Catalytic hydrodenitrogenation of quinoline in a trickle-bed reactor. Effect of hydrogen sulfide

Abstract

Studies at 350, 375, and 390/sup 0/C and 6.9 MPa showed that the presence of H/sub 2/S (generated in situ from CS/sub 2/) in the overall reaction network somewhat inhibits hydrogenation and dehydrogenation reactions but markedly accelerates hydrogenolysis reactions, for a net increase in the overall rate of hydrodenitrogenation (HDN). These effects are similar to those observed previously in vapor-phase reactions. H/sub 2/S has little effect on the activation energies for the hydrogenation and dehydrogenation reactions, but it significantly reduces those for the hydrogenolysis reactions. Certain plugging problems encountered upon reacting 5,6,7,8-tetrahydroquinoline are attributed to formation of a trimer imine as an intermediate. The presence of Tetralin in the liquid inhibits the overall hydrodenitrogenation reaction, indicating that inhibition by competitive adsorption is more important than the accelerating hydrogen-donor capability that Tetralin exhibits in some homogeneous reactions.