ACID-CATALYZED CRACKING OF PARAFFINIC HYDROCARBONS .2. EVIDENCE FOR THE PROTONATED CYCLOPROPANE MECHANISM FROM CATALYTIC CRACKING EXPERIMENTS

Experimental results obtained in studies on catalytic cracking of normal paraffins as described in the literature are interpreted in terms of the protonated cyclopropane mechanism described in the previous paper of this series. It is shown that this mechanism is capable of explaining the observed sharp increase in reaction rate with increasing carbon number of normal paraffins above C-7 in catalytic cracking. It also provides an explanation for many characteristic features of the product spectra, such as the virtual absence of C1 and C2 as primary cracking products, the high degree of branching in the saturated fractions in contrast to the predominantly linear structures in the light olefin fractions, and the relatively low formation of C3 as compared with C4 and higher homologs under conditions where secondary cracking is minimized.