Moving from Batch to Continuous Operation for the Liquid Phase Dehydrogenation of Tetrahydrocarbazole

• Main Authors: Shen, Y., Ma'amor, A., Abu-Dharieh, J., Thompson, J.M., Kalirai, B., Stitt, E.H., Rooney, D.W.
• Format: Article
• Published: American Chemical Society 2014
• Subjects: Q Science (General); QD Chemistry
• Online Access: http://eprints.um.edu.my/11838/; http://pubs.acs.org/doi/abs/10.1021/op400217d; http://doi.org/10.1021/op400217d

Despite the numerous advantages of continuous processing, high-value chemical production is still dominated by batch techniques. In this paper, we investigate options for the continuous dehydrogenation of 1,2,3,4-tetrahydrocarbazole using a trickle bed reactor operating under realistic liquid velocities with and without the addition of a hydrogen acceptor. Here, a commercial 5 wt % Pd/Al2O3 catalyst was observed to slowly deactivate, hence proving unsuitable for continuous use. This deactivation was attributed to the strong adsorption of a byproduct on the surface of the support. Application of a base washing technique resolved this issue and a stable continuous reaction has been demonstrated. As was previously shown for the batch reaction, the addition of a hydrogen acceptor gas (propene) can increase the overall catalytic activity of the system.