GB1056175A - Improvements in or relating to the production of waxes - Google Patents

Abstract

Waxes are produced by polymerizing ethylene in the presence of a catalyst comprising a compound of the formula AlR2Hal, AlRHal2 or Al2\R3Hal3 in which R is an alkyl or alkoxy group and Hal is halogen, and also comprising a 4.valent titanium halide, the atomic ratio of aluminium to titanium being at least 1:1 with the polymerizate being kept in the fluid state at a temperature between 130 DEG and 240 DEG C. and in the presence of hydrogen in a concentration of up to 70% in the gaseous phase. Polymerization is preferably effected in the presence of an inert non-aromatic organic solvent such as petroleum ether. In the examples the catalyst, which comprises titanium tetrachloride and aluminium diethyl chloride, is heated in petroleum ether under nitrogen before the introduction of ethylene and hydrogen. Small amounts of propylene and/or n-butylene may be copolymerized with the ethylene. In one example the process is continuous. The wax formed is treated with a dilute aqueous sodium hydroxide solution, washed, and then steam distilled to remove the solvent. The waxes may be oxidized with air either before or after removing the catalyst residues, which in the former case may be after treating the wax with sodium hydroxide but before washing out the aluminium and titanium hydroxides so formed. Solutions of the waxes may be cooled to precipitate out high melting point waxes.