Process for producing ethers by reacting olefins with alcohols

Claim 1

In a process for manufacturing ethers by contacting a mixture of at least one olefin having a double bond on a tertiary carbon atom and at least one alcohol with a sulfonated ion exchange resin catalyst in the acid form, the improvement comprising passing a liquid mixture of fresh reactants comprising said at least one olefin and said at least one alcohol, together with a liquid recycle stream as hereinafter defined at a feed rate of from 0.1 to 15 times the feed rate of the fresh reactants, upwardly through a first reaction zone containing a catalyst bed of particles of said sulfonated ion exchange resin in the acid form, at a temperature of from 60° to 120° C., said temperature being lower than the boiling temperature of the constituent of highest volatility in the mixture passing through the first reaction zone at the selected pressure, while maintaining a feed rate which is sufficient to expand the volume of said catalyst bed by at least 2% and to disperse the catalyst particles therein but insufficient to carry a substantial proportion of catalyst out of said first reaction zone, the contact time being selected to convert from 60 to 95% of said olefin; discharging the liquid product mixture formed in the first reaction zone, cooling a first portion thereof, and recycling the cooled portion to the first reaction zone as said liquid recycle stream, and feeding a second portion of said liquid product mixture to a second reaction zone containing a fixed bed of said sulfonated ion exchange resin catalyst in the acid form, at a temperature of from 30° to 70° C., the temperature in the second zone being at least 10° C. lower than the outlet temperature of the first reaction zone and lower than the boiling temperature of the constituent of highest volatility in the mixture passing through the second reaction zone at the selected pressure.