Novel cationic catalysts have been found. The catalysts consist of aluminum complexes and active silicon compounds. The active species are Br Onsted acids formed by interactions between aluminum complexes and silanols. The latent catalysts which can be activated with heat or lights have been provided by employing silicon compounds which are decomposed thermally, or photochemically to form silanols. These catalysts have been applied to cure epoxy resins. The epoxy resins cured by these catalysts have been characterized by excellent electrically insulating properties. This is because the catalysts does not generate ionic impurities which cause decrease in electrical insulation properties. It was also found that this catalyst was effective for accelerating reactions between epoxy resins snd aromatic amines, and between maleimides and aromatic amines.

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The reaction of 1-butanol with hydrogen atoms has been investigated at the temperature ranging from 323 to 523 K, under 133 Pa, using a conventional discharge flow apparatus. Butanal, methanol, 1-butene, propylene and propane were mainly produced. S m all amounts of ethanol, 2-butenes, ethylene, ethane, methane and carbon monoxide were also detected (Table 1 and Fig.1). Relative amounts of butanal and 1-butene decreased as the con version of 1-butanol increased, while those of propylene, propane and ethylene were observed to increase at 323 K (Fig.2). Under the conditions of lower conversions, the selectivity of butanal decreased, and that of hydrocarbons increased at higher temperatures, while those of methanol and ethanol did not change significantly (Fig.3). Methanol, ethanol and 1-butene were not detected in the products obtained from the reaction of butanal with hydrogen atoms, which were operated under the similar conditions of 1-butanol + hydrogen atoms reaction system (Fig.4). This result suggests that butanal, methanol, ethanol and 1-butene are the primary products from the reaction of 1-butanol with hydrogen atoms. The effect of the conversion of 1-butanol on the selectivity of the reaction prod ucts were discussed based on abstraction and/or addition mechanisms of hydrogen atoms: It is suggested that the title reaction is initiated by the abstraction of hydrogen atom at a-position from OH group of 1-butanol, followed by a series of consecutive reactions of the initially produced radical with hydrogen atoms and/or 1-butanol.

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Two mutant dihydrofolate reductases (DHFRs) were prepared by replacement of glycine-121of the Eschrichia coli wild-type for alanine and valine by means of site-directed mutagenesis. Thermal denaturations (N-D transition) of the wild-type and the mutant DHFRs were investigated by high sensitivity differential scanning calorimetry. The enthalpy change associated with this transition increased in the order Val-DHFR<Ala-DHFR<wild(Gly)DHFR, that is, in the decreasing order in the hydrophobicity of these residues at the position 121. The calorimetric data of these DHFRs were analyzed according to a double deconvolution method proposed by Kidokoro et al (Biopolymers, 26, 231 (1987)). Based on this method, the thermal: transitions of three DHFRs were revealed to obey a three(N, I and D)-state model and the enthalpy functions of native, intermediate and denatared states, H, , (T), H1(T) and Hp(T), were calculated. The enthalpy difference between the native and intermediate states, 4HNI, was shown to greatly differ among three DHFRs and increase in the same order as that of an increase in the N-D transition enthalpy. In accordance with this difference, the Gibbs free energy difference between the native and denatured states, tIGND, at temperatures below the phase transition also increased in the same order, i ndicating that the thermodynamic stability of DHFRs decreases with an increase in the hydrophobicity of amino acid residues at this position.

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Effect of stretching process on rheological properties and stringiness of fibrous-structured cheese was studied. Mozzarella cheese curd was kneaded in hot water at 55 °C and stretched range from two to 25 times of its original length, then immersing the stretched curd in water at 5 °C to harden. Shear strength of parallel sample, Young's modulus and breaking strength were varied markedly with stretching operation, and tear strength was varied at low stretching times, while breaking strain was changed little. With an increase in stretching times, shear strength of parallel sample, Young's modulus, breaking strength and stringiness of fibrousstructured cheese rose. But too much stretching operation (such as 25 times) made the values lower (Figs.1, 2, 3, 6 and 7). It was suggested there is a suitable condition in stretching times for keeping high stringiness. In addition, coefficient of kinetic friction between Mozzarella cheese curd and various materials (Fig.10), ratio of shrinkage by heating (Figs.11, 12 and 13) and cooling temperature curves (Fig.14) of fibrous-structured cheese were also measured. And finally, based on knowledge obtained from a series of our reports, realized to mechanize the stretching and hardening process of fibrous-structured cheese production. t Mechanization of Fibrous-Structured Cheese Pro duction Process. V.

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Adsorption of sodium chondroitin-6-sulfate(Na2Chs) by calcium oxalate monohydrate(CaOx)was studied. Its adsorption isotherm was of high affinity type. The adsorption amount increased with an added concentration of NaC1 or CaC12, while it decreased with that of sodium oxalate. Dissolution behavior of Ox2- and Ca2+ from CaOx was incongruent (Fig.5). Ox2- was released in part by the mechanism of anion exchange with adsorbate Chs 2-. Released Ca2+ was partly captured by Ghs2- present in a mother solution, which played a role of reservoir for Ca2+. However, it was shown by the dialysis method (Fig.4) that the incongruent dissolution of CaOx is restricted through the solubility product (activity product, K. ), which was kept constant over the range of studied concentration of Na2Chs (T able 1)although the adsorption amount and degree of incongruence increased with an added concentration of Na2Chs.

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Amount of Ca2+ adsorbed by calcium oxalate (CaOx) in the presence of sodium chondroitin6-sulfate (Na2Chs) is composed of 2 components; the first is that directly adsorbed by the surface of CaOx and the second that captured by the adsorbed chondroitin-6-sulfate ion (Chs2-) as its counter ion. It was found that the former depends on the concentration of Ca2+ free from both Chs2- and CaOx in a mother solution (Fig.3). The binding ratio of Ca2+ to Chs2- was almost the same between that in the solution and that on the surfac e owing mainly to large protruding loops of adosrbed Chs2-. Oxalate anion (0x2-) competed for the adsorption sites on CaOx with Chs2- (Fig.4). Sum of the adsorption amounts of Chs2- and Ox2- behaved complicatedly with the adsorption amount of Chs2- (Fig.5) becaus e conformational change of the adsorbed Chs2- strongly affects the adsorption amount of 0x2-. Na2Chs showed a dispersing effect on the precipitate of CaOx through its adsorption (Figs.6and 7). The role of Na2Chs in inhibition of formation of urinary stones of CaOx was discussed on the basis of its dispersing/adsorption effect.

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The purpose of this study is to remove unpleasant odor gases which are generated by cooking foods. The odor gases contain acetaldehyde and trimethylamine as main ingredients. We have measured the conversion of acetaldehyde and trimethylamine over several catalysts. The activities of Ag and Mn203 are highest among the catalysts which consisted of single component. To increase activity and durability, the effect of addition of Ag to manganese oxide was studied. The activities of Ag-Mn catalysts were improved by the addition of Ag up to 40 atom%, and the maximum activity was obtained at 10 atom% (Figs.6 and 7). The thermal stability of Ag-Mn catalyst was better than Ag. These phenomena were investigated on the basis of the experimental data of XRD, XPS and TPD. On the surface of Ag-Mn catalyst calcined at 500 °C, the oxidation state of Ag was maintained. The amount of oxygen adsorbed on the surface of Ag-Mn catalyst was about 2.9 times as much as that on Mn203. These experimental data suggested that on the surface of Ag-Mn catalysts manganese oxide supplied oxygen to Ag and that oxidation conditions of Ag was maintained. This phenomenon resulted in the effiecient donation of oxygen over the whole catalyst. Consequently the activity and durability of Ag-Mn catalyst are considered to be better than other catalysts.

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Oxidized acrylonitrile fibers (Oxidized PAN-Fibers) were activated by steam at 900°C (PAN-ACF). The pore volume, pore distribution and adsorption capacities of the PAN-ACF for iodine, Methylene Blue and vitamin B12 were compared with those of pitch-based activated carbon fiber (Pitch-ACF) and phenol-based activated carbon fiber (Phenol-ACF). From these results, it is found that PAN-ACF had higher adsorption capacity for vitamin B12 than those of Pitch-ACF and Phenol-ACF. This may be due to the fact that PAN -ACF has high mesopores volume as compared with those of Phenol-ACF and Pitch-ACF. t Studies on Development of Polyacrilonitrile-based Activated Carbon Fiber. V.

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Although 1-C4H9OH is an effective Template agent for the synthesis of highly crystalline ZSM-5 zeolites, ZSM-5 type ferrisilicates could not be synthesized by using 1-C4H9OH without the addition of a source of Al. Synthetic studies at various ratios of Si02/Al203and Si02/Fe203 revealed that highly crystalline ferri-aluminosilicates with a crystal size of about 3 x 8 urn were obtained when mixtures of the starting molar ratios of 0I-1-/Si02=0.19-0.25, Si02/Al203=100--400 and Si02/Fe203 =10000 (SiO2/M203= 50, -200) were heated at 180 °C for 20 h (Figs.1, 2, Tables 1, 2). Investigations of catalytic synthesis of light olefins from methanol over the prepared zeolites indicated that the selectivity for light olefins depended upon the Al content and crystallinity of the zeolites. The best crystalline ferri-aluminosilicates with a low Al content and a large crystal size, which was synthesized at the molar ratios of Si02/Al208=200 and Si02/Fe203=100, exhibited the highest selectivity of about 50-40% for ethylene and propylene at the reaction temperature of 300-320 °C (Figs.5, 7). It was noted that the addition of Fe was effective for the synthesis of zeolites with a low Al content. The Si02/Al203 ratio could be as high as 264 in the fernaluminosilicates, while it was at most 111 in the aluminosilicates prepared without Fe. However, no clear effect of Fe on the selectivity for light olefins could be observed.

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Coating sol solutions were prepared from anhydrous ethanol solutions of Ta(0C2H5)5. With the addition of high-purity acetic acid, Ta(0C21-15)5 was partially hydrolyzed by trace amounts of water in the acetic acid used and further condensation took place. Among the sol solutions obtained, the solution (A) containing 1.2 mol% Ta(OC21-15)5 together w ith acetic acid at its molar ratio of 1.5 to Ta(0C2H5)5 was transparent and stable on storage for two months. When chelating agents (diethyl malonate, acetylacetone, ethyl acetoacetate and ethyl acetate) were added to one of the starting solutions, the agents (especially diethyl malonate)were found to remain in gels when the solution was dried at room temperature. Among these gels, one containing acetylacetone crystallized at the highest temperature of about 830 °C on heating. Ta205 gel thin films were prepared from the solution (A) by the drop-coating method, the solution was dropped on a substrate to spread over and evaporate. Preparation under dry nitrogen (-0% relative humidity) gave a transparent gel film at room temperature. DTA analysis revealed that, on heating in air, the gel film crystallized around 840 °C which was higher by about 100 °C than the crystallization temperatures of the other gels prepared under high relative humidities. On heating under nitrogen atmosphere, the exothermic peak of crystallization at 840 °C decreased extremely to be replaced by a weak exothermic peak (appearing) at 1000 °C. Preparation test under different relative humidities and substrate temperatares showed that transparent gel films were obtained regardless of substrate ternpetatures under low relative humidities, while only at somewhat elevated substrate temperatures under high humidities. t Properties of T a 205Thin Films Prepared by the Sol-Gel Process. I.

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The constituents of complex mixtures such as fossil fuels are usually analyzed by GC-FID or GC-MS. These require extensive data relating to standard samples, retention times and mass spectra. Thiophenes are the most common sulfur compounds in fossil fuels. Although there are 49 isomers of C2-C4 thiophenes, only about 6 compounds are commercially available reagents, and little data on their retention times or their mass spectra are available. Accordingly, we synthesized 36 C2-C4 thiophenes and 20 C5-thiophenes, and measured their retention times. Polymeth ylthiophenes were synthesized by transferring methyl groups from tetramethylbenzene to coexisting methylthiophenes on a silica-alumina catalyst. Other thiophenes were synthesized by allowing the thiophenes to react with alkyl bromide on aluminium chloride. The position of the alkyl group was determined by superposition of the reaction pathways and consideration of reported boiling points. The ion chromatograms of the C2-, C3-, C4- and C5-thiophenes we synthesized are shown in Figs.1, 2, 3 and 4, respectively. The names of the compounds corresponding to the peak numbers in each figure, the column retention times, and the column retention indices, using benzene (5000) and tetralin (30000) as the standard solutions, are shown in Tables 1, 2, 3 and 4.

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Heat-treatment of bis[4-(3-decylureido)phenyl]methane (DUDM) particles dispersed in paraffinic mineral oil causes morphological changes to helical, tubular and helical-rope aggregates form. In order to clarify the mechanism of this morphological change, the influence of temperature, time and cooling rate on the behavior of morphological change was studied from mainly SEM observation by using DUDM having two kind of crystal structure (r and p forms). The morphological changes were initiated at temperature of 130 °C for 9 form and at that of 150 °C for r form crystals. Because these temperature nearly corresponed with that of phase transition II of each crystal, the morphological changes will relate to the change of state (formation of a form crystal) in crystals. Morphologies of the samples treated with heat at temperature above phase transition II were mixture of unchanged platelets and changed aggregates. The proportion of each aggregate and platelet in the mixture varied with temperature and time. On the basis of above data, the forming process of tube was propos ed. The process shows as follows ( 1 ) The formation of tape, by the interaction between DUDM crystal and PMO. ( 2 ) the twist of tape (open and closed helix) ( 3 ) the formation of tube, by adhesion between the side of twisted tape. The appropriateness of that proposed process was also recognized with SEM image showing morphologies in initial stage of the formation of tube.

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The surface oxide layer of spherical iron ultrafine particles preapred by the gas vaporization method was investigated by X-ray photoelectron spectroscopy (XPS), MOssbauer spectroscopy and infrared (IR) absorption measurement. Fe 2 p XPS spectra showed the existence of iron hydroxide oxide on the surface of the oxide layer of iron ultrafine particles. It seemed that the surface of the oxide layer was not completely covered with iron hydroxide oxide, considering from the lowness of the value of C ls surface charging. The existence of FeO at the metal/oxide interface was not confirmed by depth profiling of the particles. The iron hydroxide oxide on the surface of the oxide layer was identified as amorphous iron hydroxide oxide by IR absorption measurement. Besides the iron(10 (Fe+) oxidation state, relatively large amount of iron(M) (Fe) oxidation state was observed in the MOssbauer spectra, and this implied the existence of both Fed: ), and r-Fe203 in the oxide layer. From the results of these experiments, the component of the surface oxide layer from the outside to the inner core of iron ultrafine particles was concluded as follows. amorphous Fe0(OH) and r-Fe20, I 7-Fe203 and F e s, / Fe The surface component of iron ultrafine parricles examined b y this, study are in good agreement with the surface component suggested by temperature programmed desorption (TPD) method in the previous studies. We have demonstrated the excellence of TPD method as a means for surface analysis of such small particles as ultrafine particles.

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Concentrations of formic and acetic acids in the marine atomsphere were measured at the route of an oil tanker over the East China Sea, South China Sea, Bay of Bengal, Arabian Sea, and Persian Gulf during July-September, 1991 in order to investigate their behavior over the ocean. Formic and acetic acids were measured by an automatic measurement system which consisted of a mist chamber, an ion chromatograph, a timer and so on. As a result, average concentrations in the marine atmosphere were 1.18 ppbv (n=1 068) for formic acid, 0.60 ppbv (n=1061) for acetic acid. Concentration of formic acid was higher than that of acetic acid in all sea areas. Concentrations of formic and acetic acids increased in the daytime and decreased in the nighttime. Therefore, it is considered that these acids are produced by photochemical reaction. A good correlation between concentrations of formic and acetic acids was observed in all sea areas. As for the source of these acids in the marin e atmosphere, it was found that the effect of the transport from free troposphere or land is larger than local photochemical reactions. On the other hand, the sink of these acids was mainly dry deposition except for wet deposition, and a gas-phase destruction was a minor sink. Taking into acount air-sea gas exchange for formic and acetic acids, the net flux of these gases was from the atmosphere into the ocean, while those of carbon dioxide, carbon monoxide and methane were from the ocean to the atmosphere. Therefore, it is considered that formic and acetic acids have an important role in the global carbon cycle, that is, these acids are impotant sources of carbon into the ocean.

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The carbonylation of o-, m-, and p-methylbenzyl alcohols (MBAL) to o-, m-, and p-tolylacetic acids (TAA) using supported rhodium catalyst was carried out at 130 °C and under the CO pressure 3 x 103 kPa in the liquid phase using the autoclave connected to a gas reservoir. The products were analyzed by gas chromatography and gas chromatography-mass spectrometry. Both the conversion of MBAL and the selectivity to TAA under the present reaction conditions increased with reaction time, and the conversion reached to almost 100mol% after 60 min. In the initial stage of the carbonylation of o-MBAL, o-methylbenzyl o-tolylacetate (MBTA) was mainly produced, and the carbonylation of m-MBAL also proceeded in a similar manner. In contrast, bis(p-methylbenzyl) aether (DMBE) was formed in the initial stage of the carbonylation of p-MBAL. In any reactions, the selectivity of MBTA and DMBE gradually decreased as the reaction proceeded, and after 180 min, the corresponding TAA was obtained as a major product (selectivity 45-55 mol%).

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The effects of N2 pressure and particle size on DTA curves of CaSO41.1/2 H20 have been studied by using high pressure DTA technique. The measurements were -carried out on various CaSO41/2 H20 (5 species), a-CaSO4.1/2 H20 and p-CaSO4112 I=1, 0 with different particle size (from ca.1 urn to ca.100 um). For high pressure DTA curves, the peak temperature varied with the type of hernihydrate, the particle size and N2 pressure. Under N2 pressure, the endothermic peak temperatures due to dehydration of the series of p-CaSO4112 H20 were in lower temperature range than that of a-CaSO4112 H20. In the series of p-CaSO41/2 H20, the endothermic peak temperature shift to the lower temperature with decreasing the particle size. For the fine particle group, these peaks were separated into two peaks. It was assumed that its lower endothermic peak was caused by the rearrangment in 9-CaSO4.1/2 1-120 crystal by releasing H20. Each Ca S O4.1/2 H20 was characterized by the endothermic peak temperatures due to their dehydration under N2 pressure of 1.5 MPa.

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When 4-methoxy-NNO-azoxybenzene [1 a] was kept in 20% nitric acid (HNO₃-AcOH-H₂O)at 40°C, 4-methoxy-ONN-4'-nitroazoxybenzene (6β) was obtained as a nitration product but the isomerization of 1α to 4-methoxy-ONN-azoxybenzene [1β] did not take place at all. In this reaction, 4-methoxy-NNO-4'-nitroazoxybenzene [6α] formed by para-nitration of 1α seems to isomerize to 6β immediately. However, neither nitration nor isomerization took place in the reaction of 1β with 20% nitric acid (HNO₃-AcOH-H₂O) under the similar reaction conditions. It is co nvenient method to obtain pure 1β that is the nitration of a mixtare 1α and 1β with dilute nitric acid under the mild conditions.

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For application of a ceramic membrane as a molecular sieve, various conditic; ris of preparation were examined to prepare a reproducible dynamic membrane layered by a mixture of zrei-o atid NaOH on the ceramic membrane. The ceramic membrane was coated by a mixture containing 0.05 mol drn-3 ZrC12O at various pH under 2 kg cm-2 and 1 m s-' of feed velocity at 30 °C. The suspended mixture used has a maximum viscosity at pH 3.5-4.0and the precipitation does not occur below pH 3.5. A maximum rejection (0.99) of achymotrypsin was obtained on the dynamic membrane prepared in -the region of pH 3.0.

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