Cyclic carbonate preparation useful for preparing lacquer raw material

摘要

Preparation of cyclic carbonates of formula (I) involves ester exchange of propan-1,3-diol compounds of formula (II) with carbonate esters of formula (III), with elimination of R<3>OH, and distillative depolymerisation of the resultant oligo- or polycarbonates to (I). 50-100% Distillation residue from depolymerisation is recycled to the ester exchange reaction. (HO-CH2)C(R)(R<1>) (II) (R<3>O)C=O (III) R, R<1> = hydrogen, 1-6 C alkyl, 3-7 C cycloalkyl or -CH2-OR<2>; R<2> = H, 1-4 C alkyl, (meth)allyl or benzyl; or 2 R<2> groups together are -CH2-, -CH(CH3)-, -CH(C2H5)-, -CH(C6H5)- or -CH(C3H7)-; or CRR<1> is a cyclopentane, cyclohexane, oxetane or cycloheptane ring.