7757-81-5Relevant articles and documents
Investigations on the catalytic carboxylation of olefins with CO2 towards α,β-unsaturated carboxylic acid salts: characterization of intermediates and ligands as well as substrate effects
Jevtovikj, Ivana,Manzini, Simone,Hanauer, Matthias,Rominger, Frank,Schaub, Thomas
, p. 11083 - 11094 (2015/06/25)
The carboxylation of olefins beyond ethylene towards α,β-unsaturated carboxylic acid salts and a detailed investigation on the critical steps in the catalysis are reported. The influence of two chelating phosphine ligands and several olefins on the elemental steps of the catalysis is shown. The work focusses on the formation of intermediate olefin complexes, lactone formation and base induced elimination of the lactone. The direct carboxylation of olefins is possible using nickel catalysts, which opens a new route towards the desired α,β-unsaturated carboxylic acid salts. The reaction works particularly well for 1,3-dienes and proceeds via the formation of allyl-carboxylates. The ability to form such allyl-type lactone complexes seems in this case to be the most challenging step towards satisfactory turnover numbers.
Processes for producing polyesters and producing sorbic acid
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, (2008/06/13)
The invented process for producing a polyester supplies a crotonaldehyde with a purity of 95% by weight or more to a reaction system in the reaction of ketene with crotonaldehyde. In this process, unreacted crotonaldehyde may be recovered from a reaction mixture obtained by the reaction of ketene with crotonaldehyde and may be recycled to the reaction system. The αvinylcrotonaldehyde content of the crotonaldehyde to be supplied to the reaction system is, for example, less than 0.5% by weight, and the paraldehyde content of the crotonaldehyde to be supplied to the reaction system is, for example, less than 5% by weight. By decomposing the above-prepared polyester with, for example, hydrochloric acid, a sorbic acid having a satisfactory hue can be efficiently obtained.
Process for preparing dienoic acids
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, (2008/06/13)
Dienoic acids are prepared by reaction of salts of 3-butenoic acid and vinyl halides, in the presence of catalysts which are phosphinic complexes of rhodium or nickel.