S-Acylation of aliphatic and aromatic thiols with carboxylic acids and their esters over solid acid catalysts in the gas phase at temperatures above 200°C
Benzenethiol is reacted with acetic acid in a hydrogen stream over [(Mo6Cl8)Cl4(H2O)2]·6H2O. Catalytic activity of the clusters appears above 200 °C, yielding S-phenyl thioacetate. The selectivity is 98% at 300 °C. Niobium, tantalum, and tungsten halideclusters with the same octahedral metal framework also catalyze the reaction. Benzoic acid and aliphatic carboxylic acids afford the corresponding S-phenyl
Practical and robust method for stereoselective preparations of ketene silyl (thio)acetal derivatives and NaOH-catalyzed crossed-Claisen condensation between ketene silyl acetals and methyl esters
NaHMDS–2TMSCl). The first catalytic NaOH-catalyzed crossed-Claisen condensation between ketenesilylacetals and methyl esters proceeded successfully to give a variety of α-monomethyl β-ketoesters and inaccessible α,α-disubstituted β-ketoesters. For further extension, a couple of Claisen-aldol tandem reactions of the obtained β-ketoester analogues utilizing TiCl4 and TiCl4–Bu3N reagents smoothly proceeded
Alkylthiopropionic pentaerythritol esters and solvent refining thereof
申请人:Witco Corporation
公开号:US05055606A1
公开(公告)日:1991-10-08
3-alkylthiopropionic acids which are esterified with pentaerythritol are provided. The esters are solvent refined with especially effective organic solvent blends. Tetraesters thus processed are especially useful as stabilizers for polymer resins and polymers.
3-alkylthiopropionic acids which are esterified with pentaerythritol are provided. The esters are solvent refined with especially effective solvent blends of at least two organic solvents e.g. a short chain alcohol and a short chain ester. This favours purification of the tetraester. Tetraesters thus processed are especially useful as stabilizers for polymer resins and polymers.
3-alkylthiopropionic acids are provided which are a direct addition reaction product of an alkylmercaptan and acrylic acid or an alkali metal salt thereof, the reaction being carried out by heating the reactants in the presence of an aqueous alkaline solution having a pH of at least about 11. The acids can be esterified with pentaerythritol in order to form tetraesters which are especially useful as stabilizers for polymer resins and polymers.