Yoshio Morioka

Thermal and chemical recycle of waste polymers

Abstract Catalytic degradations of polyethylene into fuel oils and of polystyrene into styrene monomer have been studied using solid acids and bases as catalysts. Solid acids such as silica-aluminas and ZSM-5 zeolite were found to be effective to degrade waste polyethylene into fuel oils, and solid bases such as BaO and K 2 O were concluded to be effective to convert waste polystyrene into styrene monomer. A design of recyclable polystyrene films will be briefly mentioned.

Freezing of the capillary liquid condensing in fine pores

Abstract As a model of a fine pore in a porous body, the cylindrical model has hitherto been used by most investigators intentionally or tacitly. In this paper, a conical pore model is found to be more general and feasible for theoretical considerations of the phase transition of capillary condensate, accompanying a change of contact angle. A new concept such as an effective contact angle or a pore radius, depending on the amount adsorbed in conical pores, is defined completely in accordance with the capillary condensation theory. On considering the freezing process of capillary condensate, it is shown that the frozen layer generated initially in the meniscus region is thickened with temperature decrease. Using this scheme of freezing process, a theoretical formula is derived for the relation between temperature and the radius of curvature of the solid-liquid interface. On the basis of this theory, it is clear that the anomalous excess in apparent heat capacity of sorbate obtained experimentally by Morrison et al. or Antoniou is reasonably attributed to the melting of the solidified condensate in fine pores.

Correlation of surface acidity with electrical conductivity of silica-supported heteropoly compounds studied by the complex-impedance method

A.c. electrical measurements and impedance analysis have been carried out to characterize silica-supported heteropoly compounds (HPC), viz. 12-molybdophosphoric acid (H3PMo12O40), 12-tungstophosphoric acid (H3PW12O40) and their sodium, potassium, and caesium salts under various conditions of humidity. The absorption of water was found to enhance the electrical conductivity of silica-supported HPC. In H3PMo12O40 and its salts supported on silica, complex-impedance plots showed one semicircular arc due to adsorbed water. For H3PW12O40 and its salts supported on silica, the plots showed two arcs; these are ascribed to fast and slow relaxation processes of orientation polarization for conductive species, supposedly protons in occuluded and adsorbed water, respectively. As the relative humidity was increased, the conductivity increased logarithmically, showing humidity-sensing characteristics. The conduction behaviour was affected by the loaded amount of HPC and the substitution of cations in HPC. The activation energy for electrical conduction of low-loaded heteropoly acid (HPA) on silica was lower than that for bulk HPA. It changed both with the amount of loaded HPA and with the substitution for hydrogen ions in the loaded HPA.The acidity function, H0, of the silica-supported HPC has been examined also in connection with their electrical behaviour. The electrical conductivity increased with increasing acidity. A linear relationship was found between the electrical conductivity and the acidity function.

NICKEL INCORPORATED INTO ANODIC POROUS ALUMINA FORMED ON AN ALUMINIUM WIRE

Porous alumina films have been prepared on the surface of an aluminium wire by anodic oxidation in an oxalic acid electrolyte. The pore size could be controlled by the anode potential, and the thickness of the alumina film was a function of the anodizing time as well as the anode potential used. Silica powders containing finely divided Ni metal particles were incorporated into the micropores of the alumina films, which were then used as wire catalysts. The wire catalyst did not require any supplementary heating during catalytic reactions, since after 1 min of applying a small voltage across the ends of the wire, a temperature of 573 K could be reached. The catalytic performance of the nickel particles mounted in the aluminium wires for the hydrogenation of but-1-ene was measured and compared with that of a conventional supported-nickel catalyst.

Degradation of polyethylene over solid acids and bases

Solid acids (ZSM-5, silica-alimina) and bases (MgO, ZnO) were employed as catalysts for the degradation of polyethylene powder at 673 K. The degradation rate over solid acids were more than two times higher than those over solid bases. The degradation products were gases (C1 to C4), oils (C5 to C20) and wax (higher than C21), analyzed by GC-MS to obtain a product distribution curve as a function of C-atom numbers. A relationship between the acid strength and amount and the product compositions were studied using silica-alumina catalysts with various Si/Al ratios, resulting in an enhancement in the gas production as the acid strength and amount increased.

Distribution of catalyst component supported on porous carriers by impregnation method.

2種類の多孔性担体に, 種々の量の ZnCl2-KCl 混合塩を含浸法により担持させた。得られた担持溶融塩触媒体についてベンゼンの吸着等温線を測定し, 細孔径分布の変化から成分の分散性を調べた。担持塩はすべて細孔内に収容されており, それ自体は無孔性であった。また, 担持状態の塩を溶融させても分散形態に変化はなかった。担持量の増加にともない, 分布曲線のピーク位置はあまり動かないが, 細孔量は細孔径の全域にわたって一様に減少した。触媒調製時の含浸液の乾燥速度を, 実験的に1000倍近くまで変化させたが分散性は変わらず, 多孔体からの含浸液の蒸発は準平衡論的過程であることがわかった。以上の実験事実から, 含浸液の蒸発は, 細孔組織の網目状構造に支配されたpercolation機構で進むと考えられる。その結果, 含浸法触媒体の担持成分は, 個々の細孔よりはるかに大きなかたまりとして不均一沈積する。この現象は, 担持量の増加とともに顕著になり, 用いた担体の細孔構造にはよらない。