Tatsuya Okazaki

Selective conversion of nitriles to amides over suspended copper catalysts

Abstract Hydrolysis of various nitriles to amides was carried out in aqueous phase over suspended copper catalysts. Cross-linked poly(4-vinylpyridine), magnesia, and silica-magnesia were used as supports. Copper-on-polymer was highly active in comparison with copper powder. In spite of the larger crystallite size, copper-on-magnesia (68 A) was much more active than copper-on-polymer (amorphous) for selective hydrolysis of nicotinonitrile to amide. A cooperative effect of copper and the basic support was suggested. However, weakly acidic silica-magnesia was favorable as support than basic magnesia for hydrolysis of aliphatic nitriles to amides. Selectivity to acrylamide over copper-on-magnesia was as high as 75%, which would be difficult to attain by the alkaline hydrolysis, but the side reaction to cyanohydrin (8%) was not negligible. Copper-on-silicamagnesia resulted in the predominant formation of acrylamide. An 88% conversion of acrylonitrile was obtained in 8 hr at 80 °C with selectivities of 97% to amide and 0.8% to cyanohydrin. Results for propionitrile and benzonitrile are also described. The present catalysts were shown to degenerate on exposure to air. Hydrogen reduction was effective for complete regeneration of the deactivated copper-on-silica-magnesia, while it was unsuccessful for copper-on-polymer. The rate of hydrolysis revealed to deviate from first order kinetics at higher conversions. The kinetic behavior was explained by the product retardation.

Effective interfacial area and liquid—side mass transfer coefficient in the upward two-phase flow of gas—liquid mixtures

Abstract The effective interfacial area a was measured, for upward two-phase flow in a tubular gas—liquid reactor in the regions of undeveloped slug, froth and annular flow, by absorbing pure oxygen into sodium sulphite solutions. The interfacial shear stress between the gas and the liquid phases was calculated from the interfacial area and the pressure gradient. The liquid—side mass transfer coefficient kL was estimated from a and the volumetric mass transfer coefficient kLa. Correlations are proposed for a, the interfacial friction factor and kL.

Copper-catalyzed oxidative coupling of diphenylmethanimine promoted by some monodentate pyridines

Abstract Aerial oxidation of diphenylmethanimine to benzophenone azine was carried out at room temperature in the presence of cuprous chloride and a monodentate pyridine, such as pyridine, γ-picoline, isoquinoline, or quinoline. Cupric chloride, hydroxide, and nitrate were inactive in the reaction, whereas CuCl2KOH and Cu(OH)2HCl were active in the presence of excess pyridine. Bidentate ligands, such as ethylenediamine and monoethanolamine, inhibited the oxidative coupling of imine. Using isoquinoline for the direct synthesis of azine from benzophenone, ammonia and molecular oxygen, the reaction temperature can be lowered and the catalysts recycled.

Properties of polyacryloylacetone for adsorption of divalent metal ions

Abstract Polyacryloylacetone (PAA) was prepared by polymerizing acryloylacetone in a sealed tube, and examined as an adsorbent of divalent metal ions. The dissociation constant of PAA and overall binding constants of PAA-metal complexes were determined from experimental data on pH titration. The adsorptions of metal ions on PAA were in the order Hg( ii ) ⪢ Cu( ii ) > Ni( ii ) > Co( ii ) > Cd( ii ) , showing high selectivity for Hg( ii ). The adsorption depended significantly on the pH of the solution. The uses of a PAA column for separation and concentration of metal ions were also examined.

Ammonia―hydrazine conversion processes. XVI: Conversion of benzophenone azine into hydrazine catalyzed by sulphonic acids in a two-phase system

Lipophilic sulphonic acids revealed excellent activity as catalysts for the hydrolysis of benzophenone azine (Ph2CNNCPh2) into hydrazine in a two-phase system of xylene and 2N sulphuric acid. High yields of hydrazine (89.8-93.2%) were obtained with a catalytic amount of dodecyl- or didecylbenzenesulphonic acid (2 mol-%, relative to the amount of azine) at 90°C for 1 h. These values are in sharp contrast to the 0.64% yield of hydrazine obtained in the absence of sulphonic acid. For high catalytic activity, dilute mineral acid should be present in the aqueous phase for effective regeneration of the free sulphonic acid. Strongly hydrophilicp-toluenesulphonic acid was extracted almost entirely into the aqueous phase and was less active catalytically at high concentrations.

Preparation of sulfonated resins as an immobilized phase-transfer catalyst for the hydrolysis of benzophenone azine to hydrazine☆☆☆

Abstract Sulfonated resins with a variety of acid-site distribution have been prepared and characterized to obtain highly active immobilized phase-transfer catalysts for conversion of benzophenone azine into hydrazine in a liquid-solid-liquid triphase system. Sulfonation of cross-linked polystyrene with concentrated H2S04 under mild conditions gave various resins of lower acidity, but X-ray microanalysis revealed the acid-site distribution to be like an eggshell, showing that the spheres were sulfonated from the external surface toward a central core. Lipophilic resins with uniform acid-site distribution were obtained by the ternary copolymerization of sodium p-styrenesulfonate, styrene, and divinylbenzene in aqueous dimethylformamide. The acidity of resins could be predicted based on the monomer content in the charge. The competing imbibition of two insoluble liquids, toluene and water, by sulfonated resins balanced at 0.8 meq/g, in good agreement with the optimum acidity for azine conversion. The value corresponds to a sulfonic group per five pendant phenyl groups of the skeletal polymer. Effect of particle size of ternary gel catalyst on the rate of azine conversion suggested the predominant contribution of acidic sites on the surface. Attempts were made to expose available sites on the surface as much as possible employing porous texture under the balanced-wetting environment. Thus moderately sulfonated resins with a macroreticular structure showed high activity for azine conversion. A reactor device capable of continuous operation of liquid-solid-liquid triphase catalysis in a flow system and the results of an illustrative run with 90% conversion over 50 h on-stream are also described.

Volumetric rate of light absorption in gas-liquid two-phase flow

The light absorption rate in a gas-liquid two-phase flow in a tubular photoreactor was measured by using the photoreduction of potassium ferrioxalate as an actinometer. The volumetric rate of light absorption was found to be enhanced by the light scattering due to the waves and numerous small bubbles in the liquid film. A simple method for determination of the volumetric rate of light absorption using the correlation for effective light path length calculated based on a radial light model is proposed. An alternative method based on the diffuse light model is also useful.