Hydrochloric Acid → Hydrochloric Acid

Participants

Reaction Steps

High conversions of 1-chloro- or 1-bromonaphthalene coupled with a long catalyst life can be achieved by the zeolites used according to the invention. The conversion of 1-chloronaphthalene over an amorphous aluminosilicate, in spite of an HCl atmosphere, dropped from 51 to 41% in the course of 4 hours (temperature 400° C., LHSV 0.2 h-1, N. N. Vorozhtsov, Jr. and A. M. Beskin, J. Gen. Chem. USSR, 24, 667/672 (1954) English edition). In contrast, an HEU-1 zeolite converted 56% of 1-chloro-naphthalene after 1 hour and 41% after 7 hours in a hydrogen atmosphere at the same temperature but 2.5 times the LHSV. The selectivity for the isomerization of 1-chloronaphthalene over HEU-1 is very high and is more than 98% at reaction temperatures of between 300° and 400° C. Naphthalene above all is formed as a by-product by elimination of HCl. Less than 0.05% of dichloronaphthalenes is formed. In the reaction of 1-bromonaphthalene, however, transbromination to naphthalene and dibromonaphthalenes occurs. The selectivity for 2-bromo-naphthalene is nevertheless very high, at 95% at 350° C. and 50% conversion.

Provenance & Evidence