ANALYSIS OF REACTION ROUTES TO FORM BRANCHED ALKANE ISOMERS IN CATALYTIC CRACKING

Formation and transformation of the branched alkanes in naphtha were analyzed during Daqing VGO's cracking on acid catalysts.The yields of branched alkanes in reaction product increased with the conversion.The branched alkanes mainly consisted of methyl alkanes,which suggested that skeletal isomerization proceeded through substituted protonated cyclopropane intermediates(PCP).Methyl alkanes consisted mainly of monomethyl alkanes,then of dimethyl alkanes,and of a little trimethyl alkanes.The long-chain branched isomers were formed mainly via intermediates such as PCB,PCPe,PCH rather than via PCP,while the multi-methyl alkanes was formed grom monomethyl alkanes via PCP.