Gas permeation through hydrogels : I. Gel cellophane membranes

Permeabilities and diffusion coefficients of various gases, Ar, N₂, O₂, CO₂, CH₄, C₂H₄, C₃H₈ and C₄H₁₀, were measured for Water-swollen gel cellophane membranes. No dependence of permeabilities on gas pressure below 1 atm was found. It was observed that the permeability coefficients were not related linearly to the coefficients in bulk water. For the two states of water in the membrane, an analytical method is presented to estimate the diffusion coefficients and the solubilities in free water and non-freezing water. It was found that the diffusion coefficients in non-freezing water were lower than those in free water, and the solubilities in non-freezing water were higher than in free water for all gases studied except CO₂ and C₂H₄, which gave reverse results.     

XPS for in situ observation of an Ag electrode on a solid electrolyte used as oxygen sensor

The Ag electrode surface of a solid electrolyte in its working state has been studied by X-ray photoelectron spectroscopy. The nature of the AgO system on the electrode is dependent on the temperature. There are three types of AgO systems at 400°C. Type 1 with an O is binding energy of 532.6 eV only appeared at 325°C. However, when the temperature was raised to 400°C, types II and III (with BEs 531.1 and 529.2 eV) appeared. These O is signals are discussed in detail.     

Synthesis of (±)-dimethyl curvularin based on the palladium-catalyzed carbonylation of 3,5-dimethoxybenzyl chloride using a butadiene telomer as a building block

Palladium-catalyzed carbonylation of 3,5-dimethoxybenzyl chloride (13) with benzyl 7-hydroxyoctanoate (12) afforded benzyl 7-(3,5-dimethoxyphenylacetoxy)octanoate (6) in 70% yield, which is the precursor of Curvularin (4). The ester (12) was easily prepared from the butadiene telomer obtained by the palladium-catalyzed reaction of butadiene with acetic acid.     

Application of olefin metathesis to organic synthesis. Syntheses of civetone and macrolides

Diethyl 9-octadecene-1,18-dioate was obtained in 87% yield based on 50% theoretical conversion by the olefin metathesis reaction catalyzed by WOCl₄-Cp₂TiMe₂. The Dieckmann condensation of this diester using potassium hydride afforded 2-ethoxycarbonylcyclo-9-heptadecenone, which was converted by hydrolysis and decarboxylation to cyclo-9-heptadecenone (civetone) as a mixture of cis and trans isomers (1.3 : 1) in 54% yield. Also 9-octadecen-18-olide was obtained in 17.9% by the metathesis of oleyl oleate.     

Pre-filtering Effect in an Iterative Deconvolution Method and Its Application to Signal Recovery in Fiber-Optic Distributed Temperature Sensors

The signal quality of a fiber-optic distributed temperature sensor based on optical time domain reflectometry (OTDR) is improved using a pre-filtering technique in the iterative deconvolution method. Investigation of the performance is proposed using iteration conditions in which recovery rate of the signal-component is equal to that of the unfiltering technique. The recovered signal in the pre-filtering technique gives a good signal-to-noise ratio (SNR), 3 times of the unfiltered signal. Consequently, improvements in the OTDR signal with SNR of from 10 to 100 are obtained under the iterations for both distance and temperature resolutions.     

Electron spin resonance of phosphorescent triplet molecules observation of the proton hyperfine structure of Δm = ±2 transitions in stretched poly (vinyl alcohol) films

By applying a microwave magnetic field parallel to an external magnetic field, ESR of naphthalene, quinoxaline, quinoline and isoquinoline in their phosphorescent triplet states has been studied at 77 K. The proton hyperfine structures in the Δm = ± 2 transitions were distinctly resolved, especially when the stretched film was used as a host, compared with observations in ethanol glasses. The assignment of these ESR signals was carried out with the aid of the stretched-film method.     

Alternating copolymerization of ethylene oxide and sulfur dioxide

Copolymerization of ethylene oxide (EO) and sulfur dioxide (SO₂) was conducted by using a variety of amines as catalyst. Aromatic tertiary amines such as quinoline and pyridine were found to show the best catalytic property of the various amines, and copolymerization was carried out in the temperature range between 0 and 80°C with the use of quinoline. The copolymerization rate was approximately first-order in quinoline, EO, and also SO₂. The copolymer, was always composed of the two monomers: 1:1 ratio, independent of the initial concentration of the monomers. The copolymer obtained was a transparent viscous material which decomposed at 218°C to afford a considerable amount of ethylene sulfite. Spectroscopic analysis of the copolymer combined with the results of elemental analysis indicates the copolymer to have the structure The polymerizability of ethylene sulfite, which might be considered an intermediate compound in the copolymerization, was also examined at 60°C for 4 hr in the presence of quinoline, and it was found that ethylene sulfite could not be polymerized under these conditions.