Method for preparing dialkyloxydianhyrohexitol by etherification of dianhydrohexitol using light alcohol, in presence of acidic catalyst

The present invention relates to a method for preparing a dialkyloxydianhyrohexitol (dimethylisosorbide) composition by etherification of dianhydrohexitol (isosorbide). The aim of the invention is to achieve a ''clean'' method that avoids the use of a methylation agent such as dimethyl sulfate or methyl chloride, which generate stoechiometric quantities of salts, or expensive dialkyl-carbonates, wherein only one of the two methyl groups participates in the preparation of mixed isosorbide ethers. Said 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 Bronsted acid properties. The present invention further relates to a device for carrying out the method according to at least one of the previous claims, characterized in that said device includes a vaporization oven and a reaction oven.