Hydrogen may be used as the fuel in suitable internal combustion engines and the possibility of using it to power motor vehicles is being considered. However, a major problem is that of storing the hydrogen in a compact, convenient form. A solution may be to use hydrogen to hydrogenate benzene to cyclohexane, which can be distributed in much the same way as petroleum products. The motorist would fill the tank of his vehicle with hydrogenated hydride, from which hydrogen would be released by an onboard catalytic dehydrogenation reactor.

Success could depend upon the dehydrogenation step, an endothermic reaction which is reversible. A report of a simulation study for a palladium on alumina catalyst indicates that a dehydrogenation reactor for cyclohexane is feasible, at least in theory (A. Touzani, D. Klvana and G. Bélanger, Int. J. Hydrogen Energy, 1984, 9, (11), 929–936). Heat normally dissipated by the cooling system could be transferred to the reactor by a system of heat pipes, and would compensate for the endothermicity of the dehydrogenation reaction.