Showing papers on "Phosphotungstic acid published in 1999"

Ammonium heteropolyacid catalized polymerization of olefins

Abstract: Calcined ammonium salts of phosphotungstic acid salts are used to polymerize C 2 -C 30 α-olefins and derivatives thereof to form highly reactive products having a high content of terminal vinylidene groups and β-isomers in resonance therewith.

Protonic Conducting Properties of Sol-Gel derived Organic/Inorganic Nanocomposites Membrane doped with Acidic Functional Molecules

Abstract: High temperature protonic conducting polymer membranes provide new technological applications in electrochemicaldevices including electrochromic displays, chemicalsensors and fuel cells. Organic/inorganimanocomposite membranes consisting of SiO2 /PEO (Polyethylene Oxides) hybrid are a remarkable family of isotropic, flexible, amorphous polymer materials, which have been synthesized through sol-gel processes. The hybrid membrane doped with acidic moieties such as monododecylphosphate or phosphotungstic acid shows good protonic conductivities at temperatures above 100°C. The protonic conducting membrane was found to be thermally stable at temperatures because of the inorganic SiO2 framework in the nanocomposites matrix.

Synthesis and Ionic Conductivity of Supramolecular Layered Silicate Hybrids of Phosphotungstates and Poly(ethylene glycol) Dicarboxylates

Abstract: The structure-directing roles of phosphotungstic acid and polyethyleneglycol dicarboxylic acid in leading to supramolecular ionic lamellar structures have been demonstrated by the sol−gel acid/base adduct formation between 3-aminopropyl triethyoxysilane and the acids. The prepared inorganic/organic hybrid phyllosilicates exhibited conductivities of up to 10-5 S/cm at 177 °C which are strongly structure-sensitive (variation by 4 orders of magnitude depending on whether a layered or an amorphous structure is realized).

Production of tricarboxystarch

Abstract: PROBLEM TO BE SOLVED: To produce a tricarboxystarch having a high carboxyl group content by oxidizing a starch with a hypohalite in the presence of a nitroxyl compound and further oxidizing the product with a peroxide in the presence of a catalyst. SOLUTION: This tricarboxystarch is produced by (A) a process in which a starch (e.g. tapioca starch) is oxidized with a hypohalite (e.g. sodium hypochlorite, etc.), in the presence of a nitroxyl compound (e.g. 2,2,6,6- tetramethylpiperadinyl-1-oxy, etc.), and (B) a process in which the product of the process A is oxidized with a peroxide (e.g. a hydrogen peroxide aqueous solution, etc.), in the presence of a catalyst (e.g. phosphotungstic acid, etc.). The resultant tricarboxystarch has a structure which has been obtained by oxidizing 60% or more in average of the CH2 OH group at the 6th position of the glucopyranose unit of the starch to COOH group, and 10% or more in average of CHOH groups at the 2nd and 3rd positions of the unit to result in ring opening and conversion to COOH groups.

Production of aromatic ketone

Abstract: PROBLEM TO BE SOLVED: To obtain an aromatic ketone in a high yield by oxidizing a specific aromatic compound with oxygen gas in the presence of a heterogeneous polyacid catalyst in a solvent in a liquid phase. SOLUTION: This method for producing an aromatic ketone (for example, acetophenone) comprises oxidizing (A) an aromatic compound having an R-CH2 group (R is an alkyl, an aryl or an allyl) (for example, ethylbenzene) with (D) oxygen gas in the presence of (B) a heterogeneous polyacid catalyst, preferably selected from phosphotungstic acid, phosphovanadotungstic acid, phosphomolybdic acid and phosphovanadomelybdic acid, in (D) a solvent, preferably dimethyl sulfoxide, in a liquid phase. In the reaction, the component B is preferably used in an amount of 0.001-30 wt.% based on the component A. The component D is preferably used in an amount of 0.01-50 pts.wt. based on the component A. The component C is also preferably used in an amount of 1 mole per mole of the component A. The reaction is preferably carried out at a reaction temperature of 50-300 deg.C at a reaction pressure of 0.1-200 kg/ cm2G.

Electro-oxidation of CO on Pd black in phosphotungstic acid

Abstract: Electro-oxidation of CO by Pd black in phosphotungstic acid (PWA) has been studied on porous gas-diffusion electrodes. Galvanostatic steady-state polarization data show that the reaction proceeds under strong activation control at low current densities. The current density at 0.5 VNHE is found to be three times higher than that in a H2SO4 reference electrolyte. X-ray photoelectron spectroscopic data on various electrochemically tested electrodes show lower oxidized Pd species in PWA than in H2SO4. It is conjectured that an increase in the electron density around Pd sites is ameliorated by PWA in relation to H2SO4, with a consequent promoting effect of the heteropolyacid towards CO electro-oxidation.

Oxidation of side chain of aromatic compound

Abstract: PROBLEM TO BE SOLVED: To obtain the subject compound in high selectivity in a state suppressed in the combustion of reaction substrates without requiring the presence of a halogen by oxidizing in an aqueous solution an aromatic compound having one or more alkyl groups which may imperfectly be oxidized. SOLUTION: This method for producing an aromatic carboxylic acid and/or an aromatic aldehyde comprises oxidizing the corresponding aromatic compound having one or more alkyl groups each having about one to eight carbon atoms or their imperfectly oxidized groups as one or more side chains (toluene, benzaldehyde, etc.), as a substrate with a molecular oxygen-containing gas (e.g. air) in the presence of a heterogeneous polyacid (e.g. phosphotungstic acid) and a transition metal (e.g. ruthenium acetonate) not combined with the heterogeneous polyacid in a buffer aqueous solution optionally containing <=1000 ppm of an ionizable halogen atom and having a pH of 1.5-10, preferably 1.5-7, at 100-300 deg.C, preferably 150-230 deg.C, at the atmospheric pressure to 100 atm, preferably 10-80 atm, for 0.1-8 hr, preferably 1-5 hr.

Catalyst for producing lower aliphatic ester, manufacture thereof, and manufacture of lower aliphatic ester using the catalyst

Abstract: PROBLEM TO BE SOLVED: To improve the lability of a catalyst by a method wherein the specific surface area of the catalyst for use in the manufacturing of a lower aliphatic ester wherein a lower aliphatic carboxylic acid is esterified with a lower olefin is set within a specific range according to BET method. SOLUTION: In a catalyst for use in the manufacture of a lower aliphatic ester wherein at least one kind of compound selected from a heteropolyacid and/or its salt is carried by a support and a lower aliphatic carboxylic acid is esterified with a lower olefin, the specific surface area of the catalyst is set according to BET method in a range of 65-350 m2/g. As a heteropolyacid to be used, at least one compound selected from the group consisting of silicotungstic acid, phosphotungstic acid, phosphomolybdic acid, etc., can be cited. As a heteropolyacid salt, at lest one compound selected from the group consisting of silicotungstic acid, phosphotungstic acid, phosphomolybdic acid, silicomolybdic acid, or lithium salt of phosphovanadmolybdic acid can be cited.

Nicotine-filtering medium for cigarette

Abstract: The present invention relates to a nicotine-filtering medium for cigarette, using hydrated silicon oxide as carrier and containing palladium salt, and is characterized by that it contains phosphomolybdic acid or phosphotungstic acid or their soluble salt and cupric salt or nickel salt or molysite, and the weight percentages of all ingredients are 90-95, 1-5, 0.05-1 and 1-5 in turn, in which ClO2 can also be added, its weight percentage is 0.05-1. The invented composite can continuously and instantaneusly convert CO into ClO2 within 3 sec., instantaneusly restore oxidation state of conversion agent, and can effectively reduce aerosol containing several toxic materials of tar and nicotine, etc..