The removal efficiency of SO₂ by the soils were studied and influence of relative humidity on the removal efficiency was also investigated. As typical soil samples, i. e. a Kanto-loam soil, soil mainly containing montmorillonite and soil containing volcanic ash were chosen. The removal efficiency of SO₂ for 50-270 mesh soils was measured at different relative humiditys. Four samples of them, except sta ndard sand, gave the maximum values at 50% relative humidity. The Kanto-loam (50-270 mesh) was divided in to three types of particle size (50-100, 150-170, 250-270 mesh). The removal efficiency of SO2 for each of the three samples was relatively higher than that for 50-270 mesh Kanto-loam, while the minimum value at 50% relative humidity was observed. The removal efficiency of SO₂ for the five samples increased with the increase in the specific surface areas at 50% relative humidity. For bentonite, Na-montmorillonite and kaolin, the removal efficiencies of SO₂ increased with the increase in relative humidity. Every clay mineral showed over 60% of removal efficiency of SO₂ at 95% relative humidity.

View full abstract

The reductive amination of 2-, 3- and 5-nonanones over platinum group metals, Raney Ni and Raney Co has been studied in ethanol in the presence of 9.3 molar ratio of ammonia to ketone at 50 °C and the hydrogen pressure of 8 MPa. With 2-nonanone, the major product was the corresponding primary amine over the metals other than Raney Ni. In contrast to the previous results with nonanal, no tertiary amine was found in the products; the secondary amine was also formed not at all (Pd, Ru, Rh, Raney Ni and Raney Co) or only to a slight extent (Os), except over Pt and Jr where it was formed in 17 and 16%selectivities, respectively. Over the catalysts other than Pd, Rh and Ir, the corresponding alcohol was formed in larger amounts than in the case of nonanal. In particular, over Raney Ni formation of the alcohol amounted to 54% which was even larger than the amount of the primary amine formed. Over Pd and Rh the alcohol was formed not at all or only slightly, and the primary amine was formed in 100 and 98%selectivities, respectively. In the presence of added ammonium acetate, the formation of alcohol and secondary amine was depressed, resulting in increased selectivities to the primary amine. Especially, the yields of primary amine increased to 100 and 98% over Raney Ni and Raney Co, respectively, in the presence of ammonium acetate. 3- and 5-Nonanones were less reactive than 2-nonanone with Pd, Pt, Rh and Ru, the reactivity decreasing in the order: 2->3->5-nonanone. In contrast, the selectivity for the formation of alcohol increased in the reverse order: 2-<3-<5-nonanone. Carbon-supported platinum metals showed much greater activites in the reductive amination than the corresponding metal blacks. Further, significant differences in the reactivities between the isomers and in the selectivities of the products have been observed between the supported and unsupported metals.

View full abstract

Sonochemical graphitization of liquid benzene has been studied. Sonochemical reaction proceeds through production and collapse of a bubble induced by ultrasonics. During the collapse, high temperature and high pressure conditions can be realized and the degradation of molecules occur, then, fine particles are formed. In order to produce carbon fine particles from liquid benzene, we attempted hydrogen abstraction by chlorine atoms which are produced through degradation of carbon tetrachloride. The formation of graphitic carbon could be confirmed through Raman spectroscopy.

View full abstract

The effect of dissolution solvents on the assay of diarsenic trioxide and the stability of arsenic (III) was evaluated by high precision coulometric titration with electrogenerated iodine. The assays obtained on a standard reference material were ca. 0.1% lower than the certified value, when it was dissolved in 2 mol dm^-3 sodium hydroxide solutions. However, when 2 mol dm^-3 sodium carbonate solutions were used for the dissolution, the assays were in good agreement with the certified value. It is apparent that the decreases in assay are mainly due to the oxidation of arsenic (III) to arsenic (V) by the high basicity and dissolved oxygen. Consequently, it is recommended to dissolve diarsenic trioxide in sodium carbonate solutions. About 20 and 4 % of arsenic (III) were lost from 1 and 1000 μg cm^-3 arsenic (III) solutions, respectively, in 2 mol dm^-3 sodium hydroxide stored in high-density polyethylene and Teflon containers for 2 months. Arsenic (III) in a sodium carbonate (2 mol dm^-3) or sodium hydroxide (ca. pH 12.5) solution remained unchanged at least for 2 or 1 month in both containers, respectively. The rate of the air oxidation of arsenic (III) was strongly dependent on the pH of solutions.

View full abstract

Three kinds of polyvinylsiances, which were different each other in the structure, were prepared by the polymerizations of vinylsilane [CH₂=CH-SiH₃] using a radical initiator catalyst, an anionic catalyst and a coordinated anionic catalyst (Ziegler-Natta catalyst). A coloress and transparent liquid polymer of molecular weight (Mn) 500-1500, which structure was [-CH₂-CH (SiH₃)-] _x [-CH₂-CH₂SiH₂-] _y, and the similar liquid polymer of molecular weight (Mn) 500-1500, which structure was [-CH (CH₃) -SiH₂-], were obtainde in high yields in the radical and the anionic polymerization, respectively. A white solid polymer, which was slightly soluble in solvent and the structure was [-CH₂-CH (SiH₃)-], was obtained in the coordinated anionic polymerization. The reaction mechanisms were proposed on the base of the reactivity of the sily1 group of vinylsilane. The polymers are stable under air and have the reactive Si-H bonds. Silicon carbide was obtained by heating the polymers at high temperature under inert gas.

View full abstract

Effects of heating rates and catalysts on thermal and catalytic degradation of poly (vinyl chloride)have been investigated. Heating rates for the dehydrochlorination stage had little effects on the product oil characteristics, whereas heating rates in the later pyrolysis stage of polyene had strong effects. Slow heating rate for the pyrolysis provided less total oil yield but more yield for low molecular weight component. By using catalysts in the pyrolysis of polyene, BTX (benzene, toluene, xylene) and naphthalene yield had remarkably increased, although total oil yield had decreased. HZSM5 was the best catalyst in this experiments and the maximum BTX and naphthalene yield was about 7 % based on the polyene.

View full abstract

A series of block copolymers, i. e., PHEMA-b-PDMS, PDMM-b-PDMS and PMDID-b-PDMS, were obtained from polymerization of 2-hydroxyethyl methacrylate (HEMA), 2, 2-dimethyl-1, 3-dioxolan-4-ylmethyl methacrylate (DMM) and 5- (5-hydroxymethyl-2, 2-dimethyl-1, 3-dioxolan-4-yl)-2, 2-dimethyl-1, 3-dioxolan-4-ylmethyl methacrylate (MDID) initiated with polydimethylsiloxane type of azo-initiator (VPS). Conversion of PDMM segment in PDMM-b-PDMS and PMDID segment in PMDID-b-PDMS into poly (2, 3-dihydroxypropyl methacrylate) (PDHPMA) and poly (2, 3, 4, 5, 6-pentahydroxyhexyl methacrylate) (PMDul) segments by hydrolysis with a dilute hydrochloric acid resulted in PDHPMA-b-PDMS and PMDul-b-PDMS, respectively. From XPS measurements of freeze dried PHEMA-b-PDMS, PDHPMA-b-PDMS and PMDul-b-PDMS samples, the hydrophilic segment was found to migrate to the surface of copolymer films in water. The contact angle of water of copolymer films decreased with increasing the amount of the hydrophilic segment. The copolymer with a hydrophilic surface suppressed the adsorption of albumin (Alb) and y-globulin (Glo) as well as platelets, less than the polydimethylsiloxane as control.

View full abstract

The relationships among the tensile strength, molecular weight and amount of end -COOH group of poly (butylene terephthalate) [PBT] were obtained during degradation process. The tensile strengt h became constant up to a certain time and then decreased sharply. This break point depended on the temperature and humidity. The logarithmic molecular weight decreased linearly and amount of -COOH group increased with time, depending on the degradation conditions. When the tensile strength is plotted against the molecular weight or amount of the COOH, the unequivocal relationships are obtained independent of the degradation conditions. The break points are observed where the tensile strength starts to drop sharply. Plotting amount of -COOH group against the logarithmic molecular weight, the straight relationships have also the break points. These results indicate that the degradation process can be evaluated by measuring amount of -COOH group and the molecular weight using only small amount of samples.

View full abstract

Sorption of a large amount of heavy oil by an exfoliated graphite was found. The maximum sorption capacity of the exfoliated graphite reached more than 80 g/g for grade-A oil with a viscosity of 4 poise and 75 g/g for grade-C heavy oil with 350 poise. Sorption for grade-A oil was completed: within 1 min a characteristic brown color of the oil disappeared. High performance of the exfoliated graphite for sorption of heavy oil, particularly for the collection of heavy oil was expected.

View full abstract

Effect of some kinds of alcohol addition to alkali solvent on hydrothermal decompositions of various kind of halogenated carbons such as chlorofluorocarbons (CFCs) with 1-4 carbons was investigated. We have already reported the perfect decomposition of the CFCs under methanolic alkaline hydrothermal treatment at lower temperature compared to supercritical water oxidation (SCWO) process. Here, in order to clarify the effect of a lcohol addition to solvent, the relation of concentration of halogenide ion and organic ions were investigated. Furthermore the organic carbons were analyzed by ¹³C-NMR to confirm the origin of the carbon whether from the oxidation of added alcohol or from the transformation of starting CFCs. It was revealed that the carbon-halogen bondings can be completely dehalogenated and the halogenide ions were released into the aqueous solution and can neutralize with alkali therefore, the perfect process for the elimination of the toxicity should be possible in the hydrothermal treatment.

View full abstract