Patent ID: 8338631

Claim:
A process for continuously preparing a dialkyl carbonate of formula (I) (R 1 O) 2 CO (I) wherein R 1 is straight-chain or branched C 1 -C 4 alkyl group, and an alkylene glycol of formula (II) R 2 (OH) 2 (II) wherein R 2 is a C 2 -C 4 -alkyl group, as by-product comprising reacting a cyclic alkylene carbonate having the following formula: wherein R 2 is a C 2 -C 4 -alkyl group, with an alcohol of formula (III) R 1 OH (III) wherein R 1 is straight-chain or branched C 1 -C 4 alkyl group, in the presence of a catalyst, wherein said reaction is carried out in countercurrent in a column, wherein said reaction comprises the steps of (A) introducing said cyclic alkylene carbonate as a stream into the upper part of said column at point (1), (B) introducing said alcohol of formula (III), which comprises said dialkyl carbonate of formula (I), as a stream into the middle or lower part of said column at point (3), and (C) introducing a stream comprising said alcohol of formula (III) as a stream into said column at a point (4) on said column below point (3), wherein the ratio of the spacing between point (1) and point (3) to the spacing between point (1) and point (4) is in the range of from 0.20 to 0.52.