Mixed aluminium oxides, their production process and their use

Abstract From the Canadian patent

Mixed aluminium oxide wherein it has the, following formula. in which X1 and X2 which can be the same or, different, represent a metal in the group of rare earths, provided that X1 and x2 are different when X1 or X2 stand for cerium lanthanum or gadolinium and provided that when X2 stands for gadolinium, lanthanum, europium terbium or dysprosium X1 stands for a metal of the group of rare earths other than cerium; M1 and M2 which can be the same or different, stand for a metal chosen from the group including magnesium and divalent transition metals; M3 stands for a trivalent transition metal; x1 stands for a number between 0.8 and 1; y1 stands for a number between 10 and 12; and x2, y2 and …