Alkylation and redistribution of methyl groups in processes of polymerization and polycondensation of cumene on acitvated birch charcoal and pressed carbon black

Conclusions

• 1. The conversions of cumene on activated birch charcoal and pressed carbon black at 400–800°, forming cymene, xylene, ethylbenzene, toluene, benzene, carbonaceous and resinous substances, and gaseous products, were studied. The processes of alkylation and redistribution of methyl groups are related to the process of formation of condensation products on the catalyst surface. Differences were noted in the specifics of the two catalysts investigated at temperatures below 600°.

• 2. Condensation products are formed only on the surface of large marcopores of the catalyst and represent chiefly polymerization products of cumene at temperatures below 500° and polycondensation products of cumene at temperatures above 600°.

• 3. A polymerization-depolymerization mechanism of the alkylation and redistribution of methyl groups in the decomposition of cumene, through the step of formation of condensation products, was proposed, with two varieties: a) direct alkylation by carboids, containing readily split out methyl groups and b) redistribution of methyl groups in the polymerization of cumene and depolymerization of polycumenes.