Investigation of dimethyl ether as an initiator in the conversion of methanol to gasoline process using H-ZSM-5

CHED 993

William M. Aumiller Jr., and Paul D. Schettler Jr., Department of Chemistry, Juniata College, Box 1055, 1700 Moore St., Huntingdon, PA 16652
The zeolite H-ZSM-5 has been studied extensively as a possible catalyst for the industrial conversion of methanol to hydrocarbons (MTH). A motivating factor for the academic interest in MTH is that the conversion to hydrocarbons is accompanied by several problems. These include the presence of an initiation period and the presence of some unwanted hydrocarbons (such as benzene) in the product. It is well understood that the first step for the conversion is an equilibrium between methanol, water and dimethyl ether. The establishment of this equilibrium is essential because it coats the pores of H-ZSM-5 and allows the conversion to take place. Recent studies have shown that hydrocarbons can be formed from dimethyl ether alone. This study focuses on the characteristics of the initiation step as a function of the pretreatment of the catalyst. In particular, we have examined the effect of pretreatment of H-ZSM-5 by dimethyl ether.