| 摘要 |
It is an object of the present invention to provide a specific apparatus and process for using a single distillation column on a low boiling point reaction mixture containing a large amount of a dialkyl carbonate and an aliphatic monohydric alcohol produced through a reactive distillation process of taking a cyclic carbonate and the aliphatic monohydric alcohol as starting materials, continuously feeding the starting materials into a continuous multi-stage distillation column in which a homogeneous catalyst is present, and carrying out reaction and distillation simultaneously in the column, so as to separate the low boiling point reaction mixture by distillation into a column top component B T having the aliphatic monohydric alcohol as a main component thereof and a column bottom component B B having the dialkyl carbonate as a main component thereof stably for a prolonged period of time industrially. Moreover, it is an object to provide such a specific apparatus and process that are inexpensive and enable the dialkyl carbonate to be separated out by distillation in an amount of, for example, not less than 2 ton / hr stably for a prolonged period of time (e.g. not less than 1000 hours, preferably not less than 3000 hours, more preferably not less than 5000 hours). It has been discovered that by using a single continuous multi-stage distillation column having a specified structure, from out of a dialkyl carbonate and a diol produced through a reactive distillation system from a cyclic carbonate and an aliphatic monohydric alcohol, a high-purity dialkyl carbonate of purity not less than 97%, preferably not less than 99%, more preferably not less than 99.9%, can be separated out by distillation on an industrial scale of not less than 2 ton / hr, preferably not less than 3 ton / hr, more preferably not less than 4 ton / hr, with a high yield stably for a prolonged period of time of not less than 1000 hours, preferably not less than 3000 hours, more preferably not less than 5000 hours. |
