EVALUATION OF CATALYSTS FOR SELECTIVE HYDROCRACKING OF POLYPHENYLS

摘要

Metal-promoted aluminas of low surface area and free from acidity were found to be the best catalysts for selectively hydrocracking the carbon-carbon bond between phenyl rings in polyphenyls in an extensive screening program carried out on biphenyl, o-, and m-terphenyls as model charge stocks. With cobalt molybdate or nickel oxide (1.3 per cent) on gamma alumina of 25 to 100 sq m/gram surface area, conversions of 60 to 95 per cent were obtained with 60-80 per cent selectivity for the desired chain-splitting reaction. Vanadia-cobalt oxide or platinum on this alumina base were also found to be active and selective for this reaction. Hydro-cracking was carried out at temperatures from 800 to 1000°F and pressures from 500 to 1000 psig. The feed was ordinarily a 10 to 50 weight per cent solution in xylene and was pumped over the catalyst at from 0.5 to 2.0 liquid volumes per hour with 10-50 moles of hydrogen per mole of polyphenyl circulated with it.