- A novel synthesis of vinyl esters from vinylversatate-10
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Vinylversatate-10 (VV10)1 1 VV 10 Vinyl Monomer, Development Product, Shell Chemical Company has successfully been used to synthesise a large number of lower vinyl esters by transvinylation in presence of mercuric acetate and sulfuric acid. The synthesis of vinylhalo esters proceeds with more difficulty. It has been observed that neither Hg(OAc)2 nor H2SO4 alone is capable of initiating the transvinylation. Furthermore, it has been found that a molar ratio 2:1 of VV10 to carboxylic acid is sufficient to drive the reaction to the right by continuous distillation of the vinyl ester formed, and as a result a high yield of vinyl ester is obtained. A mechanism for this reaction and for the formation of side products has been proposed.
- Mondal,Van Der Meer,German,Heikens
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- Catalytic pyrolysis of cellulose in ionic liquid [bmim]OTf
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This study discussed the catalytic cracking process of cellulose in ionic liquid 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([bmim]OTF) under 180 °C, 240 °C and 340 °C, found that [bmim]OTF is an effective catalyst which can effectively reduce the pyrolysis temperature(nearly 200 °C) of the cellulose. FRIR, XRD and SEM were used to analyze the structure characterization of fiber before and after the cracking; GC-MS was used for liquid phase products analysis; GC was used to analyze gas phase products. The results showed that the cellulose pyrolysis in [bmim]OTf mainly generated CO2, CO and H2, also generated 2-furfuryl alcohol, 2,5-dimethyl-1,5-diallyl-3-alcohol, 1,4-butyrolactone, 5-methyl furfural, 4-hydroxy butyric acid, vinyl propionate, 1-acetoxyl group-2-butanone, furan formate tetrahydrofuran methyl ester liquid product, and thus simulated the evolution mechanism of cellulose pyrolysis products based on the basic model of cellulose monomer.
- Qu, Guangfei,He, Weiwei,Cai, Yingying,Huang, Xi,Ning, Ping
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p. 390 - 396
(2016/05/19)
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- Ruthenium-catalyzed transvinylation - New insights
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The use of ruthenium complexes in transvinylation catalysis has been well established since the 1980s. However, the reaction mechanism and the active catalyst species, which is presumed to contain ruthenium carbonyl carboxylate entities, have so far remained elusive. In this work the synthesis and characterization of three novel ruthenium complexes comprising ruthenium carbonyl carboxylate structural motifs including two single crystal structures as well as the crystal structures of two known ruthenium complexes are reported. These new complexes and four known ruthenium complexes with appropriate structural motifs were applied in transvinylation catalysis. Mechanistic studies including identification and characterization of the active species, isotope labeling experiments and examination of the regioand stereoselectivity of the transvinylation reaction are presented, resulting in the proposal of a probable reaction mechanism, which is supported by DFT calculations on the B3LYP/6-31G* level of theory.
- Ziriakus, Jennifer,Zimmermann, Teresa K.,P?thig, Alexander,Drees, Markus,Haslinger, Stefan,Jantke, Dominik,Kühn, Fritz E.
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p. 2845 - 2859
(2014/03/21)
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- Oxidative arylation of ethylene with benzene catalyzed by Pd(OAc) 2/heteropoly acid/O2 system
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Oxidative arylation of ethylene with benzene was examined by using a Pd(OAc)2/heteropoly acid/O2 system under mild conditions. The reaction of benzene with ethylene in the presence of catalytic amounts of Pd(OAc)2 combined
- Yamada, Tomoyuki,Sakakura, Aki,Sakaguchi, Satoshi,Obora, Yasushi,Ishii, Yasutaka
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p. 738 - 742
(2008/09/20)
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- Competitive reactivity as a probe for reaction coordinates in gas-phase ion-molecule chemistry
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Using the method of competitive reactivity of two functional groups in the same molecule, anionic elimination reactions show considerable kinetic selectivity for small differences in leaving group thermochemistry, in structures of the general type YCH2CH2CH2Z, where Y and Z are good anionic leaving groups.
- Holman, Robert W.,Sumpter, Terry L.,Farrar, John,Weigel, Kurt,Bartmess, John E.
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p. 585 - 589
(2007/10/03)
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- Poly(vinyl propionate) and Poly(ethyl acrylate) - A Miscible Polymer Pair
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A new miscible polymer pair, viz. poly(vinyl propionate) (PVPr) and poly(ethyl acrylate) (PEA) is reported.Blends of these polymers form clear films, clear solutions in common solvents and have single glass transition temperatures.Miscibility of these two polymers in binary combinations with poly(methyl acrylate) (PMA) or poly(vinyl acetate) PVA was also examined.Differential scanning calorimetry (D.S.C.) reveals that PVPr + PVA, PEA + PVA, PMA + PVPr and PMA + PEA are immiscible, although the first three pairs form clear films.
- Bhattacharyya, C.,Bhattacharyya, S. N.,Mandal, B. M.
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p. 157 - 160
(2007/10/02)
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- Method for the preparation of alkenyl esters of carboxylic acids
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A novel and effective catalyst system is provided for application in the preparation of alkenyl esters of carboxylic acids by transesterification reaction. The catalyst system consists of a palladium compound as the main ingredient and a cocatalyst formed of an alkali metal compound and a copper compound, at least one of which is a halide. The catalyst ingredients are adsorbed on a solid catalyst carrier, so that repeated use of the combined catalyst or a continuous operation of the reaction can easily be facilitated.
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- Acyl Transfer Reactions in the Gas Phase. Ion-Molecule Chemistry of Vinyl Acetate
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An ion cyclotron resonance study of the ion-molecule reactions of vinyl acetate with methanol in the gas phase has revealed the formation of structurally different ions having the composition of protonated vinyl acetate.Deuterium-labeled reactants (CD3CO2CH=CH2 with CH3OH or CD3OD) gave product ions showing incorporation of up to two deuteriums in the vinyl group, indicating coexistence and interconversion of O-protonated and C-protonated vinyl acetate.Evidence was also obtained for a third MH+ ion for which the proposed structure is protonated 3-oxobutanal.This ion is believed to be formed by attack of CH3CO+ at the terminal vinylic carbon with loss of the ester acyl group as ketene.The ion reacts with methanol to give m/z 101 by loss of water.In contrast, protonated vinyl acetate reacts with methanol by an acyl transfer process to give (AcOCH3)H+, m/z 75.The related ion chemistry of vinyl propanoate, vinyl 2,2-dimethylpropanoate, and isopropenyl acetate is also described.Each of the acyl transfer reactions observed is consistent with formation of intermediate acylium ion complexes rather than tetracovalent addition complexes.Attempts were made to generate tetracovalent intermediates by an independent route from ortho esters of vinyl acetate.Dissociation of the ortho ester CH3C(OCH=CH2)2(OCH3) to dioxacarbocations was the dominant reaction, but the product ions were unreactive with H2O, CH3OH, or t-C4H9OH.The mechanistic implications of these results are discussed.
- Kim, Jhong K.,Caserio, Marjorie C.
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p. 4624 - 4629
(2007/10/02)
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- Transesterification of carboxylic acids
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Carboxylic acids may be esterified by reaction with esters in the presence of a catalytic amount of a tin halide catalyst, the reaction being effected at temperatures ranging from about 0° to about 150° C.
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