GB723169A - Improvements in or relating to olefin polymerization process - Google Patents

Abstract

Olefine polymers are prepared by polymerizing olefines in the presence of a bulk liquid polymerization catalyst being a mixture of phosphoric acid of 95 to 105 weight per cent concentration and from 20 to 70 per cent by weight of a neutral ester of phosphoric acid based on the total catalyst. Organic phosphates which may be used include those of the general formula <FORM:0723169/IV (b)/1> wherein the Rs represent alkyl, aryl, aralkyl or alkaryl radicals containing 1 to 18 carbon atoms; examples are the tri-esters of phenol, cresol, xylenol, trimethyl phenol, tri-tertiary butyl phenol and tri-propyl phenol. The phosphates may be prepared by reacting aliphatic alcohols, phenol or alkylated phenols with phosphorous pentoxide or with phosphorous oxychloride and removing by-product hydrochloric acid. A preferred catalyst is that obtained by reacting phenol or a mixture of phenols from petroleum with phosphorous oxychloride as above, adding 95-105 per cent phosphoric acid, feeding thereinto an olefine to alkylate the aromatic ring and allowing the catalyst to come to equilibrium at polymerization temperature. The polymerizations are preferably effected at about 200 DEG to 450 DEG F. at a pressure between atmospheric and 1000 p.s.i.g. with an olefine feed rate of about 0.1 to 2.5 vols. of liquid olefine per vol. of catalyst per hour; an emulsifying or dispersing agent may be present to improve contact between olefine and catalyst. Suitable olefine feeds are hydrocarbon feeds containing C3 and C4 olefines by themselves, in mixtures thereof or diluted with C3 and C4 paraffin. The preferred process comprises passing a preheated olefine feed upwards through a heated column containing the catalyst, the column being loaded with inert material such as carbon or porcelain or provided with stirring means; unreacted gas and polymer are removed, normally by distillation, and after separation of unreacted gas, if desired, the polymer is fractionated to recover polymer fractions. Examples describe the polymerization of C3-4 hydrocarbon fractions containing about 47 per cent olefines by means of phosphoric acid and tri-cresyl or tri-xylenyl phosphate mixtures and the improved yields are compared with those using only phosphoric acid or phosphoric acid and mineral oil as catalyst. The polymers may be blended with refinery products to produce motor or aviation gasolines or may be reacted with carbon monoxide and hydrogen to form alcohols or with aromatic hydrocarbons to form detergent alkylates.ALSO:Bulk polymerization catalysts for use in the polymerization of olefines (see Group IV(b)) consist of mixtures of phosphoric acid of 95 to 105 weight per cent concentration and from 20 to 70 per cent by weight of a neutral ester of phosphoric acid based on the total catalyst. Suitable neutral phosphate esters are those having the general formula <FORM:0723169/III/1> wherein the Rs represent alkyl, aryl, alkaryl or aralkyl radicals containing 1-18 carbon atoms, examples being the tri-esters of phenol, cresol, xylenol, tri-methyl phenol, tri-tertiary butyl phenol and tri-propyl phenol. The preferred catalyst is that obtained by reacting phenol or a mixture of phenols obtained from petroleum with phosphorus oxychloride, removing the hydrogen chloride by-product, adding 95-105 per cent phosphoric acid, feeding thereto an olefine to alkylate the aromatic ring and allowing the catalyst to come to equilibrium at polymerization temperatures.