process for the production of indole from aniline and ethylene glycol

摘要

PURPOSE:To suppress the decomposition of ethylene glycol (EG), to prevent the lowering of the yield, and to reduce the amount of aniline to be separated and recovered in the preparation of indole by the vapor phase reaction of aniline with EG, by supplying EG dividedly to the catalyst layer. CONSTITUTION:Indole is prepared by reacting aniline with ethylene glycol in vapor phase in the presence of a catalyst. In the above process, ethylene glycol is supplied dividedly to plural points along the flow of the reaction gas passing through the catalyst layer. In detail, the catalyst layer is divided into several stages, the stages are connected with each other in series, and ethylene glycol is supplied dividedly to each stage. Since the molar ratio of aniline supplied to the reactor can be reduced, the indole concentration at the outlet of the reactor can be increased. As the amount of the aniline to be recovered is reduced, it is not necessary to use a large-sized recovering apparatus and a large amount of energy, and the process is economical.