Лако-красочные материалы — производство

Besides their major use in pressure-sensitive, thermal, and photographic recording materials, triphenylmethane leuco dyes are extensively used in biological and analytical applications. They are used for detection of hydrogen peroxide in medical diagnostic kits (e. g., glucose determination, by glucose oxidase), in biotechnology process control,124,125 in analysis of biological fluids, and in wastewater treatment plants.126 […]

Triphenylmethane leuco dyes are used for photographic materials. The photographic system requires a polymer binder such as acrylic acid-methyl methacrylate copolymer115 or a copolymer of isophthalic and terephthalic acids116; a sensitizer such as 4-(4-n-amyloxyphenyl)-2,6-bis(3-ethylphenyl)- thiapyrilium perchlorate,117 a photo initiator such as hexaarylbisimi — dazole,118 and phenyl tribromomethyl sulfone, cycloalkane such as 1,2,3, 4,5-pentabromo-6-chlorocyclohexane,119 or 3-benzylidene-9-methyl-2,3-di […]

Thermal recording materials consist of a heat-sensitive layer made by dispersing a leuco triphenylmethane dye and a phenol in a binder where thetwo reactive materials are kept apart by a water — or nonpolar solvent — soluble polymer surface film. The phenolic materials are generally solids at room temperature. At the thermographic copying temperature the […]

Pressure-sensitive recording materials are obtained by dissolving a triphenylmethane leuco dye in a solvent composed of paraffin oils. The microcapsules are formed from a water-soluble106 or water-dispersible material.107,108 Leuco dyes dissolved in sunflower oil are microencapsulated in a solution containing a melamine-HCHO precondensate and coated on the back side of a paper sheet. Contact of […]

Triphenylmethanes are used mainly for nontextile purposes. Almost all of the leuco bases of triphenylmethane dyes are used in the color-forming applications, e. g., in novel types of colorless copying papers. Other applica­tions include pressure-sensitive heat-sensitive materials, high-speed photo duplicating copying papers, light-sensitive papers, ultrasonic recording pa­pers, electrothermic heat-sensitive recording papers, inks, crayons, type­written ribbons, […]

Sulfonated triphenylmethane leuco dye 73 is prepared42 by sulfonating the leuco dye 74 with 20-30% of the theoretical amount of 20 — 65% oleum at 30 — 50°C. The dye, derived from leuco base 73 by oxidation, is used in the production of black-and-white photographic film. Crystal Violet reacts with tributyl phosphite in chloroform to […]

Use of benzotriazole in the preparation of diphenylmethanes and triphenylmethanes has been reviewed.99 Benzotriazole is condensed with an aldehyde and then allowed to react with naphthols to form a diphenyl — methane benzotriazole derivative such as 69 (Scheme 9). The benzotriazole moiety in 69 is displaced by a Grignard reagent to give triphenyl­methanes.79,100 This method […]

Formation of leuco compounds from ketones is generally a two-step process. The reaction of aromatic ketone with an arene nucleophile is normally carried out in the presence of excess POCl3 with P2O5, ZnCl2, or SOCl2. POCl3 serves as solvent and also as water acceptor. Usually dyes are formed directly in this reaction. Without isolation, they […]

The reaction of an aromatic aldehyde with an aromatic nucleophile containing hydroxy or amino groups gives products with at least two identical phenyl groups19 — 83 e. g., 55, 56. Use of two different nucleophiles generally results in lower yield. Benzene and naphthalene compounds can be formylated under Vil — smeir conditions. The formyl compounds, […]

The benzhydrols are obtained by reacting an aromatic aldehyde with an arylamine or by oxidation70 of a diphenylmethane derivative with PbO2 or MnO2. The benzhydrol intermediate is then treated with an arene nucleophile in the presence of acid catalysts such as aluminum chloride,71 concentrated hydrochloric acid,55 phosphoric acid,72 or sulfuric acid73 to give triphenylmethane leuco […]