The proton dissociation of water-acetone mixtures w as investigated by the EMF measurements of a cell, consisted of glass electrode HCl in mixed solventj AgCl-Ag and glass electrode NaOH +NaC1 in mixed solvent' AgCl-Ag. The thermodynamic quantities of the proton association were interpreted in terms of the ionic solvation of H₃0⁺ and OH^- and the interaction of a water molecule with its entire environment. The contributions of the ionic solvation are unfavorable to the autoprotolysis of water, while the interaction between a water molecule and its environment makes only relatively small contributions owing to the compensation of enthalpy and entropy terms. The ion-solvent interaction was discussed on the basis of a discontinuous model in which the ion is surrounded by a local solvation layer immersed in the bulk solvent. In the transfer of H₃0⁺ and OH^- from water Ito water-acetone mixtures, the changes in enthalpy of the solvation layer were positive in the water-rich region of the water-acetone system. The enthalpy changes can be related to the enhancement of intermolecular association in the mixtures of the corresponding compositions.

View full abstract

The heat of immersion has been studied mainly for characterizing the solid surface. On the other hand, this might as well provide a clue to the study of structure of liquid, if a well-characterized solid surface were used as a solid to be immersed. This investigation attempts to search for this possibility by measuring the heat of immersion of well-defined silica gel having a large surface area and wide pores in the aqueous solutions of chlorides of uni- and bivalent cations. As the result, the heat of immersion per unit surface area of silica gel decreased linearly with the increase of the concetration of the electrolytes. This tendency seems independent of the pH change of the solution around the isoelectric point of silica. This fact indicates that the heat of immersion reflects the change of the water structure by dissolving the electrolytes.

View full abstract

As a part of research and development of the iron-brom ine based thermochemical watersplitting cycle, both hydrolysis and reproduction steps of FeBr2 have been investigated. Kinetic measurements were carried out with powder samples by means of a thermobalance. FeBr2 was hydrolyzed smoothly irrespective of its preparative me thods up to a conversion yield of 1.0 at temperatures of 500-600°C. The hydrolysis proceeded following one empirically obtained kinetic equation. The main rate determining step appeared to be the diffusion of the reactants in the product layer. The specific surface area of the Fe₈0₄ powder obtained largely depended upon the conditions of the hydrolysis. Bromination of the Fe₈0₄ powder w ith a relatively large surface area of 5.5 r n2fg was carried out even with azeotropic HBr up to a conversion of ca.0.8 at temperatures of 200-250°C, where the chemical reactions at the interface were found to be the rate determining. On the other hand, higher temperatures of 450--, 500°C and dry HBr were required for the bromination of the Fe₈0₄ powder with a small surface area of 0.2 m2/g. The reaction proceeded up to a conversion of ca.0.5 being controlled by the diffusion of the reactants in the product layer. Since both the hydrolysis and the bromination proceeded at nearly the same reactio n rate, it is expected feasible to recycle effectively more than 50% of the charged Fe₃0₄ in the process.

View full abstract

The hydrodimerizationo f methyl acrylate to dimethyl adipate w as carried out by the use of the in situ-prepared Co(0)-dimethyl fumarate complex-alkali halides-zinc systems in acetoni, trite and methanol. The effect of halogens on the reactivity was I>Br>>CI, which suggests that the catalytic species contains a halogen ligand. The highest yield was obtained when the molar ratio of dimethyl fumarate to cobalt was 2. The catalysts were inactivated by the reduction of fumarate to succinate by zinc halides and zinc. The residual fraction of dimethyl fumarate is a measure for the life and for the concentration of catalytic species. Alkali metal ions play an important role in promoting the catalysis by the following order: Na>Li≈K>Rb>Cs. The cohydrodimerization of methyl acrylate and methyl vinyl ketone was achieved in 80% selectivity when a mixture of the substrate was added dropwise within ca.15 h by use of a large excess of methyl acrylate. The catalytic species was presumed to be a Co(I)complex coordinated with two molecules of dimethyl fumarate, halogen and acetonitrile.

View full abstract

Various surface treatments have been tried on the aluminu m plates to improve both the quality of printed images and the durability of presensitized plates. It was previously proposed by the author as an improved process to coat the surface of aluminum with titanium (IV) acetylacetonato complex (TAA) obtained from the reaction between titanium (IV) isopropoxide (TPT) and acetylacetone. The relation between the conditions for surface treating with TAA and the properties of the coating was investigated in order to clarify the coated surface properties. The infrared reflectance spectra (IRRS), the contact angle and SEM studies showed how the properties of the coating such as wettabillity with water depended on the composition of treating solutions, heating and UV irradiation. These factors were found to affect largely the properties of TAA coating.† Treatments of O rganic T itanium Compoundso n Presensitized Aluminum Plates. VI.

View full abstract

The electrical resistance (R) of tin (IV) oxide thin films is reduced when films are in contact with flammable gas. Therefore, the relationship between the resistivity ratio (R in gas/R in air) of the thin films and the gas concentration was studied in detail. These thin films for observation were prepared by reaction sputtering with a metallic tin target in Ar+30%0₂ using a magnetron sputtering apparatus and were heat-treated if necessary. The results obtained are as follows; ( 1 ) The resistivity ratio increases in proportion to the distribution ratio of Miller indices (101) to (211) in the SnO₂ crystals (Fig.6). ( 2 ) The resistivity ratio depends on the gas concentration and indicates a sudden shift at a certain gas concentration (Fig.8). From these results, gas should be adsorbed in a monolayer state on the surface of the SnO₂ crystals. ( 3 ) The temperature region (Fig.4) around th e maximum value of the resistance agrees with the temperature region (Fig.10) where adsorption ion 0₂^- seems to be released f r om the surface of the crystals.

View full abstract

The relationship between anodic polarization characteristics of a hydroge n electrode consisting of a porous sintered nickel plaque with the palladium catalyst and its cell performance were studied. The hydrogen electrodes with palladium in the range of 1 mg•cm^-2 to 10 mgcm^-2were prepared by dipping the plaques into 0.5-10g/l PdC1₂ solutions. Anodic polarization curves of the hydrogen electrodes were measured in a 20% KOH solution by the ordinary method and by the current interrupter method. The cell performance in this experiment is represented by the discharge capacity of the cell consisting of the hydrogen electrode coupled with a sintered nickel electrode having a larger capacity. The polarization characteristic of the hydrogen electrodes was found to be closely related to its cell performance when the discharging current of the cell is moderate, but it becomes indifferent of the cell performance when the current increases. It is concluded that the discharging current density should not exceed the apparent exchange current density of the hydrogen electrodes.

View full abstract

Behaviours of magnetic orientation of acicular Co-containingγ-Fe ₂0₃ in paints and coating type media were investigated by measuring the magnetic properties of magnetic paints and tapes. Following resuelts were expeimnentally obtained;( 1 ) The Co-containingγ-Fe ₂0₃ in a magnetic paint rotated within 1 second after applying the orientating field and resulted in the flocculate has continuously changed into a high orientation of the particles. ( 2 ) When the magnetic field was took off, the highly aligned particles in the paint were perfectly disoriented by the reversed field interacted among the particles, but those in the coatings were only slightly disoriented. ( 3 ) For the development of a good magnetic tape with a high orientation, the solenoid was found to be more useful than the repulsive magnets.

View full abstract

The cementation of nickel in nickel sulfate solutions containing a t race of aluminum ion, and the removal of aluminum ion from the solutions were studied at 90°C. The presence of aluminum ion, even in 0.2 ppm, interfered in the cementation of nickel. The recovery of nickel metal from the solution containing 24 ppm aluminum ion was only 39.2%. On the other hand, the addition of 0.2 g of copper (II) ion or 2 g of cobalt ion to 11of the solution containing 5 ppm aluminum ion made the cementation of nickel almost perfect. Aluminum ion in the sulfate solution was removed to the extent of 3-5 ppm concentration through the neutralization with calcareous deep-sea sediments or iron powder, but about 1%of nickel ion in the solution coprecipitated. In the removal of aluminum ion to the extent of 0.2 ppm, about 10% of nickel in the solution coprecipitated.†Studies on Hydrometallurgy of Manganese Nod ules. IX.

View full abstract

Low temperature pyrolytic carbon (LTPC) was d eposited from nine kinds of chlorinated compounds of ethylene and ethane on the graphite substrate heated at 500, 600 and 700°C with a resistance furnace. The chlorinated compounds were classified into three groups on the basis of the relationship between the deposition temperature and the deposition rate. The first group consisted of cis-1, 2-dichloroethylene and trans-1, 2-dichloroethyl ene, and the second group 1, 1-dichloroethylene, 1, 1, 2-trichloroethylene, 1, 1, 1-trichloroethane and 1, 1, 2trichloroethane. The deposition of LTPC began at 500°C in the first group and at 600°C in the second group. The deposition rate of LTPC increased with a rise in the deposition temperature. The specific gravity, X-ray parameter and chemical composition of the deposited LTPC were similar in every specimen. The LTPC deposited at 700°C from dichloroethylene on the substrate in the vicinity of the nozzle point had the double layer structure (upper: columnar structure, lower: isotropic structure). From the third group consisted of vinyl chloride, 1, 1-dichloroethane and 1, 2 -dichloroethane. no deposition of LTPC was observed at 700°C. The deposition behavior of benzene used as a reference source was similar to that of the thrid group. It is therefore reasonably presumed that the di fferences in the deposition behavior among the LTPCs prepared from the three groups are ascribed to the compositions of intermediates formed at the initial step of thermal decomposition. † Studies on the Low Temperature Pyr olytic Carbon. V.

View full abstract

Isotope dilution-surface ionization mass spectrometry, contin uing to attract the attention of scientists because of its inherent theoretical and technical accuracy in environmental analyses, was applied to the determination of ppt (10¹²) level concentrations of thallium, copper, cadmium and lead in seawater samples using a quadri-spike solution of ²⁰³Tl, ⁶⁵Cu, ¹¹⁶Cdand²⁰⁶Pb. The accuracy of the proposed method is exellent in comparison with other methods. Furthermore, the method is applied to the determination of the partitioning of their concentrations between particulates and liquid phase in sea water. Samples were taken from the surface of the Western Pacific Ocean, 2 km off Muroran-shi, Hokkaido. They were partitioned between both phases by ( 1 ) filtration through a Nucleopore filter, ( 2 ) centrifuging (10000 rpm, one hour) and or ( 3 ) ultrafiltration. Their concentrations in the sample are found to be 12.8±0.1ppt for thallium, 293± 6 ppt for copper, 46.0±0.3 ppt for cadmium and 70±1 ppt for lead, while these are partitioned between particulates and liquid phase as follows, in above unit, : Nucleopore-filtration (thallium: O.14 and 12, copper 25 and 260, cadmium: 1.21 and 45.3, lead: 39 and 31), Centrifugation (thallium: 0.32 and 12.4, copper: 71 and 227, cadmium: I.74and 45.4, lead: 52 and 19), ultrafiltration (bulk of thallium and cadmium being partitioned in particulates of molecular weight smaller than 103 and/or liquid phase, while others being veiled due to contaminations from the ultrafiltration device). These figures, however, showed distinct changes reflecting a variability of coastal environments.

View full abstract

The silanized In₂0₃ electrodes which were prepared by silanization with 3-(2-aminoethylamino)propyltrimethoxysilane or r-aminopropyltriethoxysilane were coupled with hemin by using a dehydrating agent, dicyclohexylcarbodiimide (DCC). The direct dehydrative coupling between carboxyl groups of hemin and surface hydroxyl groups of In₂0₃ using DCC was also employed. The amounts of hemin immobilized on In₂0₃ electrodes were estimated by spectrophotometry and cyclic voltammetry. The spectrophotometric results were in good agreement with the cyclic voltammetric data. The cyclic voltammetry was conducted in O.1 mol/ l tetraethylammonium perchlorate in pyridine. The cyclic waves were symmetric, independent of stirring, and exhibited a linear dependence of the peak current on the potential scan rate over 50-500 mV/s range. The peak separation range of 60-70 mV was obtained in the presence of a reversible redox couple (hemin-Fe (III)/h e me-Fe (II)). As an application of the hemin-mod ified electrode to chemical analysis, its behavior toward Cu o n in pyridine was investigated. By the addition of Cu ( II), the cathodic and anodic peaks were increased. The increased peak current was proportional to the concentration of Cu (II). It is demonstrated that the increase in the peak current comes from the chemical reaction of Cu(I1)/Cu( I ) with heme-Fe(II)/hemin-Fe(II)/hemin-Fe(III).

View full abstract

The glassy carbon oxidized with KMnO₄ (GC/COOH) was coupled with iminodiacetic acid (IDA) by using a dehydrating agent, dicyclohexylcarbodiimide (DCC). Carboxyl groups on the glassy carbon were reduced to hydroxyl groups with LiA1F14, and ethylenediaminetetraacetic acid (EDTA) or 3, 6-dioxaoctane-I, 8-diamine-N, N, N', N'-tetraacetic acid (GEDTA) was slso attached to them. The comp lexon-modified electrodes were soaked in aqueous solution of Ag(I) and electrochemical behavior of collected Ag (I) on the electrodes was investigated by cyclic voltammetry. The cyclic voltammograms of collected Ag(I) on the modified electrodes in 0.1mol/l KNO₃at the scan rate of 0.05 V/s showed both reduction and oxidation peaks. It was found that all the modified electrodes, GC/IDA, GC/EDTA, and GC/GEDTA collected silver ion by soaking them in the Ag(I) solution. Redox peak potentials of collected_Ag(I) on the electrode differedfromthat of redpx peaks in the cyclic voltaxnrnogram obtained bythe unmodified electrode. The anodic peak areas with the complexon-modified electrode soaked in Ag(I) solution for 10 min were independent of pH over 2.5-9.0 range, and proportional to the concentration of Ag(I) over the range of 1-5×10^-6mol/l. By adding chloride ion in 0.1 mol// KNO₃, the anodic peak shifted to negative potential and the peak current increased about 4 times as large as that observed in the absence of chloride ion. This peak current was also proportional to the Ag(I) concentration over the range of 1.1-11×10^-6 mol/l. In this case, the anodic process was supposed to be the oxidation of Ag to its chloride.

View full abstract

Effect of supporting electrolyte and solvent on the reversible electrode potentials of ruthenium (II)- and osmium (II)-2, 2'-bipyridine complexes have been studied. The effect of supporting electrolyte, Et₄NC10₄, on the pea k potentials of various redox processes depends on the charge of complex ions involved in the redox processes, but it does not depend on the electronic structure nor on the nature of ligand. The peak potentials of redox process between complex cations shift to more negative potentials as the concentration of supporting electrolyte increases this is due to the ion pair formation between complex cations and ClO₄^- ions. The peak potentials of redox process between complex anions shift to more positive potentials with increasing concentration of supporting electrolyte because of the ion pair formation between complex anions and Et₄N⁺ ions. On the other hand, the effect of solvent on the redox potentials depends on the electronic structure of complex ions, the nature of ligand and the donor-acceptor properties of solvent. Oxidation peak potentials of cation shift to more negative potentials with increasing donor number of solvent. Reduction peak potentials shift to more positive potentials as the acceptor number of solvent increases. These medium effects mentioned above, however, are considerably small compared with those on the electrode potentials of hard metal ions. this seems due to the softness of complex ions.

View full abstract

The electrochemical behavior of glutathione (oxidized form, GSSG) on the mercury electrode has been studied in buffer solution of pH 2.5 to 10. In acetate buffer (pH 5.0), GSSG yielded 1 to 3 reduction peaks on cyclic voltammograms with increasing the concentration GSSG. GSSG in the concentration of 3.5× 10^-4 moll/ (Eτ = 0 V, V= 3 V/s) gave three reduction peaks at hanging mercury drop electrode (HMDE). The potential of the first peak was O4.2 V, the second peak being O5.1 V and the third peak being 0.7 2 V vs. SCE. The first and the third peaks had the natures of adsorption and diffusion peak, respectively. Since the second psak had the nature of both adsorption and diffusion peak, it was supposed to be the reduction peak of the multilayer. The maximum catho dic peak currents of the first peak of GSSG and the adsorption peak of glutathione (reduced form, GSH) were different from each other. This suggested that the adsorption species of GSSG and GSH were different. Traces of mercury compound were detected after the controlled potential electrolysis at 0 V vs. SCE. This result indicated the change of a little GSSG to (GS) ₂Hg. Coulometric reduction of GSSG at mercury pool of 1.0 V vs. SCE gave an n=1.9 9. Therefore the reduction schemes of the first and the thir d peaks were deduced as follows: The first peak; GSSG_ads+ 2 H ⁺ + 2^–: e→ + 2 G SHsoin Hg (GS )2Hg_ads + 2H⁺+2e⇔ 2 GSH_Boin + Hg The third peak; GSSG_soin + 2 H ⁺ + 2 e→2GSH_soln When the sweep rate was low ered to 10 m V/s, the peak current-concentration curve for GSSG was linear from 1× 10^-5 mol/l to 5× 10^-4 mol/l. The presence of GSH up to 5×10^-4mol/l had no effect on 1× 10^-4 m ol/l GSSG for simultaneous quantitative analysis for GS SG and GSH.

View full abstract

Phosphophyllite, Zn, Fe ( PO₄)₂⋅4H₄O, was heat-treated in nitr o g en gas and in air, and the chemical states of its pyrolysis products were studied by Mössbauer spectrometry, X-ray d i ffractometry, thermogravimetry, and differential thermal analysis. The formation of mono- and dihydrate of zinc-iron p h o sphate in the temperature range from 168°C to 277°C was proposed by thermogravimetric data and their Mssbauer param e ters (I. S. = 1.13 mm /s, Q. S. = 2.04 mm/s; I. S. = 1.18 m m/s, Q. S. = 2.57 mm/s). In nitroge n gas, the dehydration process of phosphophyllite was concluded as follows;
In air, the phosphophyllite decomposed to the α-form of anhydrous zinc p hosphate, the anhydrous iron (III) phosphate, and the other paramagnetic iron (III) compounds above 322°C, resulting in the oxidation of irom (II) to iron (III) ion. The reduction of iron (III) to iro n 0(II)ion proceeded by the pyrolysis above 695°C, favoring the formation of the γ-form of anh y drous zinc-iron phosphate. The pyrolysis process of phosphophyllite was concluded as follows;
The dehydration and oxidation processes of zinc-iron phosphate hydra t e by thermal treatment were discussed based upon the chemical state of iron and the conformation of the p yrolysis products. Finally, the iron state diagrams of pyrolysis products in nitrogen gas an d in air were shown in Fig.3 and Fig.5, respectively.

View full abstract

A simple, rapid and sensitive method is developed for the determination of trace amounts of cobalt by adapting a catalytic photometric detection to a flow injection system. The oxidation of chromotropic acid (1, 8-dihydroxynaphthalene-3, 6-disulfonic acid) by hydrogen peroxide is catalysed by trace amounts of cobalt and this phenomenon is used as indicator reaction for cobalt determination. The catalysed reaction is started by the injection of sample solution into the continuous reagent stream and develops in the reaction coil. As the sample zone reaches the flow-cell of the spectrophotometer, the increase in absorbance is measured at 410nm. Chromotropic acid solution (2.7 × 10^-2mol⋅dm^-3), hydrogen peroxide solution (O.4 %) and sodium carbonate solution (0.04mol⋅dm^-3, pH 11.9) were pumped at the same flow rate of 0.36 cm³min^-1. The effects of tube length, tube diameter, flow rate and sample volume on the peak height and shape were also studied and optimal conditions were proposed. A rectilinear relationship was found by injection of 20 μl sample between the peak height and the cobalt concentration up to 100 ppb. With the proposed method cobalt as low as ca.2 ppb (40pg Co) can be determined. Relative standard deviation for analysis of 50 ppb solution was 2.3% (n= 10). Of many ions tested, most do not interefere the determination when pres ent in 100 to 200-fold excess over cobalt, but the presence of 10-fold concentration of Cr(III)caused a negative error. The analytical signal is available within 50s after sample injection, which indicates a rate of analysis of ca. 60 samples/h. The method is very simple because only the injection of sample and measurement of peak height are required for analysis.

View full abstract

2, 3-Dihydro-2-thioxonaphtho[2, 3-d]thiazole-4, 9-dione [3] wasprepared from 2-amino-3chloro-1, 4-naphthoquinone [2], using sodium sulf and carbon disulfide. Thealkylations of [3] with bromoacetaldehy dediethyl acetal, chloroacetone, α-chloroacetophenone, chleroand iodoacetic acid and methyl iodide in the presence of 1.4mole ratio of base gave 2-(alkylthio) naphtho [2, 3-d] thiazole-4, 9-diones [4a]-[4e]. In the presence of alarge excess of base, trione compound [10] and ethoxy compound [11] were obtained by the solvolysis of [4]. The syntheses of 5, 10-dihydro-5, 10-dioxonaphtho [2, 3-d] thiazolo [2, 3-b] thiazolium perchlorates [5a]-[5c] were achieved by the ring closure of [4a]-[4c], using conc. sulfuric acid or polyphosphoric acid. The effects of the quinone carbonyl groups on the reactio n and properties of these compounds were discussed.

View full abstract

2-Aminonaphtho[2, 3-d]thiazole-4, 9-dione (4) was prepared by the reaction of ammonium thiocyanate with 2-acetylamino-3-chloro-1, 4-naphthoquinone (3) which in turn was obtained by amination and acetylation of 2, 3-dichloro-1, 4-naphthoquinone (1). Various thiazole-fused 1, 4 -naphthoquinone derivatives were synthesized from (4). The Sandmeyer reaction of (4) gave 2-chloro compound (6), which then afforded 2-methoxy (7), 2-methylamino (8), and 2-dimethylamino derivatives (9) when reacted with sodium methoxide, methylamine and dimethylamine, respectively. Methylation of (4) with methyl iodide afforded 2-imino-3-methyl (10) and 3-methyl-2-methylimino compound (11). The reactions of(4) with bromoacetaldehyde diethyl acetal, bromoacetone, and ce-bromoacetophenone gave tetracyclic azole compounds, imidazo [2, 1-b] naphtho [2, 3-d] thiazole-5, 10-diones (12)-(14), respectively. Compound (14) and its isomer (15) were also prepared by the reaction of (1) with 2-mercapto-4-phenylimidazole.

View full abstract

The reactions of N-(phenylsulfonyl)saccharin [1] with amines (aniline [2a], benzylamine [2b], and butylamine [2c]) in a variety of solvents at room temperature afforded the ringopened adducts, o-(substituted carbamoyl) - N- (phenylsulfonyl) benzenesulfonamides [3a]-[3c]. When heated at its melting point, [3a] gave an excellent yield of 3-anilino-1, 2-benzisothia zole 1, 1 -dioxide [4a] with the elimination of benzenesulfonic acid. The yield of the corresponding 3-(substituted amino)-1, 2-benzisothiazole 1, 1-dioxides ([4b] and [4c]) from [3b]and [3c] was low. The reactions of [3a]-[3c] with refluxing thionyl chloride produced. almost exclusively [4a]-[4c] in excellent yields. The probable reaction pathway for these reactions is presented.

View full abstract

The mechanism of hydrodenitrogenation of phenazine on a reduced molybdena-alumina catalyst was studied using a high pressure flow microreactor. The reaction was carried out in a toluene solution containing 0.25 wt% phenazine at 270-310°C under the total pressure of 100 atm with weight hourly space velocity of 10 and hydrogen flow rate of 30 l/h.
Phenazine was easily hydrogenated at temperatures below 240°C through 5, 10-dihydrophena zine successively to 1, 2, 3, 4, 4 a, 5, 10, 10a- and 1, 2, 3, 4, 6, 7, 8, 9-octahydrophenazines. Hydrogenation of phenazine to 1, 2, 3, 4, 4a, 10a-hexahydrophenazine preceded the carbon-nitrogen bond breaking in the process. The octahydrophenazines were the main products in the temperature range 240-, 270°C. Above 270°C, the amounts of aniline, benzene, cyclohexene and cyclohexane increased at the expense of the hydrogenated compounds. The hydrodenitrogenation of hexahydrophenazine to aniline and cyclohexene and of 1, 2, 3, 4, 4 a, 5, 10, 10a-octahydrophenazines to aniline and cyclohexane were found by the study of a distribution of the products and the contact time to take place that of perhydrophenazine of cyclohexane. Percentage of nitrogen removal was 90% at 310°C and the principal nitrogen compound remaining was aniline. From the investigation of the competitive hydrodenitrogenation reactions of phenazine and aniline, phenazine was found to be hydrodenitrogenated more easily than aniline. Thus, cyclohexane was produced mainly from the hydrodenitrogenation of octahydrophenazines and perphydrophenazine rather than that of aniline.

View full abstract

The effects of antioxidants(i. e. propyl 3, 4, 5-trihydroxybenzoate (TAPE), 2-t-butyl-4-methoxyphenol (TBMP), 2, 5, 7, 8-tetramethy1-2- (4, 8, 12-trimethyltridecyl) -6-chromanol (TTTC)) on the autoxidation of benzaldehyde were investigated it aqueous solutions of nonionic surfactants. In micellar systems, partition coefficients (K) between micelle and the bulk phase were calculated, and partition ratios (R) between the electrostatic layer and the core for benzaldehyde and the antioxidants were calculated. The binding sites of benzaldehyde and the antioxidants within micelles were confirmed by solubility measurements. On the basis of the experimental re sults, it was found that TAPE having the K value similar to that of benzaldehyde, and TBMP having the R value similar to that of benzaldehyde had the strong antioxidant activity in the nonmicellar (below CMC) and micellar systems (above CMC), respectively.

View full abstract

The absorption maxima of (hydroxymethyl) melamines were found to shift to longer wavelength as the number of the hydroxymethyl groups increased. The hydroxymethylation reaction of melamine was monitored by this absorption maximum. A method of determin ing molecular, species distribution in (hydroxymethyl) melamine has been devised by a combination of this phenomena and ion exchange chromatography. The hydroxymethylation r eaction of melamine was found to follow reversible second order kinetics. The equilibrium constant K was estimated to be 2.7-3.5 in a dilute solution (about 1/30 mol/l) and this small value showed that the reversible reaction was not negligible. The activation energy was evaluated to be 25.0-45.4 kcal/mol. Dehydroxymethylation reaction of (hydroxymethyl) melamine obeyed i r reversible first order kinetics and the activation energy was evaluated to be 25.0-25.4kcal/mol. This value was almost independent of the number of substituted hydroxymethyl g r oups and the pH value of the solution. The obtained molecular species distribution was qualitative l y the same as the one estimated from paper chromatography and chemical analysis, supporting the validity of this method.

View full abstract

The polymerization of methyl methacrylate (MMA) initiated by carbon black-acetylacetone system was investigated. Although the polymerization of MMA was not induced by acetyl acetone channel black (such as Neospectra II Carbolac 1, or Black Pearls 1300) -acetylacetone system showed initiating activity of the polymerization in the presence of water. On the other hand, furnace black (such as Philblack O)-acetylacetone system was unable to initiate the polymerization. The polymerization was totally inhibited by 2, 2-diphenyl-1-picrylhydrazyl or air. Therefore, it was concluded that the polymerization proceeded through a radical mechanism. To clarify the active sites on the carbon black surface for the initiation reaction, the polymerization initiated by treated carbon black-acetylacetone system was compared with that of untreated carbon black-acetylacetone system. It was found that the quinonic oxygen groups present on the surface played an important role in the initiation of the polymerization. The rate of the polymerization (Rp) was expressed by following equation: Rp=k[Neospectra II]^0.5[Acetylacetone][MMA]. The activation energy of the initiation reaction was estimated t o be 23.2kcalimol. The products obtained from the polymerization gave a stable colloidal dispersio n in good solvents for poly (methyl methacrylate) (PMMA). The phenomenon suggested that PMMA was grafted onto the carbon black surface: the grafting ratio was determined to be 30-45%.

View full abstract

The hydrogenation of ethyl benzoylformate over the platinum carbon (Pt/C) catalyst modified. with cinchonidine gave (RH)-(-)-ethyl mandelate in an optical yield of 89.5%. The asymmetric hydrogenation activity of the catalyst was strongly affected by preparation of the Pt/C catalyst. The best Pt/C catalyst was obtained by the following procedures; 1) reduction of H₂PtCl₆⋅6H₂O/ active carbon with sodium formate, 2) treatment of the resulting Pt/ C catalyst with acetic acid, and 3) preheating of the Pt/C catalyst at 300-400°C in hydrogen immediately before its modification with cinchonidine.

View full abstract

The effect of organic bases, aniline and piperidine, on the hydrogen absorption rate of bis(dimethylglyoximato) -cobalt (II), Co (Hdmg)₂, was investigated in methanol at 30°C under atmospheric pressure of hydrogen. The marked difference between the two bases was that a maximum rate was shown at the concentration of O.10 mol/l of aniline, while for _piperidine, no rate depression was shown even in a large excess of piperidine (Fig.1- (a)). The computer assisted iteration gave the stepwise stability constants of Co (Hdmg)₂B and Co (Hdmg)₂B2:145±15 and 2.02±0.08 l/mol for aniline and 56±6 and 0.00 l/mol for piperidine, respectively.

View full abstract

Kinetics of the complexation reaction between nickel(II) ion and 2-(2-thiazolylazo)-4methylphenol(TAC) in the presence of nonionic surfactants was studied. The rate of the complexation reaction is controlled by the 1: 1 chelate formation reaction which proceeds through the two reaction path in aqueous phase:The estimated rate costants and activation parameters are listed in Table 2: they are in good agreement with those determined by the solvent extraction method. From the effect of surfactant concentrations on the reaction rate, the partition constants of TAC between the micelle of the surfactant and the aqueous phase were also determined (Table 1).

View full abstract

Total calcium in serum was determined by inductively coupled argon plamsa (ICAP) emission spectrometry as well as flame (air-C₂H₂) atomic absorption and flame (N₂O-C₂H₂) atomic emission spectrometry, and all analytical values were compared with each other. According to the results, ICAP emission spectrometry provided consistent values with those obtained by flame emission and absorption (NBS recommended method) spectrometry. In ICAP emission spectrometry, calcium in serum could be measured only by diluting the serum 50- or 500- fold with deionized water, while in flame emission or absorption spectrometry La or NaCl should

View full abstract

Some negative staining properties of cellulose microfibrils biosynthesized by Acetobacter xylinum were investigated by electron microscopy and gravimetric analysis. When the neverairdried microfibrils after biosynthesis were stained with an aqueous solution of heavy metal salt, they were homogeneously stained and also had a tendency to deform. But, in the case of the air-dried microfibrils, their insides were scarcely stained. Weight percentage of stainingstuff adsorbed in the air-dried samples stained was from 9 to 11%. For the never-air-dried samples, it was about 10-20 times as much as that of the former. On the basis of the staining properties, it may be quite reasonable to consider that the bacterial cellulose microfibril after biosynthesis is in amorphous state.

View full abstract

The purpose of this investigation is to find the total mercury concentration in the weathered volcanic ash bed (so-called Kanto loam) in a non-polluted area and to compare the values with those of aqueous sediments and surface black soils which are more or less polluted. The 26 samples were collected systematically according to the columnar section of Kanto loam at Minasawa, on the southern foot of Akagi volcano. These samples were powdered, dried at room temperature and analyzed by an atomic absorption spectrometry with a reduction-vapor phase technique. Data show a considerable range from 0.077 ppm to 0.005 ppm. The average of the primary mercury concentration in northern Kanto loam is estimated to be of 0.033ppm.

View full abstract