Reactions of ethanol over HZSM-5

The conversion of ethanol to hydrocarbons was studied over a series of HZSM-5 zeolites with varying concentrations of strong Brönsted acid sites. While ethanol was found to be converted completely over all catalysts above 573 K, formation of higher hydrocarbons only occurred to a significant extent with zeolites having more than one proton per unit cell. The higher concentration of adsorbed species and hence the smaller distance between adsorbed molecules was concluded to cause this enhancement in activity. The rate of coke formation was found to be proportional to the rate of formation of aromatic hydrocarbons.