CATALYTIC TRIMERIZATION AND TETRAMERIZATION OF OLEFINIC MONOMERS

摘要

A catalyst precursor composition comprising a) a source of chromium, molybdenum or tungsten; b) a first ligand having the general formula (I); (R¹)(R²)P-X-P(R³)(R⁴) (I) wherein X is a bivalent organic bridging group; R¹ and R³ are independently selected from, hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl and substituted heterohydrocarbyl groups, with the proviso that when R¹ and R³ are aromatic groups they do not contain a polar substituent at any of the ortho-positions; R² and R⁴ are independently selected from optionally substituted aromatic groups, each R² and R⁴ bearing a polar substituent on at least one of the ortho-positions; and c) a second ligand having the general formula (II); (R^1')(R^2')P-X'-P(R^3')(R^4') (II) wherein X' is a bridging group of the formula -N(R^5')-, wherein R^5' is selected from hydrogen, a hydrocarbyl group, a substituted hydrocarbyl group, a heterohydrocarbyl group, a substituted heterohydrocarbyl group, a silyl group or derivative thereof; and R^1', R^2', R^3' and R^4' are independently selected from hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl and substituted heterohydrocarbyl groups of which at least one of R^1', R^2', R^3' and R^4' is substituted with a polar substituent, or R^1', R^2', R^3' and R^4' are independently selected from hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl and substituted heterohydrocarbyl groups, wherein any substituents on one or more of R^1', R^2', R^3' and R^4' are non-polar. The present invention also relates to a catalyst system comprising the catalyst precursor composition of the present invention and a cocatalyst.