Benzene and methylbenzenes prodn. from toluene - by thermal treatment using zeolitic catalyst with hydrogen, gp. II III and/or IV metal cations

摘要

The process concerns the prodn. of C6H6 and methylbenzenes from toluene by thermal treatment in 3 stages at 350-500 degrees C and 1-50 at. in the presence of a granulated zeolitic catalyst. The reaction mixts. obtd, in the 3 stages are (1) C6H6 and xylenes; (2) toluene and trimethylbenzenes and (3) xylenes and tetramethylbenzenes. These are sepd. the xylenes from (1) and the trimethylbenzenes from (2) being used as the charge in the second and third stages. The catalyst used contains 5-30% (as degree of exchange of the theory) of gp. II metal cations, 6-22% H and (a) 20-80% gp. III metal cations and/or (b) 24-73 gp. IV transition metal cations. The prods. are valuable raw materials in plastics mfr. The process has a higher capacity and simpler technology than usual. Coking of the catalyst is reduced by treatment in an inert gas medium and thus the stability of operation is improved.