Non-zeolitic molecular sieves (NZMS) are those molecular sieves which contain elements other than aluminum and silicon and include silicoaluminophosphates (SAPOs) described in U.S. Pat. No. 4,440,871 A, ELAPOs described in U.S. Pat. No. 4,793,984 A, MeAPOs described in U.S. Pat. No. 4,567,029 A. In a preferred aspect, an inorganic oxide for the outer layer is gamma alumina.