Characteristics of Dehydrogenation Catalysis at Solid-liquid Interface Kept with Any Temperature Gradient
Grant-in-Aid for Scientific Research (C)
|Allocation Type||Single-year Grants|
|Research Institution||Science University of Tokyo|
SAITO Yasukazu Sci.Univ.Tokyo, Fac.Eng.Prof., 工学部, 教授 (10010761)
|Project Period (FY)
1995 – 1996
Completed(Fiscal Year 1996)
|Budget Amount *help
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1996 : ¥900,000 (Direct Cost : ¥900,000)
Fiscal Year 1995 : ¥1,200,000 (Direct Cost : ¥1,200,000)
|Keywords||Liquid-film state / Dehydrogenation catalysis / Superheated / Temperature gradient / Solid-liquid interface / Equilibrium-conversion surplus / 2-Propanol / Cyclohexanes / 液膜型触媒反応 / 液相脱水素反応 / アセトン / シクロヘキサン / ベンゼン / ヒートポンプ / 水素輸送|
Carbon-supported metal catalysis dipped with insufficient amounts of organic substrates (hereafter termed as "liquid-film states") have been found to exhibit strikingly-enhanced activities of dehydrogenation under boiling conditions in comparison with those of suspended catalyst states. Following characteristics were observed at the adequate ratio of catalyst amounts to substrate amounts :
(1) The rates of evaporation from the substrate liquid phase were decreased.
(2) Temperatures of the catalyst layr were higher than that of the boiling liquid bulk.
(3) Vigorous evolution of bubbles occurred not only from the liquid bulk but also from the powder surfaces of carbon-supported catalysts.
(4) Evolved bubbles can pass through the liquid film with insufficient gas-liquid equilibration, supplying product-rich components to the gas phase.
(5) Product hydrogen were separated from the substrate vapor by fractional condensation, which resulted in no possibility of hydrogen return to the boiling reaction solution.
(6) The substrate was condensed at low temperatures and supplied directly to the catalyst, with advantageous adsorption and predominant coverage assured.
Consequently, kinetically-controlled dehydrogenation with catalysts in liquid-film states under boiling conditions undergoes at high reaction rates and one-path conversions. Product desorption from the catalyst would be coupled with the temperature gradient at the solid-liquid interface, for which common thermodynamic features are pointed out with those of "thermal diffusion" (Prigogine, 1947). Various kinds of experimental evidence were obtained for catalytic dehydrogenation of 2-propanol as well as of cyclohexanes.
Research Output (25results)