Catalysts[edit]
The reaction is catalyzed by metal complexes. Traditional catalysts are prepared by a reaction of the metal halides with alkylation agents, for example WCl6–EtOH–EtAlCl2. The traditional, industrial catalysts are ill-defined and used mainly for Petroleum products. Modern catalysts are well-defined organometallic compounds that come in two main categories, commonly known as Schrock catalysts and Grubbs' catalysts. Schrock catalysts are molybdenum(IV)- and tungsten(IV)-based, and are examples of Schrock alkylidenes.[3]