GB459217A - Improvements in the production of esters - Google Patents

Abstract

Coal tar phenols intended for the production of phosphates are purified by distillation with a small quantity of a strong acid such as sulphuric, hydrochloric, phosphoric, benzenesulphonic and naphthalenesulphonic acids, whereby moisture, pyridine bases and unsaturated hydrocarbons are removed. The distillation is preferably effected under reduced pressure, but steam distillation may be employed. The phenols, which may be fractionated before, during or after their purification, are converted into their phosphates by treatment with phosphorus halides, particularly phosphorus oxychloride. The resulting triaryl phosphates, e.g. tri-o and p-cresyl phosphates and tri-1 : 3 : 5-xylenyl phosphate, are stated to be stable to light and heat, and thereby suitable for addition to compositions containing cellulose esters or ethers, rubber or resin. The phosphates may be further purified by treatment with dilute aqueous alkali and/or aqueous permanganate. According to the example, commercial cresylic acid is heated with 0,66 per cent of concentrated sulphuric acid under a pressure of 10--40 mm. mercury and the fraction coming over at about 105--140 DEG C. is heated under reflux with phosphorus oxychloride until the evolution of hydrochloric acid ceases; the product is vacuum distilled, washed with a dilute aqueous alkali solution and finally treated with a solution of a water-soluble permanganate or with carbon black. Cellulose derivatives with which the phosphates may be incorporated comprise cellulose acetate, formate, propionate, butyrate and nitrate, as well as ethyl, methyl and benzyl celluloses, and the resulting compositions, which may also contain powdered metal, metal oxides and carbonates, natural fibres, lamp-black, logwood, dyes or lakes, softeners and other plasticizers, are useful for moulding or for making filaments, films, foils and dopes for coating fabrics. The triaryl phosphates may also be incorporated in compositions containing rubber or gums and resins, e.g. gum dammar and ester gum, or added to lacquers and other coating compositions for water - proofing, moisture-proofing and sizing. They may also be used as transformer oils, as detergents in soap, as vehicles for grinding pigments, and in waxes, polishes, and inks.