Patent ID: 8093437
Filing Date: 2012-01-10
Classification: B01D,C07C,Y02P

Abstract:
1. In an industrial process for the production of a diol in which a diol is produced by taking a cyclic carbonate and an aliphatic monohydric alcohol as starting materials, continuously feeding the starting materials into a continuous multi-stage distillation column A in which a catalyst is present, carrying out reactive distillation in said column A, continuously withdrawing a low boiling point reaction mixture A T containing a produced dialkyl carbonate and said aliphatic monohydric alcohol from an upper portion of the column A in a gaseous form, continuously withdrawing a high boiling point reaction mixture A B containing a produced diol from a lower portion of the column A in a liquid form, then continuously feeding said high boiling point reaction mixture A B into a continuous multi-stage distillation column C for separating off material having a lower boiling point than that of the diol contained in said high boiling point reaction mixture A B , continuously obtaining the material having a lower boiling point than the diol as a column top component C T and a side cut component C S , and continuously obtaining the diol substantially not containing the material having a lower boiling point than that of the diol as a column bottom component C B , wherein the improvement comprises: (a) said continuous multi-stage distillation column C comprises a continuous multi-stage distillation column comprising a stripping section having a length L (b) the enrichment section of said continuous multi-stage distillation column C has at least one chimney tray installed therein as an internal, said chimney tray having installed therein one or more chimneys each having an opening having a cross-sectional area S (cm and each of the chimneys being such that a height h (cm) from said opening of said chimney to a gas outlet of said chimney satisfies the formula (II): (c) a side cut outlet is connected to a liquid collecting portion of said chimney tray of said continuous multi-stage distillation column C.