Catalytic hydrogenation and dehydrogenation of N-ethylindole as a new heteroaromatic liquid organic hydrogen carrier

Hydrogenation of N-ethylindole was investigated over a 5 wt% Ru/Al2O3 catalyst in the temperature range of 160-190 degrees C at 9 MPa. The process was found to undergo the sequential steps of N-ethylindole -> 2H-N-ethylindole -> 4H-N-ethylindole -> 8H-N-ethylindole with rapid consumption of all intermediate species. The reverse process, dehydrogenation of octahydro-N-ethylindole, was subsequently conducted for tests over a 5 wt % Pd/Al2O3 catalyst in the same temperature range. Full dehydrogenation can be achieved with a moderate reaction rate. The released H-2 gas was found to be of a high purity. Our results indicate that N-ethylindole is a promising new member of liquid organic hydrogen carrier family. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.