Hydrogenation of α -Picoline over Co-MgO Catalyst

Abstract

Heterogeneous catalytic reaction of a-picoline in a stream of hydrogen at 280-380° C has been investigated over Co-MgO (1: 2.8) catalyst to elucidate its reaction mechanism. A pyrex-glass tube reactor of continuous flow type was used at atmospheric pressure, equipped with a micro-feeder and a product trap. The products consisting of pyridine, 2, 6-lutidine, ammonia, and methane, were analyzed by gas chromatography and titration. With regard to the reaction occurred at 300-360°C, a close correlation between 2, 6-lutidine yield(Y) and ammonia yield(X) was obtained as shown in the following linear equation, Y= 0.706X+ 1.5 (mol%) The initial rates of formation of ammonia, 2, 6-lutidine, and pyridine at 300° C were obtained as 8.8 x 10-3, 9.9x 10-3, and 6.2x 10-3 mol/g-cat. hr, respectively. In particular, under the reaction conditions of 0.33-0.97 atm. of partial pressure of hydrogen and at 300° C, interrela-tion between the rates of 2, 6-lutidine and ammonia formation was obtained, approximately, as follows: r2, 6-L = rNH3 -8.0 x 10-4 (mol/g-cat. hr) From these results, it is concluded that the 2, 6-lutidine farmation proceeds with consecutive mechanism bringing about ammonia formation by hydro-cracking of pyridine ring as the first step.