The rate of solid-acid-catalyzed reactions are greatly enhanced by the presence of hydrogen in the system. Thus, the catalytic activities of prereduced silver-exchanged Y-zeolites (AgY)for the disproportionation of ethylbenzene and isomerization of o-xylene are several times higher than those of hydrogen Y-zeolites, but only in the presence of gaseous hydrogen. The enhancing effect of hydrogen was also observed for isomerization 1-butene and dehydration of alcohols over AgY. The similar enhancing effects of hydrogen on the catalytic activities are also observed in the conversion of methanol into hydrocarbons and the isomerization of 1-butene over prereduced form of silver dodecatungstophosphate.
A dramatic enhancement; was observed in the methanol conversion over the combination catalysts of transition metal (Pd or Pt)-heteropoly acid supported on silica.
Though the catalytic systems are versatile, there are some common features: The enhancement occurs only for acid-catalyzed reactions. The enhancing effect is reversible. The adsorption amount of hydrogen on the catalysts is small. These findings indicate, that there is interconversion of molecular hydrogen in the gas, phase and protons on the surface and the activities of the protons induced from gaseousiiydrogen are far higher than those of the protons from OH groups in zeolites or from parent heteropoly acids. The mechanism of the formation of highly-active protons is discussed.

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A continuous electro-regeneration system of ion-exchange resins is proposed, where cationand anion-exchange resin particles are simultaneously regenerated while flowing separately through anode and cathode compartments, with the help of hydrogen and hydroxide ions produced by the electrolysis of water.
To aid the development of re generator system, the regeneration characteristics of cationexchange resins were examined in a fluidized bed and in moving-bed reactors provided with electrode plates 100 mm in width and 500 mm in length.
An experiment with the batch fluidized bed re actor confirmed that sodium-form cationexchange resin particles were regenerated by the hydrogen ion to the extent of 40% at 450min. The current efficiency decreased, with an increase in the extent of regeneration, to 41% at 450 min. On the other hand, the extent of regeneration with the moving bed reactor reached the maximum value of 45% for the residence times of particle from 53 to 329 min under the conditions of steady state, the current efficiency having the minimum value of 60%. The electric current during the regeneration was more stable in the moving-bed operation than in the batch fluidized-bed operation.
A lumped parameter model si mulates the sequential changes in the variables measured in the batch fluidized bed, and estimates the steady-state values of the extent of regeneration and the current efficiency in the moving bed. The model also, suggests that the resistance to particle-liquid mass transfer is negligibly small and that the amount of hydrogen transferring through an anion-exchange membrane in the form of the hydrogensulfate ion is small in the moving bed but appreciable in the batch fluidized bed.

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For long-chain azobenzene derivatives containing different polar head groups and the chromophore in various positions of normal hydrocarbon chain (CAzoC, , , X, n and m: carbon numbers of the chains, X: polar group), the monolayer characteristics in the surface pressurearea isotherms and spectroscopic behaviors in the UV, visible and IR spectra of LB films have been studied to clarify the molecular arrangements in the films and their correlation with molecular structures and temperature. In the case of X= -COOH and -NHCH₂CH₂NH₂, stable condensed monolayers are formed and the azobenzene chromophores are closely packed with the long axis oriented almost vertically in the films. For X =-N⁺(CH₃)₂CH₂CH₂OH, the molecular orientation and packing are significantly dependent on the carbon numbers [n, m], temperature, surface pressure and the composition of the aqueous subphase. For example, the compounds of [6, 10] and [12, 5] give expanded monolayers at lower temperatures and the molecular long axes tend to incline. In addition, photoisomerization of the azobenzene derivatives in the mono- and multilayers has been examined. The cis→trans isomerization occurs predominantly, whereas the reverse reaction accompanied with an increase in the molecular area is significantly retarded due to the close packing of the chromophores. In the expanded monolayer at lower pressures, the reversible photochromism can be caused to some extent.

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The surface properties of the following four kinds of magnesia were investigated; i. e. MgO (I) supplied from Japan Catalysis Society, MgO(II) prepared by heating MgO(I) with water at 70-80°C for 3 h (called as hydrothermal treatment), followed by the calcination at 400-800°C, MgO(III) and MgO(IV) prepared by the impregnation of MgO(I) and MgO(II) in aqueous solution of NaOH and methanol solution of NaN₃, respectively, following by the calcination at 400-800°C. The sodium content in MgO(III) and MgO(IV) was 2 wt% respectively. The surface area of MgO(II), (III) and (IV) except MgO(I) decreased by the increase of calcination temperature as shown in Fig.1. Especially the extent of the decrease was noticeable in both MgO(II) and (III), prepared by using water. The larger surface area of MgO(II) was obtained by the calcination in vacuo rather than in air. The causes of th e higher values of the surface area, the basicity and the concentration of one-electron donor center of MgO(II) than MgO(I) may be ascribed to the irregularity of its crystalline state as observed in X-ray diffraction (Fig.2) and also to the removal of impurities such as halogen and alkaline metals (Table 2).
The basicity of magnesia sam ples was measured by the titration method with the solution of benzoic acid in benzene, by the irreversible adsorption of BF₃ and CO₂ with spring balance, the pulse methods (only in the case of CO₂) and the temperature-programmed desorption (TPD) method. The basicity of MgO(I) showed to be maximum by the calcination at 600°C except being maximum at 500°C in the case of BF₃ (Figs.3 and 4). The amount of adsorption of BF₃ was 2 or 3 times larger than that of CO₂, indicating that BF₃ appeared to adsorb on other sites than the basic one or with multilayer. The adsorbed amount of CO₂ by the spring balance method was larger (ca.2 times) than that by the pulse method as shown in Fig.5 and the adsorbed amount of CO₂ was correlated to the amount of the basic strength of pKa>15.0 in comparison with the results from the titration method (Fig.6). The order of the basicity of MgO(I) to (IV) by the pulse method was as follows: MgO(III)>MgO(IV)>MgO(II)>MgO(I) (Fig.7). In the case of the pulse method, CO₂ may slightly adsorb on the weak basic site, when compared with the results of TPD method (Fig.8), indicating the slow adsorption rate on the relatively weak sites. The stronger basic sites were obtained by the addition of sodium compounds, especially the superstrong basicity such as pKa>35 was found in MgO(IV). The stronger basicity was detected in MgO(III) and (IV) as seen in TPD experiments after CO₂ adsorption by pulse (Table 1 and Fig.9). The concentration of one-electron donor center increased in MgO(II) compared with in MgO(I) (Table 3). Thus the hydrothermal treatment of MgO(I) greatly improved the surface properties.

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From the polarographic behavior of copper(II), lead(II), cadmium (II) and manganese(II) in nitrilotris(methylene)tris[phosphonic acid] (NTMP, H₆L) solutions at an ionic strength of O.4 adjusted with sodium perchlorate, the species of the metal complexes and their stability constants were determined. In the pH ranges from 3.4 to 4.9 for copper, 3.5 to 4.5 for lead, 4.5 to 5.0 for cadmium and at pH 5.6 for manganese, the species of MH₃L^-, MH₂L^2- and MHL^3- were ascertained and the logarithms of their overall stability constants at 25°C were 5.6, 7.7 and 10.6 for copper complexes, 5.3, 7.0 and 10.1 for lead complexes, 3.6, 4.6and 6.7 for cadmium complexes, and 3.3, 4.4 and 5.7 for manganese complexes. Flotation of NTMP by complexing with iron(III) and the NTMP complexes of copper (II), lead(II), cadmium(II) and manganese(II) was investigated in a cell (20 cm×2.7 cm I.D.). Recoveries of 4.0×10^-4 mol⋅dm^-3 of NTMP and 1.6×10^-4 mol⋅dm^-3 of the NTMP complexes were 100%, and 98.8, 97.9, 92.8 and 81.2 %, respectively, using 1.2×10^-3 mol⋅dm^-3 of dodecylammon ium acetate(DAA) for the former and 8.0×10^-4 mol⋅dm^-3 of DAA for the latter as a surfactant at pH 7.0. 1420 ppm of Cl^-196 ppm of SO₄^2- and 3100 ppm of NO^3- did not interfere with the flotation. It seems that the flotation of NTMP and the complexes proceeds through the formation of the ion pair R_nIMH_??_L, where n=6-n-i, and R and n denote the cation of DAA and the charge of the metal, respectively.

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A rapid method using an iodide-selective electrode was proposed for the determination of lactalbumin, egg albumin and bovine serum albumin by potentiometric argentimetric titration of iodide ions, liberated in proportion to the amount of albumin at constant temperature when albumin was treated with an iodine-methanol solution.
The reaction ratios of standard amino acids to iodine, effect of amounts of iodine, effect of methanol, effect of temperature, effect of added sulfuric acid, effect of reaction time, effect of concomitant compounds and precision data of albumin were discussed.
Recommended procedure is as follows. A sample containing 0.05-60 mg lactalbumin, 0.470 mg egg albumin or 0.5-120 mg bovine serum albumin was taken into a 50 ml-titration cell and treated with 10 ml of 50 mmol⋅dm^-3 iodine-methanol solution. In addition, 3 ml of 1mol⋅dm^-3 sulfuric acid was introduced into sample solution. The volume was adjusted with distilled water to 50 ml which was then titrated potentiometrically with a 0.5-20 mmol⋅dm°C standard silver nitrate solution. The temperature was maintained at 30°C through these procedures.
By addition of sulfuric acid, potential jump of titration curve was enhanced. Lactalbumin (0.05-60 mg), egg albumin (0.4, -70 mg) and bovine serum albumin (0.5-120 mg) were determined with a coefficient of variation of less than 4.8% at 30°C. The calibration curves of lactalbumin, egg albumin and bovine serum albumin were shown by the equations of Y=0.285 X+ O.058 (r= O.999), Y=O.208 X-1-0.022 (r =0.999) and Y = 0.153 X-0.028 (r= 0.999), respectively; Y being the silver nitrate weight added in mg, X albumin weight in mg and r correlation coefficients.

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At pH 7.0 to 8.5 dodecylbenezenesulfonate up to 100 ppm. is completely coprecipitated with mixed hydroxides of aluminium and zinc or aluminium and copper(II) which are formed by adding sodium hydroxide to an equimolar (5×10³ mol⋅dm^-3) solution of aluminium and zinc ions or aluminium and copper(II) ions. The presence of 1×10^-3 mol⋅dm^-3 calcium, magnesium and sulfate ion slightly interfered the coprecipitation with the mixed hydroxide_ of aluminium and zinc. Dodecylsuifate and bis(2-ethylhexyl) sulfosuccinate (anionic surfactant)were also completely coprecipitated. However, benzethonium chloride (cationic surfactant)was coprecipitated less than 10% and Triton X-100 (nonionic surfactant) was not coprecipitated with the mixed hydroxides.

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Photochromic properties of 1′-(substituted benzy1)-3′, 3′-dimethy1-6-nitrospiro[2H-1-benzopyran2, 2′-indoline] were examined as a function of aryl substituents and solvent. The fading reaction kinetics in toluene follow a first-order relationship and a Hammett plot of the fading rate constant gave a linear correlation and the p-value was computed to be O.43. The fading reaction kinetics in ethanol were, on the other hand, resolved in two simultaneous first-order reactions with rate constants k1 and k2. Hammett plot of k1 gave ρ=0.35, while that of k2 afforded ρ2= -0.29. These results are interpreted as indicating that the initial fast fading reaction (k1) takes place from the merocyanine formed directly from the excited spiropyran but that the final slow fading reaction (k2) may be resulting from merocyanine-ethanol adducts which are formed by the reaction of the excited spiropyran with ethanol and gradually decompose to give the colored merocyanine.

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The quaternary ammonium salts containing polyfluoroalkyl group, RfCF₂CH₂N⁺R(CH₃)₂[2a-c-R]I^- (Rf=H(CF₂)n-, a;n=1, b;n=3, c;n=5), were synthesized by the reactions of N, N -dimethyl-1H, 1H, ωH-perfluoroalkylamines, RfCF₂CH₂N(CH₃)₂ [1a-c], with various alkyl iodides (RI, R=CH₂, C₂H₅, n-C₃H₇ n-C₄H₉); CH₃I^- reacted easily with [1a-c] to give [2a-c-CH₃]I^- in high yields (90-94%), while the yields of [2ac-R]I^- in the reactions with the other RI depended on the chain length of alkyl group of RI.
The reactions of [2ac-CH₃]X^- with bases were investigated. [2a-c-CH₃]X^- reacted easily with equimolar amount of aqueous NaOH solution at 20°C to give RfCF=CHN⁺(CH₃)₃X^- [3a-c]X^- quantitatively. The configuration of [3]X^- thus obtained was only Z-form. In the reaction with RONa (R=CH₃, C₂H₅) in the corresponding alcohol, Rf(RO)C=CHN⁺(CH₃)₃X^- [4a-c-OR]X^- were obtained in high yields as a sole product without formation of [3]X^-. The reactions with RSNa (R=CH₃, C₆H₅)n H₂O afforded RfCF=CH(RS) [5a-c-SR] and Rf(RS)C=CH(RS) [6a-c-(RS)₂] as main products. The product distribution ([5] and [6]) did not vary with difference of R in RS^- but was effected with chain length of Rf group in [2]X^-.

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The oxidation of ethylene with thallium (III) chloride in aqueous hydrochloric acid solution was investigated. The reaction proceeded very slowly, and almost no reaction took place under normal pressure.
Ethylene co uld be oxidized smoothly under high pressure and yielded 2-chloroethanol (ethylene chlorohydrin, ECH) along with the known products, ethylene glycol (EG) and acetaldehyde (AA). It was disclosed that the higher the atomic ratio [Cl^-]/[Tl³⁺] in the solution is, the higher the selectivity (and the yield) of ECH is. When the atomic ratio was high ([Cl^-]/[Tl³⁺]>10), EG and AA were scarcely formed and ECH was selectively produced. Maximum yield of ECH was about 90%.
The reaction feature by thallium(III) chloride differed from that by aqueous thallium (III) sulfate, nitrate, acetate or tetrafluoroborate. It was suggested that the reaction proceeds, by a similar route to the mechanism which was previously proposed for oxypalladation of ethylene by Henry.

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Nine novel diazaparacycloanthracenophanes [1a]-[1i] with different substituents on the bridged chains were synthesized from 9, 10-bis(chloromethyl)anthracene and 1, 4-his(N-substituted aminomethyl)benzenes (Fig.1). Their spectroscopic and photochemical properties were studied. The quantum yield of fluorescence of these compounds decreased (Table 4) in order of the degree of the disappearance of fine structure in the electronic spectrum, which implies the transannular π-electronic interaction (Fig.2 and Table 2). Among the derivatives with same kind substituents, their excited singlet lifetime was shortened, and the absorption maximum was bathochromically shifted in the similar order (Tablps 2 and 4). These results seem to reflect the effect of steric character of the substituents.

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The para-selective chlorination of alkylbenzenes has been investigated by using chemicallymodified silica gel catalysts. The catalysts listed in Table 1 were prepared by anchoring reactions as shown in Scheme 1. The effect of the type of the anchoring group on the plo ratio of chlorination of cumene was examined in carbon tetrachloride. The catalysts having dinitrobenzamide moiety showed high para-selectivity. Thus, SIL-17 and -18 gave the plo values of 4.38 and 4.82, respectively, whereas unmodified silica gel gave the value of 1.16. The solvent effect on the pia ratio suggested that the electrostatic interaction between the anchoring group and substrate and/or electrophile plays an important role for improvement of the para-selectivity. The activation of chlorine and the chlorination occur on the silica gel surface. The product distribution and the results of the competitive chlorination of alkyl- and halobenzenes with benzene showed the chlorination to be a typical electrophilic aromatic substitution. The chlorination of cumene and toluene without solvent was also examined. The catalyst, SIL-11, had good durability, and could be easily recovered by decantation for reuse.

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Curcuphenol [3] and its cyclized product 8-hydroxycalamenene [4], the naturally occurring phenolic sesquiterpenes, were synthesized.
Starting from 4-(2-hydroxy-4- methylphenyl)-4-oxobutyric acid [10], 2-methy1-6-(2-hydroxy4-methylpheny1)-2-heptanol [6], a precursor of [3], was prepared via 4-(2-methoxy4-methylphenyl)pentanoic acid [12]. The cyclodehydration of the tertiary alcohol [6] with the acid catalysts such as hydrobromic acid, p-toluenesulfonic acid, and polyphosphoric acid yielded a mixture of [4] and its isomer 5-hydroxy-4-isopropyl-1, 7-dimethyltetralin [5]. Each of the cyclization products was a diastereomer mixture. In the tetralin [4] the amount of cis isomer was slightly larger than that of trans isomer, and [5] consisted of about cis isomer 30% and trans isomer 70%.
In order to identify (±)-ci s-8-hydroxycalamenene [4], it was synthesized from the tetralone derivative [7] which was prepared from the carboxylic acid [12].8-Hydroxycadalene [9] was also synthesized from [7].

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Poly[imino(chloro-1, 4-phenylene)iminocarbonyl-1, 4-phenylenecarbonyl] (CIP-T) was prepared by low-temperature solution polycondensation of 2-chloro-p-phenylenediamine with terephthaloyl dichloride in the presence of lithium carbonate as the acid accepter in N-methy12-pyrrolidone (NMP).
It was difficul t to enhance the mechanical properties of C1P-T films by cold and heat drawings at a constant temperature. Therefore, the films were drawn at 30°C in NMP and then were heat-treated under a tension of 425 MPa (the temperature was raised from room temperature to 370°C at the heating rate of 25°C/min). The values of the tensile modulus, the strength at break and the breaking energy of 2.5-fold drawn and heat-treated films (sample 4 were 84.4, 1.51 GPa and 14.9 MPa, respectively. These values are about 42, 7.9 and 0.3 t imes as large as those of the undrawn films (sample 1 )).
The values of the tensile modulus, the strength at b reak and breaking energy of the sample (4) were changed to 87.1, 1.38 GPa and 11.2 MPa after 2 hours of heat aging at 400°C in air. These results indicated that the draw and heat-treated materials were suited for a durable use below 400°C.

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In order to clarify the effects of chemical structures of substituted groups on the thermal stability of isocyanurate and 2-oxazolidinone rings in the air, the kinetics of the thermal degradation of 1, 3, 5-tris(substituted phenyl)isocyanurates [1] and 3-(substituted phenyl)-5(phenoxymethyl)-2-oxazolidinones [2] have been investigated. By heating [1] or [2] under the flow of dry air at the temperature around 300°C, [1] was depolymerized into substituted phenyl isocyanate, and the cleavage of [2] proceeded through the formation of carbon dioxide and some intermidiates which were further decomposed, forming aniline, phenol, and various hydrocarbons. It was found that the thermal degradation of both [1] and [2] followed a first order reaction with respect to [1] or [2] (Fig.3), the apparant rate constants k were determined from the first-order plots for [1] or [2] (Tables 2, 3), and the activation energies and frequency factors were calculated (Table 4).
The thermal degradation rate constants k for [2] were larger than those for [1], and the thermal stability of [1] was higher than that of [2]. In the thermal degradations of both [1] and [2], ln k gave a linear plot with substituent constants a, and then Hammetts' p lots were proved to be valid. The constants p of the Hammetts'plots were positive in both reactions. From these results, it was concluded that the thermal stability was raised with increasing electron-donating properties, namely higher electron density of the carbonyl carbon and nitrogen in isocyanurate or 2-oxazolidinone ring.

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Oxygen permeability of La_1-xSr_xCo_1-yFe_yO₃ perovskite-type oxides was studied in the temperature range between room temperature and 870°C. Oxides which contain only La ions at A sites (x=0) scarcely permeated oxygen in the temperature range examined, while all the Sr-substituted oxides more or less showed oxygen permeability at temperatures above 500°C (Figs.3 and 4). The oxygen permeability was affected by both A site and B site compositions, though A site composition was more influential. With the increases in Sr and Co contents, the rate of oxygen permeation at fixed temperatures increased and the onset temperature of oxygen permeation lowered (Fig.4). The amount of oxygen desorbed from the oxide bulk, which was a measure of the amount of oxide ion vacancies, increased with increasing Sr content (Fig.6), showing that the promotion effect of Sr on the oxygen permeability is attributed to the formation of oxide ion vacancies. On the other hand, the amount of oxygen desorption was mostly independent on the B site composition (Fig.7). In this case, the increasing mobility of oxide ions in the crystal lattice with an increase in Co content seems to be responsible for the change of oxygen permeability. It has turned out that the present perovskite-type oxides have the rate of oxygen permeation, which was greater than that of calcia-stabilized zirconia by one or two orders of magnitude (Fig.8), and the sufficiently large oxygen permeation coefficient (Fig.9). These results indicate that the La_1-xSr_xCo_1-yFe_yO₃ are promising materials for the oxygen separating (extracting) membrane at elevated temperatures.

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Phase transition of magnesium phthalocyanine (MgPc) and its application to optical recording medium of DRAW type were investigated. λmax in the absorption spectrum of thin film (x1-type), obtained by treating vacuum deposited film with various halogenated solvents in-, culding chloroform, shifted from 820 nm to 690 nm upon heat treatment above 110°C. The change of the thin film and crystals treated with chloroform upon heat treatment by means of absorption spectrometry, DSC and X-ray diffractometry. It was found that the spectral change is based on the phase transition from xi-form to α-form through an intermediate phase. Coated film of xi-type associates of MgPc, dispersed in polymer matrix, was obtaind from the chloroform solution of MgPc and polymer such as poly(methyl methacrylate) and poly(ethyleneco-vinyl acetate). Depending upon the matrix polymer, the associated MgPc were found to dissociate into monomers and to be dispersed homogeneously in the matrix upon heat treatment. The irradiation of semiconductor laser light (wavelength: 830 nm, power: 3-10mW, beam diameter: 1 μm) on the vacuum deposited film and coated film of x1-type resulted the transmittance increase suggesting the possible application to an optical recording medium.

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The influence of sulfur by-products in viscose on the effect of viscose regeneration retardants has been studied by spinning of the so-called white viscose mixed with the usual viscose, or of the white viscose added with sodium sulfide or sodium trithiocarbonate. Cyclohexylamine (CHA) and polyethylene glycol 1500 (PEG) were added to the adove-mentioned viscose as a regeneration retardant. The white viscose which contains very little sulfur by-products was prepared by treating the usual viscose with anion-exchange resin.
The white viscose gives a low D-value in spinning and a high degree of swelling in gelfiber. The effect of either CHA or PEG as a regeneration retardant cannot be observed in case of the white viscose, but it increases with increasing mixing ratio of the usual viscose to the white viscose (Figs.2 to 4).
Addition of sodium trithiocar bonate to the white viscose exerts a positive influence on the effect of regeneration retardants (Figs.10 to 13), while the addition of sodium sulfide does not give influence on it (Figs.8 and 9). This shows that sulfur by-products in viscose, especially sodium trithiocarbonate, play an important role for the action of regeneneration retardant.
The content of bonded zinc per bonded sulfur in gel-fiber during spinning is lower under the conditions where the prominent effect of regeneration retardant appears (Fig.5). Based on these experimental results, a mechanism of the regeneration retardant is discussed.

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The influence of molecular weight of polyethylene glycol on its effect as a viscose regeneration retardant has been studied by spinning of the modified viscose containing 0.1 wt% of polyethylene glycol with molecular weight of 300 to 20000.
The effect of molecular weight on the D-value, bon ded sulfur content, swelling degree and load/elongation curve of undrawn gel-fiber is maximal in a molecular weight range from 1500to 4000 (Figs.2 to 5). The change of polyethylene glycol content in the gel-fiber during spinning is determined. It is found that polyethylene glycol with molecular weight of 1500to 4000 remains longer and more in the gel-fiber (Table 2).
Two chemical reactions of polyethylene glycol in acidic so lutions have been observed-precipitation reactions with tungustosilicic acid and with potassium hexacyanoferrate(II). Both precipitates are generated only in acidic solutions and the polyethylene glycol of lower molecular weight gives partly soluble, dense precipitates, while that of higher molecular weight forms immediately and efficiently bulk precipitates (Tables 3 and 4).
The mechanism of the regeneration retardation by polyethylene glycol is discussed based on the experimental results.

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The volatilization rates of trichloroethylene, 1, 1, 1-trichloroethane, and tetrachloroethylene from the water moving downstream in the inclined channel to the atmosphere were measured. together with the oxygen-reaeration rates. The concentration dropsof the chlorinated hydrocarbons from flowing water, attributable to their volatilizations were exponential with respect to the distance of downstream of the channel. The depletion rates, observed under the various flowing water conditions, agreed well with those estimated from the observed oxygen-reaeration rates and the volatilization coefficients of the chlorinated hydrocarbons, which is defined as the ratio of the volatilization rate constant of the hydrocarbons to the oxygen-reaeration rate constant. Therefore, if the oxygen-reaeration rate constant is available in a river, the volatilization rate of the chlorinated hydrocarbons in the river can be estimated by the multiplication of the oxygen-reaeration rate constant and their volatilization coefficients. The half distance, in which the concentration of the chlorinated hydrocarbons in the rivers drops by half, was discussed.

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At the reduction of cytochrome c mediated by Methylene Blue(MB) as a mediator in aqueous solution, β-cyclodextrin-1, 4-dihydronicotinamide (β-CD-NAH), which has a hydrophobic'cavity, showed higher catalytic ability than other model compounds by the influence of its hydrophobic cavity, because this reduction proceeds through a complex formation between MB. and β-CD-NAH. It was found that cyclohexanol acted as a competitive inhibito r, and the reduction of MB with β-CD-NAH was the rate-determining step in this reaction.

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The polymerization of methyl methacrylate (MMA) was investigated by use of cholesterol (Chol) as an initiating radical source. Chol showed initiating ability of polymeri zation in the presence of a small amount of Fe(III) salts, such as FeCl₃ or Fe₂(SO₄)₃ (the optimum ratio of Chol to Fe(III) salts existed; Fig.1), although the polymerization was not induced by Chol alone. The polymerization was inhibited by the addition of p-benzoquinone. The overall activation energies for the polymerization were estimated to be 42.9 kJ⋅mol^-1 (for FeCl₃ system) and 49.7 kJkJ⋅mol^-1 (for Fe₂(SO₄)₃ system), respectively. The kinetic study was made keeping the ratio of Chol to FeCl3 constant ([Chol]/[FeCl₃] =50; Table 1 and Fig.5), and the rate of polymerization (Rp) was given by the following equation:
Rp=k[MMA] [Chold-FeCl₃]^0.5
Radical initiating polymerization was as sumed to be produced through the redox reaction between the hydrogen at 17-position of Chol and Fe(III).

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Conformational analyses of 2′, 3′-O-methylene- [1], 2′, 3′-O-isopropylidene- [2], 2′, 3′-O-isobutylmethylene- [3], 2′, 3′-O-diheptylmethylene- [4], and 2′, 3′-O-diphenylmethyleneuridine [5] are examined by interpretation of proton magnetic resonance coupling constants and quantitative application of the nuclear overhauser effect (NOE). Dihedral anglesφ 1′, 2′ and φ 3′, 4′ in DMSO-d₆ at 22±1°C are slightly broadened in the order [1]>[2]>[3]≅[4]≅[5] because of the effect of steric barrier of alkylidene group. Under the same conditions, these compounds are found to exist primary in the syn-like conformation from NOE measurement. It is clarified that the population of the anti-conformation such as 2, 2′- and 2, 3′-anhydro nucleosides increases ([4]>[5]≅[3]>[2]>[1]) with the increase of bulkiness of the substituent of 2′, 3′-O-alkylidene group.

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