925-06-4Relevant articles and documents
Esterification of bio-based succinic acid in biphasic systems: Comparison of chemical and biological catalysts
Delhomme, Clara,Goh, Serena L.M.,Kuehn, Fritz E.,Weuster-Botz, Dirk
experimental part, p. 39 - 47 (2012/09/07)
Different chemical and biological catalysts were screened for the biphasic esterification of aqueous solutions of succinic acid with 1-octanol. Among them, DBSA, Nafion NR-50 and Novozym 435 were found to be the most attractive catalysts. The pH, the temperature and the catalyst concentration had high impacts on the reaction rates. The optimization of the reaction conditions with a single-variable approach for the chemical catalysts and a Response Surface Methodology for the enzyme allowed an increase of the rates by a factor 1.5 for DBSA, 2.3 for Nafion NR-50 and 1.3 for Novozym 435. Real fermentation broths produced from recombinant Escherichia coli could be successfully esterified with conversions up to 93% for DBSA and 70% for Nafion NR-50 and Novozym 435 as catalysts. Finally, DBSA was selected as the cheapest and most active option. Besides, the esters were isolated with a purity of 83% from fermentation broth solutions. DBSA also catalyzed the esterification of succinic acid from fermentation broth with many alcohols creating a broad spectrum of interesting esters. The esters might then be used as end-product, hydrolyzed back to pure succinic acid or hydrogenated.
HYDROPHOBIC POLYSACCHARIDES WITH DIESTER- OR CARBONATE ESTER-CONTAINING LINKAGES HAVING ENHANCED DEGRADATION
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, (2010/12/29)
Hydrophobic α(1→4)glucopyranose polymers with enhanced degradation properties are described. Between the α(1→4)glucopyranose polymeric portion and the hydrophobic portion exists a linker portion having a chemistry that facilitates degradation of the polymer. Diester and carbonate ester linker chemistries are exemplified. Biodegradable matrices can be formed from these polymers, and the matrices can be used for the preparation of implantable and injectable medical devices wherein the matrix is capable of degrading in vivo at an increased rate. Matrices including and capable of releasing a bioactive agent in vivo are also described.
Process for preparing diesters of dicarboxylic acids
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, (2008/06/13)
A process for preparing a diester of a dicarboxylic acid having two more carbon atoms than the unsaturated hydrocarbon used as the starting material, which comprises subjecting an unsaturated hydrocarbon, carbon monoxide and an alcohol to reaction in the presence of a platinum group metal or a salt thereof; a compound selected from the group consisting of nitric acid, a nitrogen oxide and an ester of nitrous acid; and a halogen compound.