Nissan Chemical Industries Limited

Makoto Kawashima

Yoshitane Watanabe

Keitaro Suzuki

Kenji Tanimoto

Mikio Ando

Teruyuki Koshi

Tsutomu Kagamimiya

The invention relates to a process for producing diantimony pentoxide having a high oxidation purity. A process for producing an aqueous sol of diantimony pentoxide, which comprises mixing diantimony trioxide (SbO) and an aqueous hydrogen peroxide solution in an aqueous medium, and after the temperature has reached from 50 to 80&#xb0; C., reacting the diantimony trioxide with the aqueous hydrogen peroxide solution while keeping the reaction temperature at a level not higher by at least 10&#xb0; C. than a desired set temperature in the temperature range, to thereby obtain a sol having dispersed in the aqueous medium diantimony pentoxide particles which have a primary particle size of from 2 to 50 nm and which have a diantimony trioxide/diantimony pentoxide weight ratio of not higher than 5 wt %.

Process for producing antimony pentaoxide

A method for preparing a stable silica sol having an SiO.sub.2 concentration of 40% or less, the colloidal particles of said silica having a particle size of 40 to 500 nm, as measured by dynamic light-scattering and having an elongated shape having a thickness of 5 to 40 nm and an elongation of 5 to 30 times the thickness in only one plane, the method comprising the steps (a), (b) and (c): (a) mixing an aqueous solution of Ca or Mg salt with an aqueous solution of active silicic acid having an SiO.sub.2 concentration of 1 to 6% and a pH value of 2 to 5, or with an aqueous acidic silica sol having a particle size of 3 to 30 nm, an SiO.sub.2 concentration of 0.5 to 25% and a pH value of 1 to 5 in a weight ratio of 1500 to 10000 ppm of (CaO or MgO)/SiO.sub.2 ; (b) mixing an alkali metal hydroxide with the solution obtained by step (a) in a molar ratio of 20 to 300 as SiO.sub.2 /M.sub.2 O, wherein M represents an alkali metal atom; and (c) heating the mixture obtained by step (b) at 60.degree. to 300.degree. C. for 0.5 to 40 hours.

Elongated-shaped silica sol and method for preparing the same

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Sodegaura, Japan

Makoto Kawashima