A process for producing an ethylbenzene product having a purity of at least 99.50 percent based on the weight of ethylbenzene present in the product by the ethylation of the benzene present in non-extracted feed, e.g., non-extracted hydrocarbon composition. The non-extracted feed is substantially free of both C.sub.4- hydrocarbons and the C.sub.7+ aromatic hydrocarbons and contains benzene and benzene coboilers. The process is carried out in the liquid phase, in the presence of an acid-active catalyst containing MCM-22 family molecular sieve, and under specified conditions.