THE CONVERSION OF METHANOL AND OTHER O-COMPOUNDS TO HYDROCARBONS OVERZEOLITE-BETA

The conversion of alcohols, ethers, and carbonyl compounds using zeoli te beta, zeolite ZSM-5, and zeolite Y are compared and contrasted. The proton form of zeolite beta is found to be as active as H-ZSM-5 for t his reaction, whereas zeolite Y is much less active. Zeolite beta give s isobutane as the major product from methanol conversion under all re action conditions tested, together with significant selectivities to C 2 and C3 hydrocarbons. The conversions of ethanol and propanol over ze olite beta lead to the almost exclusive formation of the corresponding alkene via water elimination. This is in contrast to ZSM-5, and hence zeolite beta does not exhibit the rapid secondary conversion reaction s typified by ZSM-5 for alcohol conversion reactions. The high selecti vity to iso-C4 hydrocarbons is also found for zeolite beta for the con version of acetone and acetic acid. The results are discussed in terms of the possible mechanisms for the formation of iso-C4 hydrocarbons i n high selectivity for zeolite beta. (C) 1994 Academic Press, Inc.