AbstractKinetic measurements have been made on the polymerization of ethylene to low molecular weight products using a soluble catalyst formed by the interaction ofsec‐butyl titanate and aluminum triethyl. A maximum in catalyst activity occured at ratio Al:Ti = 2.5:1 and a scheme is proposed to explain this observation. An interesting feature of the polymerization is the existence of a well‐defined cut‐off pressure of ethylene below which no polymerization occ