Ausimont S.p.a.

Sibit, S.p.a.

Other

Montedison S.p.a.

Montecatini Edison S.p.a.

Carlo Scotti

Michele Merenda

Alberto Pagliari

Renato C Pace

Giorgio Angeloni

Roberto Del Bianco

Mario Visca

Giampiero Basile

Sergio Carra'

Ugo Montiglio

Pierfrancesco Aspes

Sergio Vanni

Paolo Vallini

Loris Guidi

The invention relates to liquid peroxidic compositions containing:

Liquid peroxidic compositions

New catalysts for photo-assisted (i.e. promoted by light) oxidation-reduction (redox) reactions are disclosed. These catalysts consist of colloidal particles of a semiconductor, containing on their surface a reduction catalyst and an oxidation catalyst. In a first class of catalysts, the semiconductor has a difference of energy between valence band and conduction band such as to allow the hole-electron separation by absorption of visible light. This semiconductor is selected, in the case of the photo-decomposition of water, from the group consisting of TiO.sub.2 doped with Mn, Cr, or Cr and Nb; CdS doped with In or Ga; SrTiO.sub.3 doped with Cr or Mn; gallium phosphide; and cadmium sulphoselenide. In the case of the other photo-decomposition reactions, the semiconductor is selected from the group consisting of the above-mentioned compounds and CdS. In a second class of catalysts, the semiconductor has a difference of energy between valence band and conduction band such as not to permit the hole-electron separation by absorption of visible light. This semiconductor is selected, in the case of the photo-decomposition of water, from the group consisting of SrTiO.sub.3 and Nb.sub.2 O.sub.5. In the case of the other photo-decompositon reactions, the semiconductor is selected from the group consisting of the above-mentioned compounds and TiO.sub.2 doped with Nb.

Catalysts for photo-assisted oxidation-reduction reactions

A process for tanning hides for soles or insoles with ammonium titanyl sulphate. The hides, subjected to soaking, liming, fleshing, and deliming, are first treated with ammonium sulphate. Successively, ammonium titanyl sulphate as well as citric acid or an alkali metal citrate are gradually added to the bath, while maintaining the temperature of the bath at a value not exceeding 37.degree. C. and a pH at values ranging from 1.7 to 2.5. After each addition, the hides are treated until they have absorbed at least 90% of the soluble Ti (IV). Sodium sulphite and hexamethylenetetramine are then gradually added: this addition is such as to bring the final pH of the bath to 3.8-4.5 and to exhaust the bath in soluble Ti (IV). NaHCO.sub.3 is successively added until a pH value of the bath ranging from 4.0 to 5.0 is reached, such pH being maintained for at least 2 hours. At least one tanning treatment with a tannin, either prior to the treatment with ammonium titanyl sulphate (pretanning), or after the treatment with NaHCO.sub.3 (additional tanning), is carried out, said tanning being accomplished with a synthetic or vegetable tannin in the former case, and with a synthetic tannin in the latter case.

Process for tanning hides

This invention concerns a new product consisting of TiO.sub.2 particles having pigmentary granulometric and morphological characteristics. It includes a chemically reactive coating consisting of a mixture of oxides and oxychlorides selected from the group consisting of Al.sub.2 O.sub.3 and AlOCl; SiO.sub.2 and SiOCl.sub.2 ; and ZrO.sub.2 and ZrOCl.sub.2. The particles of reactive TiO.sub.2 product are prepared as follows: the surface of the TiO.sub.2 particles is activated by thermally treating the particles in a moving bed with an anhydrous gas at 400.degree.-600.degree. C. The particles are then made to react in a moving bed at 350.degree. C. to 600.degree. C., in the presence of a carrier gas, with an inorganic chloride selected from the group consisting of AlCl.sub.3, SiCl.sub.4 and ZrCl.sub.4. This new product is useful, for instance, in TiO.sub.2 pigments coated with organic molecules which provide an affinity for the vehicles of paints.

Post-treated titanium dioxide and process for producing same

Composition comprising a highly ferromagnetic CrO.sub.2 having deposited on the surface thereof an insoluble or sparingly soluble compound, thereby rendering the composition essentially non-reactive to water or oxidizable organic substances. Compound comprises either an oxide or hydroxide of Si and/or Ti.

Stabilized chromium dioxide compositions

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Voghera, Italy

Carlo Scotti