The control of gas transport though polymer membranes is of primary concern in the development of new gas separation membranes. Here, a new possibility for gas separation is presented using an asymmetric fluorinated polyimide membrane with an ultrathin and defect-free skin layer. The structure of the asymmetric membrane fabricated by a dry/wet phase inversion process showed an ultrathin skin layer and sponge-like structure characterized by the presence of macrovoids. We have prepared a series of asymmetric membranes with different skin layer thicknesses from 10 to 5.0 × 10³ nm by the dry/wet phase inversion. Four gas permeances through the asymmetric membrane decreased in the order, CO₂ > O₂ > N₂ > CH₄, and the trend was in accordance with the kinetic diameter of gas molecules. The gas selectivity of the asymmetric membrane increases with a decrease in the surface skin layer thickness, which may be due to the fact that the surface skin layer of the membrane with a thinner thickness forms a more packed structure.

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The effectiveness of Li⁺–Al³⁺ and Mg²⁺–Al³⁺ layered double hydroxide (LDH) intercalated with CO₃²⁻ or Cl⁻ as a reaction media for benzylation of benzyl alcohol with benzyl bromide in toluene was examined. Among a series of LDHs, Li⁺–Al³⁺ LDH was found to be effective. For instance, a reaction in the presence of Li⁺–Al³⁺–CO₃²⁻ heat-treated at 200 °C gave the desired benzylated products in 93% yield by refluxing for 6 h. Also, Li⁺–Al³⁺–Cl⁻ heat-treated at 150 °C gave the benzylated product in 78% yield for same conditions. In the case of Mg²⁺–Al³⁺ LDH, it is found that it possessed less activity, showing reduced yields 34% for containing CO₃²⁻ and 2–6% for containing Cl⁻ respectively.

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The formation of Al–Li layered double hydroxide (LDH) by a homogeneous precipitation method using urea as a precipitant has been investigated as a function of solution composition, aging temperature and time. When the mixed aqueous solution of Al(NO₃)₃ and LiNO₃ containing urea was heated, the solution pH was gradually increased with the thermal hydrolysis of urea and a white precipitate began to form at pH 5.7–6.1 in the temperature range of 80–90 °C. The crystallinity of the solid products was found to be influenced by the reaction conditions.
A quite highly crystallined Al–Li LDH, with a basal spacing of 7.83 Å, was obtained from the mixed solution of Al/Li molar ratio of less than 0.10 (0.166 mol dm⁻³ Li⁺) and urea concentration of more than 1.0 mol dm⁻³ at above 85 °C for 3–5 h. The typical LDH product has a chemical composition of Al_2.17Li_1.00(OH)_6.83(CO₃)_0.34 · yH₂O and is an aggregate of hexagonal plate-like shape particle with lateral dimensions of about 2 μm. From the analytical results of the solid products obtained during the aging, it was found that amorphous aluminium hydroxide was precipitated first and then LDH was gradually crystallized by the reaction of the aluminium hydroxide precipitate with Li⁺ ion in the solution.

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Trifluoromethylation of the alicyclic perfluoroimines, perfluoro(5,6-dihydro-2H-1,4-oxazine) (1) and perfluoro(3,4-dihydro-2H-pyrrole) (2), was achieved by using trimethyl(trifluoromethyl)silane (3). Successive trifluoromethylations occurred even when an equimolar amount of 3 was used in both cases so that mono-, di-, and tri-substituted products were formed. In addition to this successive trifluoromethylation, the dimer formation was accompanied in the case of 2, giving three dimers with or without trifluoromethyl substitutents. The reaction mechanism and the solvent effect on the orientation of the trifluoromethylation and the product distribution were discussed. The influence of the substitution of the fluorine bonded to imidoyl carbon of 1 and 2 for a 2,2,2-trifluoroethoxy group on the trifluoromethylation reaction was also investigated.

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Inorganic fine particles of calcium carbonate and magnesium hydroxide were treated with phosphoric acid alkyl esters and stearic acid as a reference by the following method: The fine particles were suspended in ethanol dissolved with the treating agent and then ethanol was evaporated. The amounts of treating agent were set between 0 to 2.1 times of the amount completely covered the particle surfaces. The adhesion states of the treating agents to the fine particles were analyzed by the contact angle to water, the sedimentation volume in cyclohexane, the solvent extraction, and melting behaviors. In all cases of magnesium hydroxide series, the treating agents were ionically bonded to the particle surface as mono-molecular layer of the agent with their alkyl chains pointing outward. In the case of treating calcium carbonate with stearic acid, stearic acid molecules were not bonded but absorbed to calcium carbonate particle surfaces with their alkyl chains pointing outward. In the case of treating calcium carbonate with phosphoric acid alkyl esters, phosphate groups were ionically bonded to the particle surfaces at the first layer and adhered on them by ionic interaction at the second and third layers, generally with alkyl chains pointing outward.

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Silver halides were deposited in the core of the double-layer by the decomposition of silver complex and trialkoxy(haloalkyl)silanes. The complex, bis[3-(2-aminoethyl)aminopropyl(trimethoxy)silane]silver(I) nitrate, was prepared from silver nitrate and [3-(2-aminoethyl)aminopropyl]trimethoxysilane in a glove box filled with nitrogen gas and co-hydrolyzed with tetraethoxysilane. The core particles were prepared by titration of copolymer from tetraethoxysilane, the silver complex, 3-bromopropyl(triethoxy)silane and chloromethyl(trimethoxy)silane into the mixture of methanol and ammonia water. Subsequently, the core was coated with the shell formed via titration of tetraethyoxysilane. The resulting particles were larger in diameter than the core particles. The scanning electron micrograph observation has proved that those particles are spherical and that the particle size distribution is narrow. Silver chloride was only deposited in particles when the silver complex and chloromethyl(trimethoxy)silane were used as the precursor. On the other hand, silver bromide was generated when 3-bromopropyl(triethoxy)silane or its mixture with chloromethyl(trimethoxy)silane was employed for the formation of silver halide. Deposited silver halides in particles were detected on the samples heated up to 700 °C by the X-ray diffraction measurement.

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A composite ceramic separator of La(Ca)CrO₃/La(Sr)MnO₃ has been developed for a substrate-type, planar solid oxide fuel cell. La(Ca)CrO₃ was plasma-sprayed onto the porous thick La(Sr)MnO₃ substrate. As-sprayed films of calcium(II)-doped lanthanum chromate, La_0.7Ca_0.35Cr_0.95O₃ and La_0.8Ca_0.22Cr_0.98O₃ showed high gas permeability of 10⁻⁷–10⁻⁶ cm⁴ g⁻¹ s⁻¹ and SEM observation showed surface cracks. After sintering the as-sprayed films at 1473 K for 2 h in air, the sintered films showed no surface cracks and showed improvement of gas permeability of less than 1 × 10⁻⁸ cm⁴ g⁻¹ s⁻¹. The peaks of CaCrO₄ and La₂CrO₆ were observed in the XRD spectra of the powders and as-sprayed films for both components of La(Ca)CrO₃. However, those peaks disappeared and the peaks of La₂O₃ and CaO were observed in the sintered films. The lattice parameters of the sintered films of La_0.7Ca_0.35Cr_0.95O₃ were larger than those of the as-sprayed films, whereas those of La_0.8Ca_0.22Cr_0.98O₃ were almost same before and after the sintering. WDX-SEM analysis of the sintered films of La_0.7Ca_0.35Cr_0.95O₃ showed that CaO precipitated like an island on the surface of the sintered films. During the sintering process, dissolution of CaCrO₄ and La₂CrO₆ seems likely to promote sintering of La(Ca)CrO₃. However, La₂O₃ and CaO precipitated from the melted CaCrO₄ and La₂CrO₆ accompanied with the sintering process of La(Ca)CrO₃. Because of the low CaO precipitation in the sintered films, La_0.8Ca_0.22Cr_0.98O₃ is considered to be preferable materials for solid oxide fuel cell composite ceramic separators.

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