Direct prepn. of di:methyl ether - from synthesis gas with controllable purity, useful for aerosols or for domestic and industrial heating

摘要

The direct prodn. of dimethyl ether (I) from synthesis gas in high yield and controllable purity is claimed by gas reaction of H2/CO/CO2 mixts. at 1-10 MPa and 200-300 deg.C. with catalyst mixts. consisting of a methanol forming component and a dehydrating component. (I) together with CO2 are washed from the product gas arising from the synthesis step using a wash liq. after sepn. of the liq. reaction prods. at synthesis pressure and are recovered in a subsequent desportion step at an intermediate pressure between the synthesis pressure and the pressure of the first sepn. column. The resulting (I) contg. CO2 is either sepd. or fed together with the liq. reaction prod. to the first sepg. column of a 3 stage column system where another wash liq. is fed in a counter current fashion and CO2 and has boiling components including an amt. of (I) are taken off overhead. (I) is then produced to the desired purity by means of a second distillation column. USE/ADVANTAGE - The process allows the direct prodn. of (I) from synethesis gas in a simple and cost effective manner with high yield and controllable purity. (I) is a substitute for fluorochlorocarbons in aerosols and as a liquified gas for domestic and industrial use.