PROCESS FOR THE PRODUCTION OF DIMETHYL ETHER USEFUL AS A PROPELLANT

摘要

A process for producing dimethyl ether useful as a propellant by dehydrating methanol and recovering dimethyl ether from the dehydrated product by distillation, which comprises (A) a reaction step wherein the dehydration reaction of methanol is conducted in a vapour phase under pressure of from 2 to 50 kg/cm2G in the presence of a solid acid catalyst, (B) a first distillation step wherein the reaction mixture formed by the above reaction step is cooled and introduced into a pressurized distillation column under pressure of at least 5 kg/cm2G; refined dimethyl ether is obtained as a side stream; substance having a boiling point lower than that of dimethyl ether is distilled from the top; and the bottom is withdrawn, and (C) a second distillation step wherein said bottom is introduced into a second distillation column under pressure lower than the pressure of the pressurized distillation column; unreacted methanol is recovered as a side stream from the second distillation column; substance having a boiling point lower than that of methanol is distilled from the top; and the bottom is withdrawn, whereby (D) the unreacted methanol recovered from the second distillation step is recycled to the reaction step.