RU2107689C1 - Method for production of esters of alkylphosphonic acids - Google Patents

Abstract

FIELD: organic chemistry. SUBSTANCE: desired esters have common formula RP(O)(OR′)(OR″) where R is C₁-C₂-alkyl or halogenated alkyl, R′ and R″ are C₄-C₈.-alkyl. RP(O)Cl₂. is used as reagent 1, alcohol being used as reagent 2. Reaction is carried out at 0-30 C in the medium of solvent, saturated hydrocarbon having normal structure (e.g. petroleum ether, hexane) is used as said solvent. EFFECT: improved efficiency of the method.

Description

где
R - алкил C₁-C₂, галогеналкил;
R', R'' - алкил C₄-C₈.The invention relates to organoelemental chemistry, specifically to a technology for producing higher esters of alkylphosphonic acids of the General formula

Where
R is C ₁ -C ₂ alkyl, haloalkyl;
R ', R''is C ₄ -C ₈ alkyl.

 These esters are extractants and are used for the separation of rare earths, as well as in the purification of copper electrolytes from arsenic.

A known method of producing higher esters of alkylphosphonic acids by reacting dichloride of alkylphosphonic acid with an excess of higher alcohol, taken in a ratio of 1: 2.2 (mol), respectively, when heated to 100 ^o C in an inert solvent (dichloroethane).

 The disadvantage of the prototype method is the low yield, as well as the formation of a mixture of acid and full esters, the selection of which full esters of alkylphosphonic acid is difficult, and distillation under high vacuum does not allow to obtain pure products. The output of full ether 60 - 70%.

 The aim of the invention is to increase the yield and quality of the resulting full ester.

The goal is achieved:
a) introducing into the reaction mixture the most effective solvent — saturated hydrocarbons of normal structure or a mixture thereof, for example hexane, petroleum ether;
b) carrying out the process at a temperature of 0 - 30 ^o C, preferably 10 - 20 ^o C.

The process of interaction of alkylphosphonic anhydride with higher alcohol, taken in a molar ratio of 1: 2.2, respectively, in a solvent - saturated hydrocarbons of normal structure at a temperature of 0 - 30 ^o C, better than 10 - 20 ^o C, allowing to increase the yield of full ester, for example "hexarana", at the synthesis stage, to 92 - 97%, to reduce the content of acidic impurities in the reaction mass, which, in turn, leads to an increase in product yield and a decrease in the amount of wastewater generated during their neutralization and subsequent isolation new product.

 The yield of the whole product according to the proposed method is 90 - 96%.

The total amount of wastewater 4 m ³ / t of the finished product.

According to the proposed method, the production of esters of alkylphosphonic acids is as follows. Higher alcohol and solvent are poured into a reactor equipped with a stirrer, thermometer, dropping funnel and refrigerator. In alcohol at a temperature of 0 - 10 ^o C and a residual pressure of 200 - 760 mm RT.article dichloride is dosed. At the end of dosage, the reaction mass is kept in solution at a temperature of 0 - 30 ^o C, preferably 10 - 20 ^o C, for 3 to 4 hours to complete the reaction, after which a 15 - 20% caustic solution is dosed into it with stirring. sodium in an amount of 100 to 150 mg / g-mol of the starting dichloride.

 The resulting mixture was separated in a separatory funnel, the organic layer was washed twice with water with a total volume of 700-850 ml / g-mol of the starting dichloride, and after separation in a separatory funnel, the solvent and unreacted alcohol were removed by steam distillation.

The residue is a finished product - diester, containing at least 95% of the basic substance. In the process of isolation of unreacted alcohol, 150-200 ml of condensate is obtained, which is a water-alcohol emulsion. Alcohol after delamination of the emulsion and drying is returned to the cycle. The total volume of wastewater is 0.9-1.2 l / g-mol of the starting dichloride or 4 m ³ / t of the finished product.

Example 1. To 93.2 g (0.715 g mol) of 2-ethylhexyl alcohol with stirring at a temperature of 10 ^o C and atmospheric pressure add 43.2 g (0.352 g mol) of dichloride, 120 ml of petroleum ether and after exposure for 4 hours - 90 ml of a 17% aqueous sodium hydroxide solution.

After separation, 250 ml of organic and 90 ml of a water-salt layer are isolated. The organic layer was washed twice with water with a total volume of 250 ml, and petroleum ether was distilled off from the washed organic layer. Unreacted alcohol is removed by steam distillation. In this case, the finished product is obtained in an amount of 100.2 g with a diester content of 95.2%. The diester yield of the starting dichloride is 90%. The total volume of wastewater is 1.2 l / g-mol of dichloride or 3.8 m ³ / t of the finished product.

The elemental composition of the finished product:
Found,%: P 9.21; C 64.21; H 11.72; O 14.86.

 Calculated,%: P 9.67; C 63.72; H 11.64; O 14.97.

 Example 2. It differs from example 1 in that hexane (200 ml) is used as a solvent. The product is obtained from 124.8 g (0.987 g mol) of alcohol and 59.6 g (0.448 g mol) of dichloride.

To neutralize acidic impurities serves 100 ml of a 16% sodium hydroxide solution. 136.7 g of product are obtained with a basic substance content of 96.5%. The dichloride diester yield was 91.9%. The total volume of wastewater is 1.1 l / g-mol of the starting dichloride or 3.4 m ³ / t of the finished product.

Elemental composition of the starting product:
Found,%: P 9.33; C 63.99; H 11.80; O 14.88.

 Calculated,%: P 9.67; C 63.72; H 11.64; O 14.98.

 Example 3. Carried out analogously to example 1. As the starting reagents take butyl alcohol and ethylphosphonic dichloride in the amount of 0.715 and 0.325 g mol, respectively.

 The yield of diester is 92.5%.

Elemental composition of the starting product:
Found,%: P 13.70; C 54.48; H 10.50; O 22.32.

 Calculated,%: P 13.94; C 54.03; H 10.43; O 21.60.

 Example 4. Carry out analogously to example 1.

 Hexyl alcohol and chloromethylphosphonic dichloride in the amount of 1.144 and 0.526 g mol, respectively, are taken as the starting reagent.

 The yield of diester is 95.7%.

Elemental composition of the starting product:
Found,%: P 9.89; C 53.14; H 9.60; O 16.06; Cl 11.31.

 Calculated,%: P 10.39; C 52.26; H 9.38; O 16.08; Cl 11.89.

 Thus, the proposed method for the production of full esters of alkylphosphonic acids allows to increase the yield of diester 60 - 70% to 92 - 97% at the synthesis stage by 1.2 times the total yield, to improve the quality of the finished product (at least 95%) to reduce the amount of wastewater.

Claims (1)

The method of obtaining complete esters of alkylphosphonic acids of the General formula

where R is alkyl C ₁ - C ₂ or haloalkyl;
R ', R''- alkyl C ₄ - C ₈ ,
the interaction of alkylphosphonic acid dichloride with a higher alcohol in a solvent, characterized in that, in order to increase the yield and quality of the target product, saturated hydrocarbons of normal structure — petroleum ether, hexane and the process — are conducted at 0-30 ^° C. as a solvent.