Development of Solid Superbase by Controlled Oxygen Anion Generation

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1. A highly basic solid catalyst was obtained by dispersing metal salts over supports at the surface density of 10 - 15 x 10^<18> K^+ ions m^<-2> and activating them at proper temperature in an inert atmosphere. Metal salts can be the nitrate or carbonate of group 1 elements. Effective supports were alumina and zirconia; silica and titania are ineffective.2. The catalyst exhibited high activity in the isomerizations of cis-but-2-ene, 3-methyl-but-l-ene, propa-1,2-diene and α-pinene, and the isomerization/dehydrogenation of cyclohexadiene to benzene, cyclohexene and hydrogen, and of limonene to p-cymene3. From TPD and IR/Raman spectroscopy, it was found that mounted metal salts exist as both an agglomerated phase when the surface density is high and an ion-separated phase when the surface density is low. The former decomposes at the temperature close to its own decomposition temperature, while the latter decomposes far below the decomposition temperature and was attributed to the anion decomposition that may be free from its counter cation.4. The generation of basic property closely relates to the anion decomposition. NO_3^- decomposes to NO_2 + O^- and CO_2 decomposes to CO_2 + O^<2->. It is suspected that the liberated oxygen anion(s) constitutes basic centers.5. It is speculated that liberated oxygen anions can be discriminated from the anions of metal oxide supports in case of alumina and zirconia, while can not on titania support. Metal salts can only exist as agglomerated phase on silica support that was confirmed by XRD. Effectiveness of support could be the difference of the discrimination ability of liberated oxygen anions from those of supports. The loss of basicity at elevated temperatures could be attributed to the leveling of both oxygen anions.