TILLVARATAGANDE AV DIMETYLETER UR OLEFINISKA C3-C5-FLOEDEN I VAETSKEFAS

Feedstocks of olefinic hydrocarbons having from three to five carbon atoms which contain dimethyl ether impurity in amounts of from 1 to 5000 ppm (wt.) are purified in the liquid phase by contact with an adsorbent comprising a crystalline zeolitic molecular sieve having the faujasite crystal structure. It have been found that contrary to expectations based on prior observations of the catalytic properties of synthetic faujasites, the faujasite adsorbents are significantly more resistant toward coking and consequent deactivation than are zeolite adsorbents having smaller pore diameters. The invention is particularly beneficial when utilized as an adjunct to the process for preparing alkyl tertiary alkyl ethers by the reaction of a primary alcohol such as methanol with C4-5 tertiary olefins such as isobutylene in admixture with other non-reactive olefins and paraffins.