A continuous process for the preparation of phenyl methyl carbonate starting from phenol, dimethyl carbonate and a transesterification catalyst, which comprises:
- (a) carrying out the process in a first distillation column consisting of a lower reactive section and an upper rectification section and in a second rectification column;
- (b) feeding to the top of the reaction section of the first column a stream (I) containing phenol and optionally dimethylcarbonate in a ratio equal to or higher than 60/40 by weight and all of the catalyst;
- feeding to the bottom of the reactive section of the same column a stream (II), comprising a stream or part of a stream (III) extracted from the bottom of the second column, containing dimethylcarbonate and optionally phenol in a ratio equal to or higher than 80/20 by weight;
- the streams (I) and (II) being fed in such a quantity that the ratio between the total moles of dimethylcarbonate and phenol fed ranges from 2:1 and 10:1;
- feeding to the top of the rectification section of the first column a stream (IV) which consists of the reflux of the column, having the composition of a stream (v) taken from the top of the column itself and fed to the second column, in such a quantity that the weight ratio of the reflexed liquid (stream IV) to the distillate (stream V) is within the range of 0.2-0.8;
- c) extracting from the bottom of the reactive section of the first column a stream (VI) essentially containing all the non-reacted phenol, phenyl methyl carbonate and any possible diphenylcarbonate produced, the transesterification catalyst and a fraction of the dimethyl carbonate fed so that the molar ratio in this stream between the dimethylcarbonate and the phenol is between 0.5 and 5;
- extracting from the top of the rectification section of the first column, a stream V, essentially containing dimethylcarbonate and all or basically all of the methanol produced by the reaction;
- d) feeding to an intermediate section of the second column a stream (V) extracted from the top of the first column;
- e) extracting from the top of the second column a stream (VII) containing all or practically all of the methanol fed to the second column and dimethyl carbonate in a ratio of more than 50% by weight;
- extracting from the bottom of the second column a stream (III) essentially consisting of the remaining dimethylcarbonate;
- f) recycling said stream III or part of it to the bottom of the first column.