| abstract |
It is an object of the present invention, when producing a dialkyl carbonate and a diol industrially in a large amount (e.g. not less than 2 ton / hr for the dialkyl carbonate and not less than 1.3 ton / hr for the diol) through a reactive distillation system of taking a cyclic carbonate and an aliphatic monohydric alcohol as starting materials, continuously feeding the starting materials into a continuous multi-stage distillation column in which a catalyst is present, and carrying out reaction and distillation simultaneously in the column, is to provide a specific process that enables the dialkyl carbonate and the diol to be produced each with high selectivity and high productivity 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), and moreover enables the dialkyl carbonate produced to be separated out and purified stably for a prolonged period of time with high efficiency . It has been discovered that by carrying out reactive distillation using a continuous multi-stage distillation column A having a specified structure, and subjecting a column top component A T thus obtained to separation by distillation using a continuous multi-stage distillation column B having a specified structure, a dialkyl carbonate of high purity (e.g. not less than 97%, preferably not less than 99%, more preferably not less than 99.9%, yet more preferably not less than 99.99%) and a diol can be produced each with a high selectivity of not less than 95%, preferably not less than 97%, more preferably not less than 99%, 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, for the dialkyl carbonate, and not less than 1.3 ton / hr, preferably not less than 1.95 ton / hr, more preferably not less than 2.6 ton / hr, for the diol, 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, from a cyclic carbonate and an aliphatic monohydric alcohol. |