No abstract

The hydroisomerization and hydrocracking of n-decane and n-dodecane on an ultrastable zeolite Y, containing 0.5 wt % platinum, at T = 130-250 °C and P = 5-100 bar was Investigated. The product distributions are a unique function of the total conversion only and are typical for a carbenium ion mechanism. Primary products are the monobranched isomers of the n-alkane feed. Multibranched feed isomers and cracked products are formed in consecutive reactions. Secondary cracking reactions start at high conversion levels (>90%) only. The energetically favored cleavage of some multibranched feed isomers is more probable than the previously proposed exclusive cracking of monobranched feed isomers.

No abstract

The kinetics of the catalytic oxidation of hydrogen sulfide by molecular oxygen have been studied in the temperature range 20-250°C. The primary reaction product is sulfur which may undergo further oxidation to SO9 at temperatures above 200°C. From the kinetics of this autocatalytic reaction we derived an oxidation-reduction mechanism. The two rate influencing steps are the chemisorption of oxygen and the reaction between dissociatively chemisorbed HsS and chemisorbed oxygen. The high activation energy for the formation of SO2 (120 kJ mol-1) explains the high selectivity towards sulfur, although SO2 is thermodynamically the most favored product. At temperatures above 3OO"C, where the formation of SO2 occurs readily, the SO2 may be an intermediate in the reaction of H2S with 02 leading to S and HzO.

Es wird die Konzentrations‐ und Temperaturabhängigkeit (20‐250°C) der Geschwindigkeit der H2 S‐Oxidation mit molekularem O2 an verschiedenen porösen Materialien ( ;z.B. Molekularsieb 13X, 7‐AI2O3) untersucht.