Selective hydrogenation of vinyl acetylene

Claim 1

IN THE METHOD IN WHICH A COMPOSITION CONTAINING A PRINCIPAL AMOUNT OF BUTADIENE, A CONTAMINANT AMOUNT OF VINYL ACETYLENE, SUCH AMOUNT BEING FORMED AS A BY-PRODUCT OF MANUFACTURE OF CRUDE BUTADIENE AND LESSER AMOUNTS OF OTHER ACETYLENES IS TREATED WITH HYDROGEN IN THE PRESENCE OF A CATALYST TO PRODUCE A PRODUCT CONTAINING SIGNIFICANTLY LESS VINYL ACETYLENE, THE IMPROVEMENT WHICH CONSISTS OF: USING A FEEDSTOCK CONTAINING ABOUT 0.7 TO ABOUT 1.0 PE CENT VINYL ACETYLENE, AND CONDUCTING THE HYDROGENATION AT MIXED PHASE CONDITIONS COMPRISING BOTH LIQUID PHASE AND VAPOR PHASE CONDITIONS, SUCH MIXED PHASE FEATURING A PRESSURE OF ABOUT SEVEN ATMOSPHERES AND WITHIN THE RANGE FROM ABOUT SIX TO ABOUT ELEVEN ATMOSPHERES AND SUCH MIXED PHASE FEATURING AN AVERAGE TEMPERATURE IN EACH OF TWO CATALYST BEDS WITHIN THE RANGE FROM ABOUT 40*C. TO ABOUT 60*C., WHEREBY THE UNIT RATIO OF SELECTIVITY OF VINYL ACETYLENE CONVERSION TO BUTADIENE CONVERSION IS GREATER THAN 80 AT A VINYL ACETYLENE CONVERSION GREATER THAN 70 PE CENT, SUCH SELECTIVITY RATIO BEING MORE THAN 50 PE CENT BETTER THAN AT COMPARABLE CONDITIONS OTHER THAN LIQUID PHASE OPERATION AT A PRESSURE OF ABOUT 20 ATMOSPHERES, SAID HYDROGENATION BEING CONDUCTED IN CONTACT WITH A CATALYST CONSISTING ESSENTIALLY OF SORPTIVE ALUMINA AND FROM 0.05 TO 0.2 PER CENT PALLADIUM, THE CATALYST BEING DISTRIBUTED IN TWO BEDS WITH INTERSTAGE COOLING AND INTERSTAGE HYDROGEN INJECTION, THE HYDROGEN TO VINYL ACETYLENE RATIO BEING ABOUT 1 IN THE FIRST REACTOR AND BEING NOT MORE THAN ABOUT FIVE IN THE SECOND REACTOR, WHEREBY THE LOSS OF BUTADIENE IS ONLY ABOUT 1.28 KILOGRAM OF BUTADIENE PE KILOGRAM OF CONVERSION OF VINYL ACETYLENE.