Aromatic from ethylene

A simple approach to make p-xylene from ethylene could help the chemical industry reduce its dependency on crude oil by allowing natural gas or biogas supplies to act as a feedstock. Maurice Brookhart and colleagues at the University of North Carolina at Chapel Hill, USA, have developed a synthetic route from ethylene to the aromatic. First, they form a trimer from ethylene to generate a six-carbon intermediate, which, following dehydrogenation, undergoes a Diels–Alder reaction with an additional ethylene molecule to form 3,6-dimethylcyclohexene. Catalytic dehydrogenation of this with platinum over alumina yields a good supply of p-xylene with minimal by-products.