also demonstrated by the late-stage diversification of drug molecules.

  6. General regularities of olefin epoxidation by hydroperoxide catalyzed by V, W and Ti compounds

    International Nuclear Information System (INIS)

    Sapunov, V.N.; Sharykin, V.G.; Logvinov, A.S.; Litvintsev, I.Yu.; Lebedev, N.N.

    1983-01-01

    The kinetic analysis of cyclohexane epoxidation by ethylbenzene hydroperoxide when catalyzed by titanium- and tungsten cyclohexandiolates has shown that the reaction follows the main regularities of hydroperoxide epoxidation previously established for catalysis by molybdenum- and vanadiUm compounds. The catalyst activity varies depending on the metal nature and forms the following series: Mo>V>W>Ti, which agrees with their π-acceptor capacity. During the cyclohexane epoxidation on all catalysts the hydroperoxide activities vary according to the following series: ethylbenzene hydroperoxide>cumene>tertiarybutyl>tertiaryamyl. Correlation relationships between the olefine structure, characterized by th constants, and the reactivity of olefines are foUnd. The reaction sensitivity during catalysis by WV, and Ti cyclohexandiolates is -1.2, -1.0- and -1.3, respectively. The mechanism of hydroperoxide epoxidation of olefine is discussed

  7. At the frontier between heterogeneous and homogeneous catalysis: hydrogenation of olefins and alkynes with soluble iron nanoparticles.

    Science.gov (United States)

    Rangheard, Claudine; de Julián Fernández, César; Phua, Pim-Huat; Hoorn, Johan; Lefort, Laurent; de Vries, Johannes G

    2010-09-28

    The use of non-supported Fe nanoparticles in the hydrogenation of unsaturated C-C bonds is a green catalytic concept at the frontier between homogeneous and heterogeneous catalysis. Iron nanoparticles can be obtained by reducing Fe salts with strong reductants in various solvents. FeCl(3) reduced by 3 equivalents of EtMgCl forms an active catalyst for the hydrogenation of a range of olefins and alkynes. Olefin hydrogenation is relatively fast at 5 bar using 5 mol% of catalyst. The catalyst is also active for terminal olefins and 1,1' and 1,2-cis disubstituted olefins while trans-olefins react much slower. 1-Octyne is hydrogenated to mixtures of 1-octene and octane. Kinetic studies led us to propose a mechanism for this latter transformation where octane is obtained by two different pathways. Characterization of the nanoparticles via TEM, magnetic measurements and poisoning experiments were undertaken to understand the true nature of our catalyst.

  8. Reaction of Aldehydes/Ketones with Electron-Deficient 1,3,5-Triazines Leading to Functionalized Pyrimidines as Diels-Alder/Retro-Diels-Alder Reaction Products: Reaction Development and Mechanistic Studies.

    Science.gov (United States)

    Yang, Kai; Dang, Qun; Cai, Pei-Jun; Gao, Yang; Yu, Zhi-Xiang; Bai, Xu

    2017-03-03

    Catalytic inverse electron demand Diels-Alder (IEDDA) reactions of heterocyclic aza-dienes are rarely reported since highly reactive and electron-rich dienophiles are often found not compatible with strong acids such as Lewis acids. Herein, we disclose that TFA-catalyzed reactions of electron-deficient 1,3,5-triazines and electron-deficient aldehydes/ketones can take place. These reactions led to highly functionalized pyrimidines as products in fair to good yields. The reaction mechanism was carefully studied by the combination of experimental and computational studies. The reactions involve a cascade of stepwise inverse electron demand hetero-Diels-Alder (ihDA) reactions, followed by retro-Diels-Alder (rDA) reactions and elimination of water. An acid was required for both ihDA and rDA reactions. This mechanism was further verified by comparing the relative reactivity of aldehydes/ketones and their corresponding vinyl ethers in the current reaction system.

  9. First examples of intramolecular addition of primary amidyl radicals to olefins

    Energy Technology Data Exchange (ETDEWEB)

    Gaudreault, P.; Drouin, C.; Lessard, J. [Sherbrooke Univ., PQ (Canada). Dept. de Chimie

    2005-07-01

    This paper presents the first examples of radical cyclization involving a primary amidyl radical and a pendant olefin. Amidyl radicals have attracted interest in terms of their structure, reactivity, and ways to generate them. The intramolecular addition of an amidyl radical on a pendant olefin appears to be a powerful synthetic tool for creating nitrogen-containing heterocycles. Although several examples of cyclization involving secondary amidyl radicals are cited in the the literature, there are no examples of a successful cyclization involving a primary amidyl radical. This is because all attempts to prepare the usual radical precursors have failed when applied to olefinic primary amides. This study reveals that N-(phenylthio) derivatives of olefinic primary amides can be easily prepared and that nitrogen heterocycles resulting from their radical cyclization can be obtained in good to very good yields. Four olefinic primary amides were chosen as models for radical cyclization of primary amidyl radicals. They were prepared from the corresponding carboxylic acids via the acid chlorides. Conversion of primary amides into suitable amidyl radical precursors was also examined. The study showed that N-(phenylthio) amides could be easily prepared by following a slightly modified protocol developed by Esker and Newcomb, by reacting the anion of the amide with phenylsulfenyl chloride. In particular, olefinic N-(phenylthio) amides were prepared and used as primary amidyl radical precursors in a reaction with a solution of 2,2'-azobis(isobutyronitrile) in catalytic quantities and tributyltin hydride in benzene. The resulting yields of cyclic products ranged from 63 to 85 per cent. The intent of the study was to demonstrate that it is no longer necessary to prepare an N-protected precursor and then remove the protecting group after cyclization. Further studies are currently underway. 10 refs., 1 tab.

  10. The progress of SINOPEC methanol-to-olefins (S-MTO) technology

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hongxing; Xie, Zaiku; Zhao, Guoliang [SINOPEC Shanghai Research Institute of Petrochemical Technology (China)

    2013-11-01

    It is widely recognized that naphtha steam crackers and FCC units are the main current sources of ethylene and propylene. On the condition of high oil price, olefin producers are striving to develop new economical routes to produce ethylene and propylene with low-cost feedstocks. Methanol to olefins (MTO) has aroused great attention in recent years, and SINOPEC has developed a new kind of MTO process named S-MTO which features high olefins selectivity, high methanol conversion and low catalyst consumption. Puyang Zhongyuan 200 KTA S-MTO has been in steady operation for more than 17 months. The catalyst used in the process is based on a silicoaluminophosphate, SAPO-34, which has very high carbon selectivity to low carbon olefins. Results from the commercial plant show that S-MTO process converts methanol to ethylene and propylene at about 81% carbon selectivity. The carbon selectivity approaches 92% if butenes are also accounted for as part of the product. Typically, the ratio of propylene to ethylene can range from 0.6 to 1.3. When combined with OCC (Olefin Catalytic Cracking) process to convert the heavier olefins, the overall yield of ethylene and propylene can increase to 85% {proportional_to} 87% and propylene-ethylene ratios of more than 1.5 are achievable. Other co-products include very small amounts of C1-C4 paraffins, hydrogen, CO and CO{sub 2}, as well as heavier oxygenates only with ppm level. Because of the quick deactivation of MTO catalyst, a kind of high efficiency fast fluidized bed reactor is adopted. The activity of deactivated catalyst is recovered by burning the coke in the regenerator. This paper gives an updated introduction of S-MTO technology developed by SINOPEC SRIPT. (orig.)

  11. Nitrogen-Doped Carbon Encapsulated Nickel/Cobalt Nanoparticle Catalysts for Olefin Migration of Allylarenes

    DEFF Research Database (Denmark)

    Kramer, Søren; Mielby, Jerrik Jørgen; Buss, Kasper Spanggård

    2017-01-01

    Olefin migration of allylarenes is typically performed with precious metal-based homogeneous catalysts. In contrast, very limited progress has been made using cheap, earth-abundant base metals as heterogeneous catalysts for these transformations - in spite of the obvious economic and environmental...... advantages. Herein, we report on the use of an easily prepared heterogeneous catalyst material for the migration of olefins, in particular allylarenes. The catalyst material consists of nickel/cobalt alloy nanoparticles encapsulated in nitrogen-doped carbon shells. The encapsulated nanoparticles are stable...

  12. Cis/trans Coordination in olefin metathesis by static and molecular dynamic DFT calculations

    KAUST Repository

    Poater, Albert

    2014-05-25

    In regard to [(N-heterocyclic carbene)Ru]-based catalysts, it is still a matter of debate if the substrate binding is preferentially cis or trans to the N-heterocyclic carbene ligand. By means of static and molecular dynamic DFT calculations, a simple olefin, like ethylene, is shown to be prone to the trans binding. Bearing in mind the higher reactivity of trans isomers in olefin metathesis, this insight helps to construct small alkene substrates with increased reactivity. © 2014 Springer Science+Business Media New York.

  13. Cis/trans Coordination in olefin metathesis by static and molecular dynamic DFT calculations

    KAUST Repository

    Poater, Albert; Correa, Andrea; Pump, Eva; Cavallo, Luigi

    2014-01-01

    In regard to [(N-heterocyclic carbene)Ru]-based catalysts, it is still a matter of debate if the substrate binding is preferentially cis or trans to the N-heterocyclic carbene ligand. By means of static and molecular dynamic DFT calculations, a simple olefin, like ethylene, is shown to be prone to the trans binding. Bearing in mind the higher reactivity of trans isomers in olefin metathesis, this insight helps to construct small alkene substrates with increased reactivity. © 2014 Springer Science+Business Media New York.

  14. Kinetics of H-D exchange in olefins with complicating reactions

    International Nuclear Information System (INIS)

    Trokhimets, A.I.

    1979-01-01

    The kinetics of H-D-exchange is considered for olefins under conditions when simple and complicated exchange occur together with hydrogenation. If hydrogenation takes place in the system, it is theoretically impossible to derive the integrated rate equation for the accumulation of deuterium in the olefin. The variation of the concentration of different deuteroolefins during the process can be calculated numerically. A method is proposed for evaluating the contribution of individual steps to the overall process and determining the rate constants of the most important reactions. (author)

  15. Synthetic lubricants based on copolymers of n-butyl methacrylate and α-olefins

    Directory of Open Access Journals (Sweden)

    Đakov Tatjana A.

    2002-01-01

    Full Text Available Synthetic fluids obtained by the copolymerization of α -olefins with alkyl esters of unsaturated carboxylic acids have a unique combination of properties of non-polar poly-a-olefins (PAOs and polar esters in a single molecule. These compounds are characterized by superior thermal, oxidative and hydrolytic stability, miscibility with mineral and synthetic base oils solubility of additives and neutral elastomer behavior. Depending on the molar masses and comonomer ratios in the copolymer molecule, synthetic fluids with a wide range of properties are obtained. These compounds are valuable components in lubricating oil formulations for different applications.

  16. Dithioacetals as an Entry to Titanium-Alkylidene Chemistry: A New and Efficient Carbonyl Olefination.

    Science.gov (United States)

    Breit, Bernhard

    1998-03-02

    Wittig, Horner-Wadsworth-Emmons, Julia-Lythgoe, Tebbe, Grubbs, and Petasis-when it comes to carbonyl olefinations, these names are familiar to all chemistry students. In the future, the name Takeda will probably have to be added to this list. His recent work on the formation of titanium-alkylidene species from dithioacetals has provided organic chemists with a remarkable method for carbonyl olefination that is generally applicable under neutral to Lewis acidic conditions. © 1998 WILEY-VCH Verlag GmbH, Weinheim, Fed. Rep. of Germany.

  17. The right computational recipe for olefin metathesis with ru-based catalysts: The whole mechanism of ring-closing olefin metathesis

    KAUST Repository

    Poater, Albert

    2014-10-14

    The initiation mechanism of ruthenium methylidene complexes was studied detailing mechanistic insights of all involved reaction steps within a classical olefin metathesis pathway. Computational studies reached a good agreement with the rarely available experimental data and even enabled to complement them. As a result, a highly accurate computational and rather cheap recipe is presented; M06/TZVP//BP86/SVP (PCM, P = 1354 atm).

  18. The right computational recipe for olefin metathesis with ru-based catalysts: The whole mechanism of ring-closing olefin metathesis

    KAUST Repository

    Poater, Albert; Pump, Eva; Vummaleti, Sai V. C.; Cavallo, Luigi

    2014-01-01

    The initiation mechanism of ruthenium methylidene complexes was studied detailing mechanistic insights of all involved reaction steps within a classical olefin metathesis pathway. Computational studies reached a good agreement with the rarely available experimental data and even enabled to complement them. As a result, a highly accurate computational and rather cheap recipe is presented; M06/TZVP//BP86/SVP (PCM, P = 1354 atm).

  19. Stability of cracked naphthas from thermal and catalytic processes and their additive response. Part II. Composition and effect of olefinic structures

    Energy Technology Data Exchange (ETDEWEB)

    Nagpal, J.M.; Joshi, G.C.; Rastogi, S.N. [Indian Institute of Petroleum, Dehradun (India)

    1995-05-01

    Olefinic concentrates were separated from two naphthas, one from fluid catalytic cracking (FCC) and one thermal crackate, using column chromatography. The composition and structure of the olefins were determined by a combination of analytical techniques. FCC naphthas contain relatively higher levels of conjugated dienes. The monoolefins are highly branched. The thermal crackates have higher levels of {alpha}-olefins and abound in mono-, di-, tri- and conjugated cyclic olefins. Stability tests on these olefinic concentrates blended in low-S,N straight-run naphtha showed that cyclic olefins are very active gum formers. Representative commercial antioxidants (hindered phenols and phenylenediamines) both gave good responses to different olefin concentrate test blends. Hindered phenols had a marginally better effect. 14 refs., 5 figs., 3 tabs.

  20. Prediction of properties of new halogenated olefins using two group contribution approaches

    DEFF Research Database (Denmark)

    Montagud, Maria E. Mondejar; Cignitti, Stefano; Abildskov, Jens

    2017-01-01

    The increasingly restrictive regulations for substances with high ozone depletion and global warming potentials are driving the search for new sustainable fluids with low environmental impact. Recent research works have pointed out the great potential of fluorine- and chlorine-based olefins as re...

  1. RUTHENIUM-CATALYZED TANDEM OLEFIN MIGRATION-ALDOL AND MANNICH-TYPE REACTIONS IN IONIC LIQUID.

    Science.gov (United States)

    In the presence of a catalytic amount of RuCl2(PPh3)3, a cross-coupling of 3-buten-2-ol with aldehydes and imines was developed via a tandem olefin migration--aldol--Mannich reaction in bmim[PF6]. With In(OAc)3 as a co-catalyst, a-vinylbenzyl alcohol and aldehydes underwent sim...

  2. Steam cracking and methane to olefins: Energy use, CO2 emissions and production costs

    NARCIS (Netherlands)

    Ren, T.; Patel, M.K.|info:eu-repo/dai/nl/18988097X; Blok, K.|info:eu-repo/dai/nl/07170275X

    2008-01-01

    While most olefins (e.g., ethylene and propylene) are currently produced through steam cracking routes, they can also possibly be produced from natural gas (i.e., methane) via methanol and oxidative coupling routes. We reviewed recent data in the literature and then compared the energy use, CO2

  3. NATO Advanced Study Institute on Ring-opening Metathesis Polymerization of Olefins and Polymerization of Alkynes

    CERN Document Server

    1998-01-01

    The first NATO Advanced Study Institute on Olefin Metathesis and Polymerization Catalysts was held on September 10-22, 1989 in Akcay, Turkey. Based on the fundamental research of RRSchrock, RGrubbs and K.B.Wagener in the field of ring opening metathesis polymerization (ROMP), acyclic diene metathesis (ADMET) and alkyne polymerization, these areas gained growing interest within the last years. Therefore the second NATO-ASI held on metathesis reactions was on Ring Opening Metathesis Po­ lymerization of Olefins and Polymerization of Alkynes on September 3-16, 1995 in Akcay, Turkey. The course joined inorganic, organic and polymer chemists to exchange their knowledge in this field. This volume contains the main and short lectures held in Akcay. To include ADMET reactions better into the title of this volume we changed it into: Metathesis Polymerization of Olefins and Alkyne Polymerization. This volume is addressed to research scientists, but also to those who start to work in the area of olefin metathesis and al...

  4. Radiation-induced copolymerization of α,β,β-trifluoroacrylonitrile with α-olefin

    International Nuclear Information System (INIS)

    Matsuda, O.; Kostov, G.K.; Tabata, Y.; Machi, S.

    1979-01-01

    Homopolymerization and copolymerization of α,β,β-trifluoroacrylonitrile (FAN) with α-olefins were carried out in bulk by γ-ray irradiation at 25 0 C. FAN gives very small quantities of brown and greasy low molecular weight polymer. Cyano groups in FAN polymer were found to be readily hydrolyzed to acid amide groups in the atmosphere. FAN was found to copolymerize with ethylene, propylene, and isobutylene via a radical mechanism to form equimolar copolymers in a wide range of monomer compositions. The polymerization rate increases linearly with FAN fraction in the monomer mixture. These copolymers are also hydrolyzed in the atmosphere, and the hydrolysis proceeds with more difficulty for the copolymer with higher α-olefin. The reactivity ratios r 1 (FAN) and r 2 (α-olefin) were determined to be 0.01 and 0.12 for the FAN/ethylene copolymerization and 0.01 and 0.07 for the FAN/propylene copolymerization. These results confirm that an alternating copolymerization takes place in the FAN/α-olefin system

  5. Ru-Based Complexes with Quaternary Ammonium Tags Immobilized on Mesoporous Silica as Olefin Metathesis Catalysts

    Czech Academy of Sciences Publication Activity Database

    Pastva, Jakub; Skowerski, K.; Czarnocki, S. J.; Žilková, Naděžda; Čejka, Jiří; Bastl, Zdeněk; Balcar, Hynek

    2014-01-01

    Roč. 4, č. 9 (2014), s. 3227-3236 ISSN 2155-5435 R&D Projects: GA ČR(CZ) GAP106/12/0189 Institutional support: RVO:61388955 Keywords : olefin metathesis * heterogeneous catalysts * mesoporous molecular sieves Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 9.312, year: 2014

  6. Immobilisation of homogeneous olefin polymerisation catalysts. Factors influencing activity and stability

    NARCIS (Netherlands)

    Severn, J.R.; Chadwick, J.C.

    2013-01-01

    The activity and stability of homogeneous olefin polymerisation catalysts, when immobilised on a support, are dependent on both chemical and physical effects. Chemical factors affecting catalyst activity include the ease of formation of the active species, which is strongly dependent on the

  7. Catalysts for production of lower olefins from synthesis gas: A review

    NARCIS (Netherlands)

    Torres Galvis, H.M.; de Jong, K.P.

    2013-01-01

    C2 to C4 olefins are traditionally produced from steam cracking of naphtha. The necessity for alternative production routes for these major commodity chemicals via non-oil-based processes has driven research in past times during the oil crises. Currently, there is a renewed interest in producing

  8. Omega-functionalized fatty acids, alcohols, and ethers via olefin metathesis

    Science.gov (United States)

    Methyl 17-hydroxy stearate was converted to methyl octadec-16-enoate using copper sulfate adsorbed on silica gel. This compound, possessing unsaturation at the opposite end of the chain from the carboxylate, served as a useful substrate for the olefin metathesis reaction. As a result, several fatt...

  9. Mechanism of alkylation of isobutane by olefins in the presence of sulfuric acid

    Energy Technology Data Exchange (ETDEWEB)

    Baiburskii, V.L.; Khadzhiev, S.N.; Ovsyannikov, V.P.

    1992-05-10

    The authors attempted here to examine the mechanism of alkylation of isobutane by olefins in the presence of sulfuric acid in terms of an initial stage of activation of isoparaffin. The version of formation of tert-alkyl cations and the role of the catalyst in this stage were analyzed. 10 refs., 1 fig., 1 tab.

  10. Synthesis of 7-Deoxypancratistatin from Carbohydrates by the Use of Olefin Metathesis

    DEFF Research Database (Denmark)

    Håkansson, Anders Eckart; Palmelund, Anders; Holm, H.

    2006-01-01

    from D-xylose and piperonal. The former is converted into ribofuranoside 28, which is coupled with bromide 7 in the presence of zinc, and this is followed by ring-closing olefin metathesis. Subsequent Overman rearrangement, dihydroxylation, and deprotection then affords the natural product....

  11. Radiation-induced copolymerization of methyl trifluoroacrylate with α-olefins

    International Nuclear Information System (INIS)

    Matsuda, O.; Watanabe, T.; Tabata, Y.; Machi, S.

    1978-01-01

    Paper describes the radiation-induced bulk copolymerization of methyl trifluoroacrylate with various α olefins; propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, and isobutylene. MTFA (purity above 98%) was synthesized by method described in literature. Reagent grade α-olefins were used. An equimolar mixture of MTFA and α-olefin was charged into the reactor. Trace amounts of oxygen were purged by the freeze-thaw technique. Irradiation was carried out with gamma rays from a 60 Co source under vapor pressure of the monomers at 25 0 C. The product was precipitated and washed with methanol to remove unreacted monomers, and dried under vacuum at 60 0 C. Infrared spectra of the copolymers were measured; compositions were determined from elemental analysis. Reactivity of the α-olefins appears to be related to the electron density at the double bond. All copolymers were found to have almost equimolar compositions and were soluble in polar solvents such as tetrahydrofuran and acetone. Copolymerization was inhibited completely by the addition of 1,1-diphenyl-2-picrihydrazil, but not by water, indicating that the copolymerization proceeds via a radical mechanism. 1 table; 2 figures

  12. Primary processes of the radiation-induced cationic polymerization of aromatic olefins studied by pulse radiolysis

    International Nuclear Information System (INIS)

    Brede, O.; Boes, J.; Helmstreit, W.; Mehnert, R.

    1982-01-01

    By pulse radiolysis of solutions of aromatic olefins (styrene, 1-methylstyrene, 1,1-diphenylethylene) in non-polar solvents (cyclohexane, carbon tetrachloride, n-butylchloride) the mechanism and kinetics of primary processes of radiation-induced cationic polymerization were investigated. In cyclohexane, radical cations of the olefins are generated by charge transfer from solvent cations. These cations dimerize in a diffusion-controlled reaction. The next step of chain-growth is slower by 3 to 4 orders of magnitude. In carbon tetrachloride and in n-butyl chloride growing olefin cations are produced by a reaction of radical cations with solvent as well as by addition of solvent carbonium ions to the monomer. In strongly acidic aqueous solution of olefins radical cations produced indirectly from hydroxycyclohexadienyl radicals dimerize and react in a subsequent step by deprotonation forming non-saturated dimer radicals. The reaction mechanism established shows that in the case of radiation-induced cationic polymerization it is not possible to define a uniform first step of the chain reaction. (author)

  13. Cobalt-catalyzed C-H olefination of aromatics with unactivated alkenes.

    Science.gov (United States)

    Manoharan, Ramasamy; Sivakumar, Ganesan; Jeganmohan, Masilamani

    2016-08-18

    A cobalt-catalyzed C-H olefination of aromatic and heteroaromatic amides with unactivated alkenes, allyl acetates and allyl alcohols is described. This method offers an efficient route for the synthesis of vinyl and allyl benzamides in a highly stereoselective manner. It is observed that the ortho substituent on the benzamide moiety is crucial for the observation of allylated products in unactivated alkenes.

  14. Olefins from conventional and heavy feedstocks: Energy use in steam cracking and alternative processes

    International Nuclear Information System (INIS)

    Ren Tao; Patel, Martin; Blok, Kornelis

    2006-01-01

    Steam cracking for the production of light olefins, such as ethylene and propylene, is the single most energy-consuming process in the chemical industry. This paper reviews conventional steam cracking and innovative olefin technologies in terms of energy efficiency. It is found that the pyrolysis section of a naphtha steam cracker alone consumes approximately 65% of the total process energy and approximately 75% of the total exergy loss. A family portrait of olefin technologies by feedstocks is drawn to search for alternatives. An overview of state-of-the-art naphtha cracking technologies shows that approximately 20% savings on the current average process energy use are possible. Advanced naphtha cracking technologies in the pyrolysis section, such as advanced coil and furnace materials, could together lead to up to approximately 20% savings on the process energy use by state-of-the-art technologies. Improvements in the compression and separation sections could together lead to up to approximately 15% savings. Alternative processes, i.e. catalytic olefin technologies, can save up to approximately 20%

  15. Ether-Directed ortho-C–H Olefination with a PdII/MPAA Catalyst**

    Science.gov (United States)

    Li, Gang; Leow, Dasheng; Wan, Li; Yu, Jin-Quan

    2013-01-01

    Weak coordination is powerful! A PdII-catalyzed olefination of ortho-C–H bonds of arenes directed by weakly coordinating ethers is developed using mono-protected amino acid (MPAA) ligands. This finding provides a method for chemically modifying ethers, which are abundant in natural products and drug molecules. PMID:23239120

  16. Copper(I)-catalyzed olefination of N-sulfonylhydrazones with sulfones.

    Science.gov (United States)

    Xu, Shuai; Gao, Yunpeng; Chen, Ri; Wang, Kang; Zhang, Yan; Wang, Jianbo

    2016-03-25

    The Cu(I)-catalyzed olefination of N-sulfonylhydrazones with sulfones via metal carbene intermediates is reported. This reaction uses readily available starting materials and is operationally simple, thus representing a practical method for the construction of carbon-carbon double bonds. Mechanistically, Cu(I) carbene formation and subsequent carbene migratory insertion are proposed as the key steps.

  17. Primary processes of the radiation-induced cationic polymerization of aromatic olefins studied by pulse radiolysis

    International Nuclear Information System (INIS)

    Brede, O.; Boes, J.; Helmstreit, W.; Mehnert, R.

    1981-01-01

    By pulse radiolysis of solutions of aromatic olefins (styrene, 1-methylstyrene, 1,1-diphenylethylene) in nonpolar solvents (cyclohexane, carbon tetrachloride, n-butyl chloride) the mechanism and kinetics of primary processes of radiation-induced cationic polymerization were investigated. In cyclohexane, radical cations of the olefins are generated by charge transfer from solvent cations (k about 10 11 l mol -1 s -1 ). These cations dimerize in a diffusion-controlled reaction (k approximately 10 10 l mol -1 s -1 ). The next step of chain-growth is slower by 3 to 4 orders of magnitude. Furthermore, in carbon tetrachloride and in n-butyl chloride growing olefin cations are produced by a reaction of the radical cations with the solvent as well as by addition of solvent carbonium ions to the monomer. In strongly acidic aqueous solution of olefins radical cations produced indirectly from hydroxycyclohexadienyl radicals dimerize and react in a subsequent step by deprotonation forming non-saturated dimer radicals. The established reaction mechanism shows that in the case of radiation-induced cationic polymerization it is not possible to define a uniform first step of the chain reaction. (author)

  18. Novel route to 5-position vinyl derivatives of thiolactomycin: Olefination vs. deformylation

    Science.gov (United States)

    Kim, Pilho; Barry, Clifton E.; Dowd*, Cynthia S.

    2006-01-01

    Vinyl and diene derivatives of thiolactomycin have been prepared via Horner-Wadsworth-Emmons olefination from protected 5-formyl-3,5-dimethylthiotetronic acid. Several 4-position protecting groups and a variety of phosphonates were evaluated, with MOM protection and β-ketophosphonates yielding the highest ratio of desired product to deformylated product. PMID:16699591

  19. Polymer PCF Bragg grating sensors based on poly(methyl methacrylate) and TOPAS cyclic olefin copolymer

    DEFF Research Database (Denmark)

    Johnson, Ian P; Webb, David J; Kalli, Kyriacos

    2011-01-01

    mode PCF with a core diameter of 6μm based on TOPAS cyclic olefin copolymer. Bragg grating inscription was achieved using a 30mW continuous wave 325nm helium cadmium laser. Both TOPAS and PMMA fibre have a large attenuation of around 1dB/cm in the 1550nm spectral region, limiting fibre lengths...

  20. Radiation-induced copolymerizations of perfluorovinyl acetic acid and its methyl ester with α-olefin

    International Nuclear Information System (INIS)

    Kawaguchi, M.; Watanabe, T.; Matsuda, O.; Tabata, Y.; Machi, S.

    1981-01-01

    Homopolymerizations and copolymerizations of perfluorovinyl acetic acid (FVA) and its methyl ester (MFVA) were carried out by γ radiation at a temperature of 25 0 C, a dose rate of 1 x 10 6 rad/hr, and FVA/α-olefin and MFVA/α-olefin ratios of 10/90-90/10 in the monomer mixture. FVA and MFVA gave small quantities of brown and greasy low-molecular-weight homopolymers. The polymerization rates of both FVA and MFVA were extremely small, as shown by the maximum G value of monomer consumption of 12. FVA and MFVA reacted with α-olefin to form waxlike copolymers. The copolymerization rates of both FVA and MFVA with α-olefin were remarkably larger than those of the homopolymerizations, particularly with ethylene. The polymer compositions of FVA/ethylene or MFVA/ethylene were nearly 1/2 over a wide range of the monomer compositions. The Mayo-Lewis method gave negative r 1 (FVA) and r 1 (MFVA). The polymer composition curves could be well interpreted by introducing the penultimate model

  1. Modified Julia Olefination on Anhydrides: Extension and Limitations. Application to the Synthesis of Maculalactone B.

    Science.gov (United States)

    Dussart, Nicolas; Trinh, Huu Vinh; Gueyrard, David

    2016-10-07

    The preparation of exo-enol esters from cyclic anhydrides is reported using a modified Julia olefination. The reaction is highly stereoselective. The Smiles rearrangement can be performed in a one-pot process, giving a straightforward access to exo-enol lactones. Furthermore, the reaction was extended to semistabilized sulfones, and this methodology was applied to the synthesis of maculalactone B.

  2. Improved olefinic fat suppression in skeletal muscle DTI using a magnitude-based dixon method.

    Science.gov (United States)

    Burakiewicz, Jedrzej; Hooijmans, Melissa T; Webb, Andrew G; Verschuuren, Jan J G M; Niks, Erik H; Kan, Hermien E

    2018-01-01

    To develop a method of suppressing the multi-resonance fat signal in diffusion-weighted imaging of skeletal muscle. This is particularly important when imaging patients with muscular dystrophies, a group of diseases which cause gradual replacement of muscle tissue by fat. The signal from the olefinic fat peak at 5.3 ppm can significantly confound diffusion-tensor imaging measurements. Dixon olefinic fat suppression (DOFS), a magnitude-based chemical-shift-based method of suppressing the olefinic peak, is proposed. It is verified in vivo by performing diffusion tensor imaging (DTI)-based quantification in the lower leg of seven healthy volunteers, and compared to two previously described fat-suppression techniques in regions with and without fat contamination. In the region without fat contamination, DOFS produces similar results to existing techniques, whereas in muscle contaminated by subcutaneous fat signal moved due to the chemical shift artefact, it consistently showed significantly higher (P = 0.018) mean diffusivity (MD). Because fat presence lowers MD, this suggests improved fat suppression. DOFS offers superior fat suppression and enhances quantitative measurements in the muscle in the presence of fat. DOFS is an alternative to spectral olefinic fat suppression. Magn Reson Med 79:152-159, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  3. Catalyst Design and Development for the Direct Production of Lower Olefins from Synthesis Gas

    NARCIS (Netherlands)

    Xie, J.

    2017-01-01

    The increase in global demand for lower olefins (ethylene, propylene, and butylenes) coupled with the regional diversification of carbon raw materials bring about opportunities and challenges for emerging technologies. Crude oil has been the primary carbon feedstock for the past 50 years, but

  4. Chemistry of Furan Conversion into Aromatics and Olefins over HZSM-5: A Model Biomass Conversion Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Yu-Ting; Huber, George W.

    2011-06-03

    The conversion of furan (a model of cellulosic biomass) over HZSM-5 was investigated in a thermogravimetric analysis–mass spectrometry system, in situ Fourier transform infrared analysis, and in a continuous-flow fixed-bed reactor. Furan adsorbed as oligomers at room temperature with a 1.73 of adsorbed furan/Al ratio. These oligomers were polycyclic aromatic compounds that were converted to CO, CO₂, aromatics, and olefins at temperatures from 400 to 600 °C. Aromatics (e.g., benzene, toluene, and naphthalene), oligomer isomers (e.g., benzofuran, 2,2-methylenebisfuran, and benzodioxane), and heavy oxygenates (C₁₂{sub +} oligomers) were identified as intermediates formed inside HZSM-5 at different reaction temperatures. During furan conversion, graphite-type coke formed on the catalyst surface, which caused the aromatics and olefins formation to deactivate within the first 30 min of time on-stream. We have measured the effects of space velocity and temperature for furan conversion to help us understand the chemistry of biomass conversion inside zeolite catalysts. The major products for furan conversion included CO, CO₂, allene, C₂–C₆ olefins, benzene, toluene, styrene, benzofuran, indene, and naphthalene. The aromatics (benzene and toluene) and olefins (ethylene and propylene) selectivity decreased with increasing space velocity. Unsaturated hydrocarbons such as allene, cyclopentadiene, and aromatics selectivity increased with increasing space velocity. The product distribution was selective to olefins and CO at high temperatures (650 °C) but was selective to aromatics (benzene and toluene) at intermediate temperatures (450–600 °C). At low temperatures (450 °C), benzofuran and coke contributed 60% of the carbon selectivity. Several different reactions were occurring for furan conversion over zeolites. Some important reactions that we have identified in this study include Diels–Alder condensation (e.g., two furans form benzofuran and water

  5. Ti-Catalyzed Selective Isomerization of Terminal Mono-substituted Olefins

    International Nuclear Information System (INIS)

    Lee, Hyung Soo; Lee, Gab Yong

    2005-01-01

    The isomerization of olefins occurs either by a metal hydride addition-elimination or by a π-allyl metal hydride intermediate. HCo(CO) 4 , [(C 2 H 4 ) 2 RhCl] 2 , Ni[P(OEt) 3 ] 4 , and PtCl 2 (PPh 3 ) 2 -SnCl 2 are effective catalysts for isomerization of olefins via a metal hydride addition-elimination mechanism, 3,4 and Fe 3 (CO) 12 catalyzed isomerization of 3-ethyl-1-pentene and isomerization of 1-heptene catalyzed by (PhCN) 2 PdCl 2 occur via a π-allyl metal hydride mechanism. The cis/trans ratio of 2-butene obtained from isomerization of 1-butene by RhH(CO)(PPh 3 ) 3 has also been investigated. The skeletal isomerization of olefins catalyzed by (R 3 P) 2 NiCl 2 is developed such as conversion of cis-1,4-hexadiene to trans-2-methyl-1,3-pentadiene. Titanium complexes serve as an effective catalysts for a variety of reactions such as hydroalumination, hydroboration, and hydrogenation of unsaturated hydrocarbons. We have been interested in the selective reactions of unsaturated hydrocarbons by using titanium and zirconium compounds. The reagent system composed of LiAlH 4 /Cp 2 TiCl 2 ≤ 2 in the molar ratio promotes the isomerization of 1-octene, but the detailed reaction for isomerization of olefins has not been reported. We report here a selective isomerization of olefins with low valent titanium complex generated from Cp 2 TiCl 2 (Cp=cyclopentadienyl) and LiAlH 4

  6. Cobalt carbide nanoprisms for direct production of lower olefins from syngas

    Science.gov (United States)

    Zhong, Liangshu; Yu, Fei; An, Yunlei; Zhao, Yonghui; Sun, Yuhan; Li, Zhengjia; Lin, Tiejun; Lin, Yanjun; Qi, Xingzhen; Dai, Yuanyuan; Gu, Lin; Hu, Jinsong; Jin, Shifeng; Shen, Qun; Wang, Hui

    2016-10-01

    Lower olefins—generally referring to ethylene, propylene and butylene—are basic carbon-based building blocks that are widely used in the chemical industry, and are traditionally produced through thermal or catalytic cracking of a range of hydrocarbon feedstocks, such as naphtha, gas oil, condensates and light alkanes. With the rapid depletion of the limited petroleum reserves that serve as the source of these hydrocarbons, there is an urgent need for processes that can produce lower olefins from alternative feedstocks. The ‘Fischer-Tropsch to olefins’ (FTO) process has long offered a way of producing lower olefins directly from syngas—a mixture of hydrogen and carbon monoxide that is readily derived from coal, biomass and natural gas. But the hydrocarbons obtained with the FTO process typically follow the so-called Anderson-Schulz-Flory distribution, which is characterized by a maximum C2-C4 hydrocarbon fraction of about 56.7 per cent and an undesired methane fraction of about 29.2 per cent (refs 1, 10, 11, 12). Here we show that, under mild reaction conditions, cobalt carbide quadrangular nanoprisms catalyse the FTO conversion of syngas with high selectivity for the production of lower olefins (constituting around 60.8 per cent of the carbon products), while generating little methane (about 5.0 per cent), with the ratio of desired unsaturated hydrocarbons to less valuable saturated hydrocarbons amongst the C2-C4 products being as high as 30. Detailed catalyst characterization during the initial reaction stage and theoretical calculations indicate that preferentially exposed {101} and {020} facets play a pivotal role during syngas conversion, in that they favour olefin production and inhibit methane formation, and thereby render cobalt carbide nanoprisms a promising new catalyst system for directly converting syngas into lower olefins.

  7. N-Heterocyclic Olefins as Initiators for the Polymerization of (Meth)Acrylic Monomers: A Combined Experimental and Theoretical Approach

    KAUST Repository

    Naumann, Stefan

    2017-08-25

    The zwitterionic organopolymerization of four different acrylic monomers (N,N-dimethylacrylamide, methyl acrylate, methyl methacrylate and tert-butyl methacrylate) based on neutral initiators, so-called N-heterocyclic olefins (NHOs), is presented. Scope and underlying (deactivation-)mechanisms where studied in a combined experimental and computational effort. From a range of differently structured NHOs it emerged that imidazole-, in contrast to imidazoline- and benzimidazole-derivatives, readily polymerize the selected monomers. While the additive-free reactions proceed with a relatively low degree of control to yield largely atactic material, for the acrylamide the addition of LiCl as µ-type ligand has been shown to result in a rapid and quantitative monomer consumption. The thus generated poly(N,N-dimethyl acrylamide) was found to be highly isotactic (>90% isotactic dyads) with high molecular weight (Mn = 250 000 – 650 000 g/mol, ÐM = 1.3- 1.6). Complementing DFT calculations considered the zwitterionic chain growth with respect to competing side reactions, namely spirocycles and enamine formation. It was found that NHOs with unsaturated backbone better support the zwitterionic chain growth, with the spirocycles acting as dormant species that slow down but do not quench the polymerization process. Contrasting this, enamine formation irreversibly terminates the polymerization and is found to be energetically favored. This pathway can be blocked by introduction of substituents on the exocyclic carbon of the NHO, resulting in structures like 2-isopropylidene-1,3,4,5-tetramethylimidazoline (4) which consequently deliver the most controlled polymerizations. Finally, a good correlation of the initiation energy barrier with the buried volume (%VBur) and the Parr electrophilicity index is described, allowing for a quick and reliable screening of potential monomers based on these two readily accessible parameters.

  8. Fragmentation of delta-diketones by electron impact. Olefin elimination and formation of an enol acetate ion

    International Nuclear Information System (INIS)

    Morizur, J.P.; Mercier, J.; Casals, P.F.

    1985-01-01

    Under electron impact delta-diketones lose an olefin. The mechanism and structure of the resulting ion have been established by several techniques: substitution, Mike and Cid spectra and thermochemical data [fr

  9. Manganese oxide as a promoter for C2-C4 olefin production in the hydrogenation of carbon dioxide

    International Nuclear Information System (INIS)

    Kim, C.; Chen, K.; Hanson, F.V.; Oblad, A.G.; Tsai, Y.

    1986-01-01

    A number of active research and development programs have been initiated to explore the potential of CO hydrogenation process as a source of low molecular weight (C 2 -C 4 ) olefins. Metal catalysts such as Co-Mn, Ni-zeolite, Rd and Mo have been evaluated for low molecular weight olefin selectivity. The coprecipitated Fe-Mn system (Mn/Fe=9/1) was reported to be highly olefin selective. Recently, many investigators reported supporting evidence for the promotional effect of Mn for precipitated Fe catalysts. In this study, Raney Fe promoted with Mn has been evaluated for C 2 -C 4 olefin selectivity in the hydrogenation of CO relative to coprecipitated Fe-Mn catalysts. Catalyst characterization, including BET surface area, X-ray diffraction, selective chemisorption and ESCA, has been carried to provide insight into the role of manganese in both the Coprecipitated and Raney catalyst systems

  10. PROJECT SCOPE MANAGEMENT PROCESS

    Directory of Open Access Journals (Sweden)

    Yana Derenskaya

    2018-01-01

    Full Text Available The purpose of the article is to define the essence of project scope management process, its components, as well as to develop an algorithm of project scope management in terms of pharmaceutical production. Methodology. To carry out the study, available information sources on standards of project management in whole and elements of project scope management in particular are analysed. Methods of system and structural analysis, logical generalization are used to study the totality of subprocesses of project scope management, input and output documents, and to provide each of them. Methods of network planning are used to construct a precedence diagram of project scope management process. Results of the research showed that components of the project scope management are managing the scope of the project product and managing the content of project work. It is the second component is investigated in the presented work as a subject of research. Accordingly, it is defined that project scope management process is to substantiate and bring to the realization the necessary amount of work that ensures the successful implementation of the project (achievement of its goal and objectives of individual project participants. It is also determined that the process of managing the project scope takes into account the planning, definition of the project scope, creation of the structure of project work, confirmation of the scope and management of the project scope. Participants of these subprocesses are: customer, investor, and other project participants – external organizations (contractors of the project; project review committee; project manager and project team. It is revealed that the key element of planning the project scope is the formation of the structure of design work, the justification of the number of works, and the sequence of their implementation. It is recommended to use the following sequence of stages for creating the structure of project work

  11. On the impact of olefins and aromatics in the methanol-to-hydrocarbon conversion over H-ZSM-5 catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Sun, X.; Mueller, S.; Veen, A.C. van; Lercher, J.A. [Technische Univ. Muenchen, Garching (Germany). Dept. of Chemistry

    2012-07-01

    Methanol-to-hydrocarbons processes using HZSM-5 archetype acidic zeolites or zeotype SAPO-34 catalysts are regarded as a vital suite of conversion technologies to bypass petroleum-based routes for the production of specific fuels and petrochemical commodities. Special significance of the methanol chemistry originates from its versatility enabling selective transformations towards various products. Industry demonstrated successfully implementations of Methanol-To-Gasoline, Methanol-To-Olefin, and Methanol-To-Propylene processes, although the typical single-pass selectivity remained limited and recycling is necessary. Considerable fundamental research efforts both from experimental and computational sides contributed to unravel the underlying complex reaction mechanism. The indirect hydrocarbon pool mechanism, in which Broensted acid sites combined with adsorbed light olefins or lower methylbenzenes act as active centers, is generally accepted to explain the formation of light olefins. As olefin and aromatics populated catalytic sites show different reactivity in terms of activity and selectivity to ethylene or propylene, one could envision optimizing the product distribution by suitable co-feeding of specific hydrocarbons. The present work addresses three questions with an experimental study conducted under realistic MTP operation conditions: (1) How are ethylene and propylene formed at molecular level? (2) Which reaction pathway leads to the formation of undesired hydrogen transfer products? (3) Does olefin or aromatics co-feeding change the selectivity to ethylene or propylene? Xylenes and various olefins were co-fed with methanol to achieve a detailed understanding of the reaction mechanism over acidic HZSM-5 zeolites. Results suggest, that an olefin homologation/cracking route (olefin cycle) accounts for the autocatalytic (-like) nature and the majority of methanol consumption rather than the route involving aromatic intermediates (aromatics cycle). Co

  12. Substrate Trapping in Crystals of the Thiolase OleA Identifies Three Channels That Enable Long Chain Olefin Biosynthesis*

    OpenAIRE

    Goblirsch, Brandon R.; Jensen, Matthew R.; Mohamed, Fatuma A.; Wackett, Lawrence P.; Wilmot, Carrie M.

    2016-01-01

    Phylogenetically diverse microbes that produce long chain, olefinic hydrocarbons have received much attention as possible sources of renewable energy biocatalysts. One enzyme that is critical for this process is OleA, a thiolase superfamily enzyme that condenses two fatty acyl-CoA substrates to produce a β-ketoacid product and initiates the biosynthesis of long chain olefins in bacteria. Thiolases typically utilize a ping-pong mechanism centered on an active site cysteine residue. Reaction wi...

  13. Palladium-Catalyzed Decarboxylative γ-Olefination of 2,5-Cyclohexadiene-1-carboxylic Acid Derivatives with Vinyl Halides.

    Science.gov (United States)

    Chang, Chi-Hao; Chou, Chih-Ming

    2018-04-06

    This study explores a Pd-catalyzed decarboxylative Heck-type Csp 3 -Csp 2 coupling reaction of 2,5-cyclohexadiene-1-carboxylic acid derivatives with vinyl halides to provide γ-olefination products. The olefinated 1,3-cyclohexadienes can be further oxidized to produce meta-alkylated stilbene derivatives. Additionally, the conjugated diene products can also undergo a Diels-Alder reaction to produce a bicyclo[2.2.2]octadiene framework.

  14. Highly Convergent Total Synthesis of (+)-Lithospermic Acid via a Late-Stage Intermolecular C–H Olefination

    Science.gov (United States)

    Wang, Dong-Hui; Yu, Jin-Quan

    2011-01-01

    The total synthesis of (+)-lithospermic acid is reported, which exploits two successive C–H activation reactions as the key steps. Rh-catalyzed carbene C–H insertion reaction using Davies’ catalyst built the dihydrobenzofuran core, and a late-stage intermolecular C–H olefination coupled the olefin unit with the dihydrobenzofuran core to construct the molecule in a highly convergent manner. PMID:21443224

  15. Oxidant-free Rh(III)-catalyzed direct C-H olefination of arenes with allyl acetates.

    Science.gov (United States)

    Feng, Chao; Feng, Daming; Loh, Teck-Peng

    2013-07-19

    Rh(III)-catalyzed direct olefination of arenes with allyl acetate via C-H bond activation is described using N,N-disubstituted aminocarbonyl as the directing group. The catalyst undergoes a redox neutral process, and high to excellent yields of trans-products are obtained. This protocol exhibits a wide spectrum of functionality compatibility because of the simple reaction conditions employed and provides a highly effective synthetic method in the realm of C-H olefination.

  16. The conversion of biomass to light olefins on Fe-modified ZSM-5 catalyst: Effect of pyrolysis parameters.

    Science.gov (United States)

    Zhang, Shihong; Yang, Mingfa; Shao, Jingai; Yang, Haiping; Zeng, Kuo; Chen, Yingquan; Luo, Jun; Agblevor, Foster A; Chen, Hanping

    2018-07-01

    Light olefins are the key building blocks for the petrochemical industry. In this study, the effects of in-situ and ex-situ process, temperature, Fe loading, catalyst to feed ratio and gas flow rate on the olefins carbon yield and selectivity were explored. The results showed that Fe-modified ZSM-5 catalyst increased the olefins yield significantly, and the ex-situ process was much better than in-situ. With the increasing of temperature, Fe-loading amount, catalyst to feed ratio, and gas flow rate, the carbon yields of light olefins were firstly increased and further decreased. The maximum carbon yield of light olefins (6.98% C-mol) was obtained at the pyrolysis temperature of 600°C, catalyst to feed ratio of 2, gas flow rate of 100ml/min, and 3wt% Fe/ZSM-5 for cellulose. The selectivity of C 2 H 4 was more than 60% for all feedstock, and the total light olefins followed the decreasing order of cellulose, corn stalk, hemicelluloses and lignin. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. Propagation/depropagation equilibrium and structural factors in the radiation degradation of poly(olefin sulfone)s

    International Nuclear Information System (INIS)

    Bowmer, T.N.; O'Donnell, J.H.

    1981-01-01

    The principal volatile products observed after γ irradiation of nine different poly(olefin sulfone)s in the solid state were the two comonomers, i.e., the respective olefin and sulfur dioxide. An exponential increase in yield, G (volatile products), with increasing irradiation temperature, T/sub irr/, was observed for each copolymer through the ceiling temperature, T/sub c/, for the corresponding propagation/depropagation equilibrium. Thus the G value increased by ca. 3 orders of magnitude from T/sub irr/ = 0.7 T/sub c/ to T/sub irr/ = 1.3 T/sub c/ for all of the poly(olefin sulfone)s. Depropagation sensitivity was considered to be best measured by G(SO 2 ) since radiation induced, cationic homopolymerization of the product olefin occurred to a variable extent. Five of the poly(olefin sulfone)s had similar rates of depropagation at their respective T/sub c's/ but the polysulfones of 1-hexene, cyclohexene and 2-butene showed anomalously high depropagation rates. This may be related to greater steric hinderance to segmental chain mobility in the polysulfones of the 1,2 disubstituted olefins. Poly(1-hexene sulfone) appears to be anomalous, as in other respects

  18. Detailed Mechanistic Studies on Palladium-Catalyzed Selective C-H Olefination with Aliphatic Alkenes: A Significant Influence of Proton Shuttling.

    Science.gov (United States)

    Deb, Arghya; Hazra, Avijit; Peng, Qian; Paton, Robert S; Maiti, Debabrata

    2017-01-18

    Directing group-assisted regioselective C-H olefination with electronically biased olefins is well studied. However, the incorporation of unactivated olefins has remained largely unsuccessful. A proper mechanistic understanding of olefination involving unactivated alkenes is therefore essential for enhancing their usage in future. In this Article, detailed experimental and computational mechanistic studies on palladium catalyzed C-H olefination with unactivated, aliphatic alkenes are described. The isolation of Pd(II) intermediates is shown to be effective for elucidating the elementary steps involved in catalytic olefination. Reaction rate and order determination, control experiments, isotopic labeling studies, and Hammett analysis have been used to understand the reaction mechanism. The results from these experimental studies implicate β-hydride elimination as the rate-determining step and that a mechanistic switch occurs between cationic and neutral pathway. Computational studies support this interpretation of the experimental evidence and are used to uncover the origins of selectivity.

  19. Key product development based on cyclo olefin polymer for LCD-TV

    Science.gov (United States)

    Konishi, Yuichiro; Kobayashi, Masahi; Arakawa, Kouhei

    2006-09-01

    Cyclo Olefin Polymer (COP), which was developed by Zeon Corporation, is well known and used as an optical plastic in optical markets, having unique properties such as high light transmission, low water absorption, low birefringence etc. Optes Inc, who is ZEON CORPORATION's affiliate optical parts manufacturer, has succeeded in the development of high performance optical base films. These are used for retardation and polarizing films in LCD's (Liquid Crystal Displays), made from Cyclo Olefin Polymer with own film extrusion technologies. The Optical base film developed by Optes Inc has superior properties compared with those of existing products such as polycarbonate (PC), polyethylene terephthalate (PET) and Triacetate Cellulose (TAC) base in terms of low birefringence, high optical isotropy and high dimensional stability under high humidity and temperature conditions.

  20. The activation mechanism of Ru-indenylidene complexes in olefin metathesis

    KAUST Repository

    Urbina-Blanco, César A.

    2013-05-08

    Olefin metathesis is a powerful tool for the formation of carbon-carbon double bonds. Several families of well-defined ruthenium (Ru) catalysts have been developed during the past 20 years; however, the reaction mechanism for all such complexes was assumed to be the same. In the present study, the initiation mechanism of Ru-indenylidene complexes was examined and compared with that of benzylidene counterparts. It was discovered that not all indenylidene complexes followed the same mechanism, highlighting the importance of steric and electronic properties of so-called spectator ligands, and that there is no single mechanism for the Ru-based olefin metathesis reaction. The experimental findings are supported quantitatively by DFT calculations. © 2013 American Chemical Society.

  1. Synthesis and characterization of new magnetically recoverable molybdenum nanocatalyst for epoxidation of olefins

    Energy Technology Data Exchange (ETDEWEB)

    Masteri-Farahani, M., E-mail: mfarahany@yahoo.com [Faculty of Chemistry, University of Tarbiat Moallem, Tehran (Iran, Islamic Republic of); Kashef, Z. [Faculty of Chemistry, University of Tarbiat Moallem, Tehran (Iran, Islamic Republic of)

    2012-04-15

    New heterogeneous molybdenum catalyst was prepared through covalent attachment of a Schiff base ligand on the surface of silica coated magnetite nanoparticles via aminopropyl spacer and subsequent complexation with MoO{sub 2}(acac){sub 2}. The prepared nanocatalyst was characterized with Fourier transform infrared spectroscopy, X-ray diffraction, scanning and transmission electron microscopies and vibrating sample magnetometry. Catalytic epoxidation of some olefins and allylic alcohols by prepared nanocatalyst using tert-butyl hydroperoxide and cumene hydroperoxide as oxidants was achieved with good activities and selectivities. - Highlights: Black-Right-Pointing-Pointer Silica coated magnetite nanoparticles were modified with a Schiff base ligand. Black-Right-Pointing-Pointer Next reaction with MoO{sub 2}(acac){sub 2} afforded magnetically recoverable nanocatalyst. Black-Right-Pointing-Pointer The prepared nanocatalyst catalyzed the epoxidation of olefins with TBHP.

  2. The activation mechanism of Ru-indenylidene complexes in olefin metathesis

    KAUST Repository

    Urbina-Blanco, Cé sar A.; Poater, Albert; Lé bl, Tomá š; Manzini, Simone; Slawin, Alexandra M. Z.; Cavallo, Luigi; Nolan, Steven P.

    2013-01-01

    Olefin metathesis is a powerful tool for the formation of carbon-carbon double bonds. Several families of well-defined ruthenium (Ru) catalysts have been developed during the past 20 years; however, the reaction mechanism for all such complexes was assumed to be the same. In the present study, the initiation mechanism of Ru-indenylidene complexes was examined and compared with that of benzylidene counterparts. It was discovered that not all indenylidene complexes followed the same mechanism, highlighting the importance of steric and electronic properties of so-called spectator ligands, and that there is no single mechanism for the Ru-based olefin metathesis reaction. The experimental findings are supported quantitatively by DFT calculations. © 2013 American Chemical Society.

  3. Synthesis of amide-functionalized cellulose esters by olefin cross-metathesis.

    Science.gov (United States)

    Meng, Xiangtao; Edgar, Kevin J

    2015-11-05

    Cellulose esters with amide functionalities were synthesized by cross-metathesis (CM) reaction of terminally olefinic esters with different acrylamides, catalyzed by Hoveyda-Grubbs 2nd generation catalyst. Chelation by amides of the catalyst ruthenium center caused low conversions using conventional solvents. The effects of both solvent and structure of acrylamide on reaction conversion were investigated. While the inherent tendency of acrylamides to chelate Ru is governed by the acrylamide N-substituents, employing acetic acid as a solvent significantly improved the conversion of certain acrylamides, from 50% to up to 99%. Homogeneous hydrogenation using p-toluenesulfonyl hydrazide successfully eliminated the α,β-unsaturation of the CM products to give stable amide-functionalized cellulose esters. The amide-functionalized product showed higher Tg than its starting terminally olefinic counterpart, which may have resulted from strong hydrogen bonding interactions of the amide functional groups. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Improving energy efficiency of an Olefin plant – A new approach

    International Nuclear Information System (INIS)

    Tahouni, Nassim; Bagheri, Narges; Towfighi, Jafar; Hassan Panjeshahi, M.

    2013-01-01

    Highlights: • The retrofit of an Olefin plant is studied to improve the overall energy efficiency. • Three levels of retrofit and optimization of this process are suggested. • A simultaneous method is presented to optimize low-temperature separation processes. - Abstract: Low-temperature gas separation processes are the most important gas separation routes. There is a complex interaction between core process (separation columns), associated heat exchanger network and refrigeration cycles in sub ambient processes. The aim of this paper is performing a comprehensive retrofit study of an Olefin plant (as an industrial example) to improve the overall energy efficiency. In this regard, the effect of improving column operating parameters and refrigeration cycles are first evaluated separately. Then, column operating parameters and refrigeration cycles as well as heat exchanger network are optimized simultaneously using genetic algorithm or simulated annealing. Having compared all results, one can conclude that simultaneous optimization leads to higher efficiency of the overall system

  5. Sustainable solid catalyst alkylation of commercial olefins by regeneration with supercritical isobutane

    Energy Technology Data Exchange (ETDEWEB)

    Daniel M. Ginosar; David N. Thompson; Kyle C. Burch

    2005-12-01

    Supercritical isobutane regeneration of a USY zeolite alkylation catalyst was examined in a continuous, automated reaction / regeneration system. Two feeds were studied; a synthetic isobutane / 2-butene blend, and a commercial refinery isoparaffin / olefin blend. The refinery blend was minimally treated, containing a variety of light olefins, and contaminants, including butadiene, oxygenates and sulfur, which are well known to cause severe catalyst deactivation. Synthetic feed experiments showed that high levels of butene conversion was maintained for more than 200 hours time on stream, and that product quality and catalyst maintenance was relatively stable over the course of the experiment using a 3 hour reaction / 3 hour regeneration cycle. Catalyst activity maintenance was lower when the commercial feed was employed. High levels of alkene conversion were maintained for 78 hours and 192 hours using a 3 hour reaction / 3 hour regeneration cycle and a 2 hour reaction / 2 hour regeneration cycle, respectively.

  6. A Wittig-olefination-Claisen-rearrangement approach to the 3-methylquinoline-4-carbaldehyde synthesis.

    Science.gov (United States)

    Kulkarni, Mukund G; Desai, Mayur P; Birhade, Deekshaputra R; Shaikh, Yunus B; Dhatrak, Ajit N; Gannimani, Ramesh

    2012-01-01

    Efficient syntheses are described for the synthetically important 3-methylquinoline-4-carbaldehydes 6a-h from o-nitrobenzaldehydes 1a-h employing a Wittig-olefination-Claisen-rearrangement protocol. The Wittig reaction of o-nitrobenzaldehydes with crotyloxymethylene triphenylphosphorane afforded crotyl vinyl ethers 2a-h, which on heating under reflux in xylene underwent Claisen rearrangement to give 4-pentenals 3a-h. Protection of the aldehyde group of the 4-pentenals as acetals 4a-h and subsequent oxidative cleavage of the terminal olefin furnished nitroaldehydes 5a-h. Reductive cyclization of these nitroaldehydes yielded the required 3-methylquinoline-4-carbaldehydes 6a-h in excellent yields. Therefore, an efficient method was developed for the preparation of 3-methylquinoline-4-carbaldehydes from o-nitrobenzaldehydes in a simple five-step procedure.

  7. Manganese-catalyzed Dehydrogenative Alkylation or α-Olefination of Alkyl-N-Heteroaromatics by Alcohols.

    Science.gov (United States)

    Kempe, Rhett; Zhang, Guoying; Irrgang, Torsten; Dietel, Thomas; Kallmeier, Fabian

    2018-05-02

    Catalysis involving earth-abundant transition metals is an option to help save our rare noble metal resources and is especially interesting if novel reactivity or selectivity patterns are observed. We report here on a novel reaction: the dehydrogenative alkylation or α-olefination of alkyl-N-heteroaromatics by alcohols. Manganese complexes developed in our laboratory catalyze the reaction efficiently. Fe and Co complexes stabilized by such ligands are essentially inactive. Hydrogen is liberated during the reaction and bromo or iodo functional groups and olefins can be tolerated. A variety of alkyl-N-heteroaromatics can be functionalized, and benzyl and aliphatic alcohols undergo the reaction. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Iron(II)-catalyzed intramolecular aminohydroxylation of olefins with functionalized hydroxylamines.

    Science.gov (United States)

    Liu, Guan-Sai; Zhang, Yong-Qiang; Yuan, Yong-An; Xu, Hao

    2013-03-06

    A diastereoselective aminohydroxylation of olefins with a functionalized hydroxylamine is catalyzed by new iron(II) complexes. This efficient intramolecular process readily affords synthetically useful amino alcohols with excellent selectivity (dr up to > 20:1). Asymmetric catalysis with chiral iron(II) complexes and preliminary mechanistic studies reveal an iron nitrenoid is a possible intermediate that can undergo either aminohydroxylation or aziridination, and the selectivity can be controlled by careful selection of counteranion/ligand combinations.

  9. STIR: Redox-Switchable Olefin Polymerization Catalysis: Electronically Tunable Ligands for Controlled Polymer Synthesis

    Science.gov (United States)

    2013-03-28

    production of polyethylene (PE) and polypropylene (PP) topped 53 billion pounds in 2011.1 This extreme demand has ensured that olefin polymerization...is an ideal starting monomer as it is a liquid at room temperature facilitating rapid screening and data collection without the need for cumbersome...elastomers, binders, thermoplastic elastomers, rheology modifiers, permeation selective membranes, and high strength, light-weight structural materials

  10. Microchannel fabrication on cyclic olefin polymer substrates via 1064 nm Nd:YAG laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    McCann, Ronán [Advanced Processing Technology Research Centre, Dublin City University, Glasnevin, Dublin 9 (Ireland); School of Mechanical and Manufacturing Engineering, Dublin City University, Dublin 9 (Ireland); Irish Separation Science Cluster, National Centre for Sensor Research, Dublin City University, Dublin 9 (Ireland); National Centre for Plasma Science and Technology, Dublin City University, Dublin 9 (Ireland); Bagga, Komal; Groarke, Robert [Advanced Processing Technology Research Centre, Dublin City University, Glasnevin, Dublin 9 (Ireland); School of Mechanical and Manufacturing Engineering, Dublin City University, Dublin 9 (Ireland); Irish Separation Science Cluster, National Centre for Sensor Research, Dublin City University, Dublin 9 (Ireland); Stalcup, Apryll [Irish Separation Science Cluster, National Centre for Sensor Research, Dublin City University, Dublin 9 (Ireland); School of Chemical Sciences, Dublin City University, Dublin 9 (Ireland); Vázquez, Mercedes, E-mail: mercedes.vazquez@dcu.ie [Advanced Processing Technology Research Centre, Dublin City University, Glasnevin, Dublin 9 (Ireland); Irish Separation Science Cluster, National Centre for Sensor Research, Dublin City University, Dublin 9 (Ireland); School of Chemical Sciences, Dublin City University, Dublin 9 (Ireland); Brabazon, Dermot [Advanced Processing Technology Research Centre, Dublin City University, Glasnevin, Dublin 9 (Ireland); School of Mechanical and Manufacturing Engineering, Dublin City University, Dublin 9 (Ireland); Irish Separation Science Cluster, National Centre for Sensor Research, Dublin City University, Dublin 9 (Ireland); National Centre for Plasma Science and Technology, Dublin City University, Dublin 9 (Ireland)

    2016-11-30

    Highlights: • Rapid single-step microchannel fabrication on optically transparent cyclic olefin polymer using IR Nd:YAG laser. • Ability to tailor channel depth between 12–47 μm demonstrated for single laser pass. • Use of multiple laser passes showed capability for finer depth control. • Potential applications in lab-on-chip and microfluidic devices. - Abstract: This paper presents a method for fabrication of microchannels on cyclic olefin polymer films that have application in the field of microfluidics and chemical sensing. Continuous microchannels were fabricated on 188-μm-thick cyclic olefin polymer substrates using a picosecond pulsed 1064 nm Nd:YAG laser. The effect of laser fluence on the microchannel morphology and dimensions was analysed via scanning electron microscopy and optical profilometry. Single laser passes were found to produce v-shaped microchannels with depths ranging from 12 μm to 47 μm and widths from 44 μm to 154 μm. The ablation rate during processing was lower than predicted theoretically. Multiple laser passes were applied to examine the ability for finer control over microchannel morphology with channel depths ranging from 22 μm to 77 μm and channel widths from 59 μm to 155 μm. For up to five repeat passes, acceptable reproducibility was found in the produced microchannel morphology. Infrared spectroscopy revealed oxidation and dehydrogenation of the polymer surface following laser ablation. These results were compared to other work conducted on cyclic olefin polymers.

  11. Photoredox-Catalyzed Ketyl–Olefin Coupling for the Synthesis of Substituted Chromanols

    KAUST Repository

    Fava, Eleonora

    2016-07-21

    A visible light photoredox-catalyzed aldehyde olefin cyclization is reported. The method represents a formal hydroacylation of alkenes and alkynes and provides chromanol derivatives in good yields. The protocol takes advantage of the double role played by trialkylamines (NR3) which act as (i) electron donors for reducing the catalyst and (ii) proton donors to activate the substrate via a proton-coupled electron transfer. © 2016 American Chemical Society.

  12. InCl3/NaClO: a reagent for allylic chlorination of terminal olefins

    International Nuclear Information System (INIS)

    Pisoni, Diego S.; Gamba, Douglas; Fonseca, Carlos V.; Costa, Jesse S. da; Petzhold, Cesar L.; Oliveira, Eduardo R. de; Ceschi, Marco A.

    2006-01-01

    Indium trichloride promotes the chlorination of terminal olefins in the presence of sodium hypochlorite with good results. Carvone was chosen as a model compound to examine some of the general features of this reaction, such as stoichiometry, temperature, reaction time and product conversion. Treatment of β-pinene with sodium hypochlorite in the presence of indium trichloride resulted in a facile rearrangement to selectively yield perillyl chloride, which is an important precursor for C-7 oxygenated limonenes. (author)

  13. Microchannel fabrication on cyclic olefin polymer substrates via 1064 nm Nd:YAG laser ablation

    International Nuclear Information System (INIS)

    McCann, Ronán; Bagga, Komal; Groarke, Robert; Stalcup, Apryll; Vázquez, Mercedes; Brabazon, Dermot

    2016-01-01

    Highlights: • Rapid single-step microchannel fabrication on optically transparent cyclic olefin polymer using IR Nd:YAG laser. • Ability to tailor channel depth between 12–47 μm demonstrated for single laser pass. • Use of multiple laser passes showed capability for finer depth control. • Potential applications in lab-on-chip and microfluidic devices. - Abstract: This paper presents a method for fabrication of microchannels on cyclic olefin polymer films that have application in the field of microfluidics and chemical sensing. Continuous microchannels were fabricated on 188-μm-thick cyclic olefin polymer substrates using a picosecond pulsed 1064 nm Nd:YAG laser. The effect of laser fluence on the microchannel morphology and dimensions was analysed via scanning electron microscopy and optical profilometry. Single laser passes were found to produce v-shaped microchannels with depths ranging from 12 μm to 47 μm and widths from 44 μm to 154 μm. The ablation rate during processing was lower than predicted theoretically. Multiple laser passes were applied to examine the ability for finer control over microchannel morphology with channel depths ranging from 22 μm to 77 μm and channel widths from 59 μm to 155 μm. For up to five repeat passes, acceptable reproducibility was found in the produced microchannel morphology. Infrared spectroscopy revealed oxidation and dehydrogenation of the polymer surface following laser ablation. These results were compared to other work conducted on cyclic olefin polymers.

  14. Constructing Multiply Substituted Arenes Using Sequential Pd(II)-Catalyzed C–H Olefination**

    Science.gov (United States)

    Engle, Keary M.; Wang, Dong-Hui; Yu, Jin-Quan

    2011-01-01

    Complementary catalytic systems have been developed in which the reactivity/selectivity balance in Pd(II)-catalyzed ortho-C–H olefination can be modulated through ligand control. This allows for sequential C–H functionalization for the rapid preparation of 1,2,3-trisubstituted arenes. Additionally, a rare example of iterative C–H activation, in which a newly installed functional group directs subsequent C–H activation has been demonstrated. PMID:20632344

  15. Photoredox-Catalyzed Ketyl–Olefin Coupling for the Synthesis of Substituted Chromanols

    KAUST Repository

    Fava, Eleonora; Nakajima, Masaki; Nguyen, Anh L. P.; Rueping, Magnus

    2016-01-01

    A visible light photoredox-catalyzed aldehyde olefin cyclization is reported. The method represents a formal hydroacylation of alkenes and alkynes and provides chromanol derivatives in good yields. The protocol takes advantage of the double role played by trialkylamines (NR3) which act as (i) electron donors for reducing the catalyst and (ii) proton donors to activate the substrate via a proton-coupled electron transfer. © 2016 American Chemical Society.

  16. Surface functionalization of cyclic olefin copolymer (COC) with evaporated TiO{sub 2} thin film

    Energy Technology Data Exchange (ETDEWEB)

    El Fissi, Lamia, E-mail: lamia.elfissi@uclouvain.be [ICTEAM Institute, Université catholique du Louvain, place de Levant 3, 1348 Louvain-la-Neuve (Belgium); Vandormael, Denis [SIRRIS Liege Science Park, 4102 Seraing (Belgium); Houssiau, Laurent [Research Centre in Physics of Matter and Radiation (PMR), University of Namur, Rue de Bruxelles 61, B-5000 Namur (Belgium); Francis, Laurent A. [ICTEAM Institute, Université catholique du Louvain, place de Levant 3, 1348 Louvain-la-Neuve (Belgium)

    2016-02-15

    Highlights: • TiO{sub 2}/COC (cyclic olefin copolymer) hybrid material for BioMEMS applications. • Thin layer of TiO{sub 2} was deposed on cyclic olefin copolymer using physical vapor deposition (PVD) technique. • The coating possess the highest level of adhesion with an excellent morphology of the hybrid material (TiO{sub 2}/COC). - Abstract: Cyclic olefin copolymer (COC) is a new class of thermoplastic polymers used for a variety of applications ranging from bio-sensing to optics. However, the hydrophobicity of native COC hampers the further development and application of this material [1]. In this work, we report the structural, morphological, and optical properties of the TiO{sub 2}/COC hybrid material, which provides a desirable substrate for optical devices and subsequent surface modifications. The TiO{sub 2} film on COC substrate was deposited by the evaporation method, and it was characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), profilometry and atomic force microscope (AFM). Using an UV-vis spectrophotometer, we found that the transmittance of the TiO{sub 2}/COC hybrid material in the visible domain reached 80%. The TiO{sub 2}/COC hybrid appeared to be stable in most of the assessed polar solvents and acid/basic solutions. The new TiO{sub 2}/COC hybrid material and the robust fabrication method are expected to enable a variety of BioMEMS applications.

  17. Wood-derived olefins by steam cracking of hydrodeoxygenated tall oils.

    Science.gov (United States)

    Pyl, Steven P; Dijkmans, Thomas; Antonykutty, Jinto M; Reyniers, Marie-Françoise; Harlin, Ali; Van Geem, Kevin M; Marin, Guy B

    2012-12-01

    Tall oil fractions obtained from Norwegian spruce pulping were hydrodeoxygenated (HDO) at pilot scale using a commercial NiMo hydrotreating catalyst. Comprehensive two dimensional gas chromatography (GC×GC) showed that HDO of both tall oil fatty acids (TOFA) and distilled tall oil (DTO) produced highly paraffinic hydrocarbon liquids. The hydrotreated fractions also contained fatty acid methyl esters and norabietane and norabietatriene isomers. Steam cracking of HDO-TOFA in a pilot plant revealed that high light olefin yields can be obtained, with 35.4 wt.% of ethene and 18.2 wt.% of propene at a coil outlet pressure (COP) of 1.7 bara, a dilution of 0.45 kg(steam)/kg(HDO-TOFA) and a coil outlet temperature (COT) of 820 °C. A pilot plant coking experiment indicated that cracking of HDO-TOFA at a COT of 850 °C results in limited fouling in the reactor. Co-cracking of HDO tall oil fractions with a typical fossil-based naphtha showed improved selectivity to desired light olefins, further demonstrating the potential of large scale olefin production from hydrotreated tall oil fractions in conventional crackers. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Energy and materials flows in the production of olefins and their derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Gaines, L.L.; Shen, S.Y.

    1980-08-01

    Production of olefins and their derivatives uses almost 3.5% of the oil and gas consumed annually in the United States. It is estimated that their production requires an input energy of 2 Q, which is 50% of the energy used in the production of all petrochemicals. Substantial amounts of this energy could be recovered through recycling. For example, recycling of a single plastic product, polyester soft drink bottles, could have recovered about 0.014 Q in 1979. (About 1.4 Q is used to produce plastic derivatives of olefins). Petrochemical processes use fuels as feedstocks, as well as for process energy, and a portion of this energy is not foregone and can be recovered through combustion of the products. The energy foregone in the production of ethylene is estimated to be 7800 Btu/lb. The energy foregone in plastics production ranges from 12,100 Btu/lb for the new linear low-density polyethylene to 77,200 Btu/lb for nylon 66, which is about 60% of the total energy input for that product. Further investigation of the following areas could yield both material and energy savings in the olefins industry: (1) recycling of petrochemical products to recover energy in addition to that recoverable through combustion, (2) impact of feedstock substitution on utilization of available national resources, and (3) effective use of the heat embodied in process steam. This steam accounts for a major fraction of the industry's energy input.

  19. Positive ion scavenging by olefins in trans-decalin: TRMC and product analysis studies

    International Nuclear Information System (INIS)

    Warman, J.M.; Leng, H.C. de; Haas, M.P. de; Anisimov, O.A.

    1990-01-01

    The rate constants for scavenging of the mobile positive ion in trans-decalin have been measured using the time-resolved microwave conductivity (TRMC) pulse radiolysis technique for a series of olefins and cyclopropane. For the olefins the values vary from ≤2 x 10 8 dm 3 /mol/s for ethylene to 1.6 x 10 11 dm 3 /mol/s for cyclohexene. Steady-state (γ) radiolysis of solutions of isobutene in trans-decalin results in the formation of isobutane and C 8 and C 14 products which display different dependences on solute concentration. The results are explained in terms of the formation of a complex between the solvent radical cation and isobutene which can dissociate, within a timescale of approx. 1 ns, to give isobutane or on neutralisation leads to the formation of C 14 condensation products. The C 8 products which are formed above 5 x 10 -2 mol/dm 3 are attributed to reaction of the complex with isobutene to form the olefin dimer cation. Cyclopropane is unreactive, i.e. k 8 dm 3 /mol/s, towards the mobile positive ion in trans-decalin (author)

  20. Synthesis of a gamma irradiation grafted polytetrafluoroethylene (PTFE) based olefinic copolymer

    International Nuclear Information System (INIS)

    Ferreto, Helio Fernando Rodrigues

    2006-01-01

    The extrusion of linear low density polyethylene (LLDPE) is limited by a process related defect known as 'melt fracture' or 'sharkskin', which is a surface defect of the extruded polymer. This defect results in a product with a rough surface that lacks luster and in alterations of specific surface properties. The aim of this study was to obtain a recycled polytetrafluoroethylene polymer with an olefin that could improve the extrudability of the LLDPE. The copolymer was obtained by irradiating recycled PTFE in an inert atmosphere followed by the addition of an olefinic monomer to graft the latter in the polymeric matrix (PTFE). After a certain time of contact, the copolymer was heat treated to permit recombination and elimination of the radicals, both in a reactive and/or inert atmosphere. Three olefinic monomers were used, namely; acetylene, ethylene and 1,3-butadiene. The 1,3-butadiene monomer was found to be more effective with respect to grafting. The specimens were studied using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and differential thermogravimetry (DTG). 0.2-2.0 wt% of the copolymer that was obtained was mixed with LLDPE. The rheological properties of the mixture were determined with a torque rheometer. The results indicated that the process used rendered a copolymer which when added to LLDPE, improved the extrusion process and eliminated the defect 'melt fracture'. (author)

  1. Co-Aromatization of Methane with Olefins: The Role of Inner Pore and External Surface Catalytic Sites

    Energy Technology Data Exchange (ETDEWEB)

    Yung, Matthew M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); He, Peng [University of Calgary; Jarvis, Jack [University of Calgary; Meng, Shijun [University of Calgary; Wang, Aiguo [University of Calgary; Kou, Shiyu [University of Calgary; Gatip, Richard [University of Calgary; Liu, Lijia [Soochow University; Song, Hua [University of Calgary

    2018-04-22

    The co-aromatization of methane with olefins is investigated using Ag-Ga/HZSM-5 as the catalyst at 400 degrees C. The presence of methane has a pronounced effect on the product distribution in terms of increased average carbon number and substitution index and decreased aromatic carbon fraction compared with its N2 environment counterpart. The participation of methane during the co-aromatization over the Ag-Ga/HZSM-5 catalyst diminishes as the co-fed olefin feedstock molecule becomes larger, from 1-hexene to 1-octene and 1-decene, in diameter. The effect of suppressed methane participation with larger olefinic molecules is not as significant when Ag-Ga/HY is employed as the catalyst, which might be attributed to the larger pore size of HY that gives more room to hold olefin and methane molecules within the inner pores and reduces the diffusion limitation of olefin molecules. The effect of olefin feedstock on the methane participation during the co-aromatization over Ag-Ga/HZSM-5 is experimentally evidenced by 13C and 2D NMR. The incorporation of the methane carbon atoms into the phenyl ring of product molecules is reduced significantly with larger co-fed olefins, whereas its incorporation into the substitution groups of the formed aromatic molecules is not notably affected, suggesting that the methane participation in the phenyl ring formation might preferably occur within inner pores, while its incorporation into substitution groups may mainly take place on external catalytic sites. This hypothesis is well supported by the product selectivity obtained over Ag-Ga/HZSM-5 catalysts prepared using conventional ZSM-5, ZSM-5 with the external catalytic sites deactivated, nanosize ZSM-5, ZSM-5 with a micro/meso pore structure and ZSM-5 with the inner pores blocked, and further confirmed by the isotopic labeling studies.

  2. ScienceScope: Aerospace

    CSIR Research Space (South Africa)

    CSIR

    2006-12-01

    Full Text Available In this edition of ScienceScope, innovations in and around aerodynamics research and development is explored. The publication explores activities in environmentally friendly aerospace technologies to enhance the aviation industry....

  3. Concrete decontamination scoping tests

    International Nuclear Information System (INIS)

    Archibald, K.E.

    1995-01-01

    This report details the research efforts and scoping tests performed at the Idaho Chemical Process Plant using scabbling, chemical, and electro-osmotic decontamination techniques on radiologically contaminated concrete

  4. RADAR PPI Scope Overlay

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — RADAR PPI Scope Overlays are used to position a RADAR image over a station at the correct resolution. The archive maintains several different RADAR resolution types,...

  5. Striking difference between alkane and olefin metathesis using the well-defined precursor [≡Si-O-WMe5]: Indirect evidence in favour of a bifunctional catalyst W alkylidene-hydride

    KAUST Repository

    Riache, Nassima; Callens, Emmanuel; Espinas, Jeff; Dé ry, Alexandre; Samantaray, Manoja; Dey, Raju; Basset, Jean-Marie

    2015-01-01

    Metathesis of linear alkanes catalyzed by the well-defined precursor (≡Si-O-WMe5) affords a wide distribution of linear alkanes from methane up to triacontane. Olefin metathesis using the same catalyst and under the same reaction conditions gives a very striking different distribution of linear α-olefins and internal olefins. This shows that olefin and alkane metathesis processes occur via very different pathways.

  6. Maximizing light olefins production in fluid catalytic cracking (FCC) units; Maximizacao de olefinas leves em unidades de craqueamento catalitico fluido

    Energy Technology Data Exchange (ETDEWEB)

    Pimenta, Ricardo D.M.; Pinho, Andrea de Rezende [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2004-07-01

    The Fluid Catalytic Cracking (FCC) process is widely spread over the ten PETROBRAS refineries in its thirteen industrial units. The importance of the FCC process resides on its high gasoline output, being the main supplier of this important product to the system. Additionally, FCC process is the main source of light hydrocarbons in the LPG range, including light olefins. The increasing demand for ethylene, propylene and butylenes was encouraging to concentrate the research efforts on studies about alternatives for the traditional FCC process. In the present work, the proposals from main licensors (UOP, KBR, Stone and Webster) for a light-olefins-driven FCC process (Petrochemical FCC) will be compared. Furthermore, the catalytic route for light olefins production in FCC units is also described. An additive based on ZSM- 5 zeolite, which is produced following a PETROBRAS proprietary technology, is being largely applied into the catalyst inventories of all FCC units. An analysis of different scenarios was performed to estimate the maximum potential of light olefins production from the highest possible ZSM-5 additive usage. More specifically for the case of ethylene, which production is also boosted by the same type of additive, studies are being conducted with the objective of recovering it from a C2 stream using specific units to do the splitting (UPGR). The search for increasing light olefins production in the refining processes is in line with PETROBRAS strategic plan which targeted for the company a more intense activity in the Brazilian petrochemical market (author)

  7. The effect of ultralow temperature on olefin cation formation by ionic fragmentation in the radiolysis of 2,3-dimethylbutane

    International Nuclear Information System (INIS)

    Miyazaki, Tetsuo

    1991-01-01

    The formation of olefin cations in the radiolysis of 2,3-dimethylbutane (DMB) was studied by ESR at 4.2 and 77 K. When a DMB-SF 6 mixture is γ-irradiated at 77 K, tetramethylethylene (TME) cations are formed remarkably. The formation of the TME cations, however, is suppressed at 4.2 K. When the DMB-SF 6 mixture is γ-irradiated at 4.2 K and then warmed to 77 K, TME cations are formed by thermal annealing. The TME cations are not formed by a charge transfer to olefinic impurities or olefinic products in radiolysis, but by H 2 elimination from parent DMB cations in the ground state. The remarkable formation of olefin cations at 77 K corresponds to the large yields of unsaturated dimers in the radiolysis of DMB at 77 K. The suppression of olefin cation formation at 4.2 K corresponds to the low yields of unsaturated dimers in the radiolysis of DMB at 4.2 K. (author)

  8. Full-scope training simulators

    International Nuclear Information System (INIS)

    Ugedo, E.

    1986-01-01

    The following topics to be covered in this report are: Reasons justifying the use of full-scope simulators for operator qualification. Full-scope simulator description: the control room, the physical models, the computer complex, the instructor's console. Main features of full-scope simulators. Merits of simulator training. The role of full-scope simulators in the training programs. The process of ordering and acquiring a full-scope simulator. Maintaining and updating simulator capabilities. (orig./GL)

  9. Effects of calcination and activation conditions on ordered mesoporous carbon supported iron catalysts for production of lower olefins from synthesis gas

    NARCIS (Netherlands)

    Oschatz, M; van Deelen, T W; Weber, J L; Lamme, W S; Wang, G; Goderis, B; Verkinderen, O; Dugulan, A I; de Jong, K P

    2016-01-01

    Lower C2–C4 olefins are important commodity chemicals usually produced by steam cracking of naphtha or fluid catalytic cracking of vacuum gas oil. The Fischer–Tropsch synthesis of lower olefins (FTO) with iron-based catalysts uses synthesis gas as an alternative feedstock. Nanostructured carbon

  10. Metal-free oxidative olefination of primary amines with benzylic C-H bonds through direct deamination and C-H bond activation.

    Science.gov (United States)

    Gong, Liang; Xing, Li-Juan; Xu, Tong; Zhu, Xue-Ping; Zhou, Wen; Kang, Ning; Wang, Bin

    2014-09-14

    An oxidative olefination reaction between aliphatic primary amines and benzylic sp(3) C-H bonds has been achieved using N-bromosuccinimide as catalyst and tert-butyl hydroperoxide as oxidant. The olefination proceeds under mild metal-free conditions through direct deamination and benzylic C-H bond activation, and provides easy access to biologically active 2-styrylquinolines with (E)-configuration.

  11. Argentation gas chromatography revisited: Separation of light olefin/paraffin mixtures using silver-based ionic liquid stationary phases.

    Science.gov (United States)

    Nan, He; Zhang, Cheng; Venkatesh, Amrit; Rossini, Aaron J; Anderson, Jared L

    2017-11-10

    Silver ion or argentation chromatography utilizes stationary phases containing silver ions for the separation of unsaturated compounds. In this study, a mixed-ligand silver-based ionic liquid (IL) was evaluated for the first time as a gas chromatographic (GC) stationary phase for the separation of light olefin/paraffin mixtures. The selectivity of the stationary phase toward olefins can be tuned by adjusting the ratio of silver ion and the mixed ligands. The maximum allowable operating temperature of these stationary phases was determined to be between 125°C and 150°C. Nuclear magnetic resonance (NMR) spectroscopy was used to characterize the coordination behavior of the silver-based IL as well as provide an understanding into the retention mechanism of light olefins. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Ligand-Enabled γ-C(sp3)–H Olefination of Amines: En Route to Pyrrolidines

    Science.gov (United States)

    Jiang, Heng; He, Jian; Liu, Tao

    2016-01-01

    Pd(II)-catalyzed olefination of γ-C(sp3)–H bonds of triflyl (Tf) and 4-nitrobenzenesulfonyl (Ns) protected amines is achieved. Subsequent aza-Wacker oxidative cyclization or conjugate addition of the olefinated intermediates provides a variety of C-2 alkylated pyrrolidines. Three pyridine- and quinoline-based ligands are developed to match different classes of amine substrates, demonstrating a rare example of ligand-enabled C(sp3)–H olefination reaction. The use of Ns protecting group to direct C(sp3)–H activation of alkyl amine is also a significant step towards practical C–H functionalizations of alkyl amines. PMID:26796676

  13. Tacticities study of high poly-α-olefins, from poly-1-hexene to poly-1-octadecene, obtained with metallocenes catalysts

    International Nuclear Information System (INIS)

    Silva, Luciano F. da; Galland, Griselda B.

    2003-01-01

    High poly-α-olefins such as poly-1-hexene, poly-1-octene, poly-1-decene, poly-1-dodecene, poly-1-tetradecene, poly-1-hexadecene and poly-1-octadecene were obtained with the homogeneous iso specific catalyst rac-Et[Ind]ZrCl 2 /MAO and with the homogeneous syndiospecific catalyst Me 2 C[Cp(9-Flu)]ZrCl 2 /MAO at the polymerization temperatures of 0 deg C, 30 deg C and 60 deg C. The polymers were analyzed by 13 C NMR to study the influence of the α - olefins sizes, the catalysts type and the polymerization temperatures in their tacticities. The stereospecific control of both catalytic systems decreased with the increase of the reaction temperature and with the α-olefin size. (author)

  14. Oxidizer Scoping Studies

    Energy Technology Data Exchange (ETDEWEB)

    Chancellor, Christopher John [Los Alamos National Laboratory

    2016-11-07

    The purpose of this report is to present the results of the acceptable knowledge (AK) review of oxidizers present in active waste streams, provide a technical analysis of the oxidizers, and report the results of the scoping study testing. This report will determine the fastest burning oxidizer to be used in the development of a Test Plan for Preparation and Testing of Sorbents Mixed with Oxidizer found in Transuranic Waste (DWT-TP-001). The companion report, DWT-RPT-002, Sorbent Scoping Studies, contains similar information for sorbents identified during the AK review of TRU waste streams. The results of the oxidizer and sorbent scoping studies will be used to inform the QL1 test plan. The QL1 test results will support the development of a basis of knowledge document that will evaluate oxidizing chemicals and sorbents in TRU waste and provide guidance for treatment.

  15. LogScope

    Science.gov (United States)

    Havelund, Klaus; Smith, Margaret H.; Barringer, Howard; Groce, Alex

    2012-01-01

    LogScope is a software package for analyzing log files. The intended use is for offline post-processing of such logs, after the execution of the system under test. LogScope can, however, in principle, also be used to monitor systems online during their execution. Logs are checked against requirements formulated as monitors expressed in a rule-based specification language. This language has similarities to a state machine language, but is more expressive, for example, in its handling of data parameters. The specification language is user friendly, simple, and yet expressive enough for many practical scenarios. The LogScope software was initially developed to specifically assist in testing JPL s Mars Science Laboratory (MSL) flight software, but it is very generic in nature and can be applied to any application that produces some form of logging information (which almost any software does).

  16. Synthesis and essay of an Ionomer like catalyst of olefins epoxidation

    International Nuclear Information System (INIS)

    Boyaca Mendivelso, Alejandro; Tempesti, Ezio

    1995-01-01

    The purpose of the present work is the preparation of an ionomer with base in Molybdenum and to evaluate its activity like catalyst of olefins epoxidation like alternative of synthesis of catalysts of the Hawk process. A polymer is synthesized with available functional groups to stabilize the metal starting from sodium molybdate; the characterization is made by atomic absorption, spectroscopy to GO, and X.P.S. The characterization indicates that indeed it is possible to stabilize the Mo in the main polymeric. The evaluation in reaction in liquid phase allows similar conversions to those of a homogeneous catalyst. The selective epoxidation of olefins for alkyl hydroperoxides, it has acquired great importance inside the industrial processes obtaining of propylene oxide due to the recent use of the terbutilic alcohol (co-produced together with the epoxide), as preservative in gasoline free of lead. In the environment of these processes, and in particular in the Hawk process possibilities of technological innovation, in the concerning to the heterogenization of conventional catalysts, at the moment used in homogeneous phase. The present work collaborate to some tentative that look for to generate alternative of preparation of catalysts for the process Hawk, synthesizing and testing the activity of an ionomer like epoxidation catalyst, which tries to reproduce the chemical structure of the complexes organ-metallic pear to suppress the separation stages and necessary recovery facilitating its recurrent reutilization with eventual economic repercussions in the industrial process. It is described the procedure of synthesis of the ionomer, the characterization and the evaluation of the activity in reaction under diverse conditions. Of the made characterization it comes off that the heterogenization of catalysts for olefins epoxidation, according to the Hawk process, is possible by means of the preparation of polymers modified appropriately. Likewise the evaluation in

  17. Cyclic olefin homopolymer-based microfluidics for protein crystallization and in situ X-ray diffraction

    International Nuclear Information System (INIS)

    Emamzadah, Soheila; Petty, Tom J.; De Almeida, Victor; Nishimura, Taisuke; Joly, Jacques; Ferrer, Jean-Luc; Halazonetis, Thanos D.

    2009-01-01

    A cyclic olefin homopolymer-based microfluidics system has been established for protein crystallization and in situ X-ray diffraction. Microfluidics is a promising technology for the rapid identification of protein crystallization conditions. However, most of the existing systems utilize silicone elastomers as the chip material which, despite its many benefits, is highly permeable to water vapour. This limits the time available for protein crystallization to less than a week. Here, the use of a cyclic olefin homopolymer-based microfluidics system for protein crystallization and in situ X-ray diffraction is described. Liquid handling in this system is performed in 2 mm thin transparent cards which contain 500 chambers, each with a volume of 320 nl. Microbatch, vapour-diffusion and free-interface diffusion protocols for protein crystallization were implemented and crystals were obtained of a number of proteins, including chicken lysozyme, bovine trypsin, a human p53 protein containing both the DNA-binding and oligomerization domains bound to DNA and a functionally important domain of Arabidopsis Morpheus’ molecule 1 (MOM1). The latter two polypeptides have not been crystallized previously. For X-ray diffraction analysis, either the cards were opened to allow mounting of the crystals on loops or the crystals were exposed to X-rays in situ. For lysozyme, an entire X-ray diffraction data set at 1.5 Å resolution was collected without removing the crystal from the card. Thus, cyclic olefin homopolymer-based microfluidics systems have the potential to further automate protein crystallization and structural genomics efforts

  18. Energetics of the ruthenium-halide bond in olefin metathesis (pre)catalysts

    KAUST Repository

    Falivene, Laura; Poater, Albert; Cazin, Catherine S J; Slugovc, Christian; Cavallo, Luigi

    2013-01-01

    A DFT analysis of the strength of the Ru-halide bond in a series of typical olefin metathesis (pre)catalysts is presented. The calculated Ru-halide bond energies span the rather broad window of 25-43 kcal mol-1. This indicates that in many systems dissociation of the Ru-halide bond is possible and is actually competitive with dissociation of the labile ligand generating the 14e active species. Consequently, formation of cationic Ru species in solution should be considered as a possible event. © 2013 The Royal Society of Chemistry.

  19. Cascade olefin isomerization/intramolecular Diels-Alder reaction catalyzed by N-heterocyclic carbenes.

    Science.gov (United States)

    Kowalczyk, Marcin; Lupton, David W

    2014-05-19

    The addition of an N-heterocyclic carbene to the carbonyl group of an α,β,γ,δ-unsaturated enol ester affords a hemiacetal azolium intermediate that enables a cascade olefin isomerization/Diels-Alder reaction, for which mechanistic studies implicate Lewis base catalysis. Preliminary studies into the utility of the products have been undertaken with reductive and oxidative cleavage, giving materials for potential use in complex-target synthesis. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. New synthesis of photocurable silanes and polysiloxanes bearing heterocyclic or olefinic functions

    International Nuclear Information System (INIS)

    Youssef, B.; Lecamp, L.; Garin, S.; Bunel, C.

    1999-01-01

    In this work, we described the synthesis of silanes and polysiloxanes bearing cationic photopolymerizable groups. Two new methods were used. The first one is the reaction between 3-mercapto-propyl-1-triethoxysilane (1) and chloromethylated olefins by a phase transfer catalysis. The second one is the radical addition of (1) or poly(dimethylsiloxane-co-methylmercaptopropylsiloxane) (9) to allyl or vinyl substituted heterocyclic monomers. These methods led to the expected adducts with an excellent yield. The polysiloxanes bearing heterocyclic functional groups linked through thioether bonds were photocurable by cationic route. Under UV light intensity of 17.5 mW/cm 2 , these polymers harden after 15 or 20 s

  1. Synthesis and characterization of tantalum organometallic complexes. Catalytic activity for olefins

    International Nuclear Information System (INIS)

    Baley, A.S.

    1990-11-01

    Synthesis of monoaryloxy (alcoxy) neopentyl compounds is investigated. The tantalum-oxygen bond is formed by two parallel ways from TaCl 5 or TaR 2 Cl 3 with R = neopentyl and the tantalum carbon bond from a neopentyl derivative of the main series. Some compounds were isolated and characterized by NMR, elemental analysis and sometimes X-ray structure, some others are characterized in solution only. Catalytic effect is tested by ethylene dimerization and olefin polymerization. Reactivity of tantalum aryloxy neopentyl in respect to complexing and chelating ligands is studied for preparation of neopentylidene complexes

  2. Synthesis of Chiral, Enantiopure Allylic Amines by the Julia Olefination of α-Amino Esters

    Directory of Open Access Journals (Sweden)

    Fabio Benedetti

    2016-06-01

    Full Text Available The four-step conversion of a series of N-Boc-protected l-amino acid methyl esters into enantiopure N-Boc allylamines by a modified Julia olefination is described. Key steps include the reaction of a lithiated phenylalkylsulfone with amino esters, giving chiral β-ketosulfones, and the reductive elimination of related α-acetoxysulfones. The overall transformation takes place under mild conditions, with good yields, and without loss of stereochemical integrity, being in this respect superior to the conventional Julia reaction of α-amino aldehydes.

  3. Wittig Reaction: Domino Olefination and Stereoselectivity DFT Study. Synthesis of the Miharamycins' Bicyclic Sugar Moiety.

    Science.gov (United States)

    Cachatra, Vasco; Almeida, Andreia; Sardinha, João; Lucas, Susana D; Gomes, Ana; Vaz, Pedro D; Florêncio, M Helena; Nunes, Rafael; Vila-Viçosa, Diogo; Calhorda, Maria José; Rauter, Amélia P

    2015-11-20

    2-O-Acyl protected-d-ribo-3-uloses reacted with [(ethoxycarbonyl)methylene]triphenylphosphorane in acetonitrile to afford regio- and stereoselectively 2-(Z)-alkenes in 10-60 min under microwave irradiation. This domino reaction is proposed to proceed via tautomerization of 3-ulose to enol, acyl migration, tautomerization to the 3-O-acyl-2-ulose, and Wittig reaction. Alternatively, in chloroform, regioselective 3-olefination of 2-O-pivaloyl-3-uloses gave (E)-alkenes, key precursors for the miharamycins' bicyclic sugar moiety.

  4. A new approach to ferrocene derived alkenes via copper-catalyzed olefination

    Directory of Open Access Journals (Sweden)

    Vasily M. Muzalevskiy

    2015-11-01

    Full Text Available A new approach to ferrocenyl haloalkenes and bis-alkenes was elaborated. The key procedure involves copper catalyzed olefination of N-unsubstituted hydrazones, obtained from ferrocene-containing carbonyl compounds and hydrazine, with polyhaloalkanes. The procedure is simple, cheap and could be applied for the utilization of environmentally harmful polyhalocarbons. The cyclic voltammetry study of the representative examples of the synthesized ferrocenyl alkenes shows the strong dependence of the cathodic behavior on the amount of vinyl groups: while for the monoalkene containing molecules no reduction is seen, the divinyl products are reduced in several steps.

  5. A new approach to ferrocene derived alkenes via copper-catalyzed olefination.

    Science.gov (United States)

    Muzalevskiy, Vasily M; Shastin, Aleksei V; Demidovich, Alexandra D; Shikhaliev, Namiq G; Magerramov, Abel M; Khrustalev, Victor N; Rakhimov, Rustem D; Vatsadze, Sergey Z; Nenajdenko, Valentine G

    2015-01-01

    A new approach to ferrocenyl haloalkenes and bis-alkenes was elaborated. The key procedure involves copper catalyzed olefination of N-unsubstituted hydrazones, obtained from ferrocene-containing carbonyl compounds and hydrazine, with polyhaloalkanes. The procedure is simple, cheap and could be applied for the utilization of environmentally harmful polyhalocarbons. The cyclic voltammetry study of the representative examples of the synthesized ferrocenyl alkenes shows the strong dependence of the cathodic behavior on the amount of vinyl groups: while for the monoalkene containing molecules no reduction is seen, the divinyl products are reduced in several steps.

  6. Synthesis of Chiral, Enantiopure Allylic Amines by the Julia Olefination of α-Amino Esters.

    Science.gov (United States)

    Benedetti, Fabio; Berti, Federico; Fanfoni, Lidia; Garbo, Michele; Regini, Giorgia; Felluga, Fulvia

    2016-06-21

    The four-step conversion of a series of N-Boc-protected l-amino acid methyl esters into enantiopure N-Boc allylamines by a modified Julia olefination is described. Key steps include the reaction of a lithiated phenylalkylsulfone with amino esters, giving chiral β-ketosulfones, and the reductive elimination of related α-acetoxysulfones. The overall transformation takes place under mild conditions, with good yields, and without loss of stereochemical integrity, being in this respect superior to the conventional Julia reaction of α-amino aldehydes.

  7. Palladium-Catalyzed Tandem Oxidative Arylation/Olefination of Aromatic Tethered Alkenes/Alkynes.

    Science.gov (United States)

    Gao, Yang; Gao, Yinglan; Wu, Wanqing; Jiang, Huanfeng; Yang, Xiaobo; Liu, Wenbo; Li, Chao-Jun

    2017-01-18

    We describe herein a palladium-catalyzed tandem oxidative arylation/olefination reaction of aromatic tethered alkenes/alkynes for the synthesis of dihydrobenzofurans and 2 H-chromene derivatives. This reaction features a 1,2-difunctionalization of C-C π-bond with two C-H bonds using O 2 as terminal oxidant at room temperature. The products obtained are valuable synthons and important scaffolds in biological agents and natural products. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Ruthenium(ii)-catalyzed olefination via carbonyl reductive cross-coupling.

    Science.gov (United States)

    Wei, Wei; Dai, Xi-Jie; Wang, Haining; Li, Chenchen; Yang, Xiaobo; Li, Chao-Jun

    2017-12-01

    Natural availability of carbonyl groups offers reductive carbonyl coupling tremendous synthetic potential for efficient olefin synthesis, yet the catalytic carbonyl cross-coupling remains largely elusive. We report herein such a reaction, mediated by hydrazine under ruthenium(ii) catalysis. This method enables facile and selective cross-couplings of two unsymmetrical carbonyl compounds in either an intermolecular or intramolecular fashion. Moreover, this chemistry accommodates a variety of substrates, proceeds under mild reaction conditions with good functional group tolerance, and generates stoichiometric benign byproducts. Importantly, the coexistence of KO t Bu and bidentate phosphine dmpe is vital to this transformation.

  9. Lewis Base Activation of Silyl Acetals: Iridium-Catalyzed Reductive Horner-Wadsworth-Emmons Olefination.

    Science.gov (United States)

    Dakarapu, Udaya Sree; Bokka, Apparao; Asgari, Parham; Trog, Gabriela; Hua, Yuanda; Nguyen, Hiep H; Rahman, Nawal; Jeon, Junha

    2015-12-04

    A Lewis base promoted deprotonative pronucleophile addition to silyl acetals has been developed and applied to the iridium-catalyzed reductive Horner-Wadsworth-Emmons (HWE) olefination of esters and the chemoselective reduction of the resulting enoates. Lewis base activation of silyl acetals generates putative pentacoordinate silicate acetals, which fragment into aldehydes, silanes, and alkoxides in situ. Subsequent deprotonative metalation of phosphonate esters followed by HWE with aldehydes furnishes enoates. This operationally convenient, mechanistically unique protocol converts the traditionally challenging aryl, alkenyl, and alkynyl esters to homologated enoates at room temperature within a single vessel.

  10. Pd(II)-Catalyzed Ortho- or Meta-C–H Olefination of Phenol Derivatives

    Science.gov (United States)

    Dai, Hui-Xiong; Li, Gang; Zhang, Xing-Guo; Stepan, Antonia F.

    2013-01-01

    A combination of weakly coordinating auxiliaries and ligand acceleration allows for the development of both ortho- and meta-selective C–H olefination of phenol derivatives. These reactions demonstrate the feasibility of directing C–H functionalizations when functional groups are distal to target C–H bonds. The meta-C–H functionalization of electron-rich phenol derivatives is unprecedented and orthogonal to previous electrophilic substitution of phenols in terms of regioselectivity. These methods are also applied to functionalize α-phenoxyacetic acids, a fibrate class of drug scaffolds. PMID:23614807

  11. An adaptive self-healing ionic liquid nanocomposite membrane for olefin-paraffin separations.

    Science.gov (United States)

    Pitsch, Fee; Krull, Florian F; Agel, Friederike; Schulz, Peter; Wasserscheid, Peter; Melin, Thomas; Wessling, Matthias

    2012-08-16

    An adaptive self-healing ionic liquid nanocomposite membrane comprising a multi-layer support structure hosting the ionic salt [Ag](+) [Tf(2) N](-) is used for the separation of the olefin propylene and the paraffin propane. The ionic salt renders liquid like upon complexation with propylene, resulting in facilitated transport of propylene over propane at benchmark-setting selectivity and permeance levels. The contacting with acetylene causes the ionic salt to liquefy without showing evidence of forming explosive silver acetylide. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Electrochromatography on acrylate-based monolith in cyclic olefin copolymer microchip: an attractive technology.

    Science.gov (United States)

    Ladner, Y; Cretier, G; Faure, K

    2015-01-01

    Electrochromatography (EC) on a porous monolithic stationary phase prepared within the channels of a microsystem is an attractive alternative for on-chip separation. It combines the separation mechanisms of electrophoresis and liquid chromatography. Moreover, the porous polymer monolithic materials have become popular as stationary phase due to the ease and rapidity of fabrication via free radical photopolymerization. Here, we describe a hexyl acrylate (HA)-based porous monolith which is simultaneously in situ synthesized and anchored to the inner walls of the channel of a cyclic olefin copolymer (COC) device in only 2 min. The baseline separation of a mixture of neurotransmitters including six amino acids and two catecholamines is realized.

  13. Preparation of Mesoporous SBA-16 Silica-Supported Biscinchona Alkaloid Ligand for the Asymmetric Dihydroxylation of Olefins

    Directory of Open Access Journals (Sweden)

    Shaheen M. Sarkar

    2014-01-01

    Full Text Available Optically active cinchona alkaloid was anchored onto mesoporous SBA-16 silica and the as-prepared complex was used as a heterogeneous chiral ligand of osmium tetraoxide for the asymmetric dihydroxylation of olefins. The prepared catalytic system provided 90–93% yield of vicinal diol with 92–99% enantioselectivity. The ordered mesoporous SBA-16 silica was found to be a valuable support for the cinchona alkaloid liganded osmium catalyst system which is frequently used in chemical industries and research laboratories for olefin functionalization.

  14. Dismantlable Thermosetting Adhesives Composed of a Cross-Linkable Poly(olefin sulfone) with a Photobase Generator.

    Science.gov (United States)

    Sasaki, Takeo; Hashimoto, Shouta; Nogami, Nana; Sugiyama, Yuichi; Mori, Madoka; Naka, Yumiko; Le, Khoa V

    2016-03-02

    A novel photodetachable adhesive was prepared using a photodepolymerizable cross-linked poly(olefin sulfone). A mixture of a cross-linkable poly(olefin sulfone), a cross-linking reagent, and a photobase generator functioned as a thermosetting adhesive and exhibited high adhesive strength on quartz plates comparable to that obtained for commercially available epoxy adhesives. The cured resin was stable in the absence of UV light irradiation but completely lost its adhesive strength upon exposure of glued quartz plates to UV light in conjunction with heating to 100 °C.

  15. Exploring new generations of ruthenium olefin metathesis catalysts: The reactivity of a bis-ylidene ruthenium complex by DFT

    KAUST Repository

    Poater, Albert; Credendino, Raffaele; Slugovc, Christian; Cavallo, Luigi

    2013-01-01

    Density functional theory calculations were used to predict the behaviour of a potential novel architecture of olefin metathesis catalysts, in which one of the neutral ligands of classical Ru-based catalysts, e.g. a phosphine or an N-heterocyclic carbene, is replaced by an alkylidene group. Introduction of a second alkylidene ligand favors dissociation of the remaining phosphine and the overall energy profile for the metathesis using ethylene as the probe substrate reveals that the proposed bis-alkylidene complexes might match the requirements of a good performing olefin metathesis catalyst. © 2013 The Royal Society of Chemistry.

  16. Pd(II)-catalyzed di-o-olefination of carbazoles directed by the protecting N-(2-pyridyl)sulfonyl group.

    Science.gov (United States)

    Urones, Beatriz; Gómez Arrayás, Ramón; Carretero, Juan Carlos

    2013-03-01

    Despite the significance of carbazole in pharmacy and material science, examples of the direct C-H functionalization of this privileged unit are quite rare. The N-(2-pyridyl)sulfonyl group enables the Pd(II)-catalyzed ortho-olefination of carbazoles and related systems, acting as both a directing and readily removable protecting group. This method features ample structural versatility, affording typically the double ortho-olefination products (at C1 and C8) in satisfactory yields and complete regiocontrol. The application of this procedure to related heterocyclic systems, such as indoline, is also described.

  17. Aerobic Pd-Catalyzed sp3 C–H Olefination: A Route to Both N-Heterocyclic Scaffolds and Alkenes

    Science.gov (United States)

    Stowers, Kara J.; Fortner, Kevin C.

    2011-01-01

    This communication describes a new method for the Pd/polyoxometalate-catalyzed aerobic olefination of unactivated sp3 C–H bonds. Nitrogen heterocycles serve as directing groups, and air is used as the terminal oxidant. The products undergo reversible intramolecular Michael addition, which protects the mono-alkenylated product from over-functionalization. Hydrogenation of the Michael adducts provides access to bicyclic nitrogen-containing scaffolds that are prevalent in alkaloid natural products. Additionally, the cationic Michael adducts undergo facile elimination to release α,β-unsaturated olefins, which can be elaborated in numerous C–C and C–heteroatom bond-forming reactions. PMID:21476513

  18. FedScope Employment Cubes

    Data.gov (United States)

    Office of Personnel Management — This raw data set provides Federal civilian employee population data. The scope of this raw data set includes all data elements used in the creation of the FedScope...

  19. Surface functionalization of cyclic olefin copolymer with aryldiazonium salts: A covalent grafting method

    International Nuclear Information System (INIS)

    Brisset, Florian; Vieillard, Julien; Berton, Benjamin; Morin-Grognet, Sandrine; Duclairoir-Poc, Cécile; Le Derf, Franck

    2015-01-01

    Graphical abstract: - Highlights: • An effective method to modify cyclic olefin copolymer surface. • The surface of COC was modified by covalent grafting of aryl diazonium salts. • The wettability of COC surface was modulated by diazonium salts. • Photoinitiation and chemical reduction have to be combined to graft diazonium salt on COC surface. - Abstract: Covalent immobilization of biomolecules on the surface of cyclic olefin copolymer (COC) is still a tough challenge. We developed a robust method for COC surface grafting through reaction with aryldiazonium. Chemical diazonium reduction generated an aryl radical and the formation of a grafted film layer on the organic surface. We also demonstrated that the chemical reduction of diazonium salt was not sufficient to form a film on the COC surface. UV illumination had to be combined with chemical reduction to graft an aryl layer onto the COC surface. We optimized organic film deposition by using different chemical reducers, different reaction times and reagent proportions. We characterized surface modifications by fluorescence microscopy and contact angle measurements, infrared spectroscopy, X-ray photoemission spectroscopy and Raman spectroscopy, and assessed the topography of the aryl film by atomic force microscopy. This original strategy allowed us to evidence various organic functions to graft biomolecules onto COC surfaces with a fast and efficient technique

  20. Surface functionalization of cyclic olefin copolymer with aryldiazonium salts: A covalent grafting method

    Energy Technology Data Exchange (ETDEWEB)

    Brisset, Florian, E-mail: florian.brisset@etu.univ-rouen.fr [UMR CNRS 6014 COBRA, FR 3038, Université de Rouen, 55 rue Saint Germain, 27000 Evreux (France); Vieillard, Julien, E-mail: julien.vieillard@univ-rouen.fr [UMR CNRS 6014 COBRA, FR 3038, Université de Rouen, 55 rue Saint Germain, 27000 Evreux (France); Berton, Benjamin, E-mail: benjamin.berton@univ-rouen.fr [EA 3233 SMS, Université de Rouen, 1 rue du 7ème Chasseurs, BP281, 27002 Evreux Cedex (France); Morin-Grognet, Sandrine, E-mail: sandrine.morin@univ-rouen.fr [EA 3829 MERCI, Université de Rouen, 1 rue du 7ème Chasseurs, BP281, 27002 Evreux Cedex (France); Duclairoir-Poc, Cécile, E-mail: cecile.duclairoir@univ-rouen.fr [EA 4312 LMSM, Université de Rouen, 55 rue Saint Germain, 27000 Evreux (France); Le Derf, Franck, E-mail: franck.lederf@univ-rouen.fr [UMR CNRS 6014 COBRA, FR 3038, Université de Rouen, 55 rue Saint Germain, 27000 Evreux (France)

    2015-02-28

    Graphical abstract: - Highlights: • An effective method to modify cyclic olefin copolymer surface. • The surface of COC was modified by covalent grafting of aryl diazonium salts. • The wettability of COC surface was modulated by diazonium salts. • Photoinitiation and chemical reduction have to be combined to graft diazonium salt on COC surface. - Abstract: Covalent immobilization of biomolecules on the surface of cyclic olefin copolymer (COC) is still a tough challenge. We developed a robust method for COC surface grafting through reaction with aryldiazonium. Chemical diazonium reduction generated an aryl radical and the formation of a grafted film layer on the organic surface. We also demonstrated that the chemical reduction of diazonium salt was not sufficient to form a film on the COC surface. UV illumination had to be combined with chemical reduction to graft an aryl layer onto the COC surface. We optimized organic film deposition by using different chemical reducers, different reaction times and reagent proportions. We characterized surface modifications by fluorescence microscopy and contact angle measurements, infrared spectroscopy, X-ray photoemission spectroscopy and Raman spectroscopy, and assessed the topography of the aryl film by atomic force microscopy. This original strategy allowed us to evidence various organic functions to graft biomolecules onto COC surfaces with a fast and efficient technique.

  1. Surface modification of GC and HOPG with diazonium, amine, azide, and olefin derivatives.

    Science.gov (United States)

    Tanaka, Mutsuo; Sawaguchi, Takahiro; Sato, Yukari; Yoshioka, Kyoko; Niwa, Osamu

    2011-01-04

    Surface modification of glassy carbon (GC) and highly oriented pyrolytic graphite (HOPG) was carried out with diazonium, amine, azide, and olefin derivatives bearing ferrocene as an electroactive moiety. Features of the modified surfaces were evaluated by surface concentrations of immobilized molecule, blocking effect of the modified surface against redox reaction, and surface observation using cyclic voltammetry and electrochemical scanning tunneling microscope (EC-STM). The measurement of surface concentrations of immobilized molecule revealed the following three aspects: (i) Diazonium and olefin derivatives could modify substrates with the dense-monolayer concentration. (ii) The surface concentration of immobilized amine derivative did not reach to the dense-monolayer concentration reflecting their low reactivity. (iii) The surface modification with the dense-monolayer concentration was also possible with azide derivative, but the modified surface contained some oligomers produced by the photoreaction of azides. Besides, the blocking effect against redox reaction was observed for GC modified with diazonium derivative and for HOPG modified with diazonium and azide derivatives, suggesting fabrication of a densely modified surface. Finally, the surface observation for HOPG modified with diazonium derivative by EC-STM showed a typical monolayer structure, in which the ferrocene moieties were packed densely at random. On the basis of those results, it was demonstrated that surface modification of carbon substrates with diazonium could afford a dense monolayer similar to the self-assembled monolayer (SAM) formation.

  2. Nonthermal plasma reactors for the production of light hydrocarbon olefins from heavy oil

    Directory of Open Access Journals (Sweden)

    G. Prieto

    2003-03-01

    Full Text Available During the last decade, nonthermal plasma technology was applied in many different fields, focusing attention on the destruction of harmful compounds in the air. This paper deals with nonthermal plasma reactors for the conversion of heavy oil into light hydrocarbon olefins, to be employed as gasoline components or to be added in small amounts for the catalytic reduction of nitrogen oxide compounds in the treatment of exhaust gas at power plants. For the process, the plate-plate nonthermal plasma reactor driven by AC high voltage was selected. The reactor was modeled as a function of parameter characteristics, using the methodology provided by the statistical experimental design. The parameters studied were gap distance between electrodes, carrier gas flow and applied power. Results indicate that the reactions occurring in the process of heavy oil conversion have an important selective behavior. The products obtained were C1-C4 hydrocarbons with ethylene as the main compound. Operating the parameters of the reactor within the established operative window of the system and close to the optimum conditions, efficiencies as high as 70 (mul/joule were obtained. These values validate the process as an in-situ method to produce light olefins for the treatment of nitrogen oxides in the exhaust gas from diesel engines.

  3. SOMC-Designed Silica Supported Tungsten Oxo Imidazolin-2-iminato Methyl Precatalyst for Olefin Metathesis Reactions

    KAUST Repository

    Qureshi, Ziyauddin

    2017-01-05

    Synthesis, structure, and olefin metathesis activity of a surface complex [(≡Si-O-)W(═O)(CH3)2-ImDippN] (4) (ImDipp = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-iminato) supported on silica by a surface organometallic chemistry (SOMC) approach are reported. The reaction of N-silylated 2-iminoimidazoline with tungsten(VI) oxytetrachloride generated the tungsten oxo imidazolin-2-iminato chloride complex [ImDippNW(═O)Cl3] (2). This was grafted on partially dehydroxylated silica pretreated at 700 °C (SiO2-700) to afford a well-defined monopodal surface complex [(≡Si-O-)W(═O)Cl2-ImDippN] (3). 3 underwent alkylation by ZnMe2 to produce [(≡Si-O-)W(═O)(CH3)2-ImDippN] (4). The alkylated surface complex was thoroughly characterized by solid-state NMR, elemental microanalysis, Raman, FT-IR spectroscopies, and XAS analysis. 4 proved to be an active precatalyst for self-metathesis of terminal olefins such as propylene and 1-hexene.

  4. SOMC-Designed Silica Supported Tungsten Oxo Imidazolin-2-iminato Methyl Precatalyst for Olefin Metathesis Reactions

    KAUST Repository

    Qureshi, Ziyauddin; Hamieh, Ali Imad Ali; Barman, Samir; Maity, Niladri; Samantaray, Manoja; Ould-Chikh, Samy; Abou-Hamad, Edy; Falivene, Laura; D’ Elia, Valerio; Rothenberger, Alexander; Llorens, Isabelle; Hazemann, Jean-Louis; Basset, Jean-Marie

    2017-01-01

    Synthesis, structure, and olefin metathesis activity of a surface complex [(≡Si-O-)W(═O)(CH3)2-ImDippN] (4) (ImDipp = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-iminato) supported on silica by a surface organometallic chemistry (SOMC) approach are reported. The reaction of N-silylated 2-iminoimidazoline with tungsten(VI) oxytetrachloride generated the tungsten oxo imidazolin-2-iminato chloride complex [ImDippNW(═O)Cl3] (2). This was grafted on partially dehydroxylated silica pretreated at 700 °C (SiO2-700) to afford a well-defined monopodal surface complex [(≡Si-O-)W(═O)Cl2-ImDippN] (3). 3 underwent alkylation by ZnMe2 to produce [(≡Si-O-)W(═O)(CH3)2-ImDippN] (4). The alkylated surface complex was thoroughly characterized by solid-state NMR, elemental microanalysis, Raman, FT-IR spectroscopies, and XAS analysis. 4 proved to be an active precatalyst for self-metathesis of terminal olefins such as propylene and 1-hexene.

  5. Mesoporous catalysts for the synthesis of clean diesel fuels by oligomerisation of olefins

    Energy Technology Data Exchange (ETDEWEB)

    Catani, Roberto; Rossini, Stefano [Snamprogetti SpA, Via F. Maritano 26, 20092 , MI S. Donato Milanese (Italy); Mandreoli, Monica; Vaccari, Angelo [Dipartimento di Chimica Industriale e dei Materiali, Universita di Bologna, INSTM-UdR di Bologna, Viale del Risorgimento 4, 40136 Bologna (Italy)

    2002-07-03

    Si/Al MCM-41 type mesoporous compounds, as such or containing small amounts of metal (Ni, Rh or Pt), were investigated in the synthesis of clean diesel fuels by oligomerisation of orphan olefin streams. Very good catalytic performances were obtained with C{sub 4} and C{sub 5} olefins, while almost no conversion occurred with ethylene. The activity increased with increasing reaction pressure, temperature and contact time, while high Si/Al ratios had a negative effect on both activity and catalyst stability. The presence of small amount of metal inside the mesoporous structure did not significantly modify the catalytic activity, although specific effects were detected for each element. Since the evaluation of the cetane number by H-NMR gave rise to values about 20% lower than the actual value, a new and more complex algorithm is proposed to calculate the cetane number. Using the proposed algorithm, a good correlation index was found between calculated and motor values for pure compounds. Further study is necessary to move from pure compounds to experimental mixtures.

  6. H-ZSM-5 Zeolite Model Crystals: Structure-Diffusion-Activity Relationship in Methanol-to-Olefins Catalysis.

    Czech Academy of Sciences Publication Activity Database

    Losch, P.; Pinar, A.B.; Willinger, M.G.; Soukup, Karel; Chavan, S.; Vincent, B.; Pale, P.; Louis, B.

    2017-01-01

    Roč. 345, JAN 1 (2017), s. 11-23 ISSN 0021-9517 Grant - others:NRFL(LU) 5898454 Institutional support: RVO:67985858 Keywords : zeolite * methanol-to-olefins (MTO) * model catalyst Subject RIV: CI - Industrial Chemistry, Chemical Engineering OBOR OECD: Chemical process engineering Impact factor: 6.844, year: 2016

  7. Comparison of mesoporous SSZ-13 and SAPO-34 zeolite catalysts for the methanol-to-olefins reaction

    NARCIS (Netherlands)

    Wu, L.; Hensen, E.J.M.

    2014-01-01

    Several approaches to improve the catalytic performance of SSZ-13 and SAPO-34 for application as acid catalysts in the methanol-to-olefins (MTO) reaction were explored. Silylation of mesoporous SSZ-13 with a Si/Al ratio of 20 zeolite resulted in increased lifetime in the MTO reaction. Lowering the

  8. Kinetics of olefin arylation by bis(triphenylphosphine) diacetatopalladium(II) (PPAP) and trans-cis isomerization of the latter

    Energy Technology Data Exchange (ETDEWEB)

    Ryabov, A.D.; Yatsimirskii, A.K.

    1979-01-01

    In the absence of olefins, at 70/sup 0/C, PPAP dissolved in glacial acetic acid rapidly decomposed into triphenylphosphine (TPP) oxide, biphenyl, and metallic palladium, after an induction period of about ten minutes. At lower temperatures in this solvent, pure trans-PPAP was converted into the more stable cis-isomer. The conversion was 70-80Vertical Bar3<, increased with temperature (25/sup 0/-45/sup 0/C), and was inhibited by free TPP. Interaction of PPAP with styrene in glacial acetic acid at 70/sup 0/C occurred with an induction period and gave stilbene (80Vertical Bar3< yield) and TPP oxide. The induction period was independent of the concentration of PPAP or olefin and coincided with that in PPAP decomposition in the absence of olefin. Similar regularities were observed in PPAP interaction with p-methoxystyrene and p-nitrostyrene. Apparently, the induction period involves Pd(II) reduction to a phenypalladium(0) species stabilized by TPP and is followed by rapid transfer of phenyl from palladium to olefin.

  9. Experimental study of the retention properties of a cyclo olefin polymer pillar array column in reversed-phase mode

    NARCIS (Netherlands)

    Illa, Xavi; de Malsche, Wim; Gardeniers, Johannes G.E.; Desmet, Gert; Romano-Rodriguez, Albert

    2010-01-01

    Experimental measurements to study the retention capacity and band broadening under retentive conditions using micromachined non-porous pillar array columns fabricated in cyclo olefin polymer are presented. In particular, three columns with different depths but with the same pillar structure have

  10. Bio-inspired iron and manganese complexes derived from mixed N,O ligands for the oxidation of olefins

    NARCIS (Netherlands)

    Moelands, M.A.H.

    2014-01-01

    This Thesis describes the synthesis and structural analysis of bio-inspired iron and manganese complexes used for the catalytic oxidation of olefin substrates. The development of catalytic systems for oxidation chemistry that are based on first row transition metals and that apply a green oxidant

  11. H-ZSM-5 Zeolite Model Crystals: Structure-Diffusion-Activity Relationship in Methanol-to-Olefins Catalysis.

    Czech Academy of Sciences Publication Activity Database

    Losch, P.; Pinar, A.B.; Willinger, M.G.; Soukup, Karel; Chavan, S.; Vincent, B.; Pale, P.; Louis, B.

    2017-01-01

    Roč. 345, JAN 1 (2017), s. 11-23 ISSN 0021-9517 Grant - others:NRFL(LU) 5898454 Institutional support: RVO:67985858 Keywords : zeolite * methanol -to-olefins (MTO) * model catalyst Subject RIV: CI - Industrial Chemistry, Chemical Engineering OBOR OECD: Chemical process engineering Impact factor: 6.844, year: 2016

  12. Catalytic Cracking of Triglyceride-Rich Biomass toward Lower Olefins over a Nano-ZSM-5/SBA-15 Analog Composite

    Directory of Open Access Journals (Sweden)

    Xuan Hoan Vu

    2015-10-01

    Full Text Available The catalytic cracking of triglyceride-rich biomass toward C2–C4 olefins was evaluated over a hierarchically textured nano-ZSM-5/SBA-15 analog composite (ZSC-24 under fluid catalytic cracking (FCC conditions. The experiments were performed on a fully automated Single-Receiver Short-Contact-Time Microactivity Test unit (SR-SCT-MAT, Grace Davison at 550 °C and different catalyst-to-oil mass ratios (0–1.2 g∙g−1. The ZSC-24 catalyst is very effective for transformation of triglycerides to valuable hydrocarbons, particularly lower olefins. The selectivity to C2–C4 olefins is remarkably high (>90% throughout the investigated catalyst-to-oil ratio range. The superior catalytic performance of the ZSC-24 catalyst can be attributed to the combination of its medium acid site amount and improved molecular transport provided by the bimodal pore system, which effectively suppresses the secondary reactions of primarily formed lower olefins.

  13. Effects of manganese oxide and sulphate on the olefin selectivity of iron catalysts in the Fischer Tropsch reaction

    NARCIS (Netherlands)

    Dijk, van W.L.; Niemantsverdriet, J.W.; Kraan, van der A.M.; van der Baan, Hessel

    1982-01-01

    Although it has been claimed by various authors that the addition of manganese oxide, MnO, to an iron catalyst gives a marked increase in the olefin selectivity of iron catalysts, we have been unable to confirm these claims in Fischer Tropsch experiments at 513 K for an iron manganese oxide catalyst

  14. Oxidative Heck Reaction as a Tool for Para-selective Olefination of Aniline: A DFT Supported Mechanism.

    Science.gov (United States)

    Moghaddam, Firouz Matloubi; Pourkaveh, Raheleh; Karimi, Ashkan

    2017-10-06

    This study describes the first para-selective palladium-catalyzed alkenylation of tertiary amines. This regioselective C-H activation was conducted without any chelation moieties. A series of olefins were reacted under mild reaction conditions at 60 °C, and the corresponding products were obtained in good yields with high selectivity.

  15. Rhenium-catalyzed dehydrogenative olefination of C(sp(3))-H bonds with hypervalent iodine(III) reagents.

    Science.gov (United States)

    Gu, Haidong; Wang, Congyang

    2015-06-07

    A dehydrogenative olefination of C(sp(3))-H bonds is disclosed here, by merging rhenium catalysis with an alanine-derived hypervalent iodine(III) reagent. Thus, cyclic and acyclic ethers, toluene derivatives, cycloalkanes, and nitriles are all successfully alkenylated in a regio- and stereoselective manner.

  16. A selective C-H insertion/olefination protocol for the synthesis of α-methylene-γ-butyrolactone natural products.

    Science.gov (United States)

    Lloyd, Matthew G; D'Acunto, Mariantonietta; Taylor, Richard J K; Unsworth, William P

    2016-02-07

    A regio- and stereoselective one-pot C-H insertion/olefination protocol has been developed for the late stage installation of α-methylene-γ-butyrolactones into conformationally restricted cyclohexanol-derivatives. The method has been successfully applied in the total synthesis of eudesmanolide natural product frameworks, including α-cyclocostunolide.

  17. Synthesis of 2-Alkenylquinoline by Reductive Olefination of Quinoline N-Oxide under Metal-Free Conditions.

    Science.gov (United States)

    Xia, Hong; Liu, Yuanhong; Zhao, Peng; Gou, Shaohua; Wang, Jun

    2016-04-15

    Synthesis of 2-alkenylquinoline by reductive olefination of quinoline N-oxide under metal-free conditions is disclosed. Practically, the reaction could be performed with quinoline as starting material via a one-pot, two-step process. A possible mechanism is proposed that involves a sequential 1,3-dipolar cycloaddition and acid-assisted ring opening followed by a dehydration process.

  18. Ligand-Enabled γ-C–H Olefination and Carbonylation: Construction of β-Quaternary Carbon Centers

    Science.gov (United States)

    2015-01-01

    Monoselective γ-C–H olefination and carbonylation of aliphatic acids has been accomplished by using a combination of a quinoline-based ligand and a weakly coordinating amide directing group. The reaction provides a new route for constructing richly functionalized all-carbon quaternary carbon centers at the β-position of aliphatic acids. PMID:24666182

  19. Palladium-Catalyzed C-H Functionalization Using Guanidine as a Directing Group: Ortho Arylation and Olefination of Arylguanidines

    Science.gov (United States)

    Shao, Jiaan; Chen, Wenteng; Giulianotti, Marc A.; Houghten, Richard A.; Yu, Yongping

    2012-01-01

    Palladium-catalyzed C-H functionalization using guanidine as the directing group was achieved under mild reaction conditions. Various guanidine derivatives were produced in moderate to good yields by using simple unactivated arenes or ethyl acrylate as the source of arylation or olefination respectively. PMID:23095022

  20. Amine-Controlled Divergent Reaction: Iminolactonization and Olefination in the Presence of a Cu(I) Catalyst.

    Science.gov (United States)

    Nishikata, Takashi; Itonaga, Kohei; Yamaguchi, Norihiro; Sumimoto, Michinori

    2017-05-19

    α-Bromoamides and styrenes underwent iminolactonization reactions (carbooxygenation), in which simultaneous C-C and C-O formation occurred in the presence of a copper catalyst with triethylamine as the base. Conversely, olefination reactions occurred in the presence of a Cu catalyst with piperidine as the base. The selectivities in those reactions were very high.

  1. Synthesis of a [(14) C]-steroid intermediate: an application of a nonstabilized Horner-Wadsworth-Emmons olefination approach.

    Science.gov (United States)

    Rivera, Nelo R; Ren, Sumei; Hesk, David

    2015-01-01

    Radiolabeled steroid derivative 1 was successfully prepared using a Horner-Wadsworth-Emmons approach: a [(14) C]-label was efficiently incorporated into the C-18 position of the molecule. Previously published procedures employing other olefination methods are either not applicable due to unavailability of [(14) C]-precursors or suffer from poor reactivity. Copyright © 2015 John Wiley & Sons, Ltd.

  2. Palladium-catalyzed C-H olefination of uracils and caffeines using molecular oxygen as the sole oxidant.

    Science.gov (United States)

    Zhang, Xinyu; Su, Lv; Qiu, Lin; Fan, Zhenwei; Zhang, Xiaofeng; Lin, Shen; Huang, Qiufeng

    2017-04-18

    The palladium-catalyzed oxidative C-H olefination of uracils or caffeines with alkenes using an atmospheric pressure of molecular oxygen as the sole oxidant has been disclosed. This novel strategy offers an efficient and environmentally friendly method to biologically important C5-alkene uracil derivatives or C8-alkene caffeine derivatives.

  3. Radiation-induced terpolymerization of methyl α,β,β-trifluoroacrylate with tetrafluoroethylene and α-olefin

    International Nuclear Information System (INIS)

    Matsuda, O.; Watanabe, T.; Tabata, Y.; Machi, S.

    1980-01-01

    Radiation-induced terpolymerizations of methyl α,β,β-trifluoroacrylate (MTFA) with tetrafluoroethylene (TFE) and α-olefins, such as ethylene, propylene, and isobutylene, were carried out in bulk at 25 0 C for the purpose of controlling the content of ester group in the MTFA-α-olefin alternating copolymers. These monomers polymerized to form alternating terpolymers which contained 50 mole % α-olefin in a wide range of monomer composition. The content of MTFA, namely, the ester group in polymer, can be varied without destruction of the alternating structures between fluoroolefins (MTFA, TFE) and α-olefin by changing the MTFA/TFE ratio in the monomer mixture. The relative reactivities of MTFA and TFE in the terpolymerization were discussed according to kinetic treatments by free propagating and complex mechanisms. The relation between the MTFA/TFE ratio in the monomer mixture and that in terpolymer was explained favorably by the complex mechanism. It was also concluded that the relative reactivity of MTFA is larger than that of TFE in the terpolymerizations

  4. Scope and closures

    CERN Document Server

    Simpson, Kyle

    2014-01-01

    No matter how much experience you have with JavaScript, odds are you don’t fully understand the language. This concise yet in-depth guide takes you inside scope and closures, two core concepts you need to know to become a more efficient and effective JavaScript programmer. You’ll learn how and why they work, and how an understanding of closures can be a powerful part of your development skillset.

  5. Sorbent Scoping Studies

    International Nuclear Information System (INIS)

    Chancellor, Christopher John

    2016-01-01

    The Los Alamos National Laboratory-Carlsbad Operations (LANL-CO) office was tasked by the DOE CBFO, Office of the Manager to perform a review of the acceptable knowledge (AK) to identify the oxidizers and sorbents in transuranic (TRU) waste streams, to conduct scoping studies on the oxidizers and sorbents identified in AK review to inform the Quality Level 1 (QL1) testing, and to conduct a series of QL1 tests to provide the scientific data to support a basis of knowledge document for determining the criteria for (1) accepting waste at the Waste Isolation Pilot Plant (WIPP) without treatment, (2) determining waste that will require treatment, and (3) if treatment is required, how the treatment must be performed. The purpose of this report is to present the results of the AK review of sorbents present in active waste streams, provide a technical analysis of the sorbent list, report the results of the scoping studies for the fastest-burning organic sorbent, and provide the list of organic and inorganic sorbents to be used in the development of a Test Plan for Preparation and Testing of Sorbents Mixed with Oxidizer found in Transuranic Waste (DWT-TP-001). The companion report, DWT-RPT-001, Oxidizer Scoping Studies, has similar information for oxidizers identified during the AK review of TRU waste streams. The results of the oxidizer and sorbent scoping studies will be used to inform the QL1 test plan. The QL1 test results will support the development of a basis of knowledge document that will evaluate oxidizing chemicals and sorbents in TRU waste and provide guidance for treatment.

  6. Sorbent Scoping Studies

    Energy Technology Data Exchange (ETDEWEB)

    Chancellor, Christopher John [Los Alamos National Lab. (LANL), Carlsbad, NM (United States). Difficult Waste Team

    2016-11-14

    The Los Alamos National Laboratory–Carlsbad Operations (LANL-CO) office was tasked by the DOE CBFO, Office of the Manager to perform a review of the acceptable knowledge (AK) to identify the oxidizers and sorbents in transuranic (TRU) waste streams, to conduct scoping studies on the oxidizers and sorbents identified in AK review to inform the Quality Level 1 (QL1) testing, and to conduct a series of QL1 tests to provide the scientific data to support a basis of knowledge document for determining the criteria for (1) accepting waste at the Waste Isolation Pilot Plant (WIPP) without treatment, (2) determining waste that will require treatment, and (3) if treatment is required, how the treatment must be performed. The purpose of this report is to present the results of the AK review of sorbents present in active waste streams, provide a technical analysis of the sorbent list, report the results of the scoping studies for the fastest-burning organic sorbent, and provide the list of organic and inorganic sorbents to be used in the development of a Test Plan for Preparation and Testing of Sorbents Mixed with Oxidizer found in Transuranic Waste (DWT-TP-001). The companion report, DWT-RPT-001, Oxidizer Scoping Studies, has similar information for oxidizers identified during the AK review of TRU waste streams. The results of the oxidizer and sorbent scoping studies will be used to inform the QL1 test plan. The QL1 test results will support the development of a basis of knowledge document that will evaluate oxidizing chemicals and sorbents in TRU waste and provide guidance for treatment.

  7. Ethene/ethane and propene/propane separation via the olefin and paraffin selective metal-organic framework adsorbents CPO-27 and ZIF-8.

    Science.gov (United States)

    Böhme, Ulrike; Barth, Benjamin; Paula, Carolin; Kuhnt, Andreas; Schwieger, Wilhelm; Mundstock, Alexander; Caro, Jürgen; Hartmann, Martin

    2013-07-09

    Two types of metal-organic frameworks (MOFs) have been synthesized and evaluated in the separation of C2 and C3 olefins and paraffins. Whereas Co2(dhtp) (=Co-CPO-27 = Co-MOF-74) and Mg2(dhtp) show an adsorption selectivity for the olefins ethene and propene over the paraffins ethane and propane, the zeolitic imidazolate framework ZIF-8 behaves in the opposite way and preferentially adsorbs the alkane. Consequently, in breakthrough experiments, the olefins or paraffins, respectively, can be separated.

  8. Efficient and Selective Syntheses of (all-E)- and (6E,10Z)-2′-O-Methylmyxalamides D via Pd-Catalyzed Alkenylation—Carbonyl Olefination Synergy

    Science.gov (United States)

    Wang, Guangwei; Huang, Zhihong; Negishi, Ei-ichi

    2008-01-01

    Highly efficient and selective syntheses of both (all-E) and (6E,10Z)-isomers of 2′-O-methylmyxalamide D (2 and 3), in which the crucial conjugated pentaene moieties were assembled in ≥98% stereoselectivity through the use of two Pd-catalyzed alkenylation reactions, the Horner—Wadsworth—Emmons (HWE) olefination, and either the Corey—Schlessinger—Mills modified (CSM-modified) Peterson olefination for 2 or the Still—Gennari olefination for 3, are reported. Either 2 or 3 was prepared in 16% yield in seven steps from propargyl alcohol. PMID:18593171

  9. Olefins hydro-formylation catalysed by rhodium complexes using ionic liquids; Hydroformylation des olefines par les complexes du rhodium dans les liquides ioniques

    Energy Technology Data Exchange (ETDEWEB)

    Favre, F.

    2000-10-26

    Biphasic long chain olefins hydro-formylation catalysed by rhodium complexes using ionic liquids allows a selective reaction and an easy separation of the products from the catalyst. This study reports the synthesis of ionic liquids that were used as the catalyst's solvent. Their physical and chemical properties (melting point, solubility of organic substrates) can be varied with the structure of the organic cation (imidazolium, pyridinium, pyrrolydinium) and with its substituents (nature, length, number). It depends also on the nature of the inorganic anion (hexa-fluoro-phosphate, tetrafluoroborate, tri-fluoro-acetate, triflate, bistriflylamidure...). The use of phosphorus ligands bearing ionic functions proved to be efficient to maintain the onerous rhodium catalyst in the ionic liquid phase. Phosphines, phosphites and phosphinites including anionic (sulfonate, carboxylate) or cationic (imidazolium, pyridinium, guanidinium, phosphonium) groups have been synthesised. Finally, the influences of the ligand and of the ionic liquid on the catalytic system performances are described. Selectivities in aldehydes and reaction rates proved to be highly dependent on the nature of the ligand and of the ionic liquid. The different possibilities of recycling the ionic phase containing the rhodium catalyst have been also studied. (author)

  10. Electron-deficient N-alkyloyl derivatives of thieno[3,4-c]pyrrole-4,6-dione yield efficient polymer solar cells with open-circuit voltages > 1 v

    KAUST Repository

    Warnan, Julien

    2014-05-13

    Poly(benzo[1,2-b:4,5-b′]dithiophene-thieno[3,4-c]pyrrole-4,6-dione) (PBDTTPD) polymer donors yield some of the highest open-circuit voltages (V OC, ca. 0.9 V) and fill factors (FF, ca. 70%) in conventional bulk-heterojunction (BHJ) solar cells with PCBM acceptors. Recent work has shown that the incorporation of ring substituents into the side chains of the BDT motifs in PBDTTPD can induce subtle variations in material properties, resulting in an increase of the BHJ device VOC to ∼1 V. In this contribution, we report on the synthesis of N-alkyloyl-substituted TPD motifs (TPD(CO)) and show that the electron-deficient motifs can further lower both the polymer LUMO and HOMO levels, yielding device VOC > 1 V (up to ca. 1.1 V) in BHJ solar cells with PCBM. Despite the high VOC achieved (i.e., low polymer HOMO), BHJ devices cast from TPD(CO)-based polymer donors can reach power conversion efficiencies (PCEs) of up to 6.7%, making these promising systems for use in the high-band-gap cell of tandem solar cells. © 2014 American Chemical Society.

  11. α,β-Unsubstituted meso-Positioning Thienyl BODIPY: A Promising Electron Deficient Building Block for the Development of Near Infrared (NIR) p-type Donor-Acceptor (D-A) Conjugated Polymers

    KAUST Repository

    Squeo, Benedetta

    2018-02-27

    It is demonstrated that α,β-unsubstituted meso-positioning thienyl BODIPY is an electron deficient unit that leads to the development of ultra low optical band gap (Egopt < 1 eV) π-conjugated D-A quarterthiophene polymers. Furthermore, it is revealed that the optoelectronic, electrochemical and charge transporting properties of the resulting α,β-unsubstituted meso-positioning thienyl BODIPY quaterthiophene-based polymers are alkyl side chain positioning dependent. Tail-to-tail (TT) positioning of the alkyl side chains at the two central thiophenes of the quaterthiophene segment results to lower Egopt, higher energy levels and increased hole mobility as compared to head-to-head (HH) positioning. Finally, even though the synthesized polymers exhibit high electron affinity, higher even to that of the fullerene derivative [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM), they present only p-type behaviour in field effect transistors (FETs) independent to the alkyl side chain positioning.

  12. Delocalization model of regioselectivity and reactivity of free radicals in reactions of addition to olefins

    International Nuclear Information System (INIS)

    Volovik, S.V.; Dyadyusha, G.G.; Staninets, V.I.

    1987-01-01

    On the basis of the concept of polarity (philicity) of free radicals as proposed by the authors, within the framework of methods of qualitative surfaces of potential energy (linear combinations of configurations of fragments) and stabilization energy, an effective model has been developed for the regioselectivity and reactivity of radicals in processes of addition. A critical examination is made of certain key aspects of the change in regiochemistry and reactivity with changes in the electronic structure of the free radical and substrate. The dominant trends in regioselectivity and reactivity in processes of free-radical addition to olefins are controlled by electronic effects and can be predicted by analyzing interactions of diabatic potential energy surfaces or orbital interactions for a system consisting of a free radical and an unsaturated substrate

  13. Consequences of the electronic tuning of latent ruthenium-based olefin metathesis catalysts on their reactivity

    KAUST Repository

    Żukowska, Karolina

    2015-08-20

    Two ruthenium olefin metathesis initiators featuring electronically modified quinoline-based chelating carbene ligands are introduced. Their reactivity in RCM and ROMP reactions was tested and the results were compared to those obtained with the parent unsubstituted compound. The studied complexes are very stable at high temperatures up to 140 °C. The placement of an electron-withdrawing functionality translates into an enhanced activity in RCM. While electronically modified precatalysts, which exist predominantly in the trans-dichloro configuration, gave mostly the RCM and a minor amount of the cycloisomerization product, the unmodified congener, which preferentially exists as its cis-dichloro isomer, shows a switched reactivity. The position of the equilibrium between the cis- and the trans-dichloro species was found to be the crucial factor governing the reactivity of the complexes.

  14. Deformation mechanism under essential work of fracture process in polycyclo-olefin materials

    Directory of Open Access Journals (Sweden)

    2008-06-01

    Full Text Available The fracture toughness of a glassy polycyclo-olefin (PCO was investigated by the essential work of fracture (EWF method using a double-edge notched specimens. It was shown that the PCO follows the EWF concept in the temperature range between room temperature and glass transition temperature Tg where the ligament yielding appear at a maximum point on the stress-displacement curves and subsequently the necking and tearing processes take place in the post yielding region. The essential work of fracture required for the ligament yielding drops as the temperature approaches Tg. The non-essential work of fracture attributed to tearing process after yielding is consumed to expand the plastic region and causes molecular chains to orient to the stretching direction.

  15. [Experimental research on alcohols, aldehydes, aromatic hydrocarbons and olefins emissions from alcohols fuelled vehicles].

    Science.gov (United States)

    Zhang, Fan; Wang, Jian-Hai; Wang, Xiao-Cheng; Wang, Jian-Xin

    2013-07-01

    Using two vehicles fuelled with pure gasoline, M15, M30 and pure gasoline, E10, E20 separately, 25 degrees C normal temperature type I emission test, -7 degrees C low temperature type VI emission test and type IV evaporation emission test were carried out. FTIR, HPLC and GC-MS methods were utilized to measure alcohols, aldehydes, aromatic hydrocarbons and olefins emissions. The test results indicate that at the low as well as normal ambient temperature, as the alcohols proportion increasing in the fuel, unburned methanol, formaldehyde, acetaldehyde increase proportionally, benzene, toluene, ethylene, propylene, 1,3-butadiene and isobutene decrease slightly. The unregulated emissions at the low ambient temperature are significantly higher than those at the normal ambient temperature. The difference of HC emissions in the entire process of evaporative emission tests of E10, gasoline and M15 fuels is slight. There is a small difference of unregulated emissions in the diurnal test of three fuels.

  16. Consequences of the electronic tuning of latent ruthenium-based olefin metathesis catalysts on their reactivity

    KAUST Repository

    Żukowska, Karolina; Pump, Eva; Pazio, Aleksandra E; Woźniak, Krzysztof; Cavallo, Luigi; Slugovc, Christian

    2015-01-01

    Two ruthenium olefin metathesis initiators featuring electronically modified quinoline-based chelating carbene ligands are introduced. Their reactivity in RCM and ROMP reactions was tested and the results were compared to those obtained with the parent unsubstituted compound. The studied complexes are very stable at high temperatures up to 140 °C. The placement of an electron-withdrawing functionality translates into an enhanced activity in RCM. While electronically modified precatalysts, which exist predominantly in the trans-dichloro configuration, gave mostly the RCM and a minor amount of the cycloisomerization product, the unmodified congener, which preferentially exists as its cis-dichloro isomer, shows a switched reactivity. The position of the equilibrium between the cis- and the trans-dichloro species was found to be the crucial factor governing the reactivity of the complexes.

  17. Light olefins from synthesis gas using ruthenium on rare earth oxide catalysts

    International Nuclear Information System (INIS)

    Bruce, L.; Hardin, S.; Hoang, M.; Turney, T.

    1988-01-01

    The interaction of ruthenium carbonyl, Ru/sub 3/(CO)/sub 12/ with rare earth oxides of high surface area, >50m/sup 2/g/sup -1/, has been studied. [Ru/sub 3/(μ H)(CO)/sub 10/(μ-OM=)] is formed on holmia, but on lanthana only [Ru(CO)/sub 2/]/sub n/ species are observed. Reduction of the carbonyl ligands takes place at <573K to give catalysts for the hydrogenation of carbon monoxide with activity and selectivity dependent on the particular rare earth oxide and pretreatment. Over ceria, the product is up to 55 wt% C2-5 olefins. A similar selectivity is obtained over lanthana only after redispersion through a reduction-oxidation-reduction cycle

  18. Surface activation of cyclo olefin polymer by oxygen plasma discharge: a molecular dynamics study

    International Nuclear Information System (INIS)

    Soberon, Felipe

    2014-01-01

    Thermoplastic substrates made of cyclo olefin polymer (COP) are treated with oxygen plasma discharges to introduce polar groups at the surface. This is the first step in the process of surface functionalization of COP substrates used in biosensor devices. A molecular dynamics model of basic COP structure is implemented using the second-generation reactive empirical bond order (REBO) potentials for hydrocarbon–oxygen interactions. The model includes covalent bond and Van der Waals interactions. The bombardment of a COP surface with mono-energetic atomic oxygen ions, energy in the range 1-35 eV, is simulated and reported here. The dynamics of the substrate modification reveals that the substrate top layer is de-hydrogenated and subsequently builds up an oxygen–carbon matrix layer, ∼10 Å thick. Analysis of the modified substrates indicates that surface yield is predominantly peroxide groups. (paper)

  19. Alkylation of mixed olefins with isobutane in a stratco chemical reactor

    Energy Technology Data Exchange (ETDEWEB)

    Vichailak, M. [ABB Lummus Global Inc., Houston, TX (United States); Hopper, J.R.; Yaws, C.L. [Lamar Univ., Beaumont, TX (United States); Pike, R.W. [Louisiana State Univ., Baton Rouge, LA (United States)

    1996-12-31

    The 17 reaction model for the sulfuric acid alkylation of isobutane with propylene as proposed by Langley and Pike has been used to simulate the effluent refrigeration reactor. The simulation conditions selected to minimize the formation of light and heavy by-product were determined to be: Temperature: 9 - 10 {degrees}C,- Isobutane/Olefin Ratio: 8 - 10; % Volume of Acid: 50 %. The reactor effluent composition from the simulation program has been used to compare with several sets of published data with reasonable agreement. This model has been extrapolated to simulate the alkylation of isobutane with butylenes and amylenes. The model will be optimized with commercial data. 9 refs., 6 figs., 1 tab.

  20. Effect of norbornene content on laser ablation of cyclic olefin copolymers

    International Nuclear Information System (INIS)

    Leech, Patrick W.

    2010-01-01

    The ablation of cyclic olefin copolymers (COC) by 5 ns/248 nm laser has been examined as a function of norbornene content (61-82 wt.%). The dependence of ablation rate on laser fluence, repetition rate and pulse number has been determined over the range of composition of the copolymers. The ablation rate has increased logarithmically with laser fluence in accordance with the Beer-Lambert relationship. An increase in norbornene content has resulted in an increase in ablation rate and a decrease in threshold fluence. These trends have been attributed to a higher intramolecular rigidity of the chain structure in COC with increasing norbornene content. The morphology of the ablated surfaces was characterised by the formation of voids at high norbornene contents.

  1. Dual Ligand-Enabled Nondirected C-H Olefination of Arenes.

    Science.gov (United States)

    Chen, Hao; Wedi, Philipp; Meyer, Tim; Tavakoli, Ghazal; van Gemmeren, Manuel

    2018-02-23

    The application of the Pd-catalyzed oxidative C-H olefination of arenes, also known as the Fujiwara-Moritani reaction, has traditionally been limited by the requirement for directing groups on the substrate or the need to use the arene in large excess, typically as a (co)solvent. Herein the development of a catalytic system is described that, through the combined action of two complementary ligands, makes it possible to use directing-group-free arenes as limiting reagents for the first time. The reactions proceed under a combination of both steric and electronic control and enable the application of this powerful reaction to valuable arenes, which cannot be utilized in excess. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Vacuum ultraviolet-induced surface modification of cyclo-olefin polymer substrates for photochemical activation bonding

    International Nuclear Information System (INIS)

    Kim, Young-Jong; Taniguchi, Yoshinao; Murase, Kuniaki; Taguchi, Yoshihiro; Sugimura, Hiroyuki

    2009-01-01

    The surface of cyclo-olefin polymer (COP) was treated with vacuum ultraviolet (VUV) light at 172 nm wavelength to improve the wettability and adhesion properties. Through VUV treatment in air, the terminal groups of the COP surface were oxidized into oxygen functional groups, containing C-O, C=O, and COO components, making the COP surface hydrophilic. The extent of oxygenation was evaluated by XPS and FTIR-ATR spectra, and it was shown that the surface properties, hydrophilicity, and functionalization were dependent on both VUV irradiation distance and irradiation time, which have an effect on the concentration of oxygen functional groups. VUV-light treatment with a short irradiation distance was more effective in introducing oxygen functional groups.

  3. Heat integration of an Olefins Plant: Pinch Analysis and mathematical optimization working together

    Directory of Open Access Journals (Sweden)

    M. Beninca

    2011-03-01

    Full Text Available This work explores a two-step, complexity reducing methodology, to analyze heat integration opportunities of an existing Olefins Plant, identify and quantify reduction of energy consumption, and propose changes of the existing heat exchanger network to achieve these goals. Besides the analysis of plant design conditions, multiple operational scenarios were considered to propose modifications for handling real plant operation (flexibility. On the strength of plant complexity and large dimension, work methodology was split into two parts: initially, the whole plant was evaluated with traditional Pinch Analysis tools. Several opportunities were identified and modifications proposed. Modifications were segregated to represent small and independent portions of the original process. One of them was selected to be re-analyzed, considering two scenarios. Reduction of problem dimension allowed mathematical methodologies (formulation with decomposition, applying LP, MILP and NLP optimization methods to synthesize flexible networks to be applied, generating a feasible modification capable of fulfilling the proposed operational scenarios.

  4. The Mechanism of Rh-Catalyzed Transformation of Fatty Acids to Linear Alpha olefins

    Directory of Open Access Journals (Sweden)

    Sondre H. Hopen Eliasson

    2017-12-01

    Full Text Available Linear alpha olefins (LAOs are key commodity chemicals and petrochemical intermediates that are currently produced from fossil resources. Fatty acids are the obvious renewable starting material for LAOs, which can be obtained via transition-metal-catalyzed decarbonylative dehydration. However, even the best catalysts that have been obtained to date, which are based on palladium, are not active and stable enough for industrial use. To provide insight for design of better catalysts, we here present the first computationally derived mechanism for another attractive transition-metal for this reaction, rhodium. By comparing the calculated mechanisms and free energy profiles for the two metals, Pd and Rh, we single out important factors for a facile, low-barrier reaction and for a stable catalyst. While the olefin formation is rate limiting for both of the metals, the rate-determining intermediate for Rh is, in contrast to Pd, the starting complex, (PPh32Rh(COCl. This complex largely draws its stability from the strength of the Rh(I–CO bond. CO is a much less suitable ligand for the high-oxidation state Rh(III. However, for steric reasons, rhodium dissociates a bulkier triphenylphosphine and keeps the carbonyl during the oxidative addition, which is less favorable than for Pd. When compared to Pd, which dissociates two phosphine ligands at the start of the reaction, the catalytic activity of Rh also appears to be hampered by its preference for high coordination numbers. The remaining ancillary ligands leave less space for the metal to mediate the reaction.

  5. The SCOPE Mission

    International Nuclear Information System (INIS)

    Fujimoto, M.; Tsuda, Y.; Saito, Y.; Shinohara, I.; Takashima, T.; Matsuoka, A.; Kojima, H.; Kasaba, Y.

    2009-01-01

    In order to reach the new horizon of the space physics research, the Plasma Universe, via in-situ measurements in the Earth's magnetosphere, SCOPE will perform formation flying observations combined with high-time resolution electron measurements. The simultaneous multi-scale observations by SCOPE of various plasma dynamical phenomena will enable data-based study of the key space plasma processes from the cross-scale coupling point of view. Key physical processes to be studied are magnetic reconnection under various boundary conditions, shocks in space plasma, collisionless plasma mixing at the boundaries, and physics of current sheets embedded in complex magnetic geometries. The SCOPE formation is made up of 5 spacecraft and is put into the equatorial orbit with the apogee at 30 Re (Re: earth radius). One of the spacecraft is a large mother ship which is equipped with a full suite of particle detectors including ultra-high time resolution electron detector. Among other 4 small spacecraft, one remains near (∼10 km) the mother ship and the spacecraft-pair will focus on the electron-scale physics. Others at the distance of 100∼3000 km(electron∼ion spatial scales) from the mother ship will monitor plasma dynamics surrounding the mother-daughter pair. There is lively on-going discussion on Japan-Europe international collaboration (ESA's Cross-Scale), which would certainly make better the coverage over the scales of interest and thus make the success of the mission, i.e., clarifying the multi-scale nature of the Plasma Universe, to be attained at an even higher level.

  6. Scope selection and control

    International Nuclear Information System (INIS)

    Guglielmi, F.

    2011-01-01

    OPG is preparing for a 4-unit refurbishment program at Darlington later in this decade. Key efforts underway include the selection of the right refurbishment scope that will allow Darlington to achieve top-decile performance post-refurbishment. For this to be possible, it is imperative that (1) plant/equipment condition be well understood, (2) post-refurbishment performance objectives be clearly defined, and (3) regulatory and other risks be carefully assessed and mitigated. Significant engineering, operations and maintenance support is required to complete this phase of the project cycle.

  7. Homogeneous dihydroxylation of olefins catalyzed by OsO(4)(2-) immobilized on a dendritic backbone with a tertiary nitrogen at its core position.

    Science.gov (United States)

    Fujita, Ken-Ichi; Inoue, Kensuke; Tsuchimoto, Teruhisa; Yasuda, Hiroyuki

    2012-01-01

    OsO(4)(2-) immobilized on a poly(benzyl ether) dendrimer with a tertiary nitrogen at its core position efficiently catalyzed the homogeneous dihydroxylation of olefins with a low level of osmium leaching. The dendritic osmium catalyst could be applied to the wide range of olefins. Furthermore, the dendritic osmium catalyst was recovered by reprecipitation and then reused up to five times.

  8. OsO(4) in ionic liquid [Bmim]PF(6): a recyclable and reusable catalyst system for olefin dihydroxylation. remarkable effect of DMAP.

    Science.gov (United States)

    Yao, Qingwei

    2002-06-27

    [reaction: see text] The combination of the ionic liquid [bmim]PF(6) and DMAP provides a most simple and practical approach to the immobilization of OsO(4) as catalyst for olefin dihydroxylation. Both the catalyst and the ionic liquid can be repeatedly recycled and reused in the dihydroxylation of a variety of olefins with only a very slight drop in catalyst activity.

  9. On the nature of acidic centers in the deep oxidation of olefins over CdMoO/sub 4/: temperature-programmed desorption/Mass spectrometer investigation

    Energy Technology Data Exchange (ETDEWEB)

    Forzatti, P. (Politec. Milano); Kotzev, N.; Gencheva, L.; Pasquon, I.; Shopov, D.; Villa, P.L.

    1980-10-01

    Propylene and 1-butene were adsorbed at room temperature on cadmium molybdate, a poorly selective catalyst for olefin oxidation Temperature-programed desorption occurred at low temperature (145/sup 0/C for propylene, 100/sup 0/C for butene) from a reversibly adsorbed species on A sites, and at high temperature (400/sup 0/C for both olefins) from B sites in dissociated form. The A-sites were apparently vacancies or surface defects, which were destroyed when the cata

  10. Distributions of imidacloprid, imidacloprid-olefin and imidacloprid-urea in green plant tissues and roots of rapeseed (Brassica napus) from artificially contaminated potting soil.

    Science.gov (United States)

    Seifrtova, Marcela; Halesova, Tatana; Sulcova, Klara; Riddellova, Katerina; Erban, Tomas

    2017-05-01

    Imidacloprid-urea is the primary imidacloprid soil metabolite, whereas imidacloprid-olefin is the main plant-relevant metabolite and is more toxic to insects than imidacloprid. We artificially contaminated potting soil and used quantitative UHPLC-QqQ-MS/MS to determine the imidacloprid, imidacloprid-olefin and imidacloprid-urea distributions in rapeseed green plant tissues and roots after 4 weeks of exposure. In soil, the imidacloprid/imidacloprid-urea molar ratios decreased similarly after the 250 and 2500 µg kg -1 imidacloprid treatments. The imidacloprid/imidacloprid-urea molar ratios in the root and soil were similar, whereas in the green plant tissue, imidacloprid-urea increased more than twofold compared with the root. Although imidacloprid-olefin was prevalent in the green plant tissues, with imidacloprid/imidacloprid-olefin molar ratios of 2.24 and 1.47 for the 250 and 2500 µg kg -1 treatments respectively, it was not detected in the root. However, imidacloprid-olefin was detected in the soil after the 2500 µg kg -1 imidacloprid treatment. Significant proportions of imidacloprid-olefin and imidacloprid-urea in green plant tissues were demonstrated. The greater imidacloprid supply increased the imidacloprid-olefin/imidacloprid molar ratio in the green plant tissues. The absence of imidacloprid-olefin in the root excluded its retransport from leaves. The similar imidacloprid/imidacloprid-urea ratios in the soil and root indicated that the root serves primarily for transporting these substances. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  11. An expedient procedure for the oxidative cleavage of olefinic bonds with PhI(OAc)2, NMO, and catalytic OsO4.

    Science.gov (United States)

    Nicolaou, K C; Adsool, Vikrant A; Hale, Christopher R H

    2010-04-02

    PhI(OAc)(2) in the presence of OsO(4) (cat.) and 2,6-lutidine cleaves olefinic bonds to yield the corresponding carbonyl compounds, albeit, in some cases, with alpha-hydroxy ketones as byproduct. A more practical and clean protocol to effect oxidative cleavage of olefinic bonds involves NMO, OsO(4) (cat.), 2,6-lutidine, and PhI(OAc)(2).

  12. Scoping Study: Networked Microgrids.

    Energy Technology Data Exchange (ETDEWEB)

    Trinklei, Eddy; Parker, Gordon; Weaver, Wayne; Robinett, Rush; Babe Gauchia, Lucia; Ten, Chee-Wooi; Bower, Ward; Glover, Steven F.; Bukowski, Steve

    2014-10-01

    This report presents a scoping study for networked microgrids which are defined as "Interoperable groups of multiple Advanced Microgrids that become an integral part of the electricity grid while providing enhanced resiliency through self-healing, aggregated ancillary services, and real-time communication." They result in optimal electrical system configurations and controls whether grid-connected or in islanded modes and enable high penetrations of distributed and renewable energy resources. The vision for the purpose of this document is: "Networked microgrids seamlessly integrate with the electricity grid or other Electric Power Sources (EPS) providing cost effective, high quality, reliable, resilient, self-healing power delivery systems." Scoping Study: Networked Microgrids September 4, 2014 Eddy Trinklein, Michigan Technological University Gordon Parker, Michigan Technological University Wayne Weaver, Michigan Technological University Rush Robinett, Michigan Technological University Lucia Gauchia Babe, Michigan Technological University Chee-Wooi Ten, Michigan Technological University Ward Bower, Ward Bower Innovations LLC Steve Glover, Sandia National Laboratories Steve Bukowski, Sandia National Laboratories Prepared by Michigan Technological University Houghton, Michigan 49931 Michigan Technological University

  13. Catalysts for liquid phase oxidation of olefins and sulfur compounds; Catalyseurs pour l'oxydation en phase liquide d'olefines et de composes soufres

    Energy Technology Data Exchange (ETDEWEB)

    Palomeque Santiago, J.F.

    2002-07-01

    Several basic, acid and acid-base catalysts were studied for the epoxidation of olefins activated or not and dibenzo-thiophene.Hydrotalcite activation by thermic treatment and in situ re-hydration improves catalytic activity for 2-cyclohexene-1-one and isophorone. Bronsted basic sites were found to be more active than Lewis sites. Total conversion of 2-cyclohexene-1-one is reached in 1.5 h in polar solvents. W{sub 7}O{sub 24}{sup 6-} Iso-poly-anion was exchanged onto a meixnerite by a new preparation method, A meso-porous solid was obtained with good catalytic properties for cyclohexene epoxidation 100% selective to epoxide. W{sub 7}O{sub 24}{sup 6-} and WO{sub 5}{sup 2-} anions and phenyl and dodecyl-phospho-tungstates were grafted on hydrotalcites. Due to the acid-base characteristics of these solid catalysts, cyclohexene yields products of allylic reactions. Mg-La, and Mg-Al-La mixed oxides were synthesized and mixed phases were gotten. Their basic characteristics account for hydrogen peroxide decomposition which prevents DBT oxidation reaction to sulfone. On the contrary, Mg-Al re-hydrated hydrotalcites are very active for this reaction and remove 100% of sulfur compounds in 1 hour. New catalyst W-ZrO{sub 2} were synthesized with high acid properties. stable structure with temperature and high DBT conversion in less than 5 minutes of reaction. These catalytic systems can be applied for hydrocarbon desulfurization of fuels like naphtha, gas oil and kerosene. (author)

  14. Application of a silver–olefin coordination polymer as a catalytic curing agent for self-healing epoxy polymers

    International Nuclear Information System (INIS)

    Everitt, D T; Coope, T S; Trask, R S; Bond, I P; Wass, D F

    2015-01-01

    A silver–olefin based coordination polymer was prepared in a simple, one step process to act as an initiator to facilitate the ring-opening polymerization of epoxides. Thermal analysis found the complex to be capable of curing a range of commercially available epoxy resins used in the manufacture of conventional composite materials. Curing of the oligomeric diglycidyl ether bisphenol A resin, Epon 828, in combination with a non-toxic solvent, ethyl phenylacetate, was studied by differential scanning calorimetry. The mechanical characterization of the resultant cured polymers was conducted by single lap shear tests. Tapered double cantilever beam (TDCB) test specimens containing 2.5 pph of silver–olefin initiator, both with and without embedded microcapsules, were analyzed for their healing performance. Healing efficiency values were found to be strongly dependent on the applied healing temperature. A mean recovery of 74% fracture load was found in TDCB samples after being healed at 70 °C for 48 h. (paper)

  15. Scope of strategic marketing

    Directory of Open Access Journals (Sweden)

    Bradley Frank

    2004-01-01

    Full Text Available Marketing is a philosophy that leads to the process by which organizations, groups and individuals obtain what they need and want by identifying value, providing it, communicating it and delivering it to others. The core concepts of marketing are customers needs, wants and values; products, exchange, communications and relationships. Marketing is strategically concerned with the direction and scope of the long-term activities performed by the organization to obtain a competitive advantage. The organization applies its resources within a changing environment to satisfy customer needs while meeting stakeholder expectations. Implied in this view of strategic marketing is the requirement to develop a strategy to cope with competitors, identify market opportunities, develop and commercialize new products and services, allocate resources among marketing activities and design an appropriate organizational structure to ensure the perform once desired is achieved.

  16. Allylic chlorination of terpenic olefins using a combination of MoCl{sub 5} and NaOCl

    Energy Technology Data Exchange (ETDEWEB)

    Boualy, Brahim; Firdoussi, Larbi El; Ali, Mustapha Ait; Karim, Abdellah, E-mail: elfirdoussi@ucam.ac.m [Universite Cadi Ayyad, Marrakech (Morocco). Faculte des Sciences Semlalia. Lab. de Chimie de Coordination

    2011-07-01

    MoCl{sub 5} is applied as efficient agent in allylic chlorination of terpenic olefins in the presence of NaOCl as chlorine donor. Various terpenes are converted to the corresponding allylic chlorides in moderate to good yield under mild and optimized reaction conditions. Different molybdenum precursors are also studied. Among them, MoO{sub 3} gives good yield, but after a longer reaction time. (author)

  17. Cobalt-Iron-Manganese Catalysts for the Conversion of End-of-Life-Tire-Derived Syngas into Light Terminal Olefins.

    Science.gov (United States)

    Falkenhagen, Jan P; Maisonneuve, Lise; Paalanen, Pasi P; Coste, Nathalie; Malicki, Nicolas; Weckhuysen, Bert M

    2018-03-26

    Co-Fe-Mn/γ-Al 2 O 3 Fischer-Tropsch synthesis (FTS) catalysts were synthesized, characterized and tested for CO hydrogenation, mimicking end-of-life-tire (ELT)-derived syngas. It was found that an increase of C 2 -C 4 olefin selectivities to 49 % could be reached for 5 wt % Co, 5 wt % Fe, 2.5 wt % Mn/γ-Al 2 O 3 with Na at ambient pressure. Furthermore, by using a 5 wt % Co, 5 wt % Fe, 2.5 wt % Mn, 1.2 wt % Na, 0.03 wt % S/γ-Al 2 O 3 catalyst the selectivity towards the fractions of C 5+ and CH 4 could be reduced, whereas the selectivity towards the fraction of C 4 olefins could be improved to 12.6 % at 10 bar. Moreover, the Na/S ratio influences the ratio of terminal to internal olefins observed as products, that is, a high Na loading prevents the isomerization of primary olefins, which is unwanted if 1,3-butadiene is the target product. Thus, by fine-tuning the addition of promoter elements the volume of waste streams that need to be recycled, treated or upgraded during ELT syngas processing could be reduced. The most promising catalyst (5 wt % Co, 5 wt % Fe, 2.5 wt % Mn, 1.2 wt % Na, 0.03 wt % S/γ-Al 2 O 3 ) has been investigated using operando transmission X-ray microscopy (TXM) and X-ray diffraction (XRD). It was found that a cobalt-iron alloy was formed, whereas manganese remained in its oxidic phase. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Iodine-Catalyzed Direct Olefination of 2-Oxindoles and Alkenes via Cross-Dehydrogenative Coupling (CDC) in Air.

    Science.gov (United States)

    Huang, Hong-Yan; Wu, Hong-Ru; Wei, Feng; Wang, Dong; Liu, Li

    2015-08-07

    A direct intermolecular olefination of sp(3) C-H bond between 2-oxindoles and simple alkenes via a Cross-Dehydrogenative Coupling (CDC) strategy has been developed. In the absence of additional base, moderate to excellent yields have been obtained by using a catalytic amount of iodine with atmospheric oxygen as the reoxidant. Based on the observation of a radical capture experiment, the transformation is proposed to proceed via a radical process.

  19. N-Heterocyclic Carbene-Catalyzed Olefination of Aldehydes with Vinyliodonium Salts To Generate α,β-Unsaturated Ketones.

    Science.gov (United States)

    Rajkiewicz, Adam A; Kalek, Marcin

    2018-04-06

    An organocatalyzed metal-free, direct olefination of aldehydes with vinyliodonium salts has been achieved by an N-heterocyclic carbene-promoted C-H bond activation. The reaction proceeds under very mild conditions, delivering a range of (hetero)aryl-vinyl ketones in good yields. The retention of the double bond configuration is uniformly observed, and the application of 2-methoxyphenyl auxiliary group in iodonium salts secures a complete selectivity of the vinyl transfer.

  20. Catalytic Enantioselective Synthesis of 3,4-Unsubstituted Thiochromenes through Sulfa-Michael/Julia-Kocienski Olefination Cascade Reaction.

    Science.gov (United States)

    Simlandy, Amit Kumar; Mukherjee, Santanu

    2017-05-05

    A highly enantioselective cascade sulfa-Michael/Julia-Kocienski olefination reaction between 2-mercaptobenzaldehydes and β-substituted vinyl PT-sulfones has been realized for the synthesis of 3,4-unsubstituted 2H-thiochromenes. This reaction, catalyzed by diphenylprolinol TMS ether, proceeds through an aromatic iminium intermediate and furnishes a wide range of 2-substiuted 2H-thiochromenes with excellent enantioselectivities (up to 99:1 er).

  1. Rh(III) -Catalyzed C-H Olefination of Benzoic Acids under Mild Conditions using Oxygen as the Sole Oxidant.

    Science.gov (United States)

    Jiang, Quandi; Zhu, Changlei; Zhao, Huaiqing; Su, Weiping

    2016-02-04

    Phthalide skeletons have been synthesized for the first time through a Rh(III) -catalyzed C-H olefination of benzoic acids under mild conditions using oxygen as the sole oxidant. Aromatic acids bearing a variety of functional groups could react with diverse alkenes to afford the desired cyclized lactones or uncyclized alkenylarenes in moderate-to-excellent yields. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Remote meta-C-H olefination of phenylacetic acids directed by a versatile U-shaped template.

    Science.gov (United States)

    Deng, Youqian; Yu, Jin-Quan

    2015-01-12

    meta-C-H olefination of phenylacetic acid derivatives has been achieved using a commercially available nitrile-containing template. The identification of N-formyl-protected glycine as the ligand (Formyl-Gly-OH) was crucial for the development of this reaction. Versatility of the template approach in accommodating macrocyclopalladation processes with different ring sizes is demonstrated. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Effects of the Linking of Cyclopentadienyl and Ketimide Ligands in Titanium Half-sandwich Olefin Polymerization Catalysts

    Czech Academy of Sciences Publication Activity Database

    Varga, Vojtěch; Večeřa, M.; Gyepes, R.; Pinkas, Jiří; Horáček, Michal; Merna, J.; Lamač, Martin

    2017-01-01

    Roč. 9, č. 16 (2017), s. 3160-3172 ISSN 1867-3880 R&D Projects: GA ČR(CZ) GA14-08531S; GA ČR(CZ) GA17-13778S Institutional support: RVO:61388955 Keywords : ketimide ligands * olefin polymerization catalysts * cyclopentadienyl Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 4.803, year: 2016

  4. Synthesis of Ethylene or Propylene/1,3-Butadiene Copolymers Possessing Pendant Vinyl Groups with Virtually No Internal Olefins

    OpenAIRE

    Kenji Michiue; Makoto Mitani; Terunori Fujita

    2015-01-01

    In general, ethylene/1,3-butadiene copolymerizations provides copolymers possessing both pendant vinyls and vinylenes as olefinic moieties. We, at MCI, studied the substituent effects of C2-symmetric zirconocene complexes, rac-[Me2Si(Indenyl’)2]ZrCl2 (Indenyl’ = generic substituted indenyl), after activation on the ratio of the pendant vinyls and vinylenes of the resultant copolymers. Complexes examined in this study were rac-dimethylsilylbis (1-indenyl)zirconium dichloride (1), rac-dimethyls...

  5. Recent advances in efficient and selective synthesis of di-, tri-, and tetrasubstituted alkenes via Pd-catalyzed alkenylation-carbonyl olefination synergy.

    Science.gov (United States)

    Negishi, Ei-ichi; Huang, Zhihong; Wang, Guangwei; Mohan, Swathi; Wang, Chao; Hattori, Hatsuhiko

    2008-11-18

    Although generally considered competitive, the alkenylation and carbonyl olefination routes to alkenes are also complementary. In this Account, we focus on these approaches for the synthesis of regio- and stereodefined di- and trisubstituted alkenes and a few examples of tetrasubstituted alkenes. We also discuss the subset of regio- and stereodefined dienes and oligoenes that are conjugated. Pd-catalyzed cross-coupling using alkenyl metals containing Zn, Al, Zr, and B (Negishi coupling and Suzuki coupling) or alkenyl halides and related alkenyl electrophiles provides a method of alkenylation with the widest applicability and predictability, with high stereo- and regioselectivity. The requisite alkenyl metals or alkenyl electrophiles are most commonly prepared through highly selective alkyne addition reactions including (i) conventional polar additions, (ii) hydrometalation, (iii) carbometalation, (iv) halometalation, and (v) other heteroatom-metal additions. Although much more limited in applicability, the Heck alkenylation offers an operationally simpler, viable alternative when it is highly selective and satisfactory. A wide variety of carbonyl olefination reactions, especially the Wittig olefination and its modifications represented by the E-selective HWE olefination and the Z-selective Still-Gennari olefination, collectively offer the major alternative to the Pd-catalyzed alkenylation. However, the carbonyl olefination method fundamentally suffers from more limited stereochemical options and generally lower stereoselectivity levels than the Pd-catalyzed alkenylation. In a number of cases, however, very high (>98%) stereoselectivity levels have been attained in the syntheses of both E and Z isomers. The complementarity of the alkenylation and carbonyl olefination routes provide synthetic chemists with valuable options. While the alkenylation involves formation of a C-C single bond to a CC bond, the carbonyl olefination converts a CO bond to a CC bond. When a

  6. Structural analysis of platinum-palladium nanoparticles dispersed on titanium dioxide to evaluate cyclo-olefines reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Castillo, N., E-mail: necastillo@yahoo.co [Facultad de Quimica, Universidad Nacional Autonoma de Mexico, Edificio B, 04510 Mexico DF (Mexico); Centro de Investigacion y de Estudios Avanzados del IPN, Depto. de Fisica, Av. IPN 2508, C.P. 07360, Mexico DF (Mexico); Perez, R. [Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Campus Morelos, 62251 Cuernavaca Morelos (Mexico); Martinez-Ortiz, M.J.; Diaz-Barriga, L. [Instituto Politecnico Nacional - ESIQIE, UPALM Edif. 7, 07738 Mexico DF (Mexico); Garcia, L. [Instituto Politecnico Nacional - ESIT, UPALM, 07738 Mexico DF (Mexico); Conde-Gallardo, A. [Centro de Investigacion y de Estudios Avanzados del IPN, Depto. de Fisica, Av. IPN 2508, C.P. 07360, Mexico DF (Mexico)

    2010-04-16

    Structural and chemical properties were correlated to explain catalytic behavior of Pt-Pd/TiO{sub 2} in a cyclo-olefin reaction. Bimetallic nanoparticles supported on TiO{sub 2} were prepared by wetness impregnation techniques at different concentrations of Pt and Pd {approx}1 metallic wt%. The physicochemical properties of these metallic nanoparticles supported on TiO{sub 2} were characterized by N{sub 2} physisorption (Brunauer-Emmett-Teller-BET), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The relationship between chemical composition, physicochemical properties and particle size on the cyclo-olefin reaction was then studied. XRD and TEM results show that these nanoparticles are composed of Pt-Pd with FFC structure (a = 0.389-0.391 nm) supported on TiO{sub 2} (anatase-like structure), and the materials present tetragonal structure nanoparticles (a = 0.37842, b = 0.37842, c = 0.95146 nm). Samples with higher contents of platinum and particle sizes of 4.2 nm show the highest catalytic conversion in cyclo-olefins reaction. Finally, structural examinations of Pt{sub x}-Pd{sub (1-x)}/TiO{sub 2} based system was then conducted to study the effects of metals on the nanostructure of the materials.

  7. Structural analysis of platinum-palladium nanoparticles dispersed on titanium dioxide to evaluate cyclo-olefines reactivity

    International Nuclear Information System (INIS)

    Castillo, N.; Perez, R.; Martinez-Ortiz, M.J.; Diaz-Barriga, L.; Garcia, L.; Conde-Gallardo, A.

    2010-01-01

    Structural and chemical properties were correlated to explain catalytic behavior of Pt-Pd/TiO 2 in a cyclo-olefin reaction. Bimetallic nanoparticles supported on TiO 2 were prepared by wetness impregnation techniques at different concentrations of Pt and Pd ∼1 metallic wt%. The physicochemical properties of these metallic nanoparticles supported on TiO 2 were characterized by N 2 physisorption (Brunauer-Emmett-Teller-BET), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The relationship between chemical composition, physicochemical properties and particle size on the cyclo-olefin reaction was then studied. XRD and TEM results show that these nanoparticles are composed of Pt-Pd with FFC structure (a = 0.389-0.391 nm) supported on TiO 2 (anatase-like structure), and the materials present tetragonal structure nanoparticles (a = 0.37842, b = 0.37842, c = 0.95146 nm). Samples with higher contents of platinum and particle sizes of 4.2 nm show the highest catalytic conversion in cyclo-olefins reaction. Finally, structural examinations of Pt x -Pd (1-x) /TiO 2 based system was then conducted to study the effects of metals on the nanostructure of the materials.

  8. Heteropolytungstate nanoparticles: Microemulsion-mediated preparation and investigation of their catalytic activity in the epoxidation of olefins

    Energy Technology Data Exchange (ETDEWEB)

    Masteri-Farahani, M., E-mail: mfarahany@yahoo.com; Ghorbani, M.

    2016-04-15

    Highlights: • Keggin type Q{sub 3}PW{sub 12}O{sub 40} nanoparticles were synthesized by using microemulsion system. • The nanoparticles have uniform size of about 25 nm and spherical morphologies. • The prepared nanoparticles act as reusable catalyst in the epoxidation of olefins with H{sub 2}O{sub 2}. - Abstract: Keggin type Q{sub 3}PW{sub 12}O{sub 40} nanoparticles (Q = cetyltrimethylammonium cation) were synthesized in water-in-oil (w/o) microemulsion consisted of water/cetyltrimethylammonium bromide/n-butanol/isooctane. Reaction of Na{sub 2}WO{sub 4}, Na{sub 2}HPO{sub 4} and hydrochloric acid within water containing nanoreactors of reverse micelles resulted in the preparation of Q{sub 3}PW{sub 12}O{sub 40} nanoparticles. The resultant nanoparticles were analyzed by physicochemical methods such as FT-IR spectroscopy, X-ray diffraction, energy-dispersive X-ray analysis, thermogravimetric analyses (TGA-DTA), scanning and transmission electron microscopy and atomic force microscopy which show nearly uniform spherical nanoparticles with size of about 15 nm. Finally, catalytic activity of the Q{sub 3}PW{sub 12}O{sub 40} nanoparticles was examined in the epoxidation of olefins with H{sub 2}O{sub 2}. The prepared nanoparticles acted as recoverable and reusable catalyst in the epoxidation of olefins with H{sub 2}O{sub 2}.

  9. In Silico Olefin Metathesis with Ru-Based Catalysts Containing N-Heterocyclic Carbenes Bearing C60Fullerenes

    KAUST Repository

    Martínez, Juan Pablo

    2016-04-10

    Density functional theory calculations have been used to explore the potential of Ru-based complexes with 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene (SIMes) ligand backbone (A) being modified in silico by the insertion of a C60 molecule (B and C), as olefin metathesis catalysts. To this end, we investigated the olefin metathesis reaction catalyzed by complexes A, B, and C using ethylene as the substrate, focusing mainly on the thermodynamic stability of all possible reaction intermediates. Our results suggest that complex B bearing an electron-withdrawing N-heterocyclic carbene improves the performance of unannulated complex A. The efficiency of complex B is only surpassed by complex A when the backbone of the N-heterocyclic carbene of complex A is substituted by two amino groups. The particular performance of complexes B and C has to be attributed to electronic factors, that is, the electronic-donating capacity of modified SIMes ligand rather than steric effects, because the latter are predicted to be almost identical for complexes B and C when compared to those of A. Overall, this study indicates that such Ru-based complexes B and C might have the potential to be effective olefin metathesis catalysts. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. A kinetic mechanistic study of acid-catalyzed alkylation of isobutane with C4-olefins at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Doshi, B.M.

    1978-01-01

    A kinetic and mechanistic study of sulfuric acid-catalyzed alkylation of isobutane with C/sub 4/-Olefins at Low Temperatures(-20/sup 0/ to 0/sup 0/C) was based on a new two-step reaction sequence in which the desired first-step reactions are between acid and olefin to form sulfates and the desired second-step reactions are between sulfates and isobutane to form mostly trimethylpentanes. Linear butenes formed stable sulfates that formed alkylates of exceptionally high quality, up to 100 Research octane, whereas isobutylene and trimethylpentene mainly polymerized during the first step, and the alkylate produced had only 90 Research octane. Trimethylpentanes and dimethylhexanes, when contacted with concentrated sulfuric acid at -10/sup 0/ to +25/sup 0/C, degraded and isomerized to form C/sub 4/-C/sub 9/ and higher isoparaffins and acid-soluble hydrocarbons (conjunct polymers). For the two-step process and the degradation and isomerization reactions, kinetic models based on reaction at the interface were developed; but for isoolefins, a polymerization-cracking sequence (via C/sub 12/- and even C/sub 16/-olefins) is the preferred route. Commercial applications of the results are proposed.

  11. Ozone impact minimization through coordinated scheduling of turnaround operations from multiple olefin plants in an ozone nonattainment area

    Science.gov (United States)

    Ge, Sijie; Wang, Sujing; Xu, Qiang; Ho, Thomas

    2018-03-01

    Turnaround operations (start-up and shutdown) are critical operations in olefin plants, which emit large quantities of VOCs, NOx and CO. The emission has great potentials to impact the ozone level in ozone nonattainment areas. This study demonstrates a novel practice to minimize the ozone impact through coordinated scheduling of turnaround operations from multiple olefin plants located in Houston, Texas, an ozone nonattainment area. The study considered two olefin plants scheduled to conduct turnaround operations: one start-up and one shutdown, simultaneously on the same day within a five-hour window. Through dynamic simulations of the turnaround operations using ASPEN Plus Dynamics and air quality simulations using CAMx, the study predicts the ozone impact from the combined effect of the two turnaround operations under different starting-time scenarios. The simulations predict that the ozone impact from planned turnaround operations ranges from a maximum of 11.4 ppb to a minimum of 1.4 ppb. Hence, a reduction of up to 10.0 ppb can be achieved on a single day based on the selected two simulation days. This study demonstrates a cost-effective and environmentally benign ozone control practice for relevant stakeholders, including environmental agencies, regional plant operators, and local communities.

  12. In Silico Olefin Metathesis with Ru-Based Catalysts Containing N-Heterocyclic Carbenes Bearing C60Fullerenes

    KAUST Repository

    Martí nez, Juan Pablo; Vummaleti, Sai V. C.; Falivene, Laura; Nolan, Steven P.; Cavallo, Luigi; Solà , Miquel; Poater, Albert

    2016-01-01

    Density functional theory calculations have been used to explore the potential of Ru-based complexes with 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene (SIMes) ligand backbone (A) being modified in silico by the insertion of a C60 molecule (B and C), as olefin metathesis catalysts. To this end, we investigated the olefin metathesis reaction catalyzed by complexes A, B, and C using ethylene as the substrate, focusing mainly on the thermodynamic stability of all possible reaction intermediates. Our results suggest that complex B bearing an electron-withdrawing N-heterocyclic carbene improves the performance of unannulated complex A. The efficiency of complex B is only surpassed by complex A when the backbone of the N-heterocyclic carbene of complex A is substituted by two amino groups. The particular performance of complexes B and C has to be attributed to electronic factors, that is, the electronic-donating capacity of modified SIMes ligand rather than steric effects, because the latter are predicted to be almost identical for complexes B and C when compared to those of A. Overall, this study indicates that such Ru-based complexes B and C might have the potential to be effective olefin metathesis catalysts. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Effects of aromatics, olefins and distillation temperatures (T50 & T90) on particle mass and number emissions from gasoline direct injection (GDI) vehicles

    International Nuclear Information System (INIS)

    Zhu, Rencheng; Hu, Jingnan; Bao, Xiaofeng; He, Liqiang; Zu, Lei

    2017-01-01

    Abstratct: Fuel quality is among the primary reasons for severe vehicle pollution. A limited understanding of the effects of gasoline properties on modern vehicle emissions is one obstacle for the establishment of stricter fuel standards in China. The goal of this study was to evaluate the effects of aromatic and olefin contents and T50 and T90 (defined as the 50%v and 90%v distillation temperatures) on tailpipe emissions from gasoline direct injection (GDI) vehicles compliant with China 4 standards. Both gaseous and particle emissions using different types of gasoline were measured. Changing aromatic and olefin contents had relatively small impacts on fuel consumption. Compared with olefins and T90, the regulated gaseous emissions were impacted more by aromatics and T50. Evident decreases of the particle mass (PM) and particle number (PN) emissions were noticed when the aromatic content and T90 decreased. Reducing the olefin content slightly decreased the PM emissions and increased the PN emissions. With decreasing T50, the PM emissions increased and the PN emissions slightly decreased. These results suggest that aromatic content and T90 should be decreased to reduce particle emissions from GDI vehicles. The information presented in this study provides some suggestions for how to improve gasoline quality in China. - Highlights: • Effect of aromatics, olefins, T50 and T90 on GDI vehicle emissions was investigated. • Aromatics and olefins had little impact on fuel consumption and CO 2 emissions. • Reducing the aromatic content and T90 significantly decreased PM and PN emissions. • Changing the olefin content and T50 had a minor impact on particle emissions. • Thresholds of aromatics and T90 should be tightened in future gasoline regulations.

  14. Networked Microgrids Scoping Study

    Energy Technology Data Exchange (ETDEWEB)

    Backhaus, Scott N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dobriansky, Larisa [General MicroGrids, San Diego, CA (United States); Glover, Steve [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Liu, Chen-Ching [Washington State Univ., Pullman, WA (United States); Looney, Patrick [Brookhaven National Lab. (BNL), Upton, NY (United States); Mashayekh, Salman [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Pratt, Annabelle [National Renewable Energy Lab. (NREL), Golden, CO (United States); Schneider, Kevin [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stadler, Michael [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Starke, Michael [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wang, Jianhui [Argonne National Lab. (ANL), Argonne, IL (United States); Yue, Meng [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-12-05

    Much like individual microgrids, the range of opportunities and potential architectures of networked microgrids is very diverse. The goals of this scoping study are to provide an early assessment of research and development needs by examining the benefits of, risks created by, and risks to networked microgrids. At this time there are very few, if any, examples of deployed microgrid networks. In addition, there are very few tools to simulate or otherwise analyze the behavior of networked microgrids. In this setting, it is very difficult to evaluate networked microgrids systematically or quantitatively. At this early stage, this study is relying on inputs, estimations, and literature reviews by subject matter experts who are engaged in individual microgrid research and development projects, i.e., the authors of this study The initial step of the study gathered input about the potential opportunities provided by networked microgrids from these subject matter experts. These opportunities were divided between the subject matter experts for further review. Part 2 of this study is comprised of these reviews. Part 1 of this study is a summary of the benefits and risks identified in the reviews in Part 2 and synthesis of the research needs required to enable networked microgrids.

  15. Aerodynamic Drag Scoping Work.

    Energy Technology Data Exchange (ETDEWEB)

    Voskuilen, Tyler [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Erickson, Lindsay Crowl [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Knaus, Robert C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2018-02-01

    This memo summarizes the aerodynamic drag scoping work done for Goodyear in early FY18. The work is to evaluate the feasibility of using Sierra/Low-Mach (Fuego) for drag predictions of rolling tires, particularly focused on the effects of tire features such as lettering, sidewall geometry, rim geometry, and interaction with the vehicle body. The work is broken into two parts. Part 1 consisted of investigation of a canonical validation problem (turbulent flow over a cylinder) using existing tools with different meshes and turbulence models. Part 2 involved calculating drag differences over plate geometries with simple features (ridges and grooves) defined by Goodyear of approximately the size of interest for a tire. The results of part 1 show the level of noise to be expected in a drag calculation and highlight the sensitivity of absolute predictions to model parameters such as mesh size and turbulence model. There is 20-30% noise in the experimental measurements on the canonical cylinder problem, and a similar level of variation between different meshes and turbulence models. Part 2 shows that there is a notable difference in the predicted drag on the sample plate geometries, however, the computational cost of extending the LES model to a full tire would be significant. This cost could be reduced by implementation of more sophisticated wall and turbulence models (e.g. detached eddy simulations - DES) and by focusing the mesh refinement on feature subsets with the goal of comparing configurations rather than absolute predictivity for the whole tire.

  16. The fuel cycle scoping system

    International Nuclear Information System (INIS)

    Dooley, G.D.; Malone, J.P.

    1986-01-01

    The Fuel Cycle Scoping System (FCSS) was created to fill the need for a scoping tool which provides the utilities with the ability to quickly evaluate alternative fuel management strategies, tails assay choices, fuel fabrication quotes, fuel financing alternatives, fuel cycle schedules, and other fuel cycle perturbations. The FCSS was specifically designed for PC's that support dBASE-III(TM), a relational data base software system by Ashton-Tate. However, knowledge of dBASE-III is not necessary in order to utilize the FCSS. The FCSS is menu driven and can be utilized as a teaching tool as well as a scoping tool

  17. Rapid Prototyping of a Cyclic Olefin Copolymer Microfluidic Device for Automated Oocyte Culturing.

    Science.gov (United States)

    Berenguel-Alonso, Miguel; Sabés-Alsina, Maria; Morató, Roser; Ymbern, Oriol; Rodríguez-Vázquez, Laura; Talló-Parra, Oriol; Alonso-Chamarro, Julián; Puyol, Mar; López-Béjar, Manel

    2017-10-01

    Assisted reproductive technology (ART) can benefit from the features of microfluidic technologies, such as the automation of time-consuming labor-intensive procedures, the possibility to mimic in vivo environments, and the miniaturization of the required equipment. To date, most of the proposed approaches are based on polydimethylsiloxane (PDMS) as platform substrate material due to its widespread use in academia, despite certain disadvantages, such as the elevated cost of mass production. Herein, we present a rapid fabrication process for a cyclic olefin copolymer (COC) monolithic microfluidic device combining hot embossing-using a low-temperature cofired ceramic (LTCC) master-and micromilling. The microfluidic device was suitable for trapping and maturation of bovine oocytes, which were further studied to determine their ability to be fertilized. Furthermore, another COC microfluidic device was fabricated to store sperm and assess its quality parameters over time. The study herein presented demonstrates a good biocompatibility of the COC when working with gametes, and it exhibits certain advantages, such as the nonabsorption of small molecules, gas impermeability, and low fabrication costs, all at the prototyping and mass production scale, thus taking a step further toward fully automated microfluidic devices in ART.

  18. Mechanism-based inactivation of benzo[a]pyrene hydroxylase by aryl acetylenes and aryl olefins

    International Nuclear Information System (INIS)

    Gan, L.S.; Lu, J.Y.L.; Alworth, W.L.

    1986-01-01

    A series of aryl acetylenes and aryl olefins have been examined as substrates and inhibitors of cytochrome P-450 dependent monooxgenases in liver microsomes from 5,6-benzoflavone or phenobarbital pretreated rats. 1-Ethynylpyrene, 3-ethynylperylene, 2-ethynylfluorene, methyl 1-pyrenyl acetylene, cis- and trans-1-(2-bromovinyl)pyrene, and 1-allylpyrene serve as mechanism-based irreversible inactivators (suicide inhibitors) of benzo[a]pyrene hydroxylase, while 1-vinylpyrene and phenyl 1-pyrenyl acetylene do not cause a detectable suicide inhibition of benzo[a]pyrene hydroxylase. The mechanism-based loss of benzo[a]pyrene hydroxylase caused by the aryl acetylenes is not accompanied by a corresponding loss of the P-450 content of the microsomes (suicide destruction). The suicide inhibition by these aryl acetylenes therefore does not involve covalent binding to the heme moiety of the monooxygenase. Nevertheless, in the presence of NADPH, 3 H-labeled 1-ethynylpyrene becomes covalently attached to the cytochrome P-450 protein; the measured stoichiometry of binding is one 1-ethynylpyrene per P-450 heme unit. The authors conclude that the inhibition of benzo[a]pyrene hydroxylase produced by 1-ethynylpyrene may be related to the mechanism of suicide inhibition of P-450 activity by chloramphenicol rather than the mechanism of suicide destruction of P-450 previously described for acetylene and propyne

  19. Physical properties of metallocenes propene-higher α-olefins copolymers

    International Nuclear Information System (INIS)

    Lovisi, Humberto; Santa Maria, Luiz Claudio de; Coutinho, Fernanda M.B.

    2001-01-01

    In this work, new copolymers of propene/1-hexene (PHC) and propene/1-octene (POC) were synthesized by using a highly iso specific metallocenes catalyst system based on rac-Me 2 Si(2-ethyl,4-phenyl,1-indenyl) 2 ZrCl 2 , in the homogeneous and heterogeneous forms, methylaluminoxane (MAO) activated. An investigation about the copolymerization of propene with 1-hexene and 1-octene using this catalyst system illustrates the potential for the tailoring of propene/higher α-olefin copolymers with controlled thermal and mechanical properties by varying the comonomer concentration in the polymerization feed. Both catalyst systems showed high activity and produced random copolymers with very low or no detectable crystallinity. It was observed that properties such as enthalpy of crystallization (ΔHc), crystallization temperature (Tc), melting temperature (Tm), glass transition temperature (Tg) and elastic modulus (E') decreased in a linear pattern with increasing comonomer content in the copolymer. The effect of the short chain branch length was also investigated and it was observed that, compared to 1-hexene, much less 1-octene was necessary to disrupt the crystalline structure and impart rubbery behaviour to the copolymers. (author)

  20. Toward Green Acylation of (Heteroarenes: Palladium-Catalyzed Carbonylation of Olefins to Ketones

    Directory of Open Access Journals (Sweden)

    Jie Liu

    2017-11-01

    Full Text Available Green Friedel–Crafts acylation reactions belong to the most desired transformations in organic chemistry. The resulting ketones constitute important intermediates, building blocks, and functional molecules in organic synthesis as well as for the chemical industry. Over the past 60 years, advances in this topic have focused on how to make this reaction more economically and environmentally friendly by using green acylating conditions, such as stoichiometric acylations and catalytic homogeneous and heterogeneous acylations. However, currently well-established methodologies for their synthesis either produce significant amounts of waste or proceed under harsh conditions, limiting applications. Here, we present a new protocol for the straightforward and selective introduction of acyl groups into (hetero­arenes without directing groups by using available olefins with inexpensive CO. In the presence of commercial palladium catalysts, inter- and intramolecular carbonylative C–H functionalizations take place with good regio- and chemoselectivity. Compared to classical Friedel–Crafts chemistry, this novel methodology proceeds under mild reaction conditions. The general applicability of this methodology is demonstrated by the direct carbonylation of industrial feedstocks (ethylene and diisobutene as well as of natural products (eugenol and safrole. Furthermore, synthetic applications to drug molecules are showcased.

  1. Qualitative Survey of the Effluent from the Olefin Unit of Bandar-e-Imam Petrochemical Complex

    Directory of Open Access Journals (Sweden)

    Sima Sabzalipour

    2007-09-01

    Full Text Available This study was conducted to determine the qualitative parameters of the wastewater from the Olefin Unit of Bandar-e-Imam Petrochemical Complex in an attempt to identify the problems and to develop solutions. All the oily wastes generated in the unit under study are directed to the CPI and DAF systems where they are deoiled, diverted into the Eastern Pond, and, finally, discharged into the sea after a primary treatment process. In this study, information was collected on the process and on the effluent contaminant spreading sources in order to determined the sampling spots. Sampling was performed over 6 months and the effluent quality parameters (pH, TDS, BOD, COD, Oil, SO4=, PO4≡, and NO− were measured. Changes in the parameters were recorded on monthly, weekly, and daily bases. Combined samples were additionally used to ensure measurement accuracy. The results showed that the concentration levels of the parameters BOD, COD, oil, and phosphate ion in the effluent from the CPI system were beyond the national standards. Pollution load estimations for the relevant parameters also confirmed these results. Investigations revealed that COD and oil removal efficiencies in the CPI system were 17% and 10%, respectively, which cannot be desirable (paired sample t-test. Another problem observed was the effluent from the caustic wash tower. This effluent, which contains considerable quantities of caustic, polymer, yellow oil, and water, is discharged into the waste neutralization pond to leave the complex without further neutralization.

  2. New catalysts for selective hydrogenation of diene and acetylene hydrocarbons into olefins

    Energy Technology Data Exchange (ETDEWEB)

    Frolov, V.M.; Parenago, O.P.; Shuikina, L.P.

    1978-12-01

    New catalysts for selective hydrogenation of diene and acetylene hydrocarbons into olefins were obtained by reacting aqueous palladium, rhodium, or nickel chloride (0.005-0.05 mole/l.) at 50/sup 0/C, in an argon atmosphere with chelating nitrogen compounds, i.e., o-phenanthroline, ..cap alpha..,..cap alpha..'-dipyridyl, sodium ethylenediaminetetracetate, morpholine, branched polyethylene imines, or amino acids such as glycine, ..cap alpha..-alanine, ..beta..-phenyl-..cap alpha..-alanine, tyrosine, or histidine, and treating the complexes so obtained with sodium borohydride at 1:1-1:5 NaBH/sub 4/-metal ratios, in an aqueous medium. Palladium-based complexes showed the highest activities (20-98Vertical Bar3< conversion) and selectivities (98-100Vertical Bar3<) in heterogeneous hydrogenation of cyclopentadiene, butadiene, 1-hexyne, 1,3-cyclohexadiene, or 1,3-cyclooctadiene at 20/sup 0/-60/sup 0/C and 0.5-15 atm hydrogen, carried out in a kinetic circulation reactor or a metallic autoclave. Thus, a catalytic system based on PdCl/sub 2/ and ..beta..-phenyl-..cap alpha..-alanine converted 98Vertical Bar3< of cyclopentadiene to cyclopentene with 99Vertical Bar3< selectivity. The palladium-based catalyst did not deactivate on the contact with air.

  3. Effects of aromatics, MTBE, olefins, and T90 on urban air quality year 2005/2010

    International Nuclear Information System (INIS)

    Dunker, A.M.; Morris, R.D.; Pollack, A.K.; Cohen, J.P.; Schleyer, C.H.

    1992-01-01

    Subject to the limitations described in the Discussion, changing fuel composition changes the light-duty vehicle contribution to ozone. By the year 2005/2010, light-duty vehicles will contribute only 5 to 9% of the peak ozone in the three cities studied, because large reductions in automotive emissions are projected due to regulations now in place. For the reformulated gasolines studied, the contribution of light-duty vehicles to peak ozone can be reduced up to 26%. Reducing gasoline olefin content reduces ozone formation, due to its impact on evaporative, running-loss, and refueling and storage emissions. Lowering gasoline boiling range also reduces ozone formation by lowering the reactivity of exhaust emissions. Reducing aromatic content or adding MTBE had no clear effect on ozone formation. The emissions inventories used in the air quality modeling contain significant uncertainties. In particular, recent studies have suggested that emissions models may significantly underestimate hydrocarbon and CO emissions from today's vehicle fleet. If this is the case, the predicted ozone reductions due to reformulated gasoline reported here may be underestimated

  4. Stereoselective hydrogenation of olefins using rhodium-substituted carbonic anhydrase--a new reductase.

    Science.gov (United States)

    Jing, Qing; Okrasa, Krzysztof; Kazlauskas, Romas J

    2009-01-01

    One useful synthetic reaction missing from nature's toolbox is the direct hydrogenation of substrates using hydrogen. Instead nature uses cofactors like NADH to reduce organic substrates, which adds complexity and cost to these reductions. To create an enzyme that can directly reduce organic substrates with hydrogen, researchers have combined metal hydrogenation catalysts with proteins. One approach is an indirect link where a ligand is linked to a protein and the metal binds to the ligand. Another approach is direct linking of the metal to protein, but nonspecific binding of the metal limits this approach. Herein, we report a direct hydrogenation of olefins catalyzed by rhodium(I) bound to carbonic anhydrase (CA-[Rh]). We minimized nonspecific binding of rhodium by replacing histidine residues on the protein surface using site-directed mutagenesis or by chemically modifying the histidine residues. Hydrogenation catalyzed by CA-[Rh] is slightly slower than for uncomplexed rhodium(I), but the protein environment induces stereoselectivity favoring cis- over trans-stilbene by about 20:1. This enzyme is the first cofactor-independent reductase that reduces organic molecules using hydrogen. This catalyst is a good starting point to create variants with tailored reactivity and selectivity. This strategy to insert transition metals in the active site of metalloenzymes opens opportunities to a wider range of enzyme-catalyzed reactions.

  5. A method of automatic control of the process of compressing pyrogas in olefin production

    Energy Technology Data Exchange (ETDEWEB)

    Podval' niy, M.L.; Bobrovnikov, N.R.; Kotler, L.D.; Shib, L.M.; Tuchinskiy, M.R.

    1982-01-01

    In the known method of automatically controlling the process of compressing pyrogas in olefin production by regulating the supply of cooling agents to the interstage coolers of the compression unit depending on the flow of hydrocarbons to the compression unit, to raise performance by lowering deposition of polymers on the flow through surfaces of the equipment, the coolant supply is also regulated as a function of the flows of hydrocarbons from the upper and lower parts of the demethanizer and the bottoms of the stripping tower. The coolant supply is regulated proportional to the difference between the flow of stripping tower bottoms and the ratio of the hydrocarbon flow from the upper and lower parts of the demethanizer to the hydrocarbon flow in the compression unit. With an increase in the proportion of light hydrocarbons (sum of upper and lower demethanizer products) in the total flow of pyrogas going to compression, the flow of coolant to the compression unit is reduced. Condensation of the given fractions in the separators, their amount in condensate going through the piping to the stripping tower, is reduced. With the reduction in the proportion of light hydrocarbons in the pyrogas, the flow of coolant is increased, thus improving condensation of heavy hydrocarbons in the separators and removing them from the compression unit in the bottoms of the stripping tower.

  6. Mechanism of Propylene Oxide Polymerization Promoted by N-Heterocyclic Olefins

    KAUST Repository

    Al-Ghamdi, Miasser

    2017-01-11

    We report a mechanistic DFT investigation of the organopolymerization of propylene oxide (PO) promoted by N-heterocyclic olefins (NHOs) in combination with benzylic alcohol (BnOH). Calculations support the experimentally based hypothesis of two competing pathways, namely, the anionic and zwitterionic pathways. The former is based on an acid–base cooperativity between BnOH and the NHO, promoting ring opening of PO by BnO–. The latter occurs through the formation of a zwitterionic adduct by nucleophilic attack of the exocyclic carbon atom of the NHO on the PO, with the concerted ring opening of PO. The two initiating species cannot interconvert, and chain elongation can proceed from both initiation adducts. Potential energy surfaces were computed for a set of NHOs to clarify the effects of the steric and electronic properties of the NHO on the system reactivity. The results achieved represent useful insight toward the synthesis of PPO with better properties with respect to the polymer obtained with the experimental tested systems because the computationally proposed NHO system is the only one that favors the mechanism leading to higher molecular weight.

  7. Study of Syngas Conversion to Light Olefins by Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Hossein Atashi

    2013-01-01

    Full Text Available The effect of adding MgO to a precipitated iron-cobalt-manganese based Fischer-Tropsch synthesis (FTS catalyst was investigated via response surface methodology. The catalytic performance of the catalysts was examined in a fixed bed microreactor at a total pressure of 1–7 bar, temperature of 280–380°C, MgO content of 5–25% and using a syngas having a H2 to CO ratio equal to 2.The dependence of the activity and product distribution on MgO content, temperature, and pressure was successfully correlated via full quadratic second-order polynomial equations. The statistical analysis and response surface demonstrations indicated that MgO significantly influences the CO conversion and chain growth probability as well as ethane, propane, propylene, butylene selectivity, and alkene/alkane ratio. A strong interaction between variables was also evidenced in some cases. The decreasing effect of pressure on alkene to alkane ratio is investigated through olefin readsorption effects and CO hydrogenation kinetics. Finally, a multiobjective optimization procedure was employed to calculate the best amount of MgO content in different reactor conditions.

  8. Nanodispersed Suspensions of Zeolite Catalysts for Converting Dimethyl Ether into Olefins

    Science.gov (United States)

    Kolesnichenko, N. V.; Yashina, O. V.; Ezhova, N. N.; Bondarenko, G. N.; Khadzhiev, S. N.

    2018-01-01

    Nanodispersed suspensions that are effective in DME conversion and stable in the reaction zone in a three-phase system (slurry reactor) are obtained from MFI zeolite commercial samples (TsVM, IK-17-1, and CBV) in liquid media via ultrasonic treatment (UST). It is found that the dispersion medium, in which ultrasound affects zeolite commercial sample, has a large influence on particle size in the suspension. UST in the aqueous medium produces zeolite nanoparticles smaller than 50 nm, while larger particles of MFI zeolite samples form in silicone or hydrocarbon oils. Spectral and adsorption data show that when zeolites undergo UST in an aqueous medium, the acid sites are redistributed on the zeolite surface and the specific surface area of the mesopores increases. Preliminary UST in aqueous media of zeolite commercial samples (TsVM, IK-17-1, and CBV) affects the catalytic properties of MFI zeolite nanodispersed suspensions. The selectivity of samples when paraffins and olefins form is largely due to superacid sites consisting of OH groups of hydroxonium ion H3O+.

  9. Developing linear-alpha-olefins technology. From laboratory to a commercial plant

    Energy Technology Data Exchange (ETDEWEB)

    Meiswinkel, A.; Woehl, A.; Mueller, W.; Boelt, H. [Linde AG, Pullach (Germany)

    2011-07-01

    Linear {alpha}-Olefins (LAOs) are used in several applications in chemical industry. Together with SABIC (Saudi Basic Industries Corporation) Linde jointly developed the {alpha}-SABLIN technology for a full range LAO plant as well as a 1-Hexene selective ''On Purpose'' technology (LAO OP) to cover the rapidly increasing demand for this specific comonomer. The {alpha}-SABLIN as well as the OP technology are both homogenously catalyzed systems. This is raising special challenges concerning process and reactor design compared to much more established heterogeneous systems in chemical industry. E.g., the reactor concept is a bubble-column which allows efficient mixing as well as cooling of the reaction mixture. The development of the process was based on laboratory experiments which - based on an initial conceptual design for a large scale technical process - were first transformed into a pilot device before the commercial plant was designed, engineered and successfully started up and declared as commercialized. Today the {alpha}-SABLIN technology is the only LAO technology with a commercial reference which is free for licensing. A lot of experience and knowledge from the {alpha}-SABLIN development and commercial operation was gained. Although newly developed OP technology is based on a different catalytic system, this experience is now utilized and transformed within the commercialization of this new technological development. (orig.)

  10. FedScope Accessions Cubes

    Data.gov (United States)

    Office of Personnel Management — This raw data set provides the actual number of personnel actions ("Transfer-Ins" and "New Hires") that have taken place within a Fiscal Year. The scope of this raw...

  11. Radar Plan Position Indicator Scope

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Radar Plan Position Indicator Scope is the collection of weather radar imagery for the period prior to the beginning of the Next Generation Radar (NEXRAD) system...

  12. The Rearrangement of 1-Methylcyclohex-1-ene during the Hydrodesulfurization of FCC Gasoline over Supported Co(Ni)Mo/Al2O3 Sulfide Catalysts: the Isolation and Identification of Branched Cyclic C7 Olefins

    Czech Academy of Sciences Publication Activity Database

    Žáček, Petr; Kaluža, Luděk; Karban, Jindřich; Storch, Jan; Sýkora, Jan

    2014-01-01

    Roč. 112, č. 2 (2014), s. 335-346 ISSN 1878-5190 R&D Projects: GA ČR GAP106/11/0902 Institutional support: RVO:67985858 ; RVO:61388963 Keywords : hydrodesulfurization * olefin hydrogenation * branched cyclic olefins Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.170, year: 2014

  13. A computational mechanistic study of Pd(ii)-catalyzed γ-C(sp3)-H olefination/cyclization of amines: the roles of bicarbonate and ligand effect.

    Science.gov (United States)

    Liu, Jian-Biao; Tian, Ying-Ying; Zhang, Xin; Wang, Lu-Lin; Chen, De-Zhan

    2018-04-03

    The detailed mechanism of palladium-catalyzed γ-C(sp3)-H olefination/cyclization of triflyl-protected amines was investigated by density functional theory (DFT) calculations. The olefinated intermediate was initially formed in the first catalytic cycle involving ligand exchange, bicarbonate-assisted C(sp3)-H bond cleavage, alkene insertion and 'reductive β-hydride elimination'. The following syn-addition and reductive elimination furnish the aza-Wacker product. The first step of reductive elimination is the rate-determining step. The mechanism unveils the important roles of bicarbonate: aiding the C-H activation and abstracting the β-proton in the second step of reductive elimination. The parallel bridging mode in the metal-olefin intermediate facilitates the syn-addition, explaining the experimentally observed stereoselectivity. The effect of the monodentate pyridine-based ligands is also discussed.

  14. Enhanced catalytic performance for light-olefins production from chloromethane over hierarchical porous ZSM-5 zeolite synthesized by a growth-inhibition strategy

    Science.gov (United States)

    Liu, Qing; Wen, Dafen; Yang, Yanran; Fei, Zhaoyang; Zhang, Zhuxiu; Chen, Xian; Tang, Jihai; Cui, Mifen; Qiao, Xu

    2018-03-01

    Hierarchical porous ZSM-5 (HP-ZSM-5) zeolites were synthesized by hydrothermal crystallization method adding triethoxyvinylsilane as the growth-inhibitor at different hydrothermal crystallized temperatures. The properties of the obtained samples were characterized by XRD, SEM, N2-sorption, uptake of ethylene, 27Al MAS NMR, NH3-TPD, and Py-IR. It was found that the mesopore was introduced and the acidity was adjusted over HP-ZSM-5 samples successfully. The hydrothermal crystallized temperature had an important influence on the porous structure and surface properties. The catalytic performance for chloromethane to light-olefins (CMTO) were also investigated. Compared with ZSM-5 samples, HP-ZSM-5 samples exhibited enhanced stability and increased selectivity of light-olefins for CMTO reaction because of the introduction of the abundant mesopore and appropriate acidity. The lifetime (the duration of chloromethane conversion >98%) and selectivity of light-olefins reached 115 h and 69.3%, respectively.

  15. Subject categories and scope descriptions

    International Nuclear Information System (INIS)

    2002-01-01

    This document is one in a series of publications known as the ETDE/INIS Joint Reference Series. It defines the subject categories and provides the scope descriptions to be used for categorization of the nuclear literature for the preparation of INIS and ETDE input by national and regional centres. Together with the other volumes of the INIS Reference Series it defines the rules, standards and practices and provides the authorities to be used in the International Nuclear Information System and ETDE. A complete list of the volumes published in the INIS Reference Series may be found on the inside front cover of this publication. This INIS/ETDE Reference Series document is intended to serve two purposes: to define the subject scope of the International Nuclear Information System (INIS) and the Energy Technology Data Exchange (ETDE) and to define the subject classification scheme of INIS and ETDE. It is thus the guide to the inputting centres in determining which items of literature should be reported, and in determining where the full bibliographic entry and abstract of each item should be included in INIS or ETDE database. Each category is identified by a category code consisting of three alphanumeric characters. A scope description is given for each subject category. The scope of INIS is the sum of the scopes of all the categories. With most categories cross references are provided to other categories where appropriate. Cross references should be of assistance in finding the appropriate category; in fact, by indicating topics that are excluded from the category in question, the cross references help to clarify and define the scope of the category to which they are appended. A Subject Index is included as an aid to subject classifiers, but it is only an aid and not a means for subject classification. It facilitates the use of this document, but is no substitute for the description of the scope of the subject categories

  16. Substrate Trapping in Crystals of the Thiolase OleA Identifies Three Channels That Enable Long Chain Olefin Biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Goblirsch, Brandon R.; Jensen, Matthew R.; Mohamed, Fatuma A.; Wackett, Lawrence P.; Wilmot, Carrie M.

    2016-11-04

    Phylogenetically diverse microbes that produce long chain, olefinic hydrocarbons have received much attention as possible sources of renewable energy biocatalysts. One enzyme that is critical for this process is OleA, a thiolase superfamily enzyme that condenses two fatty acyl-CoA substrates to produce a β-ketoacid product and initiates the biosynthesis of long chain olefins in bacteria. Thiolases typically utilize a ping-pong mechanism centered on an active site cysteine residue. Reaction with the first substrate produces a covalent cysteine-thioester tethered acyl group that is transferred to the second substrate through formation of a carbon-carbon bond. Although the basics of thiolase chemistry are precedented, the mechanism by which OleA accommodates two substrates with extended carbon chains and a coenzyme moiety—unusual for a thiolase—are unknown. Gaining insights into this process could enable manipulation of the system for large scale olefin production with hydrocarbon chains lengths equivalent to those of fossil fuels. In this study, mutagenesis of the active site cysteine in Xanthomonas campestris OleA (Cys143) enabled trapping of two catalytically relevant species in crystals. In the resulting structures, long chain alkyl groups (C12 and C14) and phosphopantetheinate define three substrate channels in a T-shaped configuration, explaining how OleA coordinates its two substrates and product. The C143A OleA co-crystal structure possesses a single bound acyl-CoA representing the Michaelis complex with the first substrate, whereas the C143S co-crystal structure contains both acyl-CoA and fatty acid, defining how a second substrate binds to the acyl-enzyme intermediate. An active site glutamate (Gluβ117) is positioned to deprotonate bound acyl-CoA and initiate carbon-carbon bond formation.

  17. Substrate Trapping in Crystals of the Thiolase OleA Identifies Three Channels That Enable Long Chain Olefin Biosynthesis.

    Science.gov (United States)

    Goblirsch, Brandon R; Jensen, Matthew R; Mohamed, Fatuma A; Wackett, Lawrence P; Wilmot, Carrie M

    2016-12-23

    Phylogenetically diverse microbes that produce long chain, olefinic hydrocarbons have received much attention as possible sources of renewable energy biocatalysts. One enzyme that is critical for this process is OleA, a thiolase superfamily enzyme that condenses two fatty acyl-CoA substrates to produce a β-ketoacid product and initiates the biosynthesis of long chain olefins in bacteria. Thiolases typically utilize a ping-pong mechanism centered on an active site cysteine residue. Reaction with the first substrate produces a covalent cysteine-thioester tethered acyl group that is transferred to the second substrate through formation of a carbon-carbon bond. Although the basics of thiolase chemistry are precedented, the mechanism by which OleA accommodates two substrates with extended carbon chains and a coenzyme moiety-unusual for a thiolase-are unknown. Gaining insights into this process could enable manipulation of the system for large scale olefin production with hydrocarbon chains lengths equivalent to those of fossil fuels. In this study, mutagenesis of the active site cysteine in Xanthomonas campestris OleA (Cys 143 ) enabled trapping of two catalytically relevant species in crystals. In the resulting structures, long chain alkyl groups (C 12 and C 14 ) and phosphopantetheinate define three substrate channels in a T-shaped configuration, explaining how OleA coordinates its two substrates and product. The C143A OleA co-crystal structure possesses a single bound acyl-CoA representing the Michaelis complex with the first substrate, whereas the C143S co-crystal structure contains both acyl-CoA and fatty acid, defining how a second substrate binds to the acyl-enzyme intermediate. An active site glutamate (Gluβ 117 ) is positioned to deprotonate bound acyl-CoA and initiate carbon-carbon bond formation. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  18. Substrate Trapping in Crystals of the Thiolase OleA Identifies Three Channels That Enable Long Chain Olefin Biosynthesis*

    Science.gov (United States)

    Goblirsch, Brandon R.; Jensen, Matthew R.; Mohamed, Fatuma A.; Wackett, Lawrence P.; Wilmot, Carrie M.

    2016-01-01

    Phylogenetically diverse microbes that produce long chain, olefinic hydrocarbons have received much attention as possible sources of renewable energy biocatalysts. One enzyme that is critical for this process is OleA, a thiolase superfamily enzyme that condenses two fatty acyl-CoA substrates to produce a β-ketoacid product and initiates the biosynthesis of long chain olefins in bacteria. Thiolases typically utilize a ping-pong mechanism centered on an active site cysteine residue. Reaction with the first substrate produces a covalent cysteine-thioester tethered acyl group that is transferred to the second substrate through formation of a carbon-carbon bond. Although the basics of thiolase chemistry are precedented, the mechanism by which OleA accommodates two substrates with extended carbon chains and a coenzyme moiety—unusual for a thiolase—are unknown. Gaining insights into this process could enable manipulation of the system for large scale olefin production with hydrocarbon chains lengths equivalent to those of fossil fuels. In this study, mutagenesis of the active site cysteine in Xanthomonas campestris OleA (Cys143) enabled trapping of two catalytically relevant species in crystals. In the resulting structures, long chain alkyl groups (C12 and C14) and phosphopantetheinate define three substrate channels in a T-shaped configuration, explaining how OleA coordinates its two substrates and product. The C143A OleA co-crystal structure possesses a single bound acyl-CoA representing the Michaelis complex with the first substrate, whereas the C143S co-crystal structure contains both acyl-CoA and fatty acid, defining how a second substrate binds to the acyl-enzyme intermediate. An active site glutamate (Gluβ117) is positioned to deprotonate bound acyl-CoA and initiate carbon-carbon bond formation. PMID:27815501

  19. Borata-Wittig olefination reactions of ketones, carboxylic esters and amides with bis(pentafluorophenyl)borata-alkene reagents.

    Science.gov (United States)

    Wang, Tongdao; Kohrt, Sonja; Daniliuc, Constantin G; Kehr, Gerald; Erker, Gerhard

    2017-08-07

    The strongly electrophilic borane derivative amino-CH 2 CH 2 CH 2 -B(C 6 F 5 ) 2 6 was α-CH deprotonated with LiTMP to give the borata-alkene {[amino-(CH 2 ) 2 -CH[double bond, length as m-dash]B(C 6 F 5 ) 2 - ][Li + ]} 2 9 which underwent facile [2 + 2] cycloaddition reactions with benzophenone or fluorenone to yield the respective 1,2-oxaboretanides 11a,b. Compounds 9 and 11 were characterized by the X-ray diffraction. Thermolysis or hydrolysis of compounds 11a,b gave the corresponding borata-Wittig olefination products 12a,b. A variety of R-CH 2 -CH 2 -B(C 6 F 5 ) 2 boranes (conveniently generated by hydroboration of terminal alkenes R-CH[double bond, length as m-dash]CH 2 with Piers' borane [HB(C 6 F 5 ) 2 ]) were analogously deprotonated to give the respective borata-alkenes 16a-e (R: Ph-CH 2 -, n C 4 H 9 , t Bu, Cy, PhCH 2 CH 2 -). They underwent "non-classical" borata-Wittig olefination reactions with ethylformate to give the respective enolether carbonylation products, or their C 1 -elongated aldehydes (after hydrolysis). The borata-alkene [Ph-(CH 2 ) 2 -CH[double bond, length as m-dash]B(C 6 F 5 ) 2 - ] [Li + HTMP] (16a) gave the respective "non-classical" borata-Wittig olefination products, the enolethers 25a,b and 27, respectively, upon treatment with methyl- or ethyl acetate or γ-butyrolactone.

  20. Advances in Phillips Polymerisation Catalysis : In-situ Synthesis of Light Linear Alpha Olefins

    NARCIS (Netherlands)

    Cicmil, D.

    2016-01-01

    Polyethylene (PE) presents a large class of polymers with an exponentially growing consumption worldwide. Although possessing a relatively simple chemical formula of the repeating CHx units, the chain length, the type and length of the branching, and density, offer a wide scope of possible PE

  1. Conventional and advanced exergoeconomic analyses applied to ethylene refrigeration system of an existing olefin plant

    International Nuclear Information System (INIS)

    Palizdar, A.; Sadrameli, S.M.

    2017-01-01

    Highlights: • Conventional and advanced exergoeconomic analyses were applied. • Investment cost for most of the components is larger than exergy destruction cost. • Most of exergy destruction and investment costs are avoidable and endogenous. • Distillation column and compressor have the highest priority to improve. - Abstract: Ethylene refrigeration system of a light olefins production plant was investigated using the conventional and advanced exergoeconomic analyses. In advanced analysis, investment and exergy destruction costs of system components are divided into endogenous/exogenous and avoidable/unavoidable parts to improve our knowledge about the refrigeration system. Results of the exergoeconomic analysis represent that the total cost of column T-1 (1217.67 $/h), compressor C-3 (864.88 $/h), compressor C-2 (250.43 $/h) and multi stream heat exchanger MSHE-1 (154.19 $/h) are larger than other components. Results of the advanced exergoeconomic analysis reveal that most of the total costs of components are endogenous and can be reduced only for column T-1 and compressor C-3. With increasing the efficiency of these two components, investment and exergy destruction costs has been decreased (1381.74 $/h). Large amounts of endogenous exergy destruction cost of components represent that the interactions between the components are not a main reason for exergy destruction. Therefore, an appropriate strategy for the enhancement of the system efficiency and profitability is to improve their performance. Based on the above results, column T-1 and compressor C-3 have the highest priority to improve the performance. Sensitivity of the analysis parameters to some important operating variables have also been investigated.

  2. Iron(II)-catalyzed intermolecular amino-oxygenation of olefins through the N-O bond cleavage of functionalized hydroxylamines.

    Science.gov (United States)

    Lu, Deng-Fu; Zhu, Cheng-Liang; Jia, Zhen-Xin; Xu, Hao

    2014-09-24

    An iron-catalyzed diastereoselective intermolecular olefin amino-oxygenation reaction is reported, which proceeds via an iron-nitrenoid generated by the N-O bond cleavage of a functionalized hydroxylamine. In this reaction, a bench-stable hydroxylamine derivative is used as the amination reagent and oxidant. This method tolerates a range of synthetically valuable substrates that have been all incompatible with existing amino-oxygenation methods. It can also provide amino alcohol derivatives with regio- and stereochemical arrays complementary to known amino-oxygenation methods.

  3. Some mass spectral and analytical aspects of deuterium labeling of straight-chain olefins. [From shale oil distillates

    Energy Technology Data Exchange (ETDEWEB)

    Earnshaw, D.G.; Doolittle, F.G.; Decora, A.W.

    1971-01-01

    A calculation method has been developed to enhance the effect of deuterium labeling in the mass spectra of linear vicinal dideuterioalkanes (LVDA). Individual LVDA can be identified from these enhanced spectra. Single carbon-number mixtures of LVD nonanes and LVD decanes have been analyzed successfully using matrices derived from spectra of standards. In addition, enhanced mass spectra have been predicted for all of the LVD heptadecanes and LVD nonadecanes. Matrices have been constructed from the predicted spectra, and preliminary tests of these matrices have been conducted. All identifications and analytical results on the LVDA studied can be used to identify the precursor olefins.

  4. Cationic Tungsten(VI) Penta-Methyl Complex: Synthesis, Characterization and its Application in Olefin Metathesis Reaction

    KAUST Repository

    Dey, Raju

    2016-04-13

    Tungsten-hexa-methyl readily reacts with B(C6F5)3 in dichloromethane and generates the corresponding well-defined cationic tungsten-penta-methyl complex which was identified precisely by 1H NMR, 13C NMR, 1H-13C NMR correlation spectroscopy. Unlike WMe6, this cationic complex has low energy barrier to form tungsten carbene intermediate, which was further supported by the fact that WMe6 alone has no activity in olefin metathesis reaction whereas the cationic complex shows catalytic activity for self-metathesis of 1-octene.

  5. Cationic Tungsten(VI) Penta-Methyl Complex: Synthesis, Characterization and its Application in Olefin Metathesis Reaction

    KAUST Repository

    Dey, Raju; Samantaray, Manoja; Callens, Emmanuel; Hamieh, Ali Imad Ali; Emwas, Abdul-Hamid M.; Abou-Hamad, Edy; Kavitake, Santosh Giridhar; Basset, Jean-Marie

    2016-01-01

    Tungsten-hexa-methyl readily reacts with B(C6F5)3 in dichloromethane and generates the corresponding well-defined cationic tungsten-penta-methyl complex which was identified precisely by 1H NMR, 13C NMR, 1H-13C NMR correlation spectroscopy. Unlike WMe6, this cationic complex has low energy barrier to form tungsten carbene intermediate, which was further supported by the fact that WMe6 alone has no activity in olefin metathesis reaction whereas the cationic complex shows catalytic activity for self-metathesis of 1-octene.

  6. P(NMe2)3-Mediated Umpolung Alkylation and Nonylidic Olefination of α-Keto Esters.

    Science.gov (United States)

    Wang, Sunewang Rixin; Radosevich, Alexander T

    2015-08-07

    A commercial phosphorus-based reagent (P(NMe2)3) mediates umpolung alkylation of methyl aroylformates with benzylic and allylic bromides, leading to either Barbier-type addition or ylide-free olefination products upon workup. The reaction sequence is initiated by a two-electron redox addition of the tricoordinate phosphorus reagent with an α-keto ester compound (Kukhtin-Ramirez addition). A mechanistic rationale is offered for the chemoselectivity upon which the success of this nonmetal mediated C-C bond forming strategy is based.

  7. Truncated borrelidin analogues: synthesis by sequential cross metathesis/olefination for the southern fragment and biological evaluation.

    Science.gov (United States)

    Gündemir-Durmaz, Tülay; Schmid, Fabian; El Baz, Yana; Häusser, Annette; Schneider, Carmen; Bilitewski, Ursula; Rauhut, Guntram; Garnier, Delphine; Baro, Angelika; Laschat, Sabine

    2016-09-21

    The construction of novel borrelidin analogues is reported in which the northern fragment is truncated to a simple hydroxyundecanecarboxylate and the original cyclopentanecarboxylic acid in the southern fragment is replaced with different six-membered rings. The required precursors were prepared by cross metathesis of the appropriate carbocycle-based homoallylic alcohol with crotonaldehyde followed by HWE olefination of the resulting enal with bromocyanophosphonate. The key aldehyde for intramolecular cross coupling was accessible by oxidation of the hydroxy group of the linked undecanecarboxylate unit. Grignard mediated macrocyclization finally yielded the borrelidin related products. The investigation is complemented by SAR studies and quantum-chemical calculations.

  8. Palladium-Catalyzed Enantioselective C-H Olefination of Diaryl Sulfoxides through Parallel Kinetic Resolution and Desymmetrization.

    Science.gov (United States)

    Zhu, Yu-Chao; Li, Yan; Zhang, Bo-Chao; Zhang, Feng-Xu; Yang, Yi-Nuo; Wang, Xi-Sheng

    2018-03-07

    The first example of Pd II -catalyzed enantioselective C-H olefination with non-chiral or racemic sulfoxides as directing groups was developed. A variety of chiral diaryl sulfoxides were synthesized with high enantioselectivity (up to 99 %) through both desymmetrization and parallel kinetic resolution (PKR). This is the first report of Pd II -catalyzed enantioselective C(sp 2 )-H functionalization through PKR, and it represents a novel strategy to construct sulfur chiral centers. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Cycloalkyl-based unsymmetrical unsaturated (U2)-NHC ligands: Flexibility and dissymmetry in ruthenium-catalysed olefin metathesis

    KAUST Repository

    Rouen, Mathieu

    2014-01-01

    Air-stable Ru-indenylidene and Hoveyda-type complexes bearing new unsymmetrical unsaturated N-heterocyclic carbene (U2-NHC) ligands combining a mesityl unit and a flexible cycloalkyl moiety as N-substituents were synthesised. Structural features, chemical stabilities and catalytic profiles in olefin metathesis of this new library of cycloalkyl-based U2-NHC Ru complexes were studied and compared with their unsymmetrical saturated NHC-Ru homologues as well as a set of commercially available Ru-catalysts bearing either symmetrical SIMes or IMes NHC ligands. © 2014 the Partner Organisations.

  10. Update: An efficient synthesis of poly(ethylene glycol)-supported iron(II) porphyrin using a click reaction and its application for the catalytic olefination of aldehydes

    KAUST Repository

    Chinnusamy, Tamilselvi R.

    2012-05-09

    The facile synthesis of polyethylene glycol (PEG)-immobilized iron(II) porphyrin using a copper-catalyzed azide-alkyne [3+2] cycloaddition "click" reaction is reported. The prepared complex 5 (PEG-C 51H 39FeN 7O) was found to be an efficient catalyst for the selective olefination of aldehydes with ethyl diazoacetate in the presence of triphenylphosphine, and afforded excellent olefin yields with high (E) selectivities. The PEG-supported catalyst 5 was readily recovered by precipitation and filtration, and was recycled through ten runs without significant activity loss. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Rapid Access to Ortho-Alkylated Vinylarenes from Aromatic Acids by Dearomatization and Tandem Decarboxylative C-H Olefination/Rearomatization.

    Science.gov (United States)

    Tsai, Hung-Chang; Huang, Yen-Hsiang; Chou, Chih-Ming

    2018-03-02

    A two-step straightforward method for the preparation of ortho-alkylated vinylarenes from readily available benzoic acids is described. The synthetic route involves the dearomatization of benzoic acids by Birch reduction providing alkylated cyclohexa-2,5-dienyl-1-carboxylic acids. The diene subsequently undergoes a decarboxylative C-H olefination followed by rearomatization to deliver ortho-alkylated vinylarene. Mechanistic studies suggest that a Pd/Ag bimetallic catalytic system is important in the tandem decarboxylative C-H olefination/rearomatization step.

  12. Atroposelective Synthesis of Axially Chiral Biaryls by Palladium-Catalyzed Asymmetric C-H Olefination Enabled by a Transient Chiral Auxiliary.

    Science.gov (United States)

    Yao, Qi-Jun; Zhang, Shuo; Zhan, Bei-Bei; Shi, Bing-Feng

    2017-06-01

    Atroposelective synthesis of axially chiral biaryls by palladium-catalyzed C-H olefination, using tert-leucine as an inexpensive, catalytic, and transient chiral auxiliary, has been realized. This strategy provides a highly efficient and straightforward access to a broad range of enantioenriched biaryls in good yields (up to 98 %) with excellent enantioselectivities (95 to >99 % ee). Kinetic resolution of trisubstituted biaryls bearing sterically more demanding substituents is also operative, thus furnishing the optically active olefinated products with excellent selectivity (95 to >99 % ee, s-factor up to 600). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Palladium(II)-Catalyzed meta-C-H Olefination: Constructing Multisubstituted Arenes through Homo-Diolefination and Sequential Hetero-Diolefination.

    Science.gov (United States)

    Bera, Milan; Maji, Arun; Sahoo, Santosh K; Maiti, Debabrata

    2015-07-13

    Divinylbenzene derivatives represent an important class of molecular building blocks in organic chemistry and materials science. Reported herein is the palladium-catalyzed synthesis of divinylbenzenes by meta-C-H olefination of sulfone-based arenes. Successful sequential olefinations in a position-selective manner provided a novel route for the synthesis of hetero-dialkenylated products, which are difficult to access using conventional methods. Additionally, 1,3,5-trialkenylated compounds can be generated upon successful removal of the directing group. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Residential ventilation standards scoping study

    Energy Technology Data Exchange (ETDEWEB)

    McKone, Thomas E.; Sherman, Max H.

    2003-10-01

    The goals of this scoping study are to identify research needed to develop improved ventilation standards for California's Title 24 Building Energy Efficiency Standards. The 2008 Title 24 Standards are the primary target for the outcome of this research, but this scoping study is not limited to that timeframe. We prepared this scoping study to provide the California Energy Commission with broad and flexible options for developing a research plan to advance the standards. This document presents the findings of a scoping study commissioned by the Public Interest Energy Research (PIER) program of the California Energy Commission to determine what research is necessary to develop new residential ventilation requirements for California. This study is one of three companion efforts needed to complete the job of determining the ventilation needs of California residences, determining the bases for setting residential ventilation requirements, and determining appropriate ventilation technologies to meet these needs and requirements in an energy efficient manner. Rather than providing research results, this scoping study identifies important research questions along with the level of effort necessary to address these questions and the costs, risks, and benefits of pursuing alternative research questions. In approaching these questions and corresponding levels of effort, feasibility and timing were important considerations. The Commission has specified Summer 2005 as the latest date for completing this research in time to update the 2008 version of California's Energy Code (Title 24).

  15. Olefins transformation catalysis by zirconium and tungsten complexes in organic and non-aqueous ionic media; Catalyse de transformation des olefines par les complexes du zirconium et du tungstene en milieux organique et ionique non aqueux

    Energy Technology Data Exchange (ETDEWEB)

    Laurent-Gerot, P

    1997-06-30

    Molten salts are suitable solvents for biphasic catalysis: melting butyl-1 methyl-3 imidazolium chloride and aluminium chloride gives a polar and aprotic ionic liquid which is not miscible with hydrocarbons but dissolves organometallic complexes. Two types of complexes have been tested in molten salts with ethyl-aluminium dichloride: zirconium complexes to synthesize light {alpha} olefins from ethene; mono-imido complexes of tungsten VI (Cl{sub 4}W = NAr) to dimerize ethene in but-1 ene and propene in dimethyl-2,3-but-1-ene. For both of these complexes, biphasic catalysis principle is always respected: the active species is present only in the ionic phase and not in the organic phase. The first complexes, biphasic principle is always respected: the active species is present only in the ionic phase and not in the organic phase. The first complexes oligomerize ethene in molten salts with low activity and the {alpha} olefins selectivity is weak. Mono-imido complexes of tungsten VI are proved to be equivalent to the systems composed with WCl{sub 6} and aniline, and they dimerize ethene in but-1 ene and propene in dimethyl-2,3-but-1 ene more efficiently in organic medium than in ionic liquid. The characterization of the active species of the system Cl{sub 4}W=NAr / EtAlCl{sub 2} shows that it is the corresponding mono-imido complex of tungsten 4. (author) 129 refs.

  16. Experimental study of the retention properties of a cyclo olefin polymer pillar array column in reversed-phase mode.

    Science.gov (United States)

    Illa, Xavi; De Malsche, Wim; Gardeniers, Han; Desmet, Gert; Romano-Rodríguez, Albert

    2010-11-01

    Experimental measurements to study the retention capacity and band broadening under retentive conditions using micromachined non-porous pillar array columns fabricated in cyclo olefin polymer are presented. In particular, three columns with different depths but with the same pillar structure have been fabricated via hot embossing and pressure-assisted thermal bonding. Separations of a mixture of four coumarins using varying mobile phase compositions have been monitored to study the relation between the retention factor and the ratio of organic solvent in the aqueous mobile phase. Moreover, the linear relation between the retention and the surface/volume ratio predicted in theory has been observed, achieving retention factors up to k=2.5. Under the same retentive conditions, minimal reduced plate height values of h(min)=0.4 have been obtained at retention factors of k=1.2. These experimental results are compared with the case of non-porous and porous silicon pillars. Similar results for the plate heights are achieved while retention factors are higher than the non-porous silicon column and considerably smaller than the porous pillar column, given the non-porous nature of the used cyclo olefin polymer. The feasibility of using this polymer column as an alternative to the pillar array silicon columns is corroborated.

  17. Novel polyoxometalate silica nano-sized spheres: efficient catalysts for olefin oxidation and the deep desulfurization process.

    Science.gov (United States)

    Nogueira, Lucie S; Ribeiro, Susana; Granadeiro, Carlos M; Pereira, Eulália; Feio, Gabriel; Cunha-Silva, Luís; Balula, Salete S

    2014-07-07

    A novel method to prepare silica nano-sized particles incorporating polyoxometalates was developed leading to a new efficient heterogeneous oxidative catalyst. Zinc-substituted polyoxotungstate [PW11Zn(H2O)O39](5-) (PW11Zn) was encapsulated into silica nanoparticles using a cross-linked organic-inorganic core, performed through successive spontaneous reactions in water. The potassium salt of PW11Zn and the composite formed, PW11Zn-APTES@SiO2, were characterized by a myriad of solid-state methods such as FT-IR, FT-Raman, (31)P and (13)C CP/MAS solid-state NMR, elemental analysis and SEM-EDS, confirming the integrity of the PW11Zn structure immobilized in the silica nanoparticles. The new composite has shown to be a versatile catalyst for the oxidation of olefins and also to catalyze the desulfurization of a model oil using H2O2 as the oxidant and acetonitrile as the solvent. The novel composite material was capable of being recycled without significant loss of activity and maintaining its structural stability for consecutive desulfurization and olefin oxidative cycles.

  18. Olefin Metathesis with Ru-Based Catalysts Exchanging the Typical N-Heterocyclic Carbenes by a Phosphine–Phosphonium Ylide

    Directory of Open Access Journals (Sweden)

    Laia Arnedo

    2017-03-01

    Full Text Available Density functional theory (DFT calculations have been used to describe the first turnover of an olefin metathesis reaction calling for a new in silico family of homogenous Ru-based catalysts bearing a phosphine–phosphonium ylide ligand, with ethylene as a substrate. Equal to conventional Ru-based catalysts bearing an N-heterocyclic carbene (NHC ligand, the activation of these congeners occurs through a dissociative mechanism, with a more exothermic first phosphine dissociation step. In spite of a stronger electron-donating ability of a phosphonium ylide C-ligand with respect to a diaminocarbene analogue, upper energy barriers were calculated to be on average ca. 5 kcal/mol higher than those of Ru–NHC standards. Overall, the study also highlights advantages of bidentate ligands over classical monodentate NHC and phosphine ligands, with a particular preference for the cis attack of the olefin. The new generation of catalysts is constituted by cationic complexes potentially soluble in water, to be compared with the typical neutral Ru–NHC ones.

  19. Conceptual design and system analysis of a poly-generation system for power and olefin production from natural gas

    International Nuclear Information System (INIS)

    Qian Yu; Liu Jingyao; Huang Zhixian; Kraslawski, Andrzej; Cui Jian; Huang Yinlun

    2009-01-01

    In this paper, a novel poly-generation system for olefin and power production from natural gas is proposed, which integrates hydrocarbon production and the combined cycle power generation. Economic and technological evaluation based on the internal rate of return (IRR) and exergy efficiency is performed. The energy integration results in the proposed poly-generation system for simultaneous production of chemical products (ethylene and propylene) and electricity being more thermodynamically efficient and economically viable than single purpose power generation and chemical products production plants. IRR and exergy efficiency of the proposed poly-generation system are higher than that of natural gas methanol to olefin (NGMTO) system, 18.9% and 49.9%, respectively. The biggest exergy destruction segments, their causes, and possible measures for improvement are investigated simulation and thermodynamic analysis. To analyze the effect of unreacted syngas recycle on the exergy efficiency and economic gains from the proposed poly-generation system, its thermoeconomic optimization model is built by combining economic with thermodynamic analysis. Optimization analysis shows that when 78% of the unreacted syngas is recycled back to the reactor in the methanol synthesization process, the thermoeconomic performance of the poly-generation system is at its optimum.

  20. Reduction of uranium(IV) and its mixtures with an olefin or an alkyne in tetrahydrofuran solutions by solvated electrons

    International Nuclear Information System (INIS)

    Koulkes-Pujo, A.M.; Le Marechal, J.F.; Le Motais, B.; Folcher, G.

    1985-01-01

    The reduction of UCl 4 and its mixtures with different olefins (stilbene, St, diphenylethylene, DPE, acenaphtylene, Ac or with diphenylacetylene (DPA) was studied by pulse radiolysis of tetrahydrofuran (THF) solutions. U(III) was formed by U(IV) reaction either with the solvated electrons created by THF radiolysis or with the transitory anions St - and DPA - . In the latter case, the reaction proceeds via a first step leading to [St-U(IV)] - or [DPA-U(IV)] - . In the case of DPE - the first species, [DPE-U(IV)] - , does not lead to U(III) but is destroyed by THF(H) + giving DPE(H). and U(IV). Ac - does not react with U(IV). A mechanistic scheme of this electron attachment is discussed as well as its implication in catalytic hydrogenation of olefins in LiAlH 4 -UCl 4 solutions. It is concluded that the catalytic effect observed is rather the result of a hydride transfer from a uranium transient compound to the alkenes. 22 references, 8 figures, 1 table

  1. Advances in Phillips Polymerisation Catalysis : In-situ Synthesis of Light Linear Alpha Olefins

    OpenAIRE

    Cicmil, D.

    2016-01-01

    Polyethylene (PE) presents a large class of polymers with an exponentially growing consumption worldwide. Although possessing a relatively simple chemical formula of the repeating CHx units, the chain length, the type and length of the branching, and density, offer a wide scope of possible PE grades, each suitable for different types of commercial application. Since the 1950s, several types of ethylene polymerisation catalysts and polymerisation processes have been developed. Linear low densi...

  2. First principle chemical kinetics in zeolites: the methanol-to-olefin process as a case study.

    Science.gov (United States)

    Van Speybroeck, Veronique; De Wispelaere, Kristof; Van der Mynsbrugge, Jeroen; Vandichel, Matthias; Hemelsoet, Karen; Waroquier, Michel

    2014-11-07

    To optimally design next generation catalysts a thorough understanding of the chemical phenomena at the molecular scale is a prerequisite. Apart from qualitative knowledge on the reaction mechanism, it is also essential to be able to predict accurate rate constants. Molecular modeling has become a ubiquitous tool within the field of heterogeneous catalysis. Herein, we review current computational procedures to determine chemical kinetics from first principles, thus by using no experimental input and by modeling the catalyst and reacting species at the molecular level. Therefore, we use the methanol-to-olefin (MTO) process as a case study to illustrate the various theoretical concepts. This process is a showcase example where rational design of the catalyst was for a long time performed on the basis of trial and error, due to insufficient knowledge of the mechanism. For theoreticians the MTO process is particularly challenging as the catalyst has an inherent supramolecular nature, for which not only the Brønsted acidic site is important but also organic species, trapped in the zeolite pores, must be essentially present during active catalyst operation. All these aspects give rise to specific challenges for theoretical modeling. It is shown that present computational techniques have matured to a level where accurate enthalpy barriers and rate constants can be predicted for reactions occurring at a single active site. The comparison with experimental data such as apparent kinetic data for well-defined elementary reactions has become feasible as current computational techniques also allow predicting adsorption enthalpies with reasonable accuracy. Real catalysts are truly heterogeneous in a space- and time-like manner. Future theory developments should focus on extending our view towards phenomena occurring at longer length and time scales and integrating information from various scales towards a unified understanding of the catalyst. Within this respect molecular

  3. Multidominance, ellipsis, and quantifier scope

    NARCIS (Netherlands)

    Temmerman, Tanja Maria Hugo

    2012-01-01

    This dissertation provides a novel perspective on the interaction between quantifier scope and ellipsis. It presents a detailed investigation of the scopal interaction between English negative indefinites, modals, and quantified phrases in ellipsis. One of the crucial observations is that a negative

  4. Commercial Art: Scope and Sequence.

    Science.gov (United States)

    Nashville - Davidson County Metropolitan Public Schools, TN.

    This scope and sequence guide, developed for a commercial art vocational education program, represents an initial step in the development of a systemwide articulated curriculum sequence for all vocational programs within the Metropolitan Nashville Public School System. It was developed as a result of needs expressed by teachers, parents, and the…

  5. Revealing Lattice Expansion of Small-Pore Zeolite Catalysts during the Methanol-to-Olefins Process Using Combined Operando X-ray Diffraction and UV–vis Spectroscopy

    KAUST Repository

    Goetze, Joris; Yarulina, Irina; Gascon, Jorge; Kapteijn, Freek; Weckhuysen, Bert M.

    2018-01-01

    In small-pore zeolite catalysts, where the size of the pores is limited by eight-ring windows, aromatic hydrocarbon pool molecules that are formed inside the zeolite during the Methanol-to-Olefins (MTO) process cannot exit the pores and are retained

  6. X-ray Imaging of Zeolite Particles at the Nanoscale : Influence of Steaming on the State of Aluminum and the Methanol-To-Olefin Reaction

    NARCIS (Netherlands)

    Aramburo, Luis R.; de Smit, Emiel; Arstad, Bjornar; van Schooneveld, Matti M.; Sommer, Linn; Juhin, Amelie; Yokosawa, Tadahiro; Zandbergen, Henny W.; Olsbye, Unni; de Groot, Frank M. F.; Weckhuysen, Bert M.

    2012-01-01

    In view of the limited oil reserves the methanol-to-olefin (MTO) process is an interesting catalytic route to provide raw materials for chemical industries. In the last decades, a vast number of studies have been devoted to increase our understanding of this important catalytic reaction leading to a

  7. Influence of the Reaction Temperature on the Nature of the Active and Deactivating Species during Methanol to Olefins Conversion over H-SSZ-13

    NARCIS (Netherlands)

    Borodina, E.; Meirer, F.; Lezcano-Gonzalez, I.; Mokhtar, M.; Asiri, A. M.; Al-Thabaiti, S. A.; Basahel, S. N.; Ruiz-Martinez, J.; Weckhuysen, B. M.

    The formation of hydrocarbon species during the methanol to olefins (MTO) reaction over zeolite H-SSZ-13 has been systematically studied at reaction temperatures between 573 and 723 K with a combination of operando UV-vis spectroscopy and online gas chromatography. It was found that the applied

  8. "Hydro-metathesis" of olefins: A catalytic reaction using a bifunctional single-site tantalum hydride catalyst supported on fibrous silica (KCC-1) nanospheres

    KAUST Repository

    Polshettiwar, Vivek

    2011-02-18

    Tantalizing hydrocarbons: Tantalum hydride supported on fibrous silica nanospheres (KCC-1) catalyzes, in the presence of hydrogen, the direct conversion of olefins into alkanes that have higher and lower numbers of carbon atoms (see scheme). This catalyst shows remarkable catalytic activity and stability, with excellent potential of regeneration. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. An array of ordered pillars with retentive properties for pressure-driven liquid chromatography fabricated directly from an unmodified cyclo olefin polymer

    NARCIS (Netherlands)

    Illa, Xavi; de Malsche, Wim; Bomer, Johan G.; Gardeniers, Johannes G.E.; Eijkel, Jan C.T.; Morante, Joan Ramon; Romano-Rodriguez, Albert; Desmet, Gert

    2009-01-01

    The current paper describes the development and characterization of a pillar array chip that is constructed out of a sandwich of cyclo olefin polymer (COP) sheets. The silicon master of a 5 cm long pillar array was embossed into the COP, yielding 4.3 µm deep pillars of 15.3 µm diameter with an

  10. Mechanistic Studies on Chabazite-Type Methanol-to-Olefin Catalysts: Insights from Time-Resolved UV/Vis Microspectroscopy Combined with Theoretical Simulations

    NARCIS (Netherlands)

    Van Speybroeck, V.; Hemelsoet, K.L.J.; De Wispelaere, K.; Qian, Q.|info:eu-repo/dai/nl/34138609X; Van der Mynsbrugge, J.; De Sterck, B.; Weckhuysen, B.M.|info:eu-repo/dai/nl/285484397; Waroquier, M.

    2013-01-01

    The formation and nature of active sites for methanol conversion over solid acid catalyst materials are studied by using a unique combined spectroscopic and theoretical approach. A working catalyst for the methanol-to-olefin conversion has a hybrid organic–inorganic nature in which a cocatalytic

  11. Revealing Lattice Expansion of Small-Pore Zeolite Catalysts during the Methanol-to-Olefins Process Using Combined Operando X-ray Diffraction and UV-vis Spectroscopy

    NARCIS (Netherlands)

    Goetze, Joris; Yarulina, I.; Gascon Sabate, J.; Kapteijn, F.; Weckhuysen, Bert M.

    2018-01-01

    In small-pore zeolite catalysts, where the size of the pores is limited by eight-ring windows, aromatic hydrocarbon pool molecules that are formed inside the zeolite during the Methanol-to-Olefins (MTO) process cannot exit the pores and are retained inside the catalyst. Hydrocarbon species whose

  12. Catalytic asymmetric dihydroxylation of olefins using a recoverable and reusable OsO(4)2- in ionic liquid [bmim][PF6].

    Science.gov (United States)

    Branco, Luís C; Afonso, Carlos A M

    2002-12-21

    The use of the solvent systems water/ionic liquid or water/ionic liquid/tert-butanol provides a recoverable, reusable, robust and simple system for the asymmetric dihydroxylation of olefins, based on the immobilization of the osmium-ligand catalyst in the ionic liquid phase.

  13. Catalytic Upgrading of Bio-Oil by Reacting with Olefins and Alcohols over Solid Acids: Reaction Paths via Model Compound Studies

    Directory of Open Access Journals (Sweden)

    Qingwen Wang

    2013-03-01

    Full Text Available Catalytic refining of bio-oil by reacting with olefin/alcohol over solid acids can convert bio-oil to oxygen-containing fuels. Reactivities of groups of compounds typically present in bio-oil with 1-octene (or 1-butanol were studied at 120 °C/3 h over Dowex50WX2, Amberlyst15, Amberlyst36, silica sulfuric acid (SSA and Cs2.5H0.5PW12O40 supported on K10 clay (Cs2.5/K10, 30 wt. %. These compounds include phenol, water, acetic acid, acetaldehyde, hydroxyacetone, d-glucose and 2-hydroxymethylfuran. Mechanisms for the overall conversions were proposed. Other olefins (1,7-octadiene, cyclohexene, and 2,4,4-trimethylpentene and alcohols (iso-butanol with different activities were also investigated. All the olefins and alcohols used were effective but produced varying product selectivities. A complex model bio-oil, synthesized by mixing all the above-stated model compounds, was refined under similar conditions to test the catalyst’s activity. SSA shows the highest hydrothermal stability. Cs2.5/K10 lost most of its activity. A global reaction pathway is outlined. Simultaneous and competing esterification, etherfication, acetal formation, hydration, isomerization and other equilibria were involved. Synergistic interactions among reactants and products were determined. Acid-catalyzed olefin hydration removed water and drove the esterification and acetal formation equilibria toward ester and acetal products.

  14. Coke formation during the methanol-to-olefin conversion: in situ microspectroscopy on individual H-ZSM-5 crystals with different Brønsted acidity

    NARCIS (Netherlands)

    Mores, D.; Kornatowski, J.; Olsbye, U.; Weckhuysen, B.M.

    2011-01-01

    Coke formation during the methanol-to-olefin (MTO) conversion has been studied at the single-particle level with in situ UV/Vis and confocal fluorescence microscopy. For this purpose, large H-ZSM-5 crystals differing in their Si/Al molar ratio have been investigated. During MTO, performed at 623 and

  15. Techno-economic assessment of different routes for olefins production through the oxidative coupling of methane (OCM) : Advances in benchmark technologies

    NARCIS (Netherlands)

    Spallina, V.; Campos Velarde, I.; Medrano, J.A.; Godini, H.; Gallucci, F.; van Sint Annaland, M.

    2017-01-01

    This paper addresses the techno-economic assessment of two technologies for olefins production from naphtha and natural gas. The first technology is based on conventional naphtha steam cracking for the production of ethylene, propylene and BTX at polymer grade. The unused products are recovered in a

  16. "Hydro-metathesis" of olefins: A catalytic reaction using a bifunctional single-site tantalum hydride catalyst supported on fibrous silica (KCC-1) nanospheres

    KAUST Repository

    Polshettiwar, Vivek; Thivolle-Cazat, Jean; Taoufik, Mostafa; Stoffelbach, Franç ois; Norsic, Sé bastien; Basset, Jean-Marie

    2011-01-01

    Tantalizing hydrocarbons: Tantalum hydride supported on fibrous silica nanospheres (KCC-1) catalyzes, in the presence of hydrogen, the direct conversion of olefins into alkanes that have higher and lower numbers of carbon atoms (see scheme). This catalyst shows remarkable catalytic activity and stability, with excellent potential of regeneration. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Effect of Drying Conditions on the Catalytic Performance, Structure, and Reaction Rates over the Fe-Co-Mn/MgO Catalyst for Production of Light Olefins

    Directory of Open Access Journals (Sweden)

    Majid Abdouss

    2018-01-01

    How to Cite: Abdouss, M., Arsalanfar, M., Mirzaei, N., Zamani, Y. (2018. Effect of Drying Conditions on the Catalytic Performance, Structure, and Reaction Rates over the Fe-Co-Mn/MgO Catalyst for Production of Light Olefins. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (1: 97-112 (doi:10.9767/bcrec.13.1.1222.97-112

  18. Reduction of titanocene dichloride with dysprosium: access to a stable titanocene(ii) equivalent for phosphite-free Takeda carbonyl olefination.

    Science.gov (United States)

    Bousrez, G; Déchamps, I; Vasse, J-L; Jaroschik, F

    2015-05-28

    The reduction of titanocene dichloride with dysprosium yields a new titanocene(ii) equivalent without the need for further stabilising ligands. This reagent can be employed in combination with dithioacetals for the olefination of different carbonyl groups and allows for a simplified all-in-one procedure.

  19. 32 CFR 651.48 - Scoping process.

    Science.gov (United States)

    2010-07-01

    ... significantly affecting the environment will go through scoping unless extenuating circumstances make it... associated environmental controversy. (4) Importance of the affected environmental parameters. (5... the affected Army organization or installation. Such integration is encouraged. (f) Scoping procedures...

  20. The High Scope Approach To Early Learning

    OpenAIRE

    French, Geraldine

    2012-01-01

    Learning Objectives: After studying this chapter the reader should be able to: • Describe the historical origins, the longitudinal research, and the theoretical underpinnings of the HighScope approach. • Identify the teaching strategies adopted by HighScope educators. • Appreciate the curriculum content. • Understand the HighScope approach to the assessment of children’s learning. • Consider some criticisms of the HighScope research and approach to early learning. This ...

  1. Conceptual design of coke-oven gas assisted coal to olefins process for high energy efficiency and low CO2 emission

    International Nuclear Information System (INIS)

    Man, Yi; Yang, Siyu; Zhang, Jun; Qian, Yu

    2014-01-01

    Highlights: • A novel coke-oven gas assisted coal to olefins (GaCTO) process is proposed. • GaCTO has higher energy efficiency and emits less CO 2 compared to coal-to-olefins process. • GaCTO proposes an idea of using redundant coke-oven gas for producing value added products. - Abstract: Olefins are one of the most important platform chemicals. Developing coal-to-olefins (CTO) processes is regarded as one of promising alternatives to oil-to-olefins process. However, CTO suffers from high CO 2 emission due to the high carbon contents of coal. In China, there is 7 × 10 10 m 3 coke-oven gas (COG) produced in coke plants annually. However, most of the hydrogen-rich COG is utilized as fuel or discharged directly into the air. Such situation is a waste of precious hydrogen resource and serious economic loss, which causes serious environmental pollution either. This paper proposes a novel co-feed process of COG assist CTO in which CH 4 of COG reacts with CO 2 in a Dry Methane Reforming unit to reduce emissions, while the Steam Methane Reforming unit produces H 2 -rich syngas. H 2 of COG can adjust the H/C ratio of syngas. The analysis shows that the energy efficiency of the co-feed process increases about 10%, while at the same time, life cycle carbon footprint is reduced by around 85% in comparison to the conventional CTO process. The economic sustainability of the co-feed process will be reached when the carbon tax would be higher than 150 CNY/t CO 2

  2. Methanol conversion to light olefins over nanostructured CeAPSO-34 catalyst: Thermodynamic analysis of overall reactions and effect of template type on catalytic properties and performance

    Energy Technology Data Exchange (ETDEWEB)

    Aghamohammadi, Sogand [Chemical Engineering Faculty, Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Reactor and Catalysis Research Center (RCRC), Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Haghighi, Mohammad, E-mail: haghighi@sut.ac.ir [Chemical Engineering Faculty, Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Reactor and Catalysis Research Center (RCRC), Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Charghand, Mojtaba [Chemical Engineering Faculty, Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Reactor and Catalysis Research Center (RCRC), Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of)

    2014-02-01

    Graphical abstract: In this research nanostructured CeAPSO-34 was synthesized to explore the effect of TEAOH and morpholine on its physiochemical properties and MTO performance. Prepared catalysts were characterized with XRD, FESEM, BET, FTIR and NH3-TPD techniques. The results indicated that the nature of the template determines the physiochemical properties of CeAPSO-34 due to different rate of crystal growth. The catalyst obtained by using morpholine showed longer life time as well as sustaining light olefins selectivity at higher values. Furthermore, a comprehensive thermodynamic analysis of overall reactions network was carried out to address the major channels of methanol to olefins conversion. - Highlights: • Introduction of Ce into SAPO-34 framework. • Comparison of CeAPSO-34 synthesized using morpholine and TEAOH. • The nature of the template determines the physiochemical properties of CeAPSO-34. • Morpholine enhances catalyst lifetime in MTO process. • Presenting a complete reaction network for MTO process. - Abstract: TEAOH and morpholine were employed in synthesis of nanostructured CeAPSO-34 molecular sieve and used in methanol to olefins conversion. Prepared samples were characterized by XRD, FESEM, EDX, BET, FTIR and NH{sub 3}-TPD techniques. XRD patterns reflected the higher crystallinity of the catalyst synthesized with morpholine. The FESEM results indicated that the nature of the template determines the morphology of nanostructured CeAPSO-34 due to different rate of crystal growth. There was a meaningful difference in the strength of both strong and weak acid sites for CeAPSO-34 catalysts synthesized with TEAOH and morpholine templates. The catalyst synthesized with morpholine showed higher desorption temperature of both weak and strong acid sites evidenced by NH{sub 3}-TPD characterization. The catalyst obtained using morpholine template had the longer lifetime and sustained desired light olefins at higher values. A comprehensive

  3. Methanol conversion to light olefins over nanostructured CeAPSO-34 catalyst: Thermodynamic analysis of overall reactions and effect of template type on catalytic properties and performance

    International Nuclear Information System (INIS)

    Aghamohammadi, Sogand; Haghighi, Mohammad; Charghand, Mojtaba

    2014-01-01

    Graphical abstract: In this research nanostructured CeAPSO-34 was synthesized to explore the effect of TEAOH and morpholine on its physiochemical properties and MTO performance. Prepared catalysts were characterized with XRD, FESEM, BET, FTIR and NH3-TPD techniques. The results indicated that the nature of the template determines the physiochemical properties of CeAPSO-34 due to different rate of crystal growth. The catalyst obtained by using morpholine showed longer life time as well as sustaining light olefins selectivity at higher values. Furthermore, a comprehensive thermodynamic analysis of overall reactions network was carried out to address the major channels of methanol to olefins conversion. - Highlights: • Introduction of Ce into SAPO-34 framework. • Comparison of CeAPSO-34 synthesized using morpholine and TEAOH. • The nature of the template determines the physiochemical properties of CeAPSO-34. • Morpholine enhances catalyst lifetime in MTO process. • Presenting a complete reaction network for MTO process. - Abstract: TEAOH and morpholine were employed in synthesis of nanostructured CeAPSO-34 molecular sieve and used in methanol to olefins conversion. Prepared samples were characterized by XRD, FESEM, EDX, BET, FTIR and NH 3 -TPD techniques. XRD patterns reflected the higher crystallinity of the catalyst synthesized with morpholine. The FESEM results indicated that the nature of the template determines the morphology of nanostructured CeAPSO-34 due to different rate of crystal growth. There was a meaningful difference in the strength of both strong and weak acid sites for CeAPSO-34 catalysts synthesized with TEAOH and morpholine templates. The catalyst synthesized with morpholine showed higher desorption temperature of both weak and strong acid sites evidenced by NH 3 -TPD characterization. The catalyst obtained using morpholine template had the longer lifetime and sustained desired light olefins at higher values. A comprehensive thermodynamic

  4. Making Patent Scopes Exceed the Technological Scopes of Scientific Inventions

    DEFF Research Database (Denmark)

    Beukel, Karin

    This paper presents the results of a grounded theory study of the transformation of scientific discoveries into patented inventions. Using an algebraic interpretive approach, the narratives collected during interviews are analyzed as Bayesian inferences and the developed theory is tested. The fin...... for searching in new directions for solutions if challenges of exploitation with regard to the scientific invention arise.......This paper presents the results of a grounded theory study of the transformation of scientific discoveries into patented inventions. Using an algebraic interpretive approach, the narratives collected during interviews are analyzed as Bayesian inferences and the developed theory is tested....... The findings recast the relationship between science and patents as a process in which the way the transformation of the scientific invention is handled has an effect on the breadth of the patent scope. Unleashing patent scope surplus is dependent on processes related to abstraction and cognitive variety...

  5. 32 CFR 989.18 - Scoping.

    Science.gov (United States)

    2010-07-01

    ... ANALYSIS PROCESS (EIAP) § 989.18 Scoping. (a) After publication of the NOI for an EIS, the EPF must... public. The result of scoping is that the proponent and EPF determine the range of actions, alternatives, and impacts to be considered in the EIS (40 CFR 1508.25). The EPF must send scripts for scoping...

  6. Heterogeneous catalytic epoxidation of C/sub 8/-C/sub 1/4 olefins by tert. -butyl hydroperoxide

    Energy Technology Data Exchange (ETDEWEB)

    Dahlmann, J; Hoeft, E; Boeden, H F; Dilcher, H

    1979-09-01

    Heterogeneous catalytic epoxidation of C/sub 8/-C/sub 14/ olefins by tert.-butyl hydroperoxide (TBHP) avoids large product losses to side reactions, associated with the use of homogeneous catalysts, such as Mo(CO)/sub 6/. With an unsupported MoO/sub 3/ catalyst, 48% TBHP conversion was achieved after one hour (vs. 24% after two hours for Mo(CO)/sub 6/) in 1-octene epoxidation at 90/sup 0/C and 2:1:3 octene/TBHP/toluene (solvent) molar ratio. The use of silica-supported catalysts, such as Bi/sub 9/PMo/sub 12/O/sub 52//30% SiO/sub 2/ (ACN, an industrial catalyst for acrylonitrile), MoO/sub 3//30% SiO/sub 2/ (D-1), 3MoO/sub 3/-Sb/sub 2/O/sub 5//50% SiO/sub 2/ (D-2), or 2MoO/sub 3/-As/sub 2/O/sub 3//50% SiO/sub 2/ (D-3) increased the conversion to 68, 67, 70, and 73%, respectively, with up to 95-99% selectivities for the epoxide. Under optimum conditions of 3:1 olefin/TBHP, 110/sup 0/C, and 2-4 g/l. catalyst, TBHP conversions in epoxidation of 1-tetradecene in a batch reactor over ACN, D-2, and D-3 after two hours were 94, 88, and 91%, respectively, but they decreased to 52, 78, and 79%, respectively, after five two-hour operating cycles. In epoxidation of 1-decene or a mixture of decene isomers (a model for the industrial olefin mixtures obtained by paraffin dehydrogenation via the Parex process) carried out in a continuous flow reactor over the D-3 catalyst at 90/sup 0/-110/sup 0/C, stable catalytic activities with TBHP conversions of approx. 90% and 90-96% selectivities for epoxides were observed for about 900 hr.

  7. Effect of Steam Deactivation Severity of ZSM-5 Additives on LPG Olefins Production in the FCC Process.

    Science.gov (United States)

    Gusev, Andrey A; Psarras, Antonios C; Triantafyllidis, Konstantinos S; Lappas, Angelos A; Diddams, Paul A

    2017-10-21

    ZSM-5-containing catalytic additives are widely used in oil refineries to boost light olefin production and improve gasoline octanes in the Fluid Catalytic Cracking (FCC) process. Under the hydrothermal conditions present in the FCC regenerator (typically >700 °C and >8% steam), FCC catalysts and additives are subject to deactivation. Zeolites (e.g., Rare Earth USY in the base catalyst and ZSM-5 in Olefins boosting additives) are prone to dealumination and partial structural collapse, thereby losing activity, micropore surface area, and undergoing changes in selectivity. Fresh catalyst and additives are added at appropriate respective levels to the FCC unit on a daily basis to maintain overall targeted steady-state (equilibrated) activity and selectivity. To mimic this process under accelerated laboratory conditions, a commercial P/ZSM-5 additive was hydrothermally equilibrated via a steaming process at two temperatures: 788 °C and 815 °C to simulate moderate and more severe equilibration industrial conditions, respectively. n -Dodecane was used as probe molecule and feed for micro-activity cracking testing at 560 °C to determine the activity and product selectivity of fresh and equilibrated P-doped ZSM-5 additives. The fresh/calcined P/ZSM-5 additive was very active in C 12 cracking while steaming limited its activity, i.e., at catalyst-to-feed (C/F) ratio of 1, about 70% and 30% conversion was obtained with the fresh and steamed additives, respectively. A greater activity drop was observed upon increasing the hydrothermal deactivation severity due to gradual decrease of total acidity and microporosity of the additives. However, this change in severity did not result in any selectivity changes for the LPG (liquefied petroleum gas) olefins as the nature (Brønsted-to-Lewis ratio) of the acid/active sites was not significantly altered upon steaming. Steam deactivation of ZSM-5 had also no significant effect on aromatics formation which was enhanced at higher

  8. A Generic Model for Prediction of Separation Performance of Olefin/Paraffin Mixture by Glassy Polymer Membranes

    Directory of Open Access Journals (Sweden)

    A.A. Ghoreyshi

    2008-02-01

    Full Text Available The separation of olefin/paraffin mixtures is an important process in petrochemical industries, which is traditionally performed by low temperature distillation with a high-energy consumption, or complex extractive distillationand adsorption techniques. Membrane separation process is emerging as an alternative for traditional separation processes with respect to low energy and simple operation. Investigations made by various researchers on polymeric membranes it is found that special glassy polymers render them as suitable materials for olefin/paraffin mixture separation. In this regard, having some knowledge on the possible transport mechanism of these processes would play a significant role in their design and applications. In this study, separation behavior of olefin/paraffin mixtures through glassy polymers was modeled by three different approaches: the so-called dual transport model, the basic adsorption-diffusion theory and the general Maxwell-Stefan formulation. The systems chosen to validate the developed transport models are separation of ethane-ethylene mixture by 6FDA-6FpDA polyimide membrane and propane-propylene mixture by 6FDA-TrMPD polyimide membrane for which the individual sorption and permeation data are available in the literature. Acritical examination of dual transport model shows that this model fails clearly to predict even the proper trend for selectivities. The adjustment of pemeabilities by accounting for the contribution of non-selective bulk flow in the transport model introduced no improvement in the predictability of the model. The modeling results based on the basic adsorption-diffusion theory revealed that in this approach only using mixed permeability data, an acceptable result is attainable which fades out the advantages of predictibility of multicomponent separation performance from pure component data. Finally, the results obtained from the model developed based on Maxwell-Stefan formulation approach show a

  9. Effect of Steam Deactivation Severity of ZSM-5 Additives on LPG Olefins Production in the FCC Process

    Directory of Open Access Journals (Sweden)

    Andrey A. Gusev

    2017-10-01

    Full Text Available ZSM-5-containing catalytic additives are widely used in oil refineries to boost light olefin production and improve gasoline octanes in the Fluid Catalytic Cracking (FCC process. Under the hydrothermal conditions present in the FCC regenerator (typically >700 °C and >8% steam, FCC catalysts and additives are subject to deactivation. Zeolites (e.g., Rare Earth USY in the base catalyst and ZSM-5 in Olefins boosting additives are prone to dealumination and partial structural collapse, thereby losing activity, micropore surface area, and undergoing changes in selectivity. Fresh catalyst and additives are added at appropriate respective levels to the FCC unit on a daily basis to maintain overall targeted steady-state (equilibrated activity and selectivity. To mimic this process under accelerated laboratory conditions, a commercial P/ZSM-5 additive was hydrothermally equilibrated via a steaming process at two temperatures: 788 °C and 815 °C to simulate moderate and more severe equilibration industrial conditions, respectively. n-Dodecane was used as probe molecule and feed for micro-activity cracking testing at 560 °C to determine the activity and product selectivity of fresh and equilibrated P-doped ZSM-5 additives. The fresh/calcined P/ZSM-5 additive was very active in C12 cracking while steaming limited its activity, i.e., at catalyst-to-feed (C/F ratio of 1, about 70% and 30% conversion was obtained with the fresh and steamed additives, respectively. A greater activity drop was observed upon increasing the hydrothermal deactivation severity due to gradual decrease of total acidity and microporosity of the additives. However, this change in severity did not result in any selectivity changes for the LPG (liquefied petroleum gas olefins as the nature (Brønsted-to-Lewis ratio of the acid/active sites was not significantly altered upon steaming. Steam deactivation of ZSM-5 had also no significant effect on aromatics formation which was enhanced at

  10. In Situ Generation of Pd-Pt Core-Shell Nanoparticles on Reduced Graphene Oxide (Pd@Pt/rGO) Using Microwaves: Applications in Dehalogenation Reactions and Reduction of Olefins.

    Science.gov (United States)

    Goswami, Anandarup; Rathi, Anuj K; Aparicio, Claudia; Tomanec, Ondrej; Petr, Martin; Pocklanova, Radka; Gawande, Manoj B; Varma, Rajender S; Zboril, Radek

    2017-01-25

    Core-shell nanocatalysts are a distinctive class of nanomaterials with varied potential applications in view of their unique structure, composition-dependent physicochemical properties, and promising synergism among the individual components. A one-pot microwave (MW)-assisted approach is described to prepare the reduced graphene oxide (rGO)-supported Pd-Pt core-shell nanoparticles, (Pd@Pt/rGO); spherical core-shell nanomaterials (∼95 nm) with Pd core (∼80 nm) and 15 nm Pt shell were nicely distributed on the rGO matrix in view of the choice of reductant and reaction conditions. The well-characterized composite nanomaterials, endowed with synergism among its components and rGO support, served as catalysts in aromatic dehalogenation reactions and for the reduction of olefins with high yield (>98%), excellent selectivity (>98%) and recyclability (up to 5 times); both Pt/rGO and Pd/rGO and even their physical mixtures showed considerably lower conversions (20 and 57%) in dehalogenation of 3-bromoaniline. Similarly, in the reduction of styrene to ethylbenzene, Pd@Pt core-shell nanoparticles (without rGO support) possess considerably lower conversion (60%) compared to Pd@Pt/rGO. The mechanism of dehalogenation reactions with Pd@Pt/rGO catalyst is discussed with the explicit premise that rGO matrix facilitates the adsorption of the reducing agent, thus enhancing its local concentration and expediting the hydrazine decomposition rate. The versatility of the catalyst has been validated via diverse substrate scope for both reduction and dehalogenation reactions.

  11. Synthesis and characterization of a homogeneous and silica supported homoleptic cationic tungsten(vi) methyl complex: application in olefin metathesis

    KAUST Repository

    Dey, Raju

    2016-08-19

    A method for the synthesis of a homogeneous cationic tungsten(VI)penta-methyl complex [(WMe5)(+)(C6F5)(3)BMe-] from neutral tungstenhexamethyl (WMe6) and a silica supported cationic tungstentetramethyl complex [( Si-O-)WMe4+ (C6F5)(3)BMe-] from a neutral silica supported tungstenpentamethyl complex [( Si-O-)WMe5] is described. In both cases a direct demethylation using the B(C6F5)(3) reagent was used. The aforesaid complexes were characterized by liquid or solid state NMR spectroscopy. Interestingly, the homogeneous cationic complex [(WMe5)(+)(C6F5)(3)BMe-] shows moderate activity whereas the supported cationic complex [( Si-O-)WMe4+(C6F5)(3)BMe-] exhibits good activity in olefin metathesis reactions.

  12. Methodologies to maximize olefins in process unit of COMPERJ; Metodologias para maximizacao de olefinas nas unidades de processamento do COMPERJ

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Maria Clara de C. dos; Seidl, Peter R.; Guimaraes, Maria Jose O.C. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica

    2008-07-01

    With the growth of the national and worldwide economy, there has been a considerable increase in demand for polyolefins, thus requiring an increase in the production of basic petrochemicals (primarily ethane and propane). Due the quality of the national oil, heavy and poor in light derivatives, it is necessary investments in processes of conversion of heavy fractions with intent to maximize production these olefins and alternative raw materials for obtaining these petrochemicals The possible alternatives studied were the expansion of the core petrochemical, changes in the refinery processing units and the construction of COMPERJ, the latter being a example of alternative that can change the current scenario. The work aims to the simulation of process units of COMPERJ with the intention of evaluate which solutions like COMPERJ can best meet the growing market of polyolefins. (author)

  13. Synthesis of 1,2,4-trioxepanes via application of thiol-olefin co-oxygenation methodology.

    Science.gov (United States)

    Amewu, Richard; Stachulski, Andrew V; Berry, Neil G; Ward, Stephen A; Davies, Jill; Labat, Gael; Rossignol, Jean-Francois; O'Neill, Paul M

    2006-12-01

    Thiol-olefin co-oxygenation (TOCO) of substituted allylic alcohols generates beta-hydroxy peroxides that can be condensed in situ with various ketones, to afford a series of functionalised 1,2,4-trioxepanes in good yields. Manipulation of the phenylsulfenyl group in 8a-8c allows for convenient modification to the spiro-trioxepane substituents. Surprisingly, and in contrast to the 1,2,4-trioxanes examined, 1,2,4-trioxepanes are inactive as antimalarials up to 1000 nM and we rationalize this observation based on the inherent stability of these systems to ferrous mediated degradation. FMO calculations clearly show that the sigma* orbital of the peroxide moiety of 1,2,4-trioxane derivatives 4a and 14b are lower in energy and more accessible to attack by Fe(II) compared to their trioxepane analogues 8b and 9b.

  14. Well-Defined Molybdenum Oxo Alkyl Complex Supported on Silica by Surface Organometallic Chemistry: A Highly Active Olefin Metathesis Precatalyst

    KAUST Repository

    Merle, Nicolas; Le Qué mé ner, Fré dé ric; Bouhoute, Yassine; Szeto, Kai C.; De Mallmann, Aimery; Barman, Samir; Samantaray, Manoja; Delevoye, Laurent; Gauvin, Ré gis M.; Taoufik, Mostafa; Basset, Jean-Marie

    2016-01-01

    The well-defined silica-supported molybdenum oxo alkyl species (SiO−)MoO(CH Bu) was selectively prepared by grafting of MoO(CH Bu)Cl onto partially dehydroxylated silica (silica) using the surface organometallic chemistry approach. This surface species was fully characterized by elemental analysis and DRIFT, solid-state NMR, and EXAFS spectroscopy. This new material is related to the active species of industrial supported MoO/SiO olefin metathesis catalysts. It displays very high activity in propene self-metathesis at mild (turnover number = 90 000 after 25 h). Remarkably, its catalytic performance outpaces those of the parent imido derivative and its tungsten oxo analogue.

  15. Moving from Classical Ru-NHC to Neutral or Charged Rh-NHC Based Catalysts in Olefin Metathesis

    Directory of Open Access Journals (Sweden)

    Albert Poater

    2016-01-01

    Full Text Available Considering the versatility of oxidation states of rhodium together with the successful background of ruthenium-N-heterocyclic carbene based catalysts in olefin metathesis, it is envisaged the exchange of the ruthenium of the latter catalysts by rhodium, bearing an open-shell neutral rhodium center, or a +1 charged one. In the framework of in silico experiments, density functional theory (DFT calculations have been used to plot the first catalytic cycle that as a first step includes the release of the phosphine. DFT is, in this case, the tool that allows the discovery of the less endergonic reaction profile from the precatalytic species for the neutral catalyst with respect to the corresponding ruthenium one; increasing the endergonic character when dealing with the charged system.

  16. Mechanism of the Ru–Allenylidene to Ru–Indenylidene Rearrangement in Ruthenium Precatalysts for Olefin Metathesis

    KAUST Repository

    Pump, Eva

    2015-06-30

    The intramolecular allenylidene RuCl2(PR3)2(C═C═CPh2) to indenylidene RuCl2(PR3)2(Ind) rearrangement that occurs during the synthesis of Ru-based precatalysts for olefin metathesis is presented. In the absence of acid, the ring closure via C–H activation was shown to be unfavored for energy barriers up to 70 kcal/mol. Thus, it turned out to be HCl (or other acid) that plays a crucial role during formation of the indenylidene, as the upper energy barrier decreases to a reasonable 35 kcal/mol. Moreover, we proved computationally that depending on the nature of the phosphine the intramolecular rearrangement is either facilitated (PPh3) or slightly hampered (PCy3), which is in line with experimental results.

  17. Synthesis and characterization of a homogeneous and silica supported homoleptic cationic tungsten(vi) methyl complex: application in olefin metathesis

    KAUST Repository

    Dey, Raju; Samantaray, Manoja; Poater, Albert; Hamieh, Ali Imad Ali; Kavitake, Santosh Giridhar; Abou-Hamad, Edy; Callens, Emmanuel; Emwas, Abdul-Hamid M.; Cavallo, Luigi; Basset, Jean-Marie

    2016-01-01

    A method for the synthesis of a homogeneous cationic tungsten(VI)penta-methyl complex [(WMe5)(+)(C6F5)(3)BMe-] from neutral tungstenhexamethyl (WMe6) and a silica supported cationic tungstentetramethyl complex [( Si-O-)WMe4+ (C6F5)(3)BMe-] from a neutral silica supported tungstenpentamethyl complex [( Si-O-)WMe5] is described. In both cases a direct demethylation using the B(C6F5)(3) reagent was used. The aforesaid complexes were characterized by liquid or solid state NMR spectroscopy. Interestingly, the homogeneous cationic complex [(WMe5)(+)(C6F5)(3)BMe-] shows moderate activity whereas the supported cationic complex [( Si-O-)WMe4+(C6F5)(3)BMe-] exhibits good activity in olefin metathesis reactions.

  18. [1+1+3] Annulation of Diazoenals and Vinyl Azides: Direct Synthesis of Functionalized 1-Pyrrolines through Olefination.

    Science.gov (United States)

    Kanchupalli, Vinaykumar; Katukojvala, Sreenivas

    2018-05-04

    A dirhodium carboxylate catalyzed [1+1+3] annulation reaction of diazoenals and vinyl azides that gives synthetically important enal-functionalized 1-pyrroline derivatives was developed. The reaction involves a novel rhodium-catalyzed olefination of diazoenals with vinyl azides via electrophilic enal carbenoids, resulting in a new class of enal acrylates. The annulation reaction was used for the direct synthesis of valuable deuterated 1-pyrrolines. Structural diversification of the enal-functionalized 1-pyrrolines resulted in the biologically important pyrrolidine-fused oxaziridine, amino acid derivatives, and a 6-azabicyclo[3.2.1]octane motif present in polycyclic alkaloids. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Relayed Regioselective Alkynylation/Olefination of Unsymmetrical Cyclic Diaryliodonium Species Catalyzed by Cu and Pd: Affording Fluorescent Cytotoxic Benzoxazoles.

    Science.gov (United States)

    Zhu, Daqian; Liu, Panpan; Lu, Wenhua; Wang, Haiwen; Luo, Bingling; Hu, Yumin; Huang, Peng; Wen, Shijun

    2015-12-21

    Although cyclic diaryliodonium species have the potential to act as valuable synthons for cascade transformations, they still remain largely unexplored. The regioselectivity associated with unsymmetrical cyclic diaryliodonium species has previously been known to pose a challenge. A regioselective relayed alkynylation and olefination of unsymmetrical cyclic diaryliodonium species has been achieved by installation of a directing amido group. These relayed transformations were delayed until an oxazole ring had formed, delivering a series of unique fluorescent benzoxazoles. Moreover, some of these synthetic benzoxazoles showed apparent inhibitory activity against malignant cancer cells. Further confocal visualization revealed that benzoxazoles targeted cell nuclei. These findings might provide a novel structural scaffold to develop desirable anticancer agents. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Well-Defined Molybdenum Oxo Alkyl Complex Supported on Silica by Surface Organometallic Chemistry: A Highly Active Olefin Metathesis Precatalyst

    KAUST Repository

    Merle, Nicolas

    2016-12-05

    The well-defined silica-supported molybdenum oxo alkyl species (SiO−)MoO(CH Bu) was selectively prepared by grafting of MoO(CH Bu)Cl onto partially dehydroxylated silica (silica) using the surface organometallic chemistry approach. This surface species was fully characterized by elemental analysis and DRIFT, solid-state NMR, and EXAFS spectroscopy. This new material is related to the active species of industrial supported MoO/SiO olefin metathesis catalysts. It displays very high activity in propene self-metathesis at mild (turnover number = 90 000 after 25 h). Remarkably, its catalytic performance outpaces those of the parent imido derivative and its tungsten oxo analogue.

  1. Ruthenium dioxide nanoparticles in ionic liquids: synthesis, characterization and catalytic properties in hydrogenation of olefins and arenes

    International Nuclear Information System (INIS)

    Rossi, Liane M.; Dupont, Jairton; Machado, Giovanna; Fichtner, Paulo F.P.; Radtke, Claudio; Baumvol, Israel J.R.; Teixeira, Sergio R.

    2004-01-01

    The reaction of NaBH 4 with RuCl 3 dissolved in 1-n-butyl-3-methylimidazolium hexafluorophosphate (BMI.PF 6 ) ionic liquid is a simple and reproducible method for the synthesis of stable RuO 2 nanoparticles with a narrow size distribution within 2-3 nm. RuO 2 nanoparticles were characterized by XRD, XPS, EDS and TEM. These nanoparticles showed high catalytic activity either in the solventless or liquid-liquid biphasic hydrogenation of olefins and arenes under mild reaction conditions. Hg(0) and CS 2 poisoning experiments and XRD and TEM analysis of particles isolated after catalysis indicated the formation of Ru(0) nanoparticles. The nanoparticles could be re-used in solventless conditions up to 10 times in the hydrogenation of 1-hexene yielding a total turnover number for exposed Ru atoms of 175,000. (author)

  2. Mechanism of the Ru–Allenylidene to Ru–Indenylidene Rearrangement in Ruthenium Precatalysts for Olefin Metathesis

    KAUST Repository

    Pump, Eva; Slugovc, Christian; Cavallo, Luigi; Poater, Albert

    2015-01-01

    The intramolecular allenylidene RuCl2(PR3)2(C═C═CPh2) to indenylidene RuCl2(PR3)2(Ind) rearrangement that occurs during the synthesis of Ru-based precatalysts for olefin metathesis is presented. In the absence of acid, the ring closure via C–H activation was shown to be unfavored for energy barriers up to 70 kcal/mol. Thus, it turned out to be HCl (or other acid) that plays a crucial role during formation of the indenylidene, as the upper energy barrier decreases to a reasonable 35 kcal/mol. Moreover, we proved computationally that depending on the nature of the phosphine the intramolecular rearrangement is either facilitated (PPh3) or slightly hampered (PCy3), which is in line with experimental results.

  3. Intermolecular Dehydrative Coupling Reaction of Arylketones with Cyclic Alkenes Catalyzed by a Well-Defined Cationic Ruthenium-Hydride Complex: A Novel Ketone Olefination Method via Vinyl C–H Bond Activation

    Science.gov (United States)

    Yi, Chae S.; Lee, Do W.

    2010-01-01

    Summary The cationic ruthenium-hydride complex [(η6-C6H6)(PCy3)(CO)RuH]+BF4− was found to be a highly effective catalyst for the intermolecular olefination reaction of arylketones with cycloalkenes. The preliminary mechanistic analysis revealed that electrophilic ruthenium-vinyl complex is the key species for mediating both vinyl C–H bond activation and the dehydrative olefination steps of the coupling reaction. PMID:20567607

  4. Conversion of Syngas-Derived C2+ Mixed Oxygenates to C3-C5 Olefins over ZnxZryOz Mixed Oxides Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Colin D.; Lebarbier, Vanessa M.; Flake, Matthew D.; Ramasamy, Karthikeyan K.; Kovarik, Libor; Bowden, Mark E.; Onfroy, Thomas; Dagle, Robert A.

    2016-04-01

    In this study we report on a ZnxZryOz mixed oxide type catalyst capable of converting a syngas-derived C2+ mixed oxygenate feedstock to isobutene-rich olefins. Aqueous model feed comprising of ethanol, acetaldehyde, acetic acid, ethyl acetate, methanol, and propanol was used as representative liquid product derived from a Rh-based mixed oxygenate synthesis catalyst. Greater than 50% carbon yield to C3-C5 mixed olefins was demonstrated when operating at 400-450oC and 1 atm. In order to rationalize formation of the products observed feed components were individually evaluated. Major constituents of the feed mixture (ethanol, acetaldehyde, acetic acid, and ethyl acetate) were found to produce isobutene-rich olefins. C-C coupling was also demonstrated for propanol feedstock - a minor constituent of the mixed oxygenate feed - producing branched C6 olefins, revealing scalability to alcohols higher than ethanol following an analogous reaction pathway. Using ethanol and propanol feed mixtures, cross-coupling reactions produced mixtures of C4, C5, and C6 branched olefins. The presence of H2 in the feed was found to facilitate hydrogenation of the ketone intermediates, thus producing straight chain olefins as byproducts. While activity loss from coking is observed complete catalyst regeneration is achieved by employing mild oxidation. For conversion of the mixed oxygenate feed a Zr/Zn ratio of 2.5 and a reaction temperature of 450oC provides the best balance of stability, activity, and selectivity. X-ray diffraction and scanning transmission electron microscopy analysis reveals the presence of primarily cubic phase ZrO2 and a minor amount of the monoclinic phase, with ZnO being highly dispersed in the lattice. The presence of ZnO appears to stabilize the cubic phase resulting in less monoclinic phase as the ZnO concentration increases. Infrared spectroscopy shows the mixed oxide acid sites are characterized as primarily Lewis type acidity. The direct relationship between

  5. Use and engineering of efflux pumps for the export of olefins in microbes

    Energy Technology Data Exchange (ETDEWEB)

    Mukhopadhyay, Aindrila [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States)

    2016-07-14

    The scope of the project is to investigate efflux pump systems in engineered host microorganisms, such as E. coli, and develop a pump engineered to export a target compound. To initiate the project in coordination with other TOTAL driven projects, the first target compound to be studied was 1-hexene. However, we were investigating other chemicals as Styrene. The main goal of the project was to generate a set of optimized efflux pump systems for microorganisms (E. coli and Streptomyces or other host) engineered to contain biosynthetic pathways to export large titers of target compounds that are toxic (or accumulate and push back biosynthesis) to the host cell. An optimized microbial host will utilize specific and efficient cell wall located pumps to extrude harmful target compounds and enable greater production of these compounds.

  6. Well-defined silica supported bipodal molybdenum oxo alkyl complexes: a model of the active sites of industrial olefin metathesis catalysts

    KAUST Repository

    Merle, Nicolas

    2017-09-25

    A well-defined, silica-supported molybdenum oxo alkyl species, ([triple bond, length as m-dash]SiO-)2Mo([double bond, length as m-dash]O)(CH2tBu)2, was prepared by the selective grafting of Mo([double bond, length as m-dash]O)(CH2tBu)3Cl onto a silica partially dehydroxylated at 200 °C using a rigorous surface organometallic chemistry approach. The immobilized bipodal surface species, partly resembling the active species of industrial MoO3/SiO2 olefin metathesis catalysts, exhibited excellent functional group tolerance in conjunction with its high activity in homocoupling, self and ring closing olefin metathesis.

  7. Well-defined silica supported bipodal molybdenum oxo alkyl complexes: a model of the active sites of industrial olefin metathesis catalysts

    KAUST Repository

    Merle, Nicolas; Le Qué mé ner, Fré dé ric; Barman, Samir; Samantaray, Manoja; Szeto, Kai C.; De Mallmann, Aimery; Taoufik, Mostafa; Basset, Jean-Marie

    2017-01-01

    A well-defined, silica-supported molybdenum oxo alkyl species, ([triple bond, length as m-dash]SiO-)2Mo([double bond, length as m-dash]O)(CH2tBu)2, was prepared by the selective grafting of Mo([double bond, length as m-dash]O)(CH2tBu)3Cl onto a silica partially dehydroxylated at 200 °C using a rigorous surface organometallic chemistry approach. The immobilized bipodal surface species, partly resembling the active species of industrial MoO3/SiO2 olefin metathesis catalysts, exhibited excellent functional group tolerance in conjunction with its high activity in homocoupling, self and ring closing olefin metathesis.

  8. IDC Reengineering Phase 2 Project Scope.

    Energy Technology Data Exchange (ETDEWEB)

    Harris, James M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-02-01

    This report provides a brief description of the scope of the IDC Reengineering Phase 2 project. It describes the goals and objectives of reengineering, the system definition, and the technical scope of the system. REVISIONS Version Date Author/Team Revision Description Authorized by 1.0 9/25/2014 SNL IDC Reengineering Team Unlimited Release for I2 M. Harris 1.1 28/01/2015 IDC Reengineering Team Align with previous IDC scope document E. Tomuta.

  9. When Ethyl Isocyanoacetate Meets Isatins: A 1,3-Dipolar/Inverse 1,3-Dipolar/Olefination Reaction for Access to 3-Ylideneoxindoles.

    Science.gov (United States)

    Yuan, Wen-Kui; Cui, Tao; Liu, Wei; Wen, Li-Rong; Li, Ming

    2018-03-16

    A new CuI/1,10-phen-catalyzed reaction for the synthesis of 3-ylideneoxindoles from readily available isatins and ethyl isocyanoacetate, in which ethyl isocyanoacetate acts as a latent two-carbon donor like the Wittig reagent, is reported. A tandem procedure including 1,3-dipolar cycloaddition/inverse 1,3-dipolar ring opening/olefination allows the preparation of 3-ylideneoxindoles with broad functional group tolerance.

  10. CH3-ReO3 on gamma-Al2O3: understanding its structure, initiation,and reactivity in olefin metathesis

    Energy Technology Data Exchange (ETDEWEB)

    Salameh, Alain; Joubert, Jerome; Baudouin, Anne; Lukens, Wayne; Delbecq, Francoise; Sautet, Philippe; Basset, Jean Marie; Coperet,Christophe

    2007-01-20

    Me-ReO3 on gamma-alumina: understanding the structure, theinitiation and thereactivity of a highly active olefin metathesiscatalyst Heterolytic splitting of the C-H bond of the methyl group ofCH3ReO3 on AlsO reactive sites of alumina as a way to generate the activesite of CH3ReO3 supported on gamma-Al203.

  11. Synthetic Studies on Bioactive Natural Polyketides: Intramolecular Nitrile Oxide-Olefin Cycloaddition Approach for Construction of a Macrolactone Skeleton of Macrosphelide B

    Directory of Open Access Journals (Sweden)

    Seung-Mann Paek

    2011-06-01

    Full Text Available Studies on the synthesis of macrosphelide B via an intramolecular nitrile oxide-olefin cycloaddition (INOC is described. In particular, an asymmetric INOC approach using phase transfer catalysts seems to be a potentially efficient and versatile procedure for the construction of the macrolactone skeleton of macrosphelide B in terms of facial selectivity. Our preliminary and unprecedented stereoselective procedure is anticipated to be usefully applied through further studies for the synthesis of the macrosphelide family.

  12. Synthesis of the EF-ring of ciguatoxin 3C based on the [2,3]-Wittig rearrangement and ring-closing olefin metathesis.

    Science.gov (United States)

    Goto, Akiyoshi; Fujiwara, Kenshu; Kawai, Ayako; Kawai, Hidetoshi; Suzuki, Takanori

    2007-12-20

    The EF-ring segment of ciguatoxin 3C, a causative toxin of ciguatera fish poisoning, was synthesized in three major steps: 1,4-addition for the C20O-C27 bond connection, chirality transferring anti selective [2,3]-Wittig rearrangement for the construction of the anti-2-hydroxyalkyl ether part, and ring-closing olefin metathesis for the F-ring formation.

  13. Application of thiol-olefin co-oxygenation methodology to a new synthesis of the 1,2,4-trioxane pharmacophore.

    Science.gov (United States)

    O'Neill, Paul M; Mukhtar, Amira; Ward, Stephen A; Bickley, Jamie F; Davies, Jill; Bachi, Mario D; Stocks, Paul A

    2004-09-02

    [reaction: see text] Thiol-olefin co-oxygenation (TOCO) of substituted allylic alcohols generates alpha-hydroxyperoxides that can be condensed in situ with various ketones to afford a series of functionalized 1,2,4-trioxanes in good yields. Manipulation of the phenylsulfenyl group in 4a allows for convenient modification to the spiro-trioxane substituents, and we describe, for the first time, the preparation of a new class of antimalarial prodrug.

  14. Preparation of silico-alumino-phosphates by the rapid crystallization method and their catalytic performance in the conversion of methanol to light olefins

    Energy Technology Data Exchange (ETDEWEB)

    Inui, T.; Matsuda, H.; Okaniwa, H.; Miyamoto, A. (Kyoto Univ. (Japan))

    1990-02-19

    Shape-selective silico-alumino-phosphates, SAPO-34 and SAPO-17, having the chabazite and erionite structure, respectively, were prepared within 4 h of hydrothermal treatment by the rapid crystallization method. They are highly effective for the selective conversion of methanol to light olefins, such as ethene, propene and butenes. It is shown that these SAPOs are more weakly acidic than typical H-ZSM-5 but more strongly acidic than H-Fe-silicates. 7 figs., 24 refs.

  15. Predicting Alkylate Yield and its Hydrocarbon Composition for Sulfuric Acid Catalyzed Isobutane Alkylation with Olefins Using the Method of Mathematical Modeling

    OpenAIRE

    Nurmakanova, А. Е.; Ivashkina, Elena Nikolaevna; Ivanchina, Emilia Dmitrievna; Dolganov, I. A.; Boychenko, S. S.

    2015-01-01

    The article provides the results of applied mathematical model of isobutane alkylation with olefins catalyzed by sulfuric acid to predict yield and hydrocarbon composition of alkylate caused by the changes in the feedstock composition and process parameters. It is shown that the alkylate produced from feedstock with less mass fraction of isobutane has lower octane value. Wherein the difference in composition of the feedstock contributes to antiknock index by the amount of 1.0-2.0 points.

  16. (E)-α,β-unsaturated amides from tertiary amines, olefins and CO via Pd/Cu-catalyzed aerobic oxidative N-dealkylation.

    Science.gov (United States)

    Shi, Renyi; Zhang, Hua; Lu, Lijun; Gan, Pei; Sha, Yuchen; Zhang, Heng; Liu, Qiang; Beller, Matthias; Lei, Aiwen

    2015-02-21

    A novel Pd/Cu-catalyzed chemoselective aerobic oxidative N-dealkylation/carbonylation reaction has been developed. Tertiary amines are utilized as a "reservoir" of "active" secondary amines in this transformation, which inhibits the formation of undesired by-products and the deactivation of the catalysts. This protocol allows for an efficient and straightforward construction of synthetically useful and bioactive (E)-α,β-unsaturated amide derivatives from easily available tertiary amines, olefins and CO.

  17. Stereoselective synthesis of 1,3-disubstituted isoindolines via Rh(III)-catalyzed tandem oxidative olefination-cyclization of 4-aryl cyclic sulfamidates.

    Science.gov (United States)

    Son, Se-Mi; Seo, Yeon Ji; Lee, Hyeon-Kyu

    2016-03-21

    Rh(III)-catalyzed tandem ortho C-H olefination of cyclic 4-aryl sulfamidates (1) and subsequent intramolecular cyclization are described. This reaction serves as a method for the direct and stereoselective synthesis of 1,3-disubstituted isoindolines (3) starting with enantiomerically enriched 4-aryl cyclic sulfamidates. In this process, the configurational integrity of the stereogenic center in the starting cyclic sulfamidate is completely retained. In addition, the process generates trans-1,3-disubstituted isoindolines exclusively.

  18. Tandem Rh-Catalyzed Oxidative C-H Olefination and Cyclization of Enantiomerically Enriched Benzo-1,3-Sulfamidates: Stereoselective Synthesis of trans-1,3-Disubstituted Isoindolines.

    Science.gov (United States)

    Achary, Raghavendra; Jung, In-A; Lee, Hyeon-Kyu

    2018-04-06

    A tandem process, involving Rh(III)-catalyzed oxidative C-H olefination of enantiomerically enriched 4-aryl-benzo-1,3-sulfamidates and subsequent intramolecular aza-Michael cyclization has been developed. The reaction produces trans-benzosulfamidate-fused-1,3-disubstituted isoindolines as major products, in which the configurational integrity of the stereogenic center in the starting material is preserved. Further transformations of the benzosulfamidate-fused-1,3-disubstituted isoindolines are described.

  19. Cyclic α-Alkoxyphosphonium Salts from (2-(Diphenylphosphino)phenyl)methanol and Aldehydes and Their Application in Synthesis of Vinyl Ethers and Ketones via Wittig Olefination.

    Science.gov (United States)

    Huang, Wenhua; Rong, Hong-Ying; Xu, Jie

    2015-07-02

    Cyclic α-alkoxyphosphonium salts have been synthesized from (2-(diphenylphosphino)phenyl)methanol and aldehydes in 36-89% yields. These phosphonium salts are bench-stable solids and undergo Wittig olefination with aldehydes under basic conditions (K2CO3 or t-BuOK) to form benzylic vinyl ethers, which are readily hydrolyzed to 1,2-disubstituted ethanones under acidic conditions. The formation mechanism of these phosphonium salts via hemiacetal is also proposed.

  20. Immobilization of Ag(i) into a metal-organic framework with -SO3H sites for highly selective olefin-paraffin separation at room temperature.

    Science.gov (United States)

    Chang, Ganggang; Huang, Minhui; Su, Ye; Xing, Huabin; Su, Baogen; Zhang, Zhiguo; Yang, Qiwei; Yang, Yiwen; Ren, Qilong; Bao, Zongbi; Chen, Banglin

    2015-02-18

    Introduction of Ag(i) ions into a sulfonic acid functionalized MOF ((Cr)-MIL-101-SO3H) significantly enhances its interactions with olefin double bonds, leading to its much higher selectivities for the separation of C2H4-C2H6 and C3H6-C3H8 at room temperature over the original (Cr)-MIL-101-SO3H and other adsorbents at room temperature.