Koshi Kusumoto

Vapor-phase direct hydration of ethylene over zirconium tungstate catalyst: I. Catalytic behavior and kinetics at atmospheric pressure

Abstract Vapor-phase direct hydration of ethylene was studied over zirconium tungstate catalyst (molar composition, W / Zr = 2.0) at atmospheric pressure. The experiments were carried out at 200–250 °C, space velocity (SV) = 400–9000 h −1 , and H 2 O/C 2 H 4 mole ratio = 0.5-2.0. The optimum temperature range to give higher space-time yield (STY) of ethanol varied with the H 2 O/C 2 H 4 mole ratio, and the STY increased with SV up to ca. 2000 h −1 . The data were kinetically well interpreted by assuming that the hydration is controlled by the surface reaction between adsorbed reactants with preferential adsorption of water. Heats of adsorption were 39 kcal/mol for water and 8.5 kcal/ mol for ethylene, and an apparent activation energy was 30 kcal/mol.

Copolymerization of chloromethylstyrene and divinylbenzene in the absence or presence of poly (vinyl chloride)

Abstract Studies of the copolymerization of chloromethylstyrene (CMS) and divinylbenzene (DVB) were done in the presence or absence of poly-(vinyl chloride) (PVC) in order to prepare anion-exchange membranes of excellent performance by the paste method. The copolymerization rate decreases when PVC is added and increases when the DVB quantity is increased in the presence of PVC. The copolymerization rate of the isomers of CMS and DVB increases in the following order: p-DVB > m-DVB > p-ethylvinylbenzene > p-CMS > m-CMS ≈ m-ethylvinylbenzene. This order is not affected by the presence of PVC. The copolymerization of CMS and DVB takes place partially in PVC particles.

Modification of anion exchange membranes by oxidation of selected chemical sites for the purpose of preventing fouling during dialysis

Abstract The base membrane containing chloromethylstyrene units, prepared by the “paste method”, was treated with oxidizing reagents to determine whether the introduction of carboxylic acid groups onto the membrane surface might make the anion exchange membrane resistant to organic Fouling by anionic organic substances. The modified base membrane was then quarternized with an aqueous solution of trimethylamine. The oxidizing treatment with an aqueous solution of potassium permanganate made the resultant anion exchange membrane resistant to organic fouling by sodium dodecylbenzenesulfonate or sodium laurylsulfate.

New anion-exchange membrane resistant to organic fouling☆

Abstract An anion-exchange membrane was modified by sulfonating the surface of the base membrane, composed of styrene-divinylbenzene copolymer and polyvinylchloride, before its chloromethylation and the subsequent quarternization. The following three points are discussed: (1) effect of surface treatment with concentrated sulfuric acid to protect the membrane against organic fouling, (2) relation between sulfonating conditions at the membrane surface and the properties of the modified anion-exchange membrane, and (3) evaluation of the modified anion-exchange membrane.

Preparation of microporous membranes from cation exchange membranes

Abstract A cation exchange membrane was prepared by the soaking technique. First, a base membrane was prepared by copolymerizing styrene and divinylbenzene in a poly(vinyl chloride) film and subsequently sulfonating it. The cation exchange membrane (Fe 3+ form) was then treated with an aqueous H 2 O 2 solution to decompose the cation exchange resin component and was thereby transformed to a microporous membrane with no cation exchange capacity. Preparation conditions of the base membrane were studied as they relate to the characteristics of the resulting microporous membrane. Also, the suitability of the microporous membrane for ultrafiltration was studied using an aqueous solution of bovine hemoglobin.