Methyl ether prepn. - by di:ethylene glycol or mono:ethylene glycol ether deriv. conversion over supported precious metal catalyst

摘要

Methyl ethers having formula Me-(OCH2CH2)-nO-R (I) (where n is integer 0-9 and R is (cyclo)alkyl or aryl, contg. max. 12-n C) are prepd. by catalytic gas-phase, conversion of diethylene glycol or its higher homologues having formula HO-CH2-CH2-(O-CH2-CH2)n-O-CH2-CH2-OH (II) (where n is 0-8). or of ethers of monoethylene glycol or its homologues having formula HO-CH2-CH2-(O-CH2-CH2)n-O-R (III) (where n is 0-9) in the presence of H2 at 250-500 degrees C. Catalyst consists of a support coated with Pd, Pt, Ru, Rh, and/or Ir, applied as a cpd. Process selectivity and yields are high. The catalysts have a long service-life. (I), esp. the diethers of ethylene glycol, are used as solvents. Mixts. of ethylene glycol dimethyl ethers are used for purifying natural gas. Ethylene glycol Me alkyl ethers are used as entrainers in distn. processes. Me aryl ethers e.g. anisole, are used as synthesis intermediates.