Alkylate is produced by catalytically converting oxygenate feedstock, such as methanol, to lower olefins comprising C.sub.2 -C.sub.4 olefins. Ethene is separated by interstage sorption of C.sub.3 + components and an isoparaffin is alkylated with C.sub.3 -C.sub.4 olefins.The improved technique comprises fractionating an olefinic feedstream containing ethene and C.sub.3 + olefinic components by contacting the olefinic feedstream in a sorption zone with a liquid hydrocarbon sorbent to selectively sorb C.sub.3 + components; reacting C.sub.3 + olefins with excess isoparaffin in a catalytic alkylation reactor to produce C.sub.7 + alkylate hydrocarbons; fractionating the alkylation reactor effluent to provide a liquid hydrocarbon fraction rich in C.sub.4 + isoparaffin for recycle to the sorption zone as lean sorbent; and recovering C.sub.7 + alkylate product from the process.