Ethylbenzene is produced by the catalytic alkylation of benzene with ethylene, or from mixed xylenes by isomer separation and catalytic isomerisation, or from 1,3-butadiene in a two-step process where the butadiene is converted to vinylcyclohexane which is then dehydrogenated.
Nearly all commercial ethylbenzene is produced by alkylation of benzene with ethylene. Earlier processes were based on liquid phase alkylation using an aluminium chloride catalyst but this route required disposal of aluminium chloride waste.
In the early 1980s, Mobil/Badger developed an alternative zeolite-based process using vapour phase alkylation, offering higher yields and purity. More recently, liquid phase processes using zeolite catalysts have been introduced. These latest technologies offer low benzene-to-ethylene ratios, which reduces the size of equipment, and lowers the production of byproducts.
Dow Chemical and Snamprogetti are developing a process for making ethylbenzene/styrene from ethane and benzene. The process combines the dehydrogenation of ethane and ethylbenzene in one unit and integrates the processes for preparing ethylene, ethylbenzene and styrene. This process is claimed to have lower costs than the conventional route to styrene, largely stemming from the low cost of ethane in relation to ethylene. A pilot plant has been operating since 2002 and commercialisation could be possible by the end of the decade.