γ-Butyrolactone (GBL) is produced by a two-stage hydrogenation of maleic anhydride (MAH) in the liquid phase: a hydrogenation of MAH to succinic anhydride (SAH) in the first stage and a hydrogenation of SAH to GBL in the second stage.
A novel ruthenium catalyst system consisting of Ru salts, trialkylphosphine and p-toluenesulfonic acid was found very effective for the hydrogenation of SAH affording GBL in selectivities above 96%. Acid promoters like p-toluenesulfonic acid induce structual change in the ruthenium complexes, leading to the cationic complexes, which show higher catalytic activity and selectivity than the neutral complexes.
A process to maximize the performance and stability of the catalyst to produce GBL was developed. Novel features of this process are the external preparation of the Ru complexes, the reaction protocol which combines over-flow reaction with stripping for the constant removal of H₂O, and the catalyst recovery system by the extraction.

View full abstract

Ca, Sr, Ce complex alkoxide solution was prepared from Ca(NO₃)₂ 4H₂0, Sr (NO₃)₂ and Ce (NO₃)₃⋅₆H₂O with ethylene glycol through sol-gel processing. Ca, Sr, Ce gel films were deposited on a silica glass substrate by spin coating method using the complex alkoxide solution. Ca_0.5Sr_0.5S 0.001CeS₂phosphor thin films were formed by firing at 750°C in flow H₂S gas. The emission spectrum of Ca_0.5Sr_0.5S⋅ 0.001CeS₂ phosphor thin films were detected nearly at 500 nm. It was equivalent to emission spectrum of Ca_0.5Sr_0.5S⋅0.001CeS₂ phosphor prepared by solid state reaction. Amorphous Ca_0.5Sr_0.5S⋅0.001CeS₂ thin film formed at 600°C also exhibited emission spectra, which were similar to those o f crystalline Ca_0.5Sr_0.5S0.001CeS₂ thin films fired at 750°C.

View full abstract

In order to remove some metal impurities such as Ti and Fe in a zirconium ore, the solvent extraction study of Zr⁴⁺, A³⁺, Ti⁴⁺ and Fe³⁺ (M^m+) in an aqueous solution containing some water-soluble sodium calix[n]arene-P-sulfonates, Na_n1_n( n = 6, 8), was carried out by using methyltrioctylammo nium chloride, MTA⁺C1^-, in chloroform. Almost all of Ti⁴⁺ and about 60% of Fe³⁺ were extracted from the aqueous solution of pH 2-3 into the chloroform phase, by forming a metal complex with 1_n^n- and associating the resultant complex with MTA⁺. On the other hand, Zr⁴⁺ and Al³⁺ were hardly extracted and remained in the aqueous phase. As a result, almost all of Ti⁴⁺ and 60% of Fe³⁺ were removed from ze, by the single extraction procedure. The extracted M^m+ was recovered from the organic phase into a 3 M H₂SO₄ (1 M=1 mol dm^-3) solution, followed by the treatment with 4 M HC1, 1_n^n- innin the organic phase was also recovered separately.

View full abstract

The oxidation of dilute ammonium ion (1500 ppm NH₄⁺) catalyzed by RuO₂ supported on Al₂O₃ was carried out at 140-220°C in an aqueous suspension phase under pressure of air, as a model for waste water treatment. Helium-diluted oxygen (19.3% O₂/He) was used as an oxidant to be capable of analyzing product N₂. Molecular nitrogen was the predominant product with NO₂- followed by the subsequent oxidation to give NO₃- with a small amount of by-product of N20. The catalyst activity in oxidation of NH₄⁺ was strongly dependent on pH values, and the reaction was not observed in acidic condition, while NH₄⁺ was quickly oxidized in basic region. The oxidation of NH₄⁺ should be carried out at high temperature around 200°C, but resulted in an increase in the unfavorable by-product NO₃- above 220°C. Besides the oxidation of NH₄⁺, molecular nitrogen was also produced through decomposition of N H4NO2 without catalyst and oxygen at lower temperature of 120-160°C. The amounts of oxygen and nitrogen contained in the products were well corresponding to the observed consumptions for oxygen and NH₄⁺.

View full abstract

The effects of axial ligands on O₂/N₂ selectivities of oxygen facilitated transport membranes containing a cobalt ( II ) complex, N, N'-bis (3-methoxysalicylidene)-2-methylpropylenediaminato-cobalt ( II )was investigated, using 4-dimethylaminopyridine (4-DMAP), dimethyl sulfoxide (DMSO) and pyrazine as an axial ligand.
The O₂/N₂ selectiv ities of the membrane with 4-DMAP, DMSO and pyrazine were 160, 3 and 2.2, respectively. The oxygenation rate in the DMSO system and the deoxygenation rate in the pyrazine system were remarkably smaller than those of the other systems.
Low O₂/N₂ selectivity in the DMSO system is due to the slow oxygenation of the complex and that in the pyrazine system is attributable to the low deoxygenation rate.
Slow oxygenation in the DMSO system may be due to the s mall overlap of dz² orbital having an unpaired electron with the antibonding orbital of oxygen.

View full abstract

Preparation of conducting polymer patterns using the photochemical oxidizing ability changes of an oxidation polymerization agent has been investigated. Photoreactive metal salts such as iron (III)chloride were used for oxidation polymerization of conducting polymers such as polypyrrole. Metal salts were reduced by exposing to ultra-violet (UV) light and missed the ability of oxidation polymerization. Therefore, conducting polypyrrole patterns have been prepared on the unirradiated part by exposing films containing iron (III) chloride to UV light through the pattern mask and then contacting with pyrrole vapor or dipping in pyrrole solution.
By this method, large and fin e conducting polymer patterns can easily be prepared on plastics, ceramics, papers, clothes, woods, etc. In addition, it may be able to prepare patterns with partially different conductivity by controlling the irradiation time of UV light and/or shades of the pattern masks.

View full abstract

A process of L-tryptophan (Trp) synthesis from indole (Ind) and L-serine by Escherichia coli transformant cells including tryptophan synthase was investigated. Usually, the reaction is strongly inhibited by Ind and Trp accumulated. Therefore, we constructed a new system of successively feeding melt Ind in to the reactor. Yield of Trp formation with this method was much larger than that with a blanket feed of Ind. In a reactor of 1 L, a concentration of Trp formed =92 g L^-1. and an amount of Trp formation pe r amount of cells = 9.2 g (g-cell)^-1 were attained through 3-h reaction. The velocity of feeding Ind per amount of cells had the least upper bound in keeping Trp formation. Rate equations were constructed based on a model where the active enzyme was changed into an inactive one through the reaction. The hypothetical equations successfully explained the reaction of Trp synthesis from Ind and L-serine.

View full abstract

The mechanical properties of polystyrene recycled using d-limonene were investigated. d-Limonene dissolves only polystyrene; the degree of extraction of other plastic is less than 2 wt%. We found that polystyrene recycled 5 times containing at least 0.3×10^-2 mol/100 g of residual limonene content retains its original mechanical properties because there is only a 12% decrease in the molecular weight of the polystyrene, whereas polystyrene recycled once using the conventional method of thermal shrinking has a 35% decrease in molecular weight compared with new polystyrene. The deviation of the molecular weight change of about 2.7 tons of polystyrene recycled using d-limonene is within 10% and the mechanical properties in this range of molecular weights are the same except impact strength and melt flow rate. The 20 wt% blend of the polystyrene recycled to TV cabinet material has the same mechanical properties, flammability and melt-flow rate if there is a small adjustment in the material composition.

View full abstract

Hygroscopic abilities of Taheebo, extracted from the bark of Tabebuia avellanedae Lorents and Griseb, were examined by physico-chemical technics in comparison with those of urea, glycerol and Dglucitol used in cosmetics. When the relative humidity increased from 31.0% to 91.0%, the increased amounts of the moisture absorption capacity of urea and D-glucitol after 24 hours standing were 133%and 98% respectively, whereas its amount of the water-extracted Taheebo was 66%. The moisture absorption capacity of urea and D-glucitol were dependent on changes in the relative humidity, while the moisture absorption capacity of water-extracted Taheebo was not greatly influenced by changes in the relative humidity. Furthermore, in the dry silica-gel desiccator, the water-extracted Taheebo showed the best moisture retention capacity among the samples tested. These results suggested that the waterextracted Taheebo was a desirable hygroscopic material because it exhibited relative high hygroscopic ability under conditions with various humidity and high moisture retention capacity even in the dry silica-gel desiccator.

View full abstract

In this study, glycosylation using diphenylphosphinate as a new leaving group was examined. When the glycosylation of various alcohols with acetylated β-D-glucopyranosyl diphenylphosphinate (1) was carried out in the presence of trimethylsilyl trifluoromethanesulfonate in nitromethane, both the corresponding glucosides and the glucosides, which were deacetylated at position 2, were produced. Three kinds of reaction paths through an ortho ester intermediate can be considered for the present glycosylation.

View full abstract