Patent ID: 7884251
Filing Date: 2011-02-08
Classification: B01D,C07C,Y02P

Abstract:
1. A process for separating out a by-produced alcohol in a case of continuously mass-producing an alkyl aryl carbonate mainly on an industrial scale using a reactive distillation system of continuously feeding a dialkyl carbonate and an aromatic monohydroxy compound into a continuous multi-stage distillation column A in which a catalyst is present and carrying out transesterification reaction and distillation simultaneously in the column A, comprising the steps of continuously withdrawing a low boiling point reaction mixture A T containing 1.5 to 10% by weight of said by-produced alcohol, 50 to 85% by weight of the dialkyl carbonate and 10 to 40% by weight of the aromatic monohydroxy compound from an upper portion of the column in a gaseous form, continuously feeding said low boiling point reaction mixture A T into a continuous multi-stage distillation column B, and carrying out separation by distillation into a low boiling point mixture B T having not less than 90% by weight of said by-produced alcohol and all or most of the remainder of the low boiling point mixture B T being dialkyl carbonate continuously withdrawn from an upper portion of the column in a gaseous form and a high boiling point mixture B B continuously withdrawn from a lower portion of the column in a liquid form, which comprises: said continuous multi-stage distillation column B is a distillation column comprising a stripping section having a length L wherein an amount of said alcohol separated out is not less than 200 kg/hr.