Normal olefins such as n-butenes can be converted to iso olefins such as isobutylene by skeletal isomerization over catalysts of boron-beta zeolites having pore sizes of at least about 5 Angstroms and containing boron in the framework structure thereof. The boron-beta zeoliteS have sufficient acidity to catalyze the skeletal isomerization of normal olefinsto iso-olefins. The catalysts can be used to produce iso-olefins for reaction with alcohols in integrated processes to produce alkyl tertiary alkyl ethers such as MTBE.
