Method for preparing a dialkyl carbonate of dianhydrohexitol

Abstract

The present invention relates to a method for preparing dialkyl carbonates of dianhydrohexitol, said method including the following steps: (a) preparing an initial reaction mixture containing at least one dianhydrohexitol, at least two mole equivalents of a dialkyl carbonate of formula and a transesterification catalyst; (b) heating the reaction mixture to a temperature greater than or equal to the boiling temperature of the formed alcohol, or of the azeotrope thereof, in a reaction chamber preferably provided with a rectification column comprising a sufficient number of theoretical distillation plates to separate the resulting alcohol from the reaction mixture. The invention also relates to certain dialkyl carbonates of dianhydrohexitols produced by said method and to the use thereof for synthesising synthetic polymers.

Description

technical field

[0001] The present invention relates to a novel process for the preparation of 1,4:3,6-dianhydrohexitol bis(alkyl carbonates), to certain novel dialkyl carbonates obtained by this process and to these dianhydro Hexitol bis(alkyl carbonates) are used in the preparation of synthetic polymers, especially as (co)monomers for the synthesis of polycarbonate and polyurethane or as The use of chain extenders of the molecular weight of the reactive end group) that reacts with the carbonate functional group. Background technique

[0002] Polycarbonates are amorphous thermoplastic materials conventionally obtained by polycondensation of diols with diphenyl carbonate, phosgene or chloromethyl chloroformate.

[0003] The toxicity of phosgene, chloromethyl chloroformate or phenol which is inevitably formed in the event of the use of diphenyl carbonate constitutes a major disadvantage in the synthesis of polycarbonates.

[0004] In the face of the depletion of fossil reso...

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