Catalysts for conversion of olefins

A composition active for converting an olefin to obtain the product of the olefin reaction which, as defined herein, can be visualized as comprising the reaction between two first pairs of carbon atoms, the two carbon atoms of each first pair being connected by an olefinic double bond, to form two new pairs from the carbon atoms of said first pairs, the two carbon atoms of each of said new pairs being connected by an olefinic double bond comprising magnesium oxide admixed with a separate disproportionation catalyst selected from the group consisting of

• 1. one or more of the group aluminum phosphate, zirconium phosphate, calcium phosphate, magnesium phosphate or titanium phosphate promoted by one or more of a sulfide of molybdenum or tungsten, or an oxide or compound convertible to the oxide by calcination of molybdenum, tungsten or rhenium, or magnesium tungstate or beryllium phosphotungstate;
• and
• 2. silica, alumina, aluminum phosphate, zirconium phosphate, calcium phosphate, magnesium phosphate, or titanium phosphate promoted by hexacarbonyl of molybdenum or tungsten;
• said magnesium oxide being present in an amount in the range of 0.1 to 20 parts by weight per part by weight of said disproportionation catalyst.