GB1000504A - Improvements in and relating to polymerization - Google Patents

Abstract

A catalyst for polymerizing mono-unsaturated alpha-olefines comprises the reaction product of a poly(hydrocarbylaluminium oxide) containing units represented by <FORM:1000504/C3/1> where R is an alkyl or aryl radical and a compound of a Group IVA, VA or VIA transition metal preferably represented by the formula MXn, where M is the transition metal, X represents a halogen atom or an organic group and n is the valence state of the transition metal. Preferably, a compound of a Group IA, IIA or IIIB metal having the formula MeR11x, where R11 represents an alkyl radical containing 1 to 12 carbon atoms, an aryl radical or a halogen or hydrogen atom, Me is the Group IA, IIA or IIIB metal and x is an integer corresponding to the valance of the metal is also present. The mole ratio of the transition metal in MXn to the aluminium in the poly(hydrocarbylaluminium oxide) is from 1 : 30 to 1 : 800. The poly (hydrocarbylaluminium oxides) are prepared by reacting an organo hydrocarbylaluminium compound having the formula R-Al-R12 with water, where R is as above and R1 represents an alkyl radical containing 1 to 12 carbon atoms, an aryl radical or a hydrogen atom and " hydrocarbyl " means a saturated alkyl or aryl radical. The reaction of water with the hydrocarbylaluminium compound is preferably carried out by adding water to a solution of the hydrocarbylaluminium compound in an anhydrous, inert, organic solvent; the concentration of the aluminium compound varying from 5% to 75% by weight. Suitable organic solvents include saturated aliphatic compounds, cycloaliphatic compounds and aromatic solvents, e.g. benzene. Hydrocarbylaluminium compounds mentioned are trialkyl and triaryl-aluminium compounds, dialkylaluminium hydrides and monoalkylaluminium dihydrides. The amount of water added to the aluminium compound may be varied from 0.25 mole to 1.25 moles of water per mole of hydrocarbylaluminium compound and the temperature is from 0 DEG to 100 DEG C. Examples illustrate the polymerization of ethylene- 4-methyl-1-pentene and butene-1 and the copolymerization of ethylene and butene-1, the polymerization being carried out at temperatures of from -10 DEG to 100 DEG C. and pressures from subatmospheric to superatmospheric, Preferably the catalyst mixture is prepared by producing the poly(hydrocarbylaluminium oxide) in a concentrated solution, taking a portion of this reaction mixture and further diluting it with diluent, adding the compound MXn and then adding to this mixture the compound MeR11x. Hydrogen may be present in the polymerization to lower the average molecular weight of the polymer formed.