Time filter

Source Type

Suciu C.V.,Fukuoka Institute of Technology | Tani S.,Fukuoka Institute of Technology | Yaguchi K.,Fuji Silysia Chemical Ltd.
Acta Mechanica | Year: 2010

In this work, fatigue fracture tests on liquid-repellent nanoporous silica micro-particles dispersed in water are reported; then, models of the grain cracking and fragmentation are proposed. Such tests can be regarded, from an external standpoint, as conducted under temporally variable but spatially uniform pressure distribution in the liquid surrounding the silica grains, or from an internal standpoint, as surface fatigue that occurs at the cyclical adsorption/desorption of water in/from the nanoporous particles. The test rig represents a compression-decompression cylinder divided into two chambers, one of constant volume and the other of variable volume. Silica is introduced inside the cavity of fixed volume, and a micro-filter is used to separate it from the chamber of variable volume, in which only water is supplied. Experimental results suggest that the fatigue fracture of silica particles occurs from the inside, explosion-like, oppositely to the previously reported implosion-like collapse of silica under wet pressurization. This is accompanied by enhancement of the hydrophilic silanol groups on the silica surface and by redistribution of the size of particles and pores. Critical numbers of cycles to achieve fracture of the silica particles obtained experimentally, and from the models of grain cracking and fragmentation, under cyclical pressurization, are in good agreement. © 2010 Springer-Verlag. Source

Okabayashi H.-F.,Nagoya Institute of Technology | Izawa K.-I.,Fuji Silysia Chemical Ltd. | Sumiya A.,Nagoya Institute of Technology | Eastoe J.,University of Bristol | O'Connor C.J.,University of Auckland
Bulletin of the Chemical Society of Japan | Year: 2010

The IR spectra in the 13001450 cm-1 region, which reflect the CH and CH2 deformation vibrational modes of the succinate skeleton, have been investigated in detail for sodium dialkylsulfonates (alkyl groups: Ethyl, n-propyl, n-butyl, n-hexyl, n-heptyl, n-octyl, n-decyl, and n-dodecyl) and sodium 1,2-bis(2-ethylhexyl)sulfosuccinate (sodium 1,2-bis(2- ethylhexyloxycarbonyl)ethanesulfonate) (AOT). The results have provided clear evidence that two configurations, arising from the difference in the torsion angles of the succinate skeleton, are preferentially stabilized in aqueous solution as well as in the solid state, depending upon the concentration. Thus, the IR spectra of this region can be used as a powerful tool for elucidation of the mechanism of the disorderorder transition in aggregate systems of AOT or its homologs at the molecular level. © 2010 The Chemical Society of Japan. Source

Fujii H.,Kitasato University | Yamada T.,Kitasato University | Hayashida K.,Kitasato University | Kuwada M.,Kitasato University | And 4 more authors.
Heterocycles | Year: 2012

A newly developed SO 3H silica gel cleaved the O-Si bonds in various aryl and alkyl silyl ethers to give the corresponding phenols and alcohols in good to excellent yield. The crude filtrates contained no silyl residues. The solid phase 29Si NMR analyses of the SO 3H silica gel strongly suggested that the silyl residues were captured by silanol groups on the surface of the silica gel. The SO 3H silica gel could be recycled at least ten times without any loss of activity. The disappearance of silyl residues in the crude filtrate was observed in even the 10th repetition. Our method provides an easily handled desilylation method that requires no further purification. Our method was also applicable to a selective desilylation reaction of a derivative 5 with different siloxy groups or desilylation of an alkaloid derivative 7. © 2012 The Japan Institute of Heterocyclic Chemistry. Source

Morikawa Y.,Aichi Center for Industry and Science and Technology | Kondo T.,Food Research Center | Hayashi N.,Aichi Center for Industry and Science and Technology | Ito M.,Fuji Silysia Chemical Ltd. | Takai K.,Sanki A. F. I. Co
Kagaku Kogaku Ronbunshu | Year: 2014

Aldehyde oxidase (AOX)-immobilized silica gel (AOX-SG) was developed as a means to remove formaldehyde in the gas phase by enzyme degradation. AOX from the formaldehyde-tolerant microorganism Paecillomyces variotii IRI017, which we newly isolated from soil, was utilized. Amino group-binding silica gel (AminoSG) was prepared by APTE (3-aminopropyl triethoxysilane) treatment. All types of AOX-immobilized silica gels were oven-dried at 50°C to constant weight, and formaldehyde degradation by the dried AOX-SG or AOX-aminoSG was examined. Humidified air containing 0.4–0.5 ppm of formaldehyde was passed continuously through SG columns packed with one of four types silica gels: SG, AminoSG, AOX-SG, and AOX-aminoSG. Formaldehyde in test air was removed in the early period in all types of SG by adsorption. With SG and AminoSG, however, formaldehyde removal decreased sharply and become zero within 20 d because of saturation of the gel by formaldehyde. With AOX-SG and AOX-aminoSG, removal of more than 90% of formaldehyde continued for more than 90 d. These results suggest that formaldehyde in the test air was adsorbed by silica gels and degraded by immobilized AOX. © 2014 The Society of Chemical Engineers, Japan. Source

Fuji Silysia Chemical Ltd. | Date: 2003-10-14

Chemicals for use in chromatography, namely, column packing materials and silica gels.

Discover hidden collaborations