GB778077A - Improvements in or relating to the preparation of allyl phosphites - Google Patents

Abstract

A method for the production of diallyl or triallyl phosphite includes the steps of slowly mixing a mixture of substantially equimolecular proportions of allyl alcohol and a tertiary amine base with a reacting proportion of phosphorus trichloride at a temperature of about 0 DEG C. or lower, the mixing being accompanied by stirring and the reaction mixture being then caused or allowed to attain ordinary temperature. When triallyl phosphite is the desired end product a mixture of three molecular proportions of allyl alcohol and of a tertiary amine base are used with one molecular proportion of phosphorus trichloride whilst if diallyl phosphite is to be prepared a mixture of two molecular proportions of allyl alcohol and of a tertiary amine base are used with one molecular proportion of phosphorus trichloride and when the reaction mixture has attained room temperature a further molecular proportion of allyl alcohol is added and the mixture allowed to stand. In each case the final mixture is separated from the deposited tertiary amine hydrochloride and the triallyl phosphite or diallyl phosphite distilled off under reduced pressure. The reaction may be carried out in an inert diluent, e.g. benzene. In examples: (1) a mixture of 3 mols. of allyl alcohol and 3 mols. of triethylamine is added to a solution of 1.5 mols. of phosphorus trichloride in benzene at 0 DEG C. with vigorous stirring and after allowing the temperature of the mixture to rise to room temperature a further 1.56 mol. of allyl alcohol is added. After allowing the mixture to stand overnight the deposited triethylamine hydrochloride is filtered off and diallyl phosphite recovered from the liquid reaction product by first washing the latter with water, drying over anhydrous sodium sulphate and then distilling under reduced pressure in the presence of hydroquinone; (2) a mixture of phosphorus trichloride (1 mol.) and benzene (2 mols.) is added slowly to a mixture, cooled to -20 DEG C., of 3 mols. allyl alcohol, 3 mols. of triethylamine and about 11 mols. benzene. The resulting mixture is allowed to stand until it is at room temperature and the triethylamine hydrochloride filtered off. The filtrate is then washed with water and sodium carbonate solution and finally distilled at reduced pressure in the presence of hydroquinone to recover triallyl phosphite.