Role of Acetic Acid Added to the Reaction Media for the Enantio-differentiating Hydrogenation of Methyl Acetoacetate Over a Tartaric Acid-modified Nickel Catalyst

The role of acetic acid added to the reaction media for the enantio-differentiating hydrogenation of methyl acetoacetate over a (R,R)-tartaric acid-in-situ-modified nickel catalyst was studied from the viewpoint of the hydrogenation rate during repeated runs. The hydrogenation of methyl acetoacetate on the “enantio-differentiating sites” of a tartaric acid-modified nickel catalyst was specifically accelerated by the acetic acid added to the reaction media to increase the enantio-differentiating ability of the catalyst. In order to increase the enantio-differentiating ability, the addition of acetic acid to the reaction media was required in each run during the repeated use of the catalyst.     

Determination of hydroperoxides and structures by high-performance liquid chromatography with post-column detection with diphenyl-1-pyrenylphosphine

A high-performance liquid chromatographic method, using post-column detection with diphenyl-1-pyrenyl-phosphine (DPPP), was developed for the quantitative and qualitative determination of isomeric lipid hydroperoxides (OOH). The OOH eluted from a normal-phase column were passed through a photodiode array detector and then mixed with DPPP solution in a reaction coil heated at 80°C. DPPP oxide formed by the reaction with OOH was determined by monitoring the fluorescence intensity at 380 nm and excitation at 352 nm. The conjugated diene OOH (13-cis, trans- and 9-cis, trans-OOH) and nonconjugated OOH (12-cis-trans- and 10-cis, trans-OOH) from photosensitized oxidation of methyl linoleate were determined in a molar ratio of 31∶29∶19∶21, respectively. However, only the two conjugated hydroperoxides were detected by ultraviolet absorption at 234 nm. Further applications were carried out for the determination of OOH of methyl oleate and methyl linolenate. This method proved to be useful for the determination of the OOH containing both conjugated and nonconjugated diene structures.     

Rapid Quenching Technique Using Thermal-Image Furnace for Glass Preparation

A new technique combining a thermal-image furnace and a twin roller is described for quenching the melt to form glass. The technique was applied to the simple system Li₂O-SiO₂, since its fundamental parameters in the estimation of critical cooling rate are available. Glass flakes were obtained in the composition Li₄SiO₄, for which a very large critical cooling rate (∼10⁹ K·s⁻¹) was needed for glass formation.     

Preparation of modified poly(vinyl chloride) containing N,N-di(β-hydroxyethyl)dithiocarbamate and its reaction with metal ions

Reaction of N,N-di(β-hydroxyethyl)dithiocarbamate ion with poly(vinyl chloride) (PVC) was undertaken, and the reaction with metal ions of the polymer obtained was investigated. The effect of γ-irradiation on the reaction with metal ion was also studied. The modified PVC (PHDC) obtained from the reaction with N,N-di(β-hydroxyethyl)dithiocarbamate ion is pale yellow even after reaction at 100°C for 5 hr in dimethylformamide (DMF); it is soluble in dipolar solvents and its chlorine content is decreased considerably. This polymer reacted well with acetate salts of copper(II), nickel(II), zinc(II), and silver(I) heterogeneously in aqueous solution because of the introduction of hydrophilic groups (two hydroxy groups). The reactivity of the metal ions toward the polymer was of the order Ag(I) ? Cu(II) > Ni(II) > Zn(II). From the result of the reaction of γ-irradiated polymer with cupric ion, the polymer was judged to have fairly good antiradiation property.     

Enantio-differentiating hydrogenation of prochiral ketones over modified nickel

This article reviews the enantio-differentiating hydrogenation of prochiral ketones over a asymmetrically modified catalyst, focusing on the hydrogenation of simple prochiral alkanones. The parameters affecting catalytic activity and enantiodifferentiating ability are considerable in number, and each parameter should be optimized in order to attain a highperformance enantio-differentiating catalyst. Optimization of the parameters and the mode of enantio-differentiation are discussed and compared with the enantio-differentiating hydrogenation of β-ketoesters.     

Surface segregation of siloxane containing component in polysiloxane‐block‐polyimide and s‐BPDA/ODA polyimide blends

Surface segregation in polymer blend systems between 3,3′,4,4′‐biphenyltetracarboxylic dianhydride/4,4′‐diaminodiphenyl ether (s‐BPDA/ODA) polyimide and block copolymer based on polysiloxane‐block‐polyimide (SPI) has been investigated. These polyimide blends, having various compositions of the SPI, were processed by a solution casting method. The glass substrate used in the film‐casting process shows significant effect on the migration of surface segregated species to enrich the air‐exposed surface, whereas the more polar s‐BPDA/ODA tends to remain close to the polar glass substrate. X‐ray photoelectron spectroscopy reveals that even at low SPI concentration, the siloxane moieties in the block copolymer tend to segregate into the air side surface. Contact angle measurement evidently indicates an enrichment of the hydrophobic siloxane fraction on the blend film surface. The average water contact angle of glass side surface is 77°C whereas that of the air side is about 102°C in every blend ratio. This behavior confirms the surface segregation phase separation in these polymer blends. Finally, the surface morphology observed by atomic force microscopy also suggests segregation type of phase separation in these blend systems. POLYM. ENG. SCI., 47:489–498, 2007. © 2007 Society of Plastics Engineers.     

Characterizing image quality of autostereoscopic displays by using the maximum luminance at each viewing position

A metric of the 3D image quality of autostereoscopic displays based on optical measurements is proposed. This metric uses each view's luminance contrast, which is defined as the ratio of maximum luminance at each viewing position to total luminance at that position. Conventional metrics of the autostereoscopic display based on crosstalk, which uses “wanted” and “unwanted” lights. However, in case of the multiple‐views‐type autostereoscopic displays, it is difficult to distinguish exactly which lights are wanted lights and which are unwanted lights. This paper assumes that the wanted light has a maximum luminance at the good stereoscopic viewing position, and the unwanted light also has a maximum luminance at the worst pseudo‐stereoscopic viewing position. By using the maximum luminance that is indexed by view number of the autostereoscopic display, the proposed method enables characterizing stereoscopic viewing conditions without using wanted/unwanted light. A 3D image quality metric called “stereo luminance contrast,” the average of both eyes' contrast, is proposed. The effectiveness of the proposed metric is confirmed by the results of optical measurement analyses of different types of autostereoscopic displays, such as the two‐view, scan‐backlight, multi‐view, and integral.     

Continual conversion of free fatty acid in rice bran oil to triacylglycerol by immobilized lipase

Rice bran oil containing 30–50% free fatty acid was continually converted to an oil containing more than 75% of triacylglycerol (TG) by means of immobilized lipase. The reaction was carried out at 60°C for 24 h with dehydration and reactant mixing by dry nitrogen flow under a positive nitrogen atmosphere. Enzymatic TG synthesis with evaporation by heating was not suitable because of the increasing peroxide value of the oil. Part of this article was presented at the annual meeting of the Japan Oil Chemists' Society at Sendai, Japan, October, 16, 1990.     

Liquefaction of subbituminous coals under apparently non-hydrogenative conditions

Reactivities of several coals of different ranks have been examined in degrading extractions with aromatic solvents under apparently non-hydrogenative reaction conditions. Pyrene and A240 pitch liquefied the fusible coals in high yields and the slightly-fusible coals in moderate yields, indicating the importance of fusibility in such liquefaction processes. A240-LS pitch is a powerful solvent for slightly-fusible coals. Considerable amounts of pyridine- or THF-soluble fractions were produced especially with A240-LS pitch. A240 pitch is a better solvent than pyrene for some slightly-fusible coals. However, the extent of depolymerization of liquefied coal, pyridine- or THF-solubility, was definitely inferior. Yields of such fractions are higher for lower-rank coals. The mechanism of coal liquefaction under apparently non-hydrogenative conditions is discussed with emphasis on the stabilization of thermal fragments derived from the coal.