- Synthesis of higher vinyl esters from ethylene and higher carboxylic acids
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A homogeneous liquid phase process for producing a vinyl carboxylate in which the carboxylate group contains at least four carbon atoms, which process comprises (1) forming a homogeneous liquid reaction mixture containing ethylene, oxygen carboxylic acid having at least three carbon atoms, a palladium (II) catalyst and a copper (II) oxidant and (2) maintaining the reaction mixture under conditions at which the ethylene and the carboxylic acid react to form the vinyl carboxylate in the homogeneous liquid reaction mixture, with the proviso that at least one of the following conditions exists during said process: (i) the copper (II) oxidant is a copper (II) carboxylate in which carboxylate group has a molecular weight that is higher than the molecular weight of the carboxylate group in the carboxylic acid; (ii) the palladium (II) catalyst is formed in situ in the reaction mixture by the oxidation of a palladium (0) colloid; and/or (iii) the reaction mixture also contains a polyglyme compound as a promoter.
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- Enzymes in Organic Synthesis. 4. Investigation of the Pancreatin-Catalyzed Acylation of cis-Cyclopent-2-ene-1,4-diol with Various Trichloroethyl and Vinyl Alkanoates
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During the pancreatin-catalyzed acetylation of the meso-diol 1 with 2,2,2-trichloroethyl acetate (2a) in tetrahydrofuran/triethylamine, the enantiomeric monoacetates 3a and ent-3a are formed at nearly equal rates. ent-3a is rapidly acetylated in a second enzyme-catalyzed step, forming 4a, whereas 3a resists further enzymatic acetylation.Thus, the monoacetate 3a can be obtained in 48 percent yield with an enantiomeric excess (e.e.) of more than 99 percent. 2,2,2-Trichloroethyl propanoate and butanoate give the corresponding monoacylation products even in slightly better yields, whereas the octanoate affords the monoacylation product with a lower enantiomeric excess. 2,2,2-Trichloroethyl monochloroacetate provides the monoacylation product in a 40 percent yield with an e.e. of 90 percent.The dichloroacetate, however, affords the diacylation product exclusively in an enzyme-independent chemical reaction.With the 2,2,2-trichloroethyl esters of isobutyric, phenylacetic, and benzoic acid no transesterification could be achieved within 24 hours.The application of vinyl acetate, however, represents a significant improvement in the synthesis of enantiomerically pure monoacetate 3a from meso-diol 1.
- Theil, Fritz,Schick, Hans,Lapitskaya, Margarita A.,Pivnitsky, Kasimir K.
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p. 195 - 200
(2007/10/02)
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- 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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p. 4205 - 4207
(2007/10/05)
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