Showing papers on "Phosphotungstic acid published in 1995"

Production of high-molecular-weight polydioxolane

Abstract: PURPOSE:To produce high-mol.-wt. polydioxolane at a mild polymn. rate, a good reproducibility, and a low cost by polymerizing 1,3-dioxolane in the presence of a composite polymn. catalyst comprising a heteropoly-acid and a carbonyl compd. CONSTITUTION:A composite polymn. catalyst is produced by mixing a heteropoly-acid (e.g. phosphotungstic acid or cobalt molybdate) witn a carbonyl compd. (e.g. acetone or methyl ethyl ketone). High-mol.-wt. polydioxolane is produced by polymerizing 1,3-dioxolane in the presence of the composite catalyst, neutralizing the resulting product with a basic substance (e.g. triethylamine or sodium hydroxide), and distilling unreacted 1,3-dioxolane, etc., from the product under a reduced pressure. Thus polydioxolane is produced without being affected by water in the environment. Because of its characteristics, such as disintegratability in cold water and solubility in warm water, polydioxolane can suitably be used for a packaging film, a textile-treating agent, etc.

Production of aliphatic tetracarboxylic acid

Abstract: PURPOSE: To obtain butane tetracarboxylic acid, etc., efficiently in high yield useful as a raw material of a polyester, etc., under suppressing the generation of a reaction by-product. CONSTITUTION: This compound expressed by formula II (e.g. butane tetracarboxylic acid) is obtained by oxidizing a dibasic acid of formula I (R 1 and R 2 are each independently H or an alkyl, etc.) or its anhydride (e.g. tetrahydrophthalic acid anhydride) with hydrogen peroxide in the presence of catalysts composed of at least one among tungstic acid, its salt and phosphotungstic acid and an N-containing aromatic carboxylic acid. COPYRIGHT: (C)1996,JPO

Production of biscatechol

Abstract: PURPOSE:To obtain a biscatechol scarcely containing structural isomers, having high purity and useful as a bailast agent for photosensitive material, etc., while suppressing the formation of higher-order condensates and increasing the productivity of binuclear compound by reacting a substituted catechol with an aldehyde in the presence of an acid catalyst. CONSTITUTION:A biscatechol such as bis(2-methyl-4,5-dihydroxyphenyl) phenylmethane (2,2'-dimethyl-4,4',5,5'-tetrahydroxytriphenylmethane) can be produced by reacting a 4-substituted catechol such as 4-methylcatechol with an aldehyde such as acetaldehyde in the presence of preferably 0.01-50wt.% (based on the 4-substituted catechol) of an acid catalyst such as phosphotungstic acid.

Production of plastic lens

Abstract: PURPOSE:To impart antistatic properties to a plastic lens while maintaining optical properties by dipping the lens in a coating solution containing a tetraalkoxysilane, a substituted alkoxysilane, a heteropoly-acid, an organic solvent, and an acid, and then heating the lens. CONSTITUTION:A plastic lens is dipped in a coating solution comprising a mixture (A) of a silane compound represented by formula I (wherein R is a 1-5C alkyl) (e.g. tetramethoxysilane) and a silane compound represented by formula II (wherein R is a 1-5C alkyl; Y is an organic group excluding OR ; and n is 1-3) (e.g. monomethyltrimethoxysilane) in a molar ratio of 80:20 to 20:80, a heteropoly-acid (B) (e.g. phosphotungstic acid), an organic solvent (C) (e.g. methanol), and a 0.01-5wt.% aqueous solution of an acid (D), the A/B/C/D ratio being 1/(0.001-0.15)/(10-100)/(1-30) by mol. The coated lens is heated at 40 deg.C or higher for 0.5 to 5 hours.

Differential reactivity of structural components of eosinophil leucocyte granules as revealed by ethanolic phosphotungstic acid.

Abstract: After glutaraldehyde fixation and ethanolic phosphotungstic acid (E-PTA) treatment before embedding, thin sections of rat bone marrow and large intestine showed a characteristic pattern of electron opacity in eosinophil leucocyte granules. In both mature eosinophils and precursor cells, the matrix appeared highly contrasted while the crystalline core revealed no electron density. Additional treatment of sections with uranyl acetate did not modify the contrasting pattern of eosinophil granules. The absence of electron dense reaction in the crystalline core after E-PTA treatment seems to originate from removal of core components. The selective reactivity of the matrix toward E-PTA could be a valuable ultrastructural marker for studies on the differentiation of specific granules along the maturation of eosinophil leucocytes.