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

The conversion of alcohols, ethers, and carbonyl compounds using zeolite 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 this reaction, whereas zeolite Y is much less active. Zeolite beta gives isobutane as the major product from methanol conversion under all reaction conditions tested, together with significant selectivities to C2 and C3 hydrocarbons. The conversions of ethanol and propanol over zeolite 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 reactions typified by ZSM-5 for alcohol conversion reactions. The high selectivity to iso-C4 hydrocarbons is also found for zeolite beta for the conversion of acetone and acetic acid. The results are discussed in terms of the possible mechanisms for the formation of iso-C4 hydrocarbons in high selectivity for zeolite beta. (C) 1994 Academic Press, Inc.