A poly(tetrafluoroethylene) (PTFE)-bonded carbon electrode with a gas-supply layer and an active layer (Fig.1) was investigated to develop a high-performance electrode for gas phase electrolysis of HBr. Investigation of th e anodic behavior by using a half cell (Fig.2) showed that the electrode performance was largely affected by the type of the carbon used (Fig.4), the pressing pressure (Fig.6), the content of PTFE (Fig.7), and the hydrophobicity of the electrode (Fig.8). The anodic potential was almost stable for 10 h at the current density of 144 mA/cm² (Fig.9). The loading of Pt catalyst was very effective on the cathodic behavior but not on the anodic one (Fig.10). The gas phase electrolysis of HBr in a fuel-cell-type electrolyzer (Fig.3) could be carried out at a current efficiency of about 100%. The performance of this cell was better than that obtained with the graphite-felt electrode; the current density of 120 mA/cm² (Fig.11) and HBr conversion of 45% (Table 1) were achieved at cell voltage of O.80 V at 423 K.

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The solid electrolyte cells using proton conductors were found to be able to detect dissolved oxygen in water at room temperature. The sensor cell consisted of the reference electrode (air/Pt, Na₂HPO₄, or NaHCO₃), the proton conductor (Sb₂O₅.4H₂0, Zr(HPO₄)₂. H₂0, or Nafion membrane), and the sensing electrode (Pt) (Table 1, Fig.1). The electromotive force (EMF) of the sensors increased linearly with an increase in the logarithm of the concentration of the dissolved oxygen in water (from ca. O.6 to 45 ppm) in the temperature range from 10 to 70°C, following the Nernst equation (Figs.3 and 4). The EMF also varied logarithmically with the concentration of HO, (Fig.8). Each slope of the Nernst equation obtained suggested two-electron reduction of oxygen molecules at the sensing electrode as follows. The 90% response time to the change in the concentration of the dissolved oxygen (4 to 40ppm) was about 10 min at 25°C and about 5 min at 70°C, respectively (Fig.3). In the pH range from 4 to 10, the EMF remained almost independent of pH (Fig.6), owing to the buffering effect of the proton conductors used (Fig.7). Furthermore, the EMF was scarcely influenced in the presence of inorganic ions such as K⁺, NO₃^-, and Cl^- up to 10^-4 mol, dm^-3 (Fig.9).

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Manganese(IV) oxide suspended in aqueous solutions is covered with acid and base surface hydroxyl groups, ≡MnOHa(a) and ≡MnOH(b). The hydroxyl groups form negative and positive sites ≡MnO^- and ≡Mn⁺, on the oxide surface, by dissociation (Fig.1). In this investigation, the difference in the surface concentrations of the charged sites, that is, the surface charge density, σ, was measured by acid-base titration of manganese(IV)oxide samples with and without heat treatment (Fig.3). The pH at which σ=0 (pzc) was higher for the heat treated sample than for the as received sample. The dissociation constant K_a, of ≡MnOH(a), and K_b, of ≡MnOH(b), were derived by considering the electrostatic effect of a on the dissociation: where ≡MnO^-.Na⁺ and ≡Mn⁺.NO₃^- are charged sites to which the cation and anion of supporting electrolyte (NaNO₃) are adsorbed, α_H and α_OH, being activities of H⁺ and 0H^- ions, and A_a and A_b being constants. The values of K_a, K_b, A_a, and A_b were determined from an analysis of the experimental σ-pH relationships. It is shown that K_a decreases while K_b increases, and A_a and A_b remain unchanged by the heat treatment of the oxide. The pzc is given by pzc=(pK_a +pK_w-pK_b)/2, where K_w is the ionic product of water, and p represents -log functions. The increase in pzc by the heat treatment is ascribed to both the increase in pK_a and the decrease in pK_b.

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In order to find out an effective adsorbent for removal of urea in blood, the urea adsorption properties of metal oxides, activated carbons, oxidized starch, and ion-exchange resins were examined in aqueous solution. Cation-exchange resins having sulfonic acid groups indicated the highest adsorptive activity for urea (Table 1). Besides commercially available strong acid cation exchangers such as Amberlite IR-120 B and Amberlyst 15, sulfonated p-vinylphenol-divinylbenzene copolymers carrying SO₃H groups exhibited a relatively high adsorptive capacity. For these resins, the amount of adsorbed urea was directly proportional to the ion-exchange capacity (Fig.2). Thus, the sulfonic acid group of the resin might participate in the urea adsorption. The adsorption of urea on Amberly st 15 was found to be of the Langmuir type (Fig.4). The amount of saturated adsorption of urea estimated from the Langmuir equation was close to the value of the ion-exchange capacity of the resin. The apparent heat of urea adsorption on Amberlyst 15 was estimated to be 12.5 kJ.mol^-1 at initial urea concentration of 35.7 mmol.l^-1 and at temperatures from 20 to 50°C. The FT-IR absorptiom spectra (Fig.6) suggested that urea molecules are attached to the ion exchangers through the bond between hydrogen atom of the sulfonic acid group of resin and the nitrogen atom of the urea molecule. Since the hydrogen bond thus formed is weak, the urea adsorption takes place reversibly.

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Adsorption isotherms and IR spectra of adsorbed methane were measured using silicalite, NaZSM-5 zeolites with different compositions (Si0₂/Al₂0₃=23.3, 38, 40.4, 49.8 in mole ratio), and HZSM-5 (Si0₂/Al₂O₃=23.3) as adsorbents. The adsorption was measured in the temperature range of 193-304 K and under pressure range of 6.7×10²-6.7×10⁴ Pa. The IR spectra were obtained at 226 K and under pressures of 1×10²-1.5×10⁴ Pa. The difference in the adsorption behavior of methane has been found between t he silicalite-CH₄ system and ZSM-5-CH₄ system: i) the isosteric heat of adsorption for the former system is much smaller than that for the latter system; and ii ) IR spectral intensity of the v_1.CH4 (-2885 cm^-1) for the former system is negligibly small while it is fairly large for the latter system. These differences are explained by the presence of strong cationic sites in the NaZSM-5. The IR intensity of OH stretching for the HZSM-5 is proportional to the intensity of the v₁ absorption, indicating that methane molecules are adsorbed on strong cationic sites. Other important information obtained are as follows: i) methane molecules tend to take a tripod orientation against the adsorption site at low coverages: ii) the mean electric field (1.0-2.5×10⁵ esu) in the zeolite pore and the mean life time of adsorption (6-9×10^-13s) little depend on the SiO₂/Al₂O₃ ratio.

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The method for preparing crystalline zirconium (IV) bis(hydrogen orthophosphate) monohydrate, Zr (HPO₄)₂. H₂0(α-ZrP), was established by the reaction of zirconium (IV) hydroxide (ZrO₂.nH₂0) or zirconium (IV) oxide(ZrO₂) with orthophosphoric acid in autoclave. In the ZrO₂.nH₂0 - H₃PO₄ and ZrO₂ - H₃PO₄ systems, the preparation of α-ZrP was mainly affected by molar ratio (P₂O₅/ZrO₂), heating temperature, heating time, and water vapor pressure in autoclave. The recommended method for the preparation of α-ZrP can be summarized as follows. A molar ratio P₂O₅/ZrO₂ is 1.2, heating temperature 175-200°C, heating time 5 h, and water vapor pressure over 10 atm. The formation of zirconium pyrophosphate, ZrP₂O₇, was predominant at more than 250°C and water vapor pressure of less than 8 atm.

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The investigation was made on the influence of dispersibility of carbon black added in slurry solutions in direct graphite furnace atomic absorption spectrometry of powder metal oxide. The oxides (Al₂O₃...3-6 μm, Fe₂O₃...2-3 μm in particle diameter) were ground, by an automatic analytical grinder and a titanium carbide mortar. The oxides were hydrophobicated with 1-dodecanol by chemical surface reforming and uniformly dispersed together with carbon black in various high-viscosity solvents by a ultrasonic agitator. The measurement of particle size was carried out by using a metal microscope. From the experimental results, it has been found that absorbance of aluminum oxide and iron oxide were increased about 1.5 times by addition of 0.5 w/v% carbon black in water and the positive interference of coexisting organic solvents (DMF, alcohols, etc.)could be avoided by addition of 1 w/v% carbon black. The dispersibility of the oxides were improved with increase of glycerol concentration, the coefficient of variation of aluminum oxide measurements being 4.3% (5 times determinations) and iron(III) oxide, 2.4% (5 times determinations) at 10% glycerol concentration. This improvement see ms to be caused by the increase of solvent viscosity by addition of glycerol. The sensitivity of aluminum oxide was improved to 0.54 ng/1% abs. and that of iron(III) oxide was O.21ng/1% abs. by addition of 1 w/v% carbon black.

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The chelate resin of malonica acid dihydrazide series which collects Cu²⁺ selectivelyw as synthesized by the polycondensation of malonic acid dihydrazide and formaldehyde in the presence of cellulose acetate, and the collecting ability for each metal ion of Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺ and Cd²⁺ was examined by a batch method. From each aqueous solution of pH 6.2 containing 500 ppm of metal ions, the collecting efficiency of Cu²⁺ was 99.8%(distribution ratio log, D=4: 8), and those of Mn²⁺, Co²⁺, Ni²⁺, Zn²⁺ and Cd²⁺ were below 20% (log D=1.8). The tendency of collection of these metal ions was Mn²⁺<Co²⁺<Ni²⁺<Cu²⁺>Zn²⁺>Cd²⁺. On the contrary, the collecting efficiency of Ni²⁺ and Zn²⁺ were more than 92% at pH 8-9. Mn²⁺ and Cd²⁺ ions scarcely interfered with the collection of Cu²⁺, whereas the Co²⁺, Ni²⁺ and Zn²⁺ interfered when they coexisted in a large quantity, and then the collecting efficiency of Cu²⁺ decreased to about 80%. The tendency of interference decreased in the order of Ni²⁺_??_Zn²⁺>Co²⁺>Cd²⁺_??_Mn²⁺. The collecting efficiency of Cu²⁺ were 91.3-99.2% (log D-=3.4-4.5) when the concentrations of Cu²⁺ were 10-100 ppm. and coexisting 10-500 ppm of Mn²⁺, Co²⁺, Ni²⁺, Zn²⁺ and Cd²⁺, respectively. The collecting efficiency of Cu²⁺ tended to lower as the concentration of Cu²⁺ was decreased and those of coexisting metal ions were increased.

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In the autoxidation of 3, 3'-methylenebis(guaiazulene) [A] at 100°C in HMPA (or DMF), eight products including two known compounds [A₂] and [E] were separated. All the new compounds [A₃], [A₄], [B], [C], [D₁], and [D₂] were derivatives of 8-(3-guaiazulenyl)3, 7-dimethylbenzofulvene whose structures were established on the basis of spectroscopic (UV, MS, IR, and NMR) data. Possible reaction pathways through radical reaction schemes are discussed for the formation of these eight products.

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The thermal decomposition of azetidine was studied below 1100 K and under the pressure of 1O^-3 Pa using a low pressure pyrolysis method (Table 1). Ethylene and methanimine were found to be main pro ducts (Fig.1). The stoichiometry of (CH₂)₃NH→C₂H₄+CH₂NH was established on the basis of mass balance of ethylene (Table 2). First order rate constants at various temperature were determined from conversion (Table 3). The three cases of biradical mechanism, k₂>k_-1, k₂=k_-1, k₂<k_-1, _were examined according to general procedure of RRKM calculation. In the first two cases, A factor was obtained by analogy with the decomposition of the oxetane (Table 4). In the third case, A factor was estimated from the entropy deference between the biradical and azetidine (Table 5) and activation entropy for the decomposition of the biradical (Table 6). High pressure Arrhenius parameters were given as follows (Fig.2), (Tables 7, 8). It can be concluded that azetidin e decomposes via biradical mechanism, and the heat of formation of the aminomethyl radicals, H_f298(H₂NCH₂.)=122±15 kJ.mol^-1, is derived from the kinetic data.

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The dipole moments were measured for 1, 1'-disubstituted ferrocenes to discuss the conformation of cyclopentadienyl rings.1, 1'-di-t-butylferrocene was concluded to be an equi valent mixture of five antiprismatic conformers (Fig.1), while the rotation of cyclopentad ienyl rings was considerably restricted in the case of 1, 1'-bis(triphenylmethyl)ferrocen e (Fig.3). For (triphenylmethyl)ferrocenes and their homologues, ¹H- and ¹³C-NMR spectra were examined and assignments of the protons and carbons of the cyclopentadienyl rings were determined. Further, the relation between the conformation and the chemical shifts was discussed. Consequently, various influences of bulky triphenylmethyl group for ¹H- and ¹³C-NMR chemical shifts were recognized.

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Polycarbosilane (PCS) is organic polymer which consists of the skeleton of Si-C bond. SiC fiber is produced from PCS by the processes of spinning, curing and heat treatment. PCS is obtained from polydimethylsilane (PS) through thermal decomposition and rearrangement reaction caused by heat treatment at a temperature above 450°C. Several reaction mechanisms in which PS was converted into PCS, have been reported. In these reports the reactions were considered to be radical rearrangement, by which Si-Si bonds are converted into Si-CH₂-Si bonds, and dehydrogenation condensation between SiH bond and SiCH₃ bond. Details and mechanism of the reaction, however, have not yet been clarifie d. In this work, the distillates with low molecular weight, which were obtained from PS through thermal reaction, were fractionated into 15 fractions (Table 2), and by the use of their IR absorption spectra, the reaction mechanism was discussed. The IR spectra of all the fractions obtained showed the peaks indicating Si-CH₂-Si bonds, and in a region below 1000 cm^-1, there were observed some of the peaks (Figs.4, 5, 6), which were not observed in PCS. Since the results of the IR spectra of the low molecular carbosilane suggested the presence of Sill, bond, it was considered that the main reaction was the dehydrogenation condensation between SiH₂ and SiCH₃ in the crosslinking reaction of PCS.

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Poly [iminocarbonyl (3-carboxy-1, 4-phenylene)carbonylimino-1, 4-phenylenemethylene-1, 4phenylene] (PA-1) was prepared by a low-temperature solution polycondensation of 4-chloroformylphthalic anhydride with bis(4-aminophenyl)methane in N, N-dimethylacetamide, and the PA-1 films were converted to poly amide-imide (PAI-1) films by heating. It was difficult to enhance the mechanical properties of PAI-1 films b y cold and heat drawing of PA-1 and PAI-1 films at a constant temperature. Therefore, two treatment methods were applied to PA-1 films. ( 1 ) The films were drawn in a DMF/H₂O mixture (40: 60, v/v) at 50°C and then heattreated under a tension of 0.78 MPa. The values of the tensile modulus, the strength at break and the breaking energy of the 3-fold drawn and heat-treated films (sample ( 4 )) were 5.6 GPa and 376 and 18.4 MPa, respectively. ( 2 ) The undrawn films were heat-treated at 200°C for 7 min and then heat-treated under a tension of 7.84 MPa (the temperature was raised from room temperature to 340°C at the heating rate of 15°C/min). The values of the tensile modulus, the strength at break and the breaking energy of the treated films (sample ( 6 )) were 6.6 GPa, 667 and 38.5 MPa, respectively. These values are about 2.5, 5.7 and 5.0 times as large as those of the undrawn PAI-1 films (sample ( 3 )). The values of the breaking energy and the strength at break of sample ( 6 ) were decreased to 29.3 and 555 MPa after 2 h heat aging at 250°C in air. These values are about 5.0 and 5.0 times as large as those of the sample ( 3 ) treated at 250°C in air. These results indicated that the drawn and heat-treated materials were suited for a durable use at around 250°C.

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Radical polymerization of styrene was carried out in the presence of methanol(non-solvent for polystyrene) at 60°C. At 30 vol% or above of methanol turbidity and precipitate were observed, but no turbidity was observed below 20 vol%. The kinetic orders of monomer and initiator were 1.4 and 0.5, respectively. The rate of initiation(R₁) was determined by an inhibitor method. The values for k_t/k_p² were derived from R₁ and the rate of polymerization (R_p), and from the relations between 1/P_n and R_p The value obtained by both methods showed a good agreement and increased with increasing methanol concentration. At the methanol concentration below 30 vol% k_t/k_p² was proportional to the reciprocal of the viscosity of the medium, but at 40 and 50 vol% of methanol the value deviated markedly from the relation. It is deduced that an increase in the encounter of propagating radicals in the presence of non-solvent could be responsible for the enhanced rate of termination.

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The dissociation of hydrated coordination of polyaluminium chloride is appreciably influenced by the hydrogen ion concentration. On this point of view, polyelectrolyte complexes (PEC) were prepared by mixing aluminium chloride hydroxide (PAC) with poly(potassium vinyl sulfate) (PVSK) at various concentrations of hydrogen ion and in different order of mixing. The aluminium content of PEC prepared at the lower hydrogen ion concentration is higher than that of the PEC prepared at higher hydrogen ion concentration. Yellowish and viscous precipitates were formed at pH 1.0 and 2.0, whereas white and powdery precipitates were obtained at pH 4.0. When the PAC solution was added dropwise to the PVSK solution at pH 4.0, two kinds of precipitates were produced. One of them consisted of a smaller amount of PAC and a larger amount of PVSK than the other one. The phase diagram (Fig.3) was obtained for PECs prepared at pH 4.0 (1-C in Table 1) in the three component system NaBr/acetone/H₂0. It was suggested that the P ECs obtained at pH 1.0 and 2.0 are the products consisting of aluminium aqua complex cation, which was formed by dissociation of the former, and PVS anion, whereas the chemical structure of PECs prepared at pH 4.0 could not be determined.

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Pulse and periodic reverse current platings of Pd-Ni alloy have been studied. The results revealed that the pulse plating, and particularly the periodic reverse current plating, can improve the properties of Pd-Ni alloy deposits. The deposit obtained by periodic reverse current plating with a cycling period of 10, -200 ms, a ratio of cathode pulse current to anode reverse pulse current 2-4, and a ratio of cathode pulse current on-time to anode reverse pulse current on time 0.5-5, is bright, smooth, compact and outstanding in the corrosion resistance. The study also demonstrated that the periodic reverse current plating is effective in decreasing grain size, smoothing surface, and improving the covering power of deposit. Moreover, we may control the composition of Pd-Ni deposit by periodic reverse current plating.

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Porous crosslinked poly[(chloromethyl)styrene]-silica gel composites were prepared by copolymerization of (chloromethyl)styrene and divinylbenzene adsorbed on the surface of silica gel. The composites were treated subsequently with triethylenetetramine in benzene. The resulting adsorbents, herein called composite adsorbents, were uniformly coated with polymer, and the specific surface area remained considerably large. In the adsorption experiments the composite adsorbents reve aled good mechanical strength and rigid property, and adsorbed various anions and metal cations rapidly. Their anionexchange capacities and adsorption capacities for metal cations were determined respectively. The rapid adsorption of the composite adsorbents is considered to be attribute d to their porous structure. This can be explained by the fact that the adsorption rate of Cr₂O₇^2- in-creased with increasing specific surface area. The composite adsorbent would be suitable for column operations.

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A vapour quenching of metallic elements is a useful means to investigate the potential metastable structures of alloys. Iron and tellurium metals were co-sputtered on the surface of polyimide film so as to prepare the condensed phases of mixed atoms of iron and tellurium. The effect of the atomic radius of the tellurium atom in a super saturated phase on a lattice constant suggests that a strong covalent bonding exists between iron and tellurium atoms in the form of CsCl type ordered lattice which has been obtained under the non equilibrium conditions. Figure 2 shows the phase diagrams of condensed films at various substrate temperatures. This indicates the effects of different numbers of thermal jumping of impinging tellurium atoms on the surface of a condensed phase. Figure 3 shows the crystallographic transformation of iron-tellurium alloy films of 0-50 at.% Te. Through the existence of metastable CsCl type ordering and virtual structures a topological continuity may be recognized to exist in the crystallographic structures.

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Usually, mercury in wastewater is removed by precipitation or adsorption method, but it is difficult to remove mercury if wastewater contains chelating agents. In this paper, the removal of Hg(II) in the presence of some ligands has been studied by using anion-exchange resin(Dowex A-1 8) chelate resin(Dowex A-1) and Sumi-chelate(chelate resin for mercury). In batchwise experiments, the presence of strong chelating agents interfered with the removal of Hg(II) by all the resins for peptone and by the chelate resin for EDTA in the pH 2-12(Fig.3). In the presence of halide ions, the extent of Hg(II) removal by the Sumi-che l ate or the chelate resin was nearly equal or less than that in the. absence of halide ions. On the other hand, Hg(II) was well removed by the anion-exchange resin, especially in the presence of KI (Figs.1, 2). Under such conditions, Hg(II) concentration was decreased from 10 mg/l to less than 0.4 μg/l by the anion-exchange resin (0.01 g/50 ml solution) even if EDTA or peptone was present (Figs.4-6). When Hg(II) solution (1 mg/l) containing EDTA (1 mmol/l) or peptone (5 g/l) was passed through a column packed with 2g of the resin, 30l (Sumichelate)and over 90l (the anion-exchange resin) of the treated solution containing les s than 0.5 μg/l of mercury were obtained by the addition of 0.017 or 0.17% KI. From these results, it is conculludgcl that, Hg(II) in wastewater can be effectively removed by the use of anion-exchange resin on the addition of KI even when wastewater contains strong chelating agents.

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To estimate the solubility of a compound in water from its total surface area(TSA) of a molecule, a modified Monte Carlo method was applied to the determination of the molecular surface area. About 500 points were distributed equally on the surface of each atom of molecule, and the number of points over the molecular surface were counted to calculate TSA of the molecule. The TSA calculated by this method had a good correlation with experimental water solubilities. Using an equation formulated from this relationship, the solubilities of 80 kinds of hydrophobic aromatic compounds were predicted and compared with experimental values. For 29 alkylbenzenes, the ratios of predicted water solubilities to the experimental ones were found to be 0.6-3, but this ratios become 0.1-10 for all the 80compounds investigated. In general, estimated water solubilities were smaller than the experimental values.

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Mercury(II) was separated and concentrated from aqueous nitrate of chloride media into six kinds of liquid surfactant membranes using the following pairs of extractants and surfactants. Dihexyl sulfide, 1, 2-bis(hexylthio)ethane and triisobutylphosphine sulfide were employed as a mobile carrier while L-glutamic acid dioleyl ester and Span 80 were employed as a surfactant. It was found that the liquid surfactant membrane containing triisobutylphosphine sulfide and L-glutamic acid dioleyl ester can much more effectively extract mercury (II) than other kinds of liquid surfactant membranes, i. e. it can lower the mercury(II) concentration in the external aqueous phase down to 1/2000 of the initial concentration(=5×10^-4mol.dm^-3) in one batch operation in the extraction from aqueous nitrate media within 15min.

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