Phthalic anhydride

PHTHALIC ANHYDRIDE

Anhydride of phthalic acid. Represents colourless crystals, almost water - insoluble, sparingly soluble in organic solvents (alcohol, ether, benzene, chloroform, etc. ).

Phthalic anhydride is received vapor - phase catalytic oxidation by oxygen of air of au xylol or naphthalene with use of stationary or fluid catalysts.

On the basis of phthalic anhydride and diols (ethylene - diethylene glycol, propylene glycol) polyethers receive; on the basis of phthalic anhydride and glycerin – the alkyd (glyptal) resins. Also phthalic anhydride easily reacts with phenols and their derivatives.

The main consumers of phthalic anhydride are the industry of plastic and paints and varnishes where it is applied to production of plasticizers, as initial reagent (together with ethylene glycol and glycerin) to synthesis of polyester resinss and alkyd resins. Besides on the basis of phthalic anhydride make different dyes, medicines, insecticides, lubricant dopes, additives for aviation fuel, for rubber and tires as vulcanization retarder.

Phthalic anhydride has to be stored in the cool, well aired room far from naked flame and oxidizers. In rooms where it is used, good local and general ventilation is necessary. In many processes phthalic anhydride is used not in firm look, and in liquid. In this case he is brought to the enterprise in reservoirs and at once pump over in system of pipelines, excepting contact with personnel and air pollution.

Phthalic anhydride — important initial product in production of different derivatives of phthalic acid; esters, phthalimide, ftalonitrit, etc.

Condensation of phthalic anhydride with phenols receive dyes, for example phenolphthalein. Significant amount of phthalic anhydride is used in production of glyptal and pentaerythritol - modified phthalic resins, intermediate products and dyes — derivative fluorescein, rhodamine and anthraquinone; pharmaceuticals, for example ftalazol and fenilin (it is applied at the increased coagulability of blood).