contain other ingredients which do not adversely affect the quality of the final catalyst but is generally essentially low phosphorus aluminum phosphate it has been found from work with aluminum phosphate that the best polymer properties such as high melt index high density good environmental stress crack resistance escr are obtained using a high p al ratio i e about 0 8 however surface area and pore volume are optimum at a lower p al ratio i e about 0 4 because of sintering at the higher ratios this invention makes it possible to have the good physical stability of a low p al ratio support since the bulk of the support is either pure alumina or low p al ratio aluminum phosphate and still have the good catalytic effect of the high ratio because of the high content of phosphorus on the surface in the case of phosphating a hydrogel it is preferred that after phosphating the water be removed to convert the hydrogel to a xerogel by means of azeotropic distillation or washing with a water miscible liquid any water miscible liquid effective in aiding in removing water can be utilized generally such liquids are relatively volatile oxygen containing organic compounds having relatively low surface tension exemplary classes of such compounds are alcohols ketones and esters particularly suitable are alcohols such as isoamyl alcohol and esters such as ethyl acetate where xerogel is phosphated it is preferred that it be converted to the xerogel from the hydrogel in the same manner particularly if it is a low phosphorus aluminum phosphate whether the starting material is alumina or a low phosphorus aluminum phosphate the invention takes advantage of.