Catalytic dehydrogenation processes and chromium catalysts for use therein

A composition of matter having the formula CraAbBc(O1−z(OH)2z)y, wherein a+b+c=1;

• wherein A is an element selected from the group consisting of Zn, Sn, Rh, Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr and Ba;
• wherein B is at least one element selected from the group consisting of Al, Si and Mg;
• wherein a is greater than 0.01 but less than 0.5;
• b is greater than 0.01 but less than or equal to 0.5;
• c is greater than 0.2 but less than or equal to 0.999;
• wherein y is determined by the sum of the oxidation states of Cr, A and B individually multiplied by the corresponding stoichiometric coefficent a, b, or c, and said sum then divided by 2;
• and z is greater than or equal to 0 but less than or equal to 2 , and when z is greater than 1 , the composition contains no oxygen as oxide.