PATENTS

3027. ----- [RUHRCHEMIE, A. G.]  [Process for Improving the Quality of Hydrocarbons by Cracking.]  German Patent Appl. R 109,371, R 553, filed Feb. 15, 1941 (Cl. IV d-23 b). TOM Reel 177, frames 1,612-1,616; Meyer Transl.  PC-S-II, Fischer-Tropsch, vol. 1, chap. 35, 1948, p. 86.

Catalytic cracking of hydrocarbons b. >200° C. gives low-boiling olefins and gasolines with satisfactory octanes. but low densities.  Catalytic cyclization of hydrocarbons is ordinarily limited to the 80°-200° C. fraction.  By combined action of cracking catalysts with cyclization catalysts, high-boiling hydrocarbons (diesel oils) may be converted  to give a heavy aromatic fraction and a low-boiling olefin fraction (propylene, butylene) unaffected by aromatization.  Best results were obtained by passing hydrocarbon vapors, pure or mixed with seam, first through a layer of cracking catalyst (acid activated fuller’s earth, with or without addition of metallic oxides) and then through a layer of cyclization catalyst (Al₂O₃, Cr₂O₃, promoted by addition of metallic oxides).  The unreacted vapor was recycled.