SU555111A1 - The method of obtaining m-dialkylphosphine phenols - Google Patents

Description

(54) METHOD FOR PRODUCING M-DIALKYLPOSPHINYLPHENOLS

one

This invention relates to the chemistry of organophosphorus compounds. A new method for preparing m-dialkylphosphinylphenols of the general formula is proposed.

m gR (0)

where R is lower alkyl,

which can be used as intermediate products in the synthesis of thermo-and fire-resistant dyes, as well as fire-resistant polycondensation polymeric materials.

A method is known for producing phenols phosphorylated at the meta position by demethylation of the corresponding methoxy derivatives of phosphines, for example, heating with 57% hydroiodic acid.

However, the severity of the conditions of this process leads to significant tarring and makes it difficult to isolate the target product from the reaction mass.

The closest to the proposed technical essence and the achieved result is a method for producing m-dialkylphosphinylphenols by oxidation of m-dialkylphosphinopheno with hydrogen peroxide.

However, to obtain the starting phosphinophenol, it is necessary to carry out a complex multistage synthesis, including, in addition, dimethylation of the methoxyaryl intermediate.

The aim of the invention is to develop a simpler process for the preparation of m-dialkylphosphinylphenols.

The proposed method for the preparation of m-dialkophosphinylphenols consists in that the hydrosulfate of m-dialkylphosphinylphenyldiazonium is reacted with an aqueous solution of sulfuric acid at the boiling point of the reaction mixture. It is advisable to use 65-70% sulfuric acid.

A distinctive feature of the method is the use of LL-dialkylphosphinylphenyldiazonium hydrosulfate and an aqueous solution of sulfuric acid as starting reagents.

An acidic aqueous solution of the diazonium salt, obtained in the usual way — by diazotization of the sulfate solution of the corresponding l-diphenylphosphinipaniline with an aqueous solution of sodium nitrite at 0–6 ° C, is added to the boiling aqueous solution of sulfuric acid and the reaction mixture is heated until the evolution of nitrogen has ceased. For the isolation of the target products, known methods are used: distillation in vacuum and recrystallization from alcohol. The yield of the desired compounds is 73-81%.

The structure of the products obtained is confirmed by complete elemental analysis data and a comparison of physical constants with known literature data.

The method of preparing M-dialkylphosphinylphenols is universal, allows the preparation of compounds with different alkyl groups, including compounds not previously described, and can be easily carried out on an industrial scale.

Example. Getting ll-dimethylphosphine.

75.0 g (0, Oz mol) of M-dimethylphosphinyl aniline were dissolved in a cooled mixture of 10 ml of water and 6.5 ml (0.12 mol) of sulfuric acid (tj 1.84 g / cm) and mixed

with 18 g of finely ground ice. After the formation of a homogeneous mixture, 2.1 g (0.03 mol) of sodium nitrite in 8 ml of water is added dropwise to a positive iodin-starch reaction while maintaining the temperature of the reaction mass 0-6 C.

The hydrosulphate / dimethylphosphinylphenyldiazonium obtained with stirring is slowly poured into a boiling solution of 20 ml of concentrated sulfuric acid (d 1.84 g / cm) in 17 ml of water, then the reaction mixture is boiled until complete elimination of nitrogen and cooled. The product is extracted (5x30 ml) with chloroform. Chloroform is distilled off, the residue is distilled. 3.9 g (78%) of M-dimethylphosphinylphenode are obtained, b.p. 164-166 ° C / 2,6 10, so pl. 148-149 ° C. After recrystallization from absolute ethanol, 3.0 g (77%) of the desired product is obtained, mp. 165.5166 ° C.

Similarly obtained M-diethiphosphinephenol, M-dppropiphosphine phenol and M -dibutylphosphine phenol. The constants of these compounds and the data of their elemental analysis are given in the table. 78

Claims (2)

The claims of phosphine phenyl diazonium are interconnected. The method of preparing M-dialkyl phosphates at the boiling point of the reaction mixture, nilphenols using a phosphorylated aromatic compound, about 5 and 5 2. The method according to claim 1, characterized in that, for the purpose of simplifying the use of 65-70% sulfur, the hydrosulfate is m-dialklnuyu acid. 555111 action with aqueous solution of sulfuric acid