an improved process is disclosed for the conversion of hydrocarbons , using a catalyst comprising a non - zeolitic molecular sieve which has been activity - moderated by controlled carbon deposition . it is of particular interest in skeletal isomerization to increase the proportion of olefins containing tertiary carbons in the product with low formation of undesirable by - products . controlled carbon deposition increases selectivity to the desired olefin isomers . product olefins may be further processed to obtain ethers , which enjoy high current interest as components for reformulated gasoline .