An Overview of the Relevant Knowledge of Phthalic Anhydride

Phthalic anhydride is an organic chemical compound with the chemical formula of C8H4O3. It is a white crystalline powder formed by the dehydration of phthalic acid molecules. Phthalic anhydride is important in organic chemistry and is used as an intermediate for the production of plasticizers, coatings, saccharin, dyes, and other organic compounds. It is insoluble in cold water but slightly soluble in hot water and ether, and soluble in ethanol, pyridine, benzene, carbon disulfide, and other organic solvents.

Properties of phthalic anhydride

White needle-shaped crystals with a slight odor that are flammable and sublimate below their boiling point. The relative density is 1.527. The melting point is 131.6℃. The boiling point is 295℃ (sublimation). The flash point (open cup) is 151.7℃, and the combustion point is 584℃. It is slightly soluble in hot water and ether, and soluble in ethanol, benzene, and pyridine.

Production of phthalic anhydride

Naphthalene catalytic oxidation method: Naphthalene is melted, vaporized, and reacted with air in a boiling or fixed-bed reactor in the presence of a catalyst, vanadium pentoxide, to produce phthalic anhydride cas gas. The crude phthalic anhydride cas is obtained by condensation and melting, and then the purified phthalic anhydride is obtained by heat treatment, vacuum distillation, condensation, and separation.

Oxidation of o-xylene: o-xylene is used as a raw material and air in the presence of catalysts, such as vanadium pentoxide, in a fixed-bed reactor for gas-phase oxidation to obtain phthalic anhydride cas, which is then refined to obtain the final product.

Applications of phthalic anhydride

Phthalic anhydride cas no is one of the important organic chemical raw materials. It can be used as an intermediate for the production of plasticizers, alkyd resins, unsaturated polyester resins, dyes and pigments, pharmaceuticals, and pesticides, among other organic compounds.

Safety of phthalic anhydride

Phthalic anhydride, like benzoic acid, has local irritant effects on the skin and mucous membranes and may cause severe inflammation and blisters, often resulting in non-healing ulcers. Its toxicity is slightly lower than that of benzoic acid. The maximum allowable concentration in the air is 2 × 10-6. In production, water spray capture method can be used to reduce the concentration of phthalic anhydride cas no in the workshop air, and operators should wear personal protective equipment.

Flake phthalic anhydride is packaged in woven bags lined with plastic bags or multi-layer moisture-proof kraft paper bags. Liquid phthalic anhydride is transported in insulated tankers. Phthalic anhydride should be stored in a dry, ventilated, light-proof, and non-flammable environment at temperatures below 40℃, with a storage period of three months. During transportation, the packaging should be intact, moisture-proof, fireproof, and so on.

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