The behavior of hydroxyl groups in 4-or-5-substituted N-(2-hydroxybenzylidene)-2-hydroxy anilines [1] (5-position CH₃[a], H[b], Cl[c], NO₂[d], SO₃H[e], 4-position: NO₂[f]) was investigated by means of IR, ¹H-NMR, ultraviolet spectroscopies and potentiometric titration. It was found that the hydroxyl group at the 2'-position (on benzylidene ring)forms an intramolecular hydrogen bond with the nitrogen atom of azomethine group and the strength decreases in the order of [1a] > [1b] > [1c] > [1d] > [1f] > [1e]. The absorption bands of [1] in several solvents were observed around 36-44 x 10³ cm^-1 (the first band) and around 25-34 x 10³ cm^-1 (the second band). Since there is no clear relationship between the shift of these bands and the kind of substituents, both benzene rings seem to be little conjugated. The values of the pK₁ and pK₂ of [1a] - [1c], [1e] and [1f] measured in 75%dioxane aqueous solution at 25±0.2%°C were 9.3-10.0 and 9.8-12.7, respectively. The former corresponds to the dissociation of hydroxyl group at the 2'-position, and the latter at the 2-position (on aniline ring). The values of the pK₁ and pK₂ of [1d] were determined to be 8.37 and 8.71 correspond to the dissociation of the hydroxyl group at the 2-position and the 2'-position, respectively. [1d] was reversed to the dissociation of other [1] J mentioned above.

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Electrochemical behavior of nitrogen monoxide, nitrous acid, and nitric acid on platinum in aqueous sulfuric acid solutions was investigated using a stationary electrode, a rotating disc electrode (RDE), and a rotating ring disc electrode (RRDE). In 4-5 mol⋅dm^-3 sulfuric acid solutions, nitrous acid and nitrogen monoxide were reduced in three and two steps, respectively. An RRDE experiment showed that nitrous acid was reduced mainly to nitrogen monoxide, nitrous oxide, and hydroxylamine in the first, second, and third reduc tion steps, respectively. The RRDE technique was also applied to an investigation of the reaction mechanism of the autocatalytic reduction of nitric acid in the presence of nitrous acid. The Schmid mechanism, which involves the formation of nitrogen monoxide, was confirmed.

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The electrochemical behavior of a graphite fluoride electrode in an alkaline solution and the properties of its discharge products were investigated. Graphite fluoride treated with a concentrated KOH solution at 55°C was effective as a cathodic active material, since it had electrochemically active surface as a result of weakend C-F bond produced by the reaction with the solution. The flatness of open and closed circuit potential of the electrode was satisfactory, and conductive carbon was detected in the discharge products from X-ray diffraction patterns. The recovery of polarization potential followed the diffusion law, ΔE=K ln_??_. Fluoride ion concentration in an alkaline electrolyte was directly proportional to the quantity of discharged electricity. It therefore can be assumed that the rate determing step of the electrode reaction is the transfer of fluoride ion into the solution phase through the reaction products.

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The solid electrolyte cells using fluoride ion conductors were able to monitor oxygen partial pressure at such a low temperature such as 50°C. The cell(sensor element) consists of three components(Table 1, Fig.1); M/MF_m reference electrode(Ag/AgF, Pb/PbF₂, Sn/SnF₂, or Bi/BiF₃), solid electrolyte(LaF₃, BiF₃, or PbF₂), and sensing electrode(Pt, Pd, or Fe-Pc). The 90% response time of the electromotive force(EMF) of the sensors at 150°C was about 2 min during increasing oxygen partial pressure and about 5 min during decreasing, respectively. The response time became longer as the temperature decreases(Fig.2). The EMF of the sensor increased linearly with an increase in the logarithm of oxygen partial pressure, in accordance with the Nernst′s law (Figs.3 and 4). The slopes of the Nernst′s equation suggested 2-electron reduction of oxygen molecules at the sensing electrodes (Table 2). At a constant oxygen pressure of 1 x 10¹⁵ Pa, the EMF of the sensor increased linearly with temperature up to 100°C, although a departure from the linearity was observed at higher ternperatures(Fig.5). The behavior of EMF were explained by assuming the following electrode reactions; MF_m + me =M mF^- (reference electrode), 0₂ + 2F_??_ + 2e =2O_??_ + 2F^- (sensing electrode), where F_??_ and O_??_, oxide ion(0^-) located at the normal F^- sites of LaF₃ lattice, respectively(Fig.6).

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The mechanochemical reactions by grinding acicular particles of γ-Fe₂O₃, Fe₃0₄, Co-modified γ-Fe₂O₃ and Co-doped γ-Fe₂O₃ were investigated. Changes in magnetic properties (coercivity, magnetization flux density, and squareness), morphology (length and axial ratio), crystallite size, specific surface area, degree of transition to α-Fe₂O₃, heat-stability, and open-pore size were measured, Influences of grinding atmosphere (temperature, humidity, and oxygen partial pressure) on the mechanochemical reaction of γ-Fe₂O₃ and Fe₃O₄ were also investigated.
In the first stage of grinding, acicular particles were cut in the longitudinal direction to have lower axial ratios, 3-4 (Figs.9, 10). The coercivity and the squareness of γ-Fe₂O₃ and Fe₃O₄, decreased at first, and then increased gradually (Fig.6). The magnetization flux density decreased with the formation of α-Fe₂O₃ (Figs.6, 7). On grinding the various magnetic materials in an atmosphere (relative humidity =50%) at 20°C: γ-Fe₂O₃ obtained by dehydration of γ-FeOOH was most easily converted into α-Fe₂O₃, and the transition into α-Fe₂O₃ occurred easily in the order of γ-Fe₂O₃, Fe₃O₄ and Co-doped γ-Fe₂O₃, whereas it did not almost occur in the case of Co-modified γ-Fe₂O₃ (Figs.5, 7, 13). Co-modified γ-Fe₂O₃ is protected from the mechanochemical reaction by the layer of cobalt ferrite at the surface of each particle. In regard to the grinding atmosphere, the presence of water in air depressed the transition, and that of oxygen accelerated it, whereas the temperature did not affect it (Fig.14). Generally, the grinding effect becomes larger with increasing the specific surface area. It was clarified by investigating the influences of grinding atmosphere and the effect of Co-Fe surface treatment that the mechanochemical transition occurs from the surface (Figs.12-15).

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Chemical forms and sizes of plutonium(III)-, (IV)-, and (IV)- hydroxide precipitates formed in nitrate or chloride solution have been studied by alkalimetry and by filtration of the precipitates using filters of various pore sizes. In the deaerated nitrate or chloride solution containing 1.29 x 10^-2 mol⋅dm^-3 of plutonium(III), polymeric precipitate of [Pu(OH)₂]⁺was formed at pH higher than 6 or 7. On the other hand, in the cases containing 2.58 x10^-4mol⋅dm^-3 of plutonium(III) the polymeric hydroxides of 10-40 μm in diameter were precipitated in nitrate solution at pH about 3 and in chloride solution at pH 3 to 5 region, and in the cases containing 1.29 x 10^-6 mol⋅dm^-3 of plutonium(III) the above hydroxides were precipitated in both nitrate and chloride solutions at pH 2 or 3. As such a low concentration of plutonium(III) was easily oxidized to plutonium(IV) by oxygen dissolved in nitrate solution at a wide range of pH, the precipitates formed by hydrolysis of plutonium(III) was identical to that due to plutonium(lV). The oxidation rate of plutonium(III) in chloride solution was smaller than that in nitrate solution. In nitrate or chloride solution containing 1.29 x10^-6 to 1.29 x10^-2 mol⋅dm^-3 of plutoniurn(IV), polymeric precipitates of [Pu(OH)₂]²⁺ere formed at pH higher than about 2. The precipitates formed in chloride solution changed to polymeric precipitates of [Pu(OH)₃]⁺ by consuming one mol of hydroxide ion at pH 4 to 6 region. The sizes of precipitates formed in nitrate solution containing 1.29 x10^-6 and 2.58 x 10^-4 moledm^-3of plutonium(IV) at pH 10 were 5-20 and 1O-4Oμm in diameter respectively, whereas that of the precipitate formed at pH 4 was slightly smaller than those in the above cases. In nitrate and chloride solutions of plutonium(VI), PuO2(OH)₂ was formed at pH higher than 5. Although hydrolytic precipitate of plutonium(VI) was not produced even when plutonium (171) solution in a high concentration, e. g.6x 10^-3 mol⋅dm^-3, was used, PuO2(OH)₂ formed was quantitatively coprecipitated with hydrolytic precipitate of plutonium(IV) when plutonium (VI)/plutonium(IV) ratio was less than 0.2.

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Thermal decomposition kinetics of NiI₂ under constant I₂ partial pressure was studied by thermogravimetry. The reaction is considered as a reaction step of the thermochemical hydrogen production process in the Ni-I-S system. At temperatures from 775 K to 869 K and under I₂ pressures from 0 to 960 Pa, the decomposition started at the NH, pellet surface and the reactant-product interface moved interior at a constant rate until the decomposed fraction, a, reached 0.6. The overall reaction rate at a constant temperature can be expressed as the difference of the constant decomposition (forward) rate, which is proportional to the equilibrium dissociation pressure of NiI₂, and the iodide formation (backward) rate, which is proportional to the I₂ pressure. The apparent activation energy of the decomposition was 147 kJ⋅mol^-1, which is very close to the heat of reaction, 152 kJ⋅mol^-1 calculated from the equilibrium dissociation pressure. The electron microscopic observations, revealed that the reaction product obtained by decomposing NiI₂ under pure He atomosphere was composed of relatively well grown cubic Ni crystals. Whereas, the decomposed product obtained under I₂-He mixture was composed of larger but disordered crystals.

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Effect of addition of tungsten metal(W) on the magnetic properties of fine acicular CrO₂particles for high density magnetic recording media has been studied. To prepare fine acicular CrO₂ particles with high coercivity by hydrothermal decomposition of chromium oxide (Cr₂O_x) under high pressure oxygen atmosphere, the tungsten and tungsten compounds were added to the starting chromium oxide. The desired particles were obtained when tungsten, WO₂, WCl6, H2WO4 or Cr2WO₂ was added as a modifier. The coercivity of CrO₂ particles without modifiers was kA/m. On the other hand, the coercivity of the CrO₂ particles increased to approximately 40 kA/m when 1.5-2.0 wt% of tungsten was added, The particles were approximately 30 nm in width and the length-to-width ratio was approximately 8. The coercivity of these particles showed their maximum value when the average chromium valence ( x ) of the starting chromiuml oxide (Cr₂Ox) was approximately 4.9. Fine embryos (-20 nm) with rutile type crystal structure, which is the same crystal structure as CrO₂, were formed by addition of the tungsten before CrO₂ particles precipitated. It is thought that fine acicular CrO₂ particles were obtained because these fine embryos acted as crystal nuclei for growth of CrO₂ particles.

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The Raman scattering intensities of the 1600 cm^-1 band of ortho-alkyl-substituted nitrobenzenes, and of the 1600 cm^-1, the 1120 cm^-1 and the; 860 cm^-1 'bands of para-substituted nitrobenzenes were examined experimentally in view of analytical applications. The latter two bands are very intense and characteristic of para-suipstituted_Ritrobenzenes, though the assignment of them is not fully determined. From the similarity of the intensity behaviour between the 1600 cm^-1 'band, which is assigned to the ring stretqhing mode, and the NO2symnietric stretching band, it was inferred that the intensity change among the samples can be attributed not to the difference in the local electron density in the vibrating moieties but to the difference in the spatial extent of electron clouds in relation- to the irthaniolecular charge transfer. This suggests that resonance Raman effect contributes to the intensities. In view of this, the excitation wavelength dependnce of the intensities (the excitation profiles) were examined for para-substituted nitrobenzenes. It was shown that the intensities of the 1600 and the 1120 cm^-1 bands are enhanced by 1.2 to 3.0 times when the excitation wavelength changes from 514.5 to 457.9 nm, while those of the 860 cm^-1 band are enhanced by 1.0 to 18.9 times: The difference in the spectral patterns among the samples due to the reversal of the: relative intensities between the 1120 and the 860 cm^-1 bands was discussed in terms of the difference in the excitation profiles.

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Carboxymethyl Sephadex C-25 (medium) was converted to hydrazinocarbonylmethyl Sephadex(HD-Sephadex) by the reaction with hydrazine hydrate-ethanol solution. N′-(Dithiocarboxy)hydrazinocarbonylmethyl Sephadex (DH-Sephadex) was prepared by the reaction of HD-Sephadex with carbon disulfide in aqueous sodium hydroxide solution. Mercury (II), copper (II), lead (II), cadmium (II) zinc (II), nickel (II), cobalt (II) and manganese (II) were collected completely from 50 ml of 1 x 10^-5 mol⋅l^-1 solution of each metal salt over the pH range of 1.0-10.3, 3.5-8.4, 4.6-5.0, 4.7-8.2, 5.0-6.7, 5.1-8.6, 5.2-8.3 and 5.6-9.6, respectively, by stirring with 0.1g of DH-Sephadex for 30 min at room temperature. The separation of mercury from manganese was carried out as follows. Both 5.00 x 10-4 mmol of two metals were collected together by passing 500 ml of a mixed metal solution at pH to 6.8 through a column packed with 0.2 g of DH-Sephadex. Manganese was eluted with 1 x 10^-1 mol⋅l^-1 EDTA solution and then mercury left on DHSephadex was eluted with conc. hydrochloric acid. The separation of mercury from other metals such as zinc and lead was also successful by the similar procedure. The separation of mercury from cobalt was carried out as follows. Mercury was collected by passing 500 ml sample solution containing 5.00 x 10^-4 mmol each of these metals at pH 1.1 through a column packed with 0.1 g of DH-Sephadex. Then cobalt in the effluent was collected with an another fresh DH-Sephadex after readjusting pH to 6.6. Mercury was eluted with conc. hydrochloric acid and DH-Sephadex collecting cobalt was dissolved with a mixture of 30%hydrogen peroxide solution(0.5 ml) and 18 mol⋅l^-1 sulfuric acid(2ml) at about 90°C in the column. Similarly, quantitative separation of mercury from other metals such as manganese, nickel, zinc, cadmium and lead was also achieved.

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1-Azabicyclo[2.2.2]octane (ABCO) gave 1-arylsulfonyl-4-(2-chloroethyl) piperidines [2a-e] in good yields by the reactions with arenesulfonyl chlorides [1a-e] in benzene. The effects of reaction solvents (Fig.4), temperatures (Fig.2 and 3, Table 2), and the substituents on the arenesulfonyl chlorides were investigated. In the reactions, 1-[2-(1-arylsulfonyl4-piperidinyl) ethyl]quinuclidinium salts (e. g. [5]) were obtained as a minor product.1, 4Diazabicyclo[2.2.2]octane (DABCO) gave similar products [6a-e] by the reactions with arenesulfonyl chlorides. The reactions of [1a] with some other tertiary amines such as triethylamine, 1-methylpyrrolidine, 1-methyl and 1-ethylpiperidine, and 1-methylmorpholine were also investigated.4-Methylpyrrolidine gave N-(4-chlorobutyl)-N-methyl-p-toluenesulfonamide [7] in a good yield at 60°C in benzene but the other amines gave only a small amount, if any, of sulfonamides under the similar reaction conditions.

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The synthesis of 2-buten-4-olides by the dehydrochlorination of α-chloro-γ-butyrolactones, α-chloro-α-methyl-γ-butyrolactones, and α, α-dichloro-γ-butyrolactones with pyridine was investigated.
The dehydrochlorination of α-chloro-γ-butyrolactones gave the corresponding 2-buten-4-olides in satisfactory yields (58-85%).
The clehydrochlorination of γ-alkyl-α, α-dichloro-γ-butyrolactones gave 4-alkylidene-2buten-4-olides in 41-74% yields, while that of γ, γ-disubstituted α, α-dichloro-γ-butyrolactones afforded 4, 4-disubstituted 2-buten-4-olides in 57-82% yields. - A mechanistic pathway leading to the 4-alkylidene-2-buten-4-olide is presented.

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The photoinitiated cycloaddition of 1, 1′-bis (methoxycarbonyl) divinylamine (BDA) [1], a cross-conjugated dienamine, with various acetylenic and ethylenic compounds was investigated.
The photocycloaddition of BDA with substituted acetylenic [8a-d] and ethylenic [10a-g], [10m-n], [10r-t], [10w-x] compounds gave no 1: 1-adduct. The reactions with dicyanoacetylene [8e] and substituted ethylenes [10h-1], [10o-q] and [10u-v] afforded 7-azabicyclo [2.2.1] hept-2-ene [9] and 7-azabicyclo[2.2.1]heptanes [11h-l], [11o-q] and [11 u-v], respectively. The 1H-NMR studies of the products [11] showed that the addition occurred stereoselectively, retaining the original configuration of the olefins. The resulting compounds [9] and [11] are all novel 7-azanorbornane derivatives. The reactions are concluded to have three significant features; ( 1 ) in order for the cycloaddition to take place, the unsaturated compounds must bear relatively strong electron-attracting groups attached to both carbon atoms of the multiple bond. ( 2 ) The extreme decrease in electron density of the double bond deactivates the reagents ([10s-t], [10w-x]). ( 3 ) The reactivity decreases as the steric hindrance in the part of the unsaturated compounds increases.

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he ring-opening reaction of propylene oxide (PO) with dichloroacetic acid (DCA) was studied kinetically in aprotic solvents, acetonitrile, nitromethane and dioxane. The PO-DCA reaction was found to obey the third-order kinetics, dependent on the first order in the PO concentration and on the second order in the DCA concentration. Overall rate constants (l²/mol²⋅s) and activation parameters (ΔH^≠ (kcal/mol) and ΔS^≠ (e. u. )) at 40° were 2.02x 10_-4, 14.2 and -30.3. in acetonitrile, 1.32x 10_-3, 11.7 and -34.6 in nitromethane, and 7.63x 10_-6, 13.4 and -39.2 in dioxane, respectively. The overall reaction rate constant k₃ contains the preliminary equilibrium constant K in the protonation of PO by DCA in the form of k₃=Kk₃′, where k₃′ is an elementary reaction rate constant for the ring cleavage of the protonated PO. The constant k3' was estimated based on K, which was calculated as the equilibrium of PO with the solvated DCA. Elementary reaction rate constants (l/mol⋅s), activation enthalpies (kcal/mol) and activation entropies (e. u. ) at 40°C were obtained as follOWs3, .53 x 10_-5, 15.1 and -30.9. in acetonitrile, 2.92 x 10_-5, 12.4 and -39.8in nitromethane, and 0.241x 10_-5, 13.9 and -40.0 in dioxane. The behavior of the PODCA reaction is similar to that of the dipole-dipole SN2 reaction in view of the elementary reaction rate dependence on the solvent polarity. It was concluded that the 1: 1 complex of PO with DCA was activated to a less extent than that of PO with a stronger acid such as trichloroacetic acid and that the participation of two molecules of DCA was predominant in the transition state of the ring cleavage. The kinetic study of the PO-DCA reaction in. tetrahydrofuran. (THF) was difficult because THF acted as a nucleophile in the transition state. The PO-DCA reaction in both carbon tetrachloride and 1, 2-dichloroethane could not be kinetically studied probably due to the self-association of DCA.

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Poly(oxy-1, 4-phenyleneiminoterephthaloylimino-1, 4-phenylene) was prepared by lowtemperature solution polycondensation using N, N-dimethylacetamide as an organic solvent. In order to achieve enhanced mechanical properties of the films, the films prepared by casting were drawn in a 10% aqueous N, N-dimethylformarnide solution and heat-treated under various conditions. The mechanical properties were investigated by means of stress-strain curve, birefringence, and X-ray diffraction pattern. The values of Young′s modulus and strength at break of the films drawn and heat-treated under tension ([10]) were 8.6 x 10¹⁰ dyn/cm² and 75.8 kg/mm², respectively. These magnitudes are about 21 and 11 times as great as those of undrawn films.

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The sorption of phenol from the aqueous solution was studied using strong basic anionexchange resins of hydroxyl- or salt-forms. The following results were obtained.(1) The adsorption isotherm was Freundlich-type for the salt-form resins. In the hydroxyl-form resins, however, the same type isotherm was obtained for the phenol adsorbed over their ion-exchange capacities.(2) In the case of desorption by water, almost all phenol was desorbed from the salt-form resins. But, in the hydroxyl-forms, only the phenol over their exchange capacities was desorbed.(3) In dilute phenol solutions, the sorption rate was controlled by film diffusion, but, in solutions with high concentration, it was cotrolled by intraparticle diffusion.(4) In the mechanism of sorption by the strong basic anion-exchange resins, phenol was mainly adsorbed on the resins in the form of non dissociated molecule. When the hydroxyl-form was used, phenol was dissociated in the resins at a high pH, and ion exchange would take place. But, in the salt-form resins, phenol hardly dissociated, and ion exchange would not occur.

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A separation technique by means of solvent extraction with ion flotation, which is called "Solvent Sublation", was studied for removing metal ions from aqueous solutions of copper (II), uranium(VI) and chromium (VI) with concentrations ranging from 1 to 5 ppm. For choosing of a proper surfactant as well as an extractant, the respective metal removals in flow manner operation were examined at a steady' state in a 1 m-height column.
The structure of the column and the operating modes were discussed from the viewpoints of efficiency for metal removal as well as of stable operation. In case of the copper (II)removal, using dodecylbenzenesulfonate as a collector and LIX 64 N as an extractant, the efficiency was not very high. On the other hand, with uramium (VI) and chromium(VI) as oxoion, considerably higher removals were obtained using DEHPA and TOA, respectively, even in the absence of surfactant ion. Such behaviors would be interpreted in terms of flotability of colligends due to the contribution of an electrostatic potential at the surface of the dispersed gas bubble, whose charge turns positive to negative wit, h increasing pH. As a result, the removal efficiency of metals in solvent sublation depends on the flotability of each ion. In conclusion, such a solvent sublation is more practicable for the separation of oxoanionic metals in aqueous solutions.

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Relative retentions of 17 polycyclic aromatic hydrocarbons (PAHs) to nonadecane (R_t1/R_t2)were determined by isothermal gas chromatography on an Aporane C87 column at every 10°C from 110 to 270°C. The relative heat of vaporization of PAHs (ΔH₁/ΔH₂) was obtained by plotting ln(Rt1/R, 2) against logarithm of the vapor pressures of nonadecane (InP₂). Then, the vapor pressure {(p₁)₂₅} and the heat of vaporization {(ΔH₁)₂₅} of each PAH at 25°C in the supercooled liquid phase were calculated from these results using the absolule vapor pressure and the heat of vaporization of nonadecane (ΔH₂) at 25°C (equations 5, 6). The (P₁)₂₅ and (ΔH₁25₂) values thus determined agreed with those calculated from the vapor pressure and the heat of vaporization at 25°C in the solid phase (Tables 3, 4). The behavior of PAHs in the atmospheric environment such as adsorption of PAHs on particulates, and the ratios of PAHs in the vapor phase to those in the particulate phase, were well explained on the basis of (p₁)₂₅ and (ΔH₁)₂₅ values in the supercooled liquid phase (Table 5).

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Many heavy metal ions and some noble metal ions are known to be adsorbed on activated carbon as complex anions or reduced forms. In this paper, the effect of SCN^- concentration on the adsorption of Cu²⁺ on activated carbon and oxidation state of copper in the equilibrium solution were investigated. Furthermore, the reduction of Cu2+ by activated carbon was studied by the use of fractional solvent extraction method of Cu⁺.
The total amount of residual copper after the adsorption showed a minimum in the range of SCN^- concentration from 10^-2 to 10^-1 mol/l and it was not agreed with the distribution curve of copper(11) complexes (Fig.4). The amount of residual Cu²⁺ was agreed with the total residual copper at the SCN^- concentration below 10^-3 mol/l, but it was negligeble at the SCN^- concentration higher than 1 mol/l in spite of the absence of activated. carbon (Fig.5). Moreover, it was proved that Cu²⁺ was reduced to Cu⁺ by activated carbon in the presence of SCN^- (Fig.6). From these results, it is concluded that Cu²⁺ is reduced to Cu⁺ by activated carbon and then Cu⁺ is adsor bed or precipitate: as Cu(SCN) at low SCN^- concentration because of its low solubility (pK_sp =14.3). At the SCN^- concentration higher than 1 mol/l, Cu²⁺ is reduced to Cu⁺ in the presence or absence of activated carbon and Cu+ forms a [Cu(SCN)₂]- complex anion (log β₂=11). At this concentration, adsorption of Cu(SCN) or [Cu(SCN)₂]- will be interfered with SCN- anion.

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The potentiometric bienzyme electrodes for glucose and choline were developed. The enzyme electrodes were constructed by cross-linking glucose oxidase or choline oxidase and peroxidase with bovine serum albiimin using glutaraldehyde on a platinum plate electrode silanized with (γ-aminopropyl) tri-ethoxysilane. It was found that the electrodes were sensitive to redox potential which depended on the change in the concentration ratio of hexacyanoferrate(III) to hexacyanoferrate(II) in the enzyme layer -caused by the enzyme reactions. A plot of the potential vs. log[substrate] gave a straight line for 0.02-0.6mmoldm-3 glucose and 0.007-0.18 mmol·dm^-3 choline, respectively. The response time was only 10 s and electrodes could be used repeatedly at room temperature for at least two months.

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We determined the number of silanol groups of four porous glasses with different pore structures by means of the Grignard method. They were prepared from borosilicate glasses by acid-leaching. The number of silanol groups was 1.945 mmol/g for the glasses with the pore radius of about 100 A and the pore volume of 0.938 ml/g, but was 0.681 mmol/g for those with the pore radius of about 20 Å and the pore volume of O.263 mug. The latter was about one-third as small as the former. On the other hand, the TGA measurements for both glasses gave almost the same weight loss due to the condensation of silanol groups. It is considered that the glasses with smaller pores give numbers of silanol groups lower than those expected from the surface area of micropores because the diffusion of Grignard reagent molecules into micropores may be inhibited.

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The chemical equilibria of bis(trifluoroacetylacetonato)nickel(II) in dimethyl sulfoxide were studied on the basis of the concentration dependence of UV spectrum, the molar conductivity curve, and the d. c. polarographic behavior. The chemical equilibria considered were
[Ni(bi-tfac)₂]⇔ [Ni(bi-tfac)(uni-tfac)] ⇔Ni(tfac)⁺+tfac^-,
where bidentate and unidentate are abbreviated as bi- and uni-, respectively. The chemical equilibria shifted upon the addition of supporting electrolyte, O.05 mol·dm^-3 TBAP.

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