Numerous observations have been reported on the inhibition of calcium carbonate deposition in aqueous solutions by addition of trace amounts of polyelectrolytes (polymers), but the mechanism of the inhibition has not been well explained yet. This investigation was planned to clalify the effects of the structure, molecular weight and chemical properties of polymers on the inhibition mechanism.
Fourteen kinds of polymers having molecular weight from 600 to 25000 and the different functional groups (carboxyl, hydroxyl and sulfo) are employed to examine their chelating ability towards Ca²⁺ ions and the ease of gelation as a function of their concentrations in dilute Ca²⁺ solutions. The results obtained were correlated with the prevention behavior of calcium carbonate deposition. It was found that ( 1 ) the chelating ability for Ca²⁺ ions increases and ( 2 ) the gelation of polymers is facilitated, as its molecular weight is increased. The chelation seems to act to inhibit the calcium carbonate deposition due to surface blocking action while the gelation leads to a reduction in the effective polymer concentration in solution. Because of the competitive functions of chelation and gelation, the maximum efficiency of inhibition was found at the intermidiate molecular weight around 4000. Both chelation and gelation are facilitated with increasing number of carboxyl groups but are retarded by introducing hydroxyl and sulfo groups.
In conclusion, polymers with high inhibiting ability for scale formation, can be designed by controlling the molecular weight and chemical structure so that high chelating ability and low gelation tendency are obtained.

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Inhibitory effects of reduction have been studied on the hydrolytic decomposition of 12-molybdophosphoric acid (PMo₁₂) in concentrated aqueous solutions, and the mechanism has been suggested to account for these effects.
As the degree of reduction increas es, the decomposition of PMo₁₂ is observed at higher temperatures in the constant PMoconcentration (Table 1) or in higher concentrations at a constant temperature of 90°C (Fig.2).
67 wt% solutions of PMo₁₂ at the degree of reduction of 4 did not form any precipitates even at 130°C.
¹³P-NMR and X-ray diffraction studies have elucidated the decomposition mechanism in reduced PMo₁₂ solutions that the nonreduced PMo₁₂ and its partially hydrolyzed species in reduced solutions are converted to 18-molybdodiphosphoric acid (P₂Mo₁₈) resulting in the precipitation of molybdenum oxides, while β-PMo₁₂(IV), α-PMo₁₂(II) and β-PMo₁₂(II) do not form their partially hydrolyzed species reflecting no direct formation of P₂Mo₁₈ through them are not expected.
The formation rate of P₂Mo₁₈ decreases with increased degrees of reduction and falls to zero at the degree of reduction of 4 (Fig.4), while the concentration of PMo₁₂ has small effects on the formation rate of P2Mo15 (Fig.3). Two signals at ³¹P-NMR in aqueous solutions of reduced PMo₁₂ are attributed to a mixture of β-PMo₁₂(II) and β-PMo₁₂(IV), and to a mixture of α-PMo₁₂(0), its partially hydrolyzed species, and α-PMo₁₂(II) (Fig.5).
The addition of 50% water-dioxane to the aqueous solutions could separate their signals and permitted quantitative measurements of the existing chemical species.
Then, the dependence of the degree of reduction on the compositi on of species was determined (Fig.8).
The concen tration of nonreduced species shown in Fig.8 is considered to be related to the formation rate of P₂Mo₁₈ or to the hydrolytic stability.
The P₂Mo₁₈ formed in reduced PMo₁₂ solution s exsists as reduced species which are also stable against the decomposition (Scheme 1).

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The preparation and properties of, a support material consisting of lanthanoid oxides and alumina have been studied for use as combustion catalysts at high temperatures. Mixtures of lanthanoid oxides and alumina were prepared by means of coprecipitation method. The specific surface area of the support with La content of 5 mol% was 37 m²/g when calcined at 1200°C for 2 h (Fig.1), and the only product identified by X-ray diffraction analysis was lanthanum β-alumina (La₂O₃.11-14 Al₂O₃) (Fig.4). Addition of Pr or Nd into Al₂O₃ gave rise to the formation of β-Al₂O₃-type compounds having specific surface area of about 20 m²/g (Fig.10). La, Pr, or Nd addition retarded the transformation of γ-Al₂O₃ to α-Al₂O₃ and associated sintering. However, addition of Y, Sm, Gd or Dy mainly gave perovskite type compounds, having specific surface area of less than 10 m²/g.
β-Al₂O₃-type compounds showed high surface area and were resistant to the thermal sintering above 1000°C.

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The reaction products of gaseous HfCl₄ with ammonia at 260-4400°C and the possible reactions during the above process were examined. From the results, the formation process of hafnium nitride by the vapor-phase reaction was discussed. Further, the properties of the hafnium nitride formed were examined.
The reaction producte of gaseous HfCl₄ with ammonia were HfCl₄·2NH₃ at 260°C, HfCl₄·2NH₃ and HfClN at 280-800°C, HfCl₄·2NH₃, HfClN, GfNX and Hf₃N₄ at 900°C, HfCl₄·2NH₃, HfNX and Hf₃N₄ at 950-1100°C, HfNX and Hf₃N₄ at 1200°C, and HfNX above 1300°C, as shown in Table 1. Above 1100°C, HCl was also formed by the decomposition of the byproduct, NH₄Cl. The reaction of gaseous HfCl₄ with ammonia is considered to start with the formation of HfCl₄·2NH₃, which reacts with ammonia to form HfClN above ca.270°C. The HfClN reacts with ammonia to form HfN, and Hf₃N₄ above ca.850°C. The HfNs is also formed by the decomposition of the Hf₃N₄ above ca.1200°C. The atomic ratios of N/Hf, x, of the HfN_x formed at 1300 and 1400°C were 1.19 and 1.15, respectively. The HfN_x formed at 1300-1400°C was uniform and ultrafine powders with the particle diameters of the order of 1/100 μm (Fig.3). The value of x decreased on heating HfN_x(x=1.19) formed by the vaporphase reaction at temperatures higher than 1000°C in an argon atmosphere and became close to that of the stoichiometric hafnium nitride being 1.02 at 1300-1400°C (Fig.4). The variation of lattice constants of HfN_x obtained in this work with the values of x was also shown in Fig.5.

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Pentaamminecarbonylruthenium(II) chloride was obtained by the controlled-potential electrolytic reduction of pentaamminechlororuthenium(III) chloride in aqueous formic acidsodium formate solutions. The spectral measurement with an optically transparent thinlayer electrode cell suggested that the reaction preceeded through pentaammineformatoruthenium(II). The kinetics of the reaction was studied polarographically at 25°C in the formate solutions containing chloride ions with the ionic strength of 0.5 mol·dm^-3. The results were explained by postulating a rate-determining step in which pentaammineformatoruthenium(II) in equilibrium with the aqua-and pentaamminechlororuthenium(II) species was converted into the carbonyl complex. The rate-determining step, was found to be accelerated by hydrogen ion and formic acid.

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The sphering of pullulan and its application to aqueous gel chromatography as a packing material were studied for the first time in the world. Pullulan spheres were prepared by the sphering of pullulan triacetate by means of the suspension and evaporation method, followed by the saponification and the crosslinking with epichlorohydrin. By adjusting the preparation conditions, pullulan spheres with the exclusion molecular weight 10³ to 10⁶ can be produced. In addition, the packing exhibits almost no interactions with sample substances, e. g. poly(oxyethylene) and pressure-resisting property. These favorable properties are attributable to the molecular structure of pullulan and the low swellig degree of pullulan spheres.

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The reactions of N'-cyano-S-methylisothioureas [1] with amines in the presence of copper (I) chloride were investigated. When the reactions were carried out under nitrogen atmosphere, the methylthio group of [1] was substituted by amines to give N"-cyanoguanidines [2]
On the other hand, addition of amines to cyano group of [1] proceeded, upon exposure to air, to form copper (II) ncomplex of N'-amidino-S-methylisothioureas[3]. In the presence of copper(I) chloride and air, [2] and N-cyano-O-ethylisourea [5] reacted with butylamine to give the corresponding biguanides [6] and N-amidino-O-ethylisourea [8]respectively. The mechanism of these reactions was discussed.

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Reactions of 2-chloromethyloxirane [1] or 2-phenyloxirane [2] with ammonium carbamates formed from carbon dioxide and aliphatic primary or secondary amines in methanol gave corresponding carbon dioxide incorporated carbamate derivatives.
3-Alkyl-5-hydroxytetrahydro-2 H-1, 3-oxazin-2-ones [3]-[5] were synthesized by intramolecular cyclization of 1-alkylcarbamoyloxy-3-chloro-2-propanol produced by the attack of carbamate anion to [1]. The attack of carbamate anion at 2- or 3-position of [2] afforded the mixture of linear carbamic esters [8]-[11].
The structure of [3] was deduced by IR, NMR, and Mass spectral data, and by alternative synthesis of [3] from 3-chloro-1, 2-propanediol [7]. The mechanisms for the formation of 3-alkyl-5-hydroxytetrahydro-2 H-1, 3-oxazin-2-ones and carbamic esters formation are discussed.

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It was found that N-[(methylthio)carbonyl]-N-trimethylsilylcyanamide(TMS-MCC)dimerized imediately incontact with water to form N-cyano-N, N'-bis[(methylthio)carbonyl]guanidine (D-MCC). This dimerization reaction proceeded smoothly at room temperature in benzene, cyclohexane or carbon tetrachloride. On the other hand, only the monomeric compound, [(methylthio)carbonyl]cyanamide (MCC), was obtained in such solvent as diethyl ether, tetrahydrofuran or dioxane. Bis[N-cyano-N-[(methylthio) carbonyl]amino]dimethylsilane (DMS-MCC) afforded D-MCC more easily. In contrast with TMS-MCC, trimethylsilylated ethoxycarbonylcyanamide (TMS-ECC) did not dimerize under the same conditions. Trimethylsilylated cyanourea (TMS-CU) reacted with cyanourea (CU) to form (N-cyanoamidino)urea
When TMS-MCC or TMS-ECC was allowed to react with amine, addition to cyano groups occurred and the corresponding guanidine derivatives were obtained.

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The effects of phenol derivatives as additives were studied on the liquefaction reaction of coal in tetralin (400°C, 30 min, 40 kg·cm^-2, in N₂).
The calculated effectiveness values of phenol derivatives were in the order: 1, 2-(OH)₂>2, 6-Bu₂^t>4-Bu^t>4-Me>1, 3-(OH)₂>unsubstituted >3-Me>2, 4, 6-Bu₃^t >2, 4, 6-Me₃>2-Me >2, 6-(MeO)₂>2-MeO-4-Me>2-Ph>2-Bu^t>2, 6-Me₂>4-Me-2, 6-Bu₂^t.
The addition effects were found to be affected by the OH bond dissociation energies in additive phenols and the formation of hydrogen bonding between additives and ether moieties in coal. Solvent refining coal obtained through the liquefaction reaction in the presence of an additive gave less amount of char on standing than that in the absence of an additive.

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Two-stage hydrocracking of heavy distillate in a coal liquid was studied to find a procedure to crack long-chain (C₁₈-C₃₀)p araffins contained in the distillate (the content: 23 wt%); under hydrogen pressure of 150 atm at 380°C of the first stage with a commercial Ni-Mo/Al₂O₃ catalyst (HDN-30) and at 420°C of the second stage with HDN-30 and silica-al umina (low alumina) catalysts. A single-stage hydrocracking of the distillate at 420°C with HDN-30alone or HDN-30 and silica-alumina cracked only 21 or 41%, respectively of C₂₅₊ paraffins. The two-stage reaction was very effective to crack their 61% principally into C₁₁-C₂₀ paraffins with least amount of dry gases (-3%). The first stage hydrogenated extensively polar and aromatic fractions in the distillate. Such fractions may be strongly adsorbed on the acidic sites of the catalyst to prohibit the interaction of paraffins with the catalyst. However, their hydrogenation, hydrodenitrogenation or hydrodeoxygenation weakens their adsorption to allow the cracking of long-chain paraffins on the acidic sites in the second stage. The reaction of model mixture of pentacosane and fluoranthene or tetrahydrofluoranthene under the same conditions confirmed the scheme of the single- and two-stage hydrocrackings described above. A better hydrogenation catalyst (KF-840, Nippon Ketjen Co., Ltd. ) with the aid of silica-alumina increased the conversion of C₂₅₊ paraffins in the distillate up to 75%in the two-stage hydrocracking.

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The binding mechanism of copper chlorophyllin (Cu-chin) with poly(N-vinylpyrrolidone)(PVP) was analyzed by use of Scatchard plot and the existence of cooperative binding was clarified. Addition of Cu-chln to PVP aqueous solution increased the viscosity drastically. This increase of viscosity can be restrained by addition of urea. This fact indicates the correlation between viscosity increase and formation of hydrogen bond. The activation energy was estimated by the measurement of temperature dependence of viscosity of PVP-Cu-chln mixture solution, and it was found that activation energy was increased with Cu-chln. concentration.
Viscoelastometry of PVP cast film showed that the position of main dispersion peak did not shift to higher temperature but to lower temperature side in the presence of Cu-chln. This phenomenum is due to the reason that the water molecule, bridged between Cu-chin and PVP, was evaporated by casting and the segmental motion was allowed to occur in the narrow region arround Cu-chin.

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A thermosetting resin consisting of the polycondensed fused-polynuclear aromatic structure was tried to prepare by heating the mixture of fused aromatic hydrocarbons (Aro), 1, 4-ben zenedimethanol (PXG) as a cross-linking agent, and acid catalyst.
The Aro used is a pyrene/phenanthrene (7/3 in molar ratio) mixture. The PXG/Aro mixture (0.50-2.00 in molar ratio) was heated with p-toluenesulfonic acid (5 wt%) in argon.
The reaction began at 120°C and was accelerated with increasing temperature.
It was suggested from IR, NMR, elemental analysis etc. that the reaction is electrophilic substitution between aromatic nucleus and benzyl cation derived from PXG. An infusible and insoluble material after curing was obtained from the raw mixture with larger PXG/Aro ratio than 1.00.
The reaction wi th PXG/Aro molar ratio 1.2 5 at 120°C for 65 min were most suitable to prepare the B-stage resin which is solid at room temperature and fuses by heating. The resulting B-stage resin showed ca.75°C of softening point and was soluble into such organic solvents at THF and quinoline.
A mould of B-stage resin became completely infusible and insoluble after heating at 120°C for 20 h and subsequent post-curing at 200°C for 1 h. The post-cured resin exhibited scarcely weight loss on heating up to 500°C at a heating rate of 10°C/min in air and nitrogen.

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Water-insoluble polyelectrolyte complex (PEC) consisting of methyl glycol chitosan (MGC), (carboxymethyl)dextran (CMD), and poly(vinyl sulfate) (PVSK) was prepared in the solution of 1.10 mol·dm^-3 HCl, and was casted into the PEC membrane from 1, 4-dioxane-hydrochloric acid solution. Transport phenomenon through the PEC membrane was investigated under various conditions. The transport ratio of Na⁺ and the electric potential difference between left and right sides of the membrane were measured. As the result the transport ratio was high when the membrane potential difference was large and was maintained for a long time. From that result, it was revealed that the driving force of transport depends on the membrane potential, Donnan potential and diffusion potential between both sides of the membrane. Cl^- exclusion (Donnan exclusion), however, was small owing to a small cation- exchange capacity (0.17 mequiv./g dry membrane). Therefore the membrane potential difference was decreased rather rapidly by Cl^- permeation (Fig.1). In addition, the transport ratio of Na+ and the membrane potential difference were also measured in the case that poly(styrenesulfonate)ion was used as a counter ion, i. e., all negative charges were fixed in one side of the membrane, and were compared with those in the case of HCl.

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Although it is difficult to use organic peroxides as the photoinitiator of imaging materials since they have sensitivity only in a short wavelength region of ultraviolet light (ca.290 nm), the range of their spectral sensitivity was extended toward longer wavelength region (500-600nm) by the addition of a sensitizing dye such as quinoline, thiazole, xanthene or merocyanine dye. The authors prepared photopolymerizable composite materials of binder polymer[poly (N-vinyl-2-pyrrolidone)] (PVP), multifunctional monomer (pentaerythritol tri acrylate), organic peroxide and sensitizing dye layers and their photographic properties initiated by organic peroxide spectrally sensitized with organic dye were investigated under ultraviolet, visible light and laser exposure. The photographic sensitivity was evaluated by the rate of photopolymerization in solid polymer matrix. The sensitivity of photopolymer which was initiated by di-t-butyl diperoxyisophthalate sensitized with 2-(p-dimethylaminostyryl)benzothiazole was 300 μJ/cm² for 488 nm argon laser light under an inart atmosphere. The photopolymer was found to follow the reciprocity law. The test pattern image could be obtained by the laser scanning exposure system at the following conditions: laser power was O.8 W, beam diameter was 25 μn, wavelength was 488 nm and scanning speed was 11.1 m/s. The initial rate of photopolymerization of acrylate monomer in solid polymer matrix was found to follow the equation derived from the kinetics of radical polymerization in solution. The rate of photopolymerization corresponded considerably to the sensitivity characteristics of photosensitive layer. In the solid polymer matrix, such as PVP, poly(oxyethylene) and poly (vinyl alcohol), the rate of photopolymerization was much higher than those obtained in other polymers such as poly(butyl methacrylate), poly(vinyl butyral), poly(α-methylstyrene)because of the interaction between the binder polymer and the monomer.

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Thermal desorption characteristics of organic solvents from activated carbon beds were investigated. Each organic solvent was desorbed with a nitrogen gas flow under various heating conditions. A part of the desorbed gas was sampled for analysis by a gas chromatograph at 1 to 2 min intervals. The rest of the desorbed gas was collected in a Tedlar bag. After the heat treatment for 30 min, the desorption efficiencies were determined in three different ways; ( 1 ) determination of gas concentration in the Tedlar bag, ( 2 ) graphical integration of desorption curve obtained from the gas analysis; and ( 3 ) extraction of residual solvent in carbon particles with carbon disulfide. There were no significant differences in the desorption efficiencies among the three methods, but the standard deviation was the largest in the method ( 2 ) and the smallest in the method ( 3 ). Desorption efficiencies increased with the desorption temperature, the initial adsorbed amount of solvent, the gas velocity and the boiling point of the solvent. Under the same conditions (4 mm of column diameter, 100 m//min of gas flow rate and 50 μl/g of initially adsorbed solvent), the relation T ₉₀=1.88T_BP was obtained between the desorption temperature, at which the des orption efficiency amounted to 90% (T₉₀), and the boiling point of solvent (T_BP). This relation held for various kinds of solvents except alcohols. The values of T₉₀ for alcohols were about 60 degrees lower than those obtained from the above relation.

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Heavy metal ions proved to be very effective for the substitution reactions of N-substituted N'-cyano-S-methylisothioureas with amines. This reaction proceeded smoothly at room ternperature to form N, N'-disubstituted N''-cyanoguanidines. Silver nitrate, mercury(I) chloride and mercury(II) chloride were found to be more useful. In the presence of silver nitrate, [(methylthio)carbonyl]cyanamide reacted with aniline to yield N-cyano-N'-phenylurea. These reactions seemed to proceed by S_N2 mechanism rather than by elimination-addition mechanism.

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Electrochemical fluorination of N-methylpiperazine [1] and 1-methylhexahydro-1, 4-diazepine [2] was investigated.
From [1], the corresponding F-N-methylpiperazine was obtained in poor yield together with ring-opened and ring-isomerized products, while only ring-opened and ring-isomerized products were formed from [2]. Yield of F-N-methylpiperazine was improved by fluorinating under higher concentration of the substrate in anhydrous hydrogen fluoride. Under these conditions, yields of ring-opened and/or ring-isomerized products from [1] and [2] were not affected.

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Copolymerizabilities of methyl vinyl ketone(M₁) with acrylamide(M₂) without catalyst were studied in tetrahydrofuran below room temperature.
Under several conditions of light, the monom er reactivity ratios were obtained as follows; r₁=0.70 and r₂=0.79 for irradiation under room light; r₁ =O.78 and r₂=0.97 for unirradiation under light; r₁=1.28 and r₂=1.23 for irradiation under UV light. The presence of oxygen gas in the copolymerization system tends to decrease the rate of copolymerization(R_p). Meanwhile, it is interesting that R_p in unirradiated systems indicated higher value than these in the irradiated system with room light or UV light. These R_p indicated the maximum values at about 50 mol% in monomer feed, and the each monomer was not homopolymerized. These phenomena might be explained by the interaction between carbonyl group and carbamoyl group.

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In order to evaluate the state of organic substances decomposed by activated sludge treatment, the components of dissolved organic substances in domestic and municipal wastewaters were investigated.
In the raw influent of domestic wastewater, the sum of proteins, carbohydrates, volatile organic acids and surfactants was about 67% of dissolved organic substances as D-TOC and in municipal wastewater about 50%; the sum of humic and fulvic acids, tannin, lignin, urea and lipids was about 10 and 23% as D-TOC, respectively. For the secondary effluent, they were about 61 and 33%, and about 21 and 39%, respectively.
The sum of proteins, carbohydrates, volatile organic acids and surfactants in domestic wastewater was larger than that in municipal wastewater.

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with 4-iodobutyl methacrylate in HMPA-water solution. The copolymers of ChSMB with acrylamide formed clear hydrogels and had high swelling capacities in distilled water. The cross-linked copolymer containing 56.9 wt% of ChSMB resisted in vitro degradation by chondroitinase ABC at 37°C. The cross-linked form was not altered even after 1140min degradation, while chondroitinesulfate as a control was completely hydrolyzed.
Thus, this synthetic method enables us to investigate a new type m aterial composed of mucopolysaccharides and a synthetic polymer which are covalently bonded to each other as a potential biocompatible material.

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