Simultaneous dehydrogenation of organic compounds and hydrogen removal by hydride forming alloys

The applicability of hydrogen-absorbing metals in dehydrogenation reactions was investigated. Based on thermodynamic considerations, operating ranges were defined within which an increase of the reactant conversion can he achieved owing to an in situ hydrogen removal by the alloy. Low plateau pressures (e.g. 473 K) are required for economic applications. An (economic) improvement of the alkane-to-alkene conversion does not seem feasible owing to the extreme pressure and temperature conditions. In the present study as a model system, 2-propanol was dehydrogenated in a batch process at 473 K and 0.1-1.0 MPa over a Cu/CuO catalyst in the presence of an excess amount of Mg2.4Ni. The hydride forming metal alloy appears to be able to affect the hydrogen balance of the experimental system owing to absorption or desorption. However, an unexpected catalytic effect of the metal hydride was observed towards condensation reactions. Owing to the loss in selectivity, Mg2.4Ni, is not applicable for an improvement of the dehydrogenation processes for secondary alcohols.