Liquid-phase dehydroganation of cyclohexanes, yielding aromatic hydrocarbons and molecular hydrogen exclusively with suspended noble metal catalysts under boiling and refluxing conditions, proceeded more efficiently in the reactor of liquid-film type than of suspention type. The catalysts suitable to this endothennic low-temperature reaction are essentially important in the newly-proposed thermo-regenerative fuel cell and chemical heat pump systems.

Efficient hydrogen evolution from the 2-propanol solution containing acetone at high concentrations was found by adoption of a large catalyst/substrate ratio under ebullient conditions. The so-called liquid-film type reaction gave both high reaction rates and low extents of rate retardation caused by the product. On this basis, a new type of the low-temperature endothermic reactor for the 2-propanol/acetone/hydrogen chemical heat pump system has been suggested.

Cycle reactions of the UT-3 between bromination of magnetite and hydrolysis of ferrous bromide in the reaction pellet were studied with packed bed reactor. (1) In the early stage of the bromination, some delaying was observed in the production of Br₂. The delay was shortened as the number of the cycle proceeded. (2) H₂ and HBr were produced steadily and stoichiometrically in the hydrolysis. (3) About 50% of produced Br₂ was shown to be trapped in the bed during the bromination, and the trapped Br₂ was released by purge with N₂. A new type reactor was proposed,which enables to separate Br₂ and HBr using trapped Br₂, effectively.

Materials compatibility was examined for the sulfuric acid processing environments in the iodine-sulfur water spitting process. The testing environments were (1) boiling conditions of 40/70/98wt% sulfuric add in the presence of iodine and hydriodic acid, and (2) gaseous mixtures of H₂O-SO³ and of H₂O-SO³-SO₂-O₂ at 850℃ .In the former enviromnents, Ta and Zr showed corrosion resistance for the boiling 40/70wt% sulfuric acids, and cast iron with 15%Si did for the boiling 98wt% sulfuric acid. For the latter environment, many high temperature alloys such as Incoloy 800, Hastelloy XR, NSC1 were found to have corrosion resistance.

Chemical heat pumps are processes which utilize the exo- and endothermic chemical reactions to store the industrial waste heat or the natural heat such as solar energy and to upgrade these heat by raising temperature or reducing it below the room temperature. The processes are useful because they enable us to use energy with high efficiency, to control working temperature easily and to store and transport energy in form of stable chemical substances without energy loss. This report includes principles and recent topics on research and development of chemical heat pumps using hydrogen.