METHOD FOR PREPARING DIALKYLOXYDIANHYROHEXITOL BY ETHERIFICATION OF DIANHYDROHEXITOL USING A LIGHT ALCOHOL, IN THE PRESENCE OF AN ACIDIC CATALYST

摘要

A method for preparing a dialkyloxydianhyrohexitol (dimethylisosorbide) composition by etherification of dianhydrohexitol (isosorbide). The aim is to achieve a “clean” method that avoids the use of a methylation agent such as dimethyl sulfate or methyl chloride, which generates stoechiometric quantities of salts, or expensive dialkyl-carbonates, wherein only one of the two methyl groups participates in the preparation of mixed isosorbide ethers. The method involves using at least one O-alkylation agent and a catalyst including an acid or an acid salt, preferably a catalyst having Lewis or BrØnsted acid properties. A device for carrying out the method wherein the device includes a vaporization oven and a reaction oven is also described.

主权项

1. A method for preparing a composition based on dialkyloxydianhydrohexitols by etherification of dianhydrohexitols with at least one O-alkylating agent, in the presence of a solid catalyst, preferably a catalyst exhibiting Lewis acid or Brønsted acid properties, and wherein the etherification agent is selected from the group comprising, and better still consisting of:
alcohols, preferably linear or branched aliphatic alcohols and, more preferably still, C1-C20 alcohols, better still methanol, ethanol, isopropanol or tert-butanol, methanol being particularly preferred, olefinic precursors of these alcohols, and mixtures thereof.