Abstract: This invention provides a process for isolating and recovering butene-1 of high purity at high yield. Firstly, a butane-butene fraction containing 0.1 to 7 wt % of isobutylene, 10 to 50 wt % of butene-1 and 5 to 20 wt % of isobutane is rectified to reduce the content of isobutane to not more than 0.1 wt %. Then, the rectified butane-butene fraction is passed through a reactor packed with an extrusion molded silica-alumina catalyst to polymerize isobutylene at a reaction velocity as high as 50 times or more of that of butene-1, thus forming oligomers of isobutylene. Finally, the hydrocarbon mixture from the reactor is rectified to remove the oligomers of isobutylene and the other C.sub.4 -hydrocarbons.

Abstract: A process for isolating and recovering butene-1 of high purity at a high yield is provided. The process comprises the steps of continuously passing a butane-butene fraction containing 0.1 to 15 wt % of isobutylene and 10 to 50 wt % of butene-1 through a first reactor packed with a strongly acidic cation exchange resin having an average particle size of from 0.2 to 10 mm at a temperature of from 30.degree. to 100.degree. C. and at a space velocity of liquid of from 0.1 to 50 hr.sup.-1 under a pressure of from 1 to 50 atm., dividing the output mixture flowing out of said first reactor into two flows at a division ratio in flow rate of 1.about.15:1, recirculating the first flow having the flow rate of 1.about.