Process for the production of ethyl tert.-alkyl ethers

A cyclic process for preparing ethyl tert.-alkyl ethers comprising the steps:

• a) contacting and reacting in a reaction zone, preferably in the liquid phase, a reaction mixture formed by combining a feedstream comprising hydrocarbons having from 4 to 5 carbon atoms and containing isoalkene with a near stoichiometric ratio of ethanol with respect to said isoalkene to produce a reaction product effluent comprising ethyl tert.-alkyl ether, at least 10,000 ppm (wt.) unreacted ethanol and unreacted C.sub.4 -C.sub.5 hydrocarbons;
• b) separating the reaction product effluent from the reaction zone in a distillation column to provide an overhead effluent stream comprising unreacted ethanol and unreacted C.sub.4 -C.sub.5 hydrocarbons and a bottoms effluent stream comprising ethyl tert.-alkyl ether and unreacted ethanol;
• c) passing the bottoms effluent stream to an adsorption zone containing a selective adsorbent to adsorb ethanol and recovering an ether product stream comprising substantially pure ethyl tert.-alkyl ether;
• and
• d) regenerating the selective adsorbent with a regenerant stream to recover ethanol and to provide a recycle stream comprising ethanol, and returning said recycle stream to said reaction zone.