Production of diolefins from olefins

Claim 1

IN A METHOD WHEREIN AN OLEFINE HAVING AT LEAST 4 CARBON ATOMS IN THE UNSATURATED CARBON CHAIN OF THE MOLECULE IS DEHYDROGENATED TO FORM A CORRESPONDING ALIPHATIC CONJUGATED DIOLEFINE BY PASSING THE OLEFINE, TOGETHER WITH STEAM, AT REACTION TEMPERATUES NOT EXCEEDING 750* C. THROUGH A BED OF A DEHYDROGENATION CATALYST COMPRISING, AS ITS CATALYTICALLY ACTIVE PRINCIPAL INGREDIENT, A NORMAL CALCIUM NICKEL ORTHO-PHOSPHATE MATERIAL HAVING, CHEMICALLY COMBINED WITH THE PHOSPHATE RADICALS, FROM 6 TO 12 ATOMS OF CALCIUM PER ATOM OF NICKEL, THE STEP OF SUPPORTING THE BED OF CATALYST ON, AND CONFINING IT BY, SURFACES OF AT LEAST ONE SUBSTANTIALLY INERT SOLID MATERIAL, OF THE GROUP CONSISTING OF NICKELFREE CHROMIUM ALLOY STEELS AND CERAMIC MATERIALS WHICH ARE SOLD AND RIGID AT THE REACTION TEMPERATURE, WHILE CARRYING OUT THE REACTION BY PASSING THE HEATED REACTION VAPORS THROUGH THE CATALYST BED AND INTO CONTACT WITH THE MATERIAL CONFINING THE BED.