SU906382A3 - Method for isolating dimethoxy- or diethoxydithiophsphoric acids or their sodium salts - Google Patents

Description

acid with an aqueous solution of sodium carbonate with Elda followed by treatment of the resulting aqueous solution of sodium oxydithiothiophosphoric acid with diethyl ether, separation of the phases, addition of hydrochloric acid to the aqueous solution and extraction of diethyl ether and phosphoric acid with diethyl ether. After the ether has been distilled off, diethoxydithiophosphoric acid is fractionated under vacuum. J 2 3 This purification method leads to positive results in laboratory conditions, but under production conditions, twofold extraction with diethyl ether because of its explosiveness and ability to ignite creates significant difficulties.

The closest in technical essence and achievable results to the proposed is a method of separating dialkoxydithiophosphoric acids or their sodium salts from the reaction mixture., Obtained from phosphorus pentasulfide and alcohol in an organic solvent medium by treating it with a 20% aqueous sodium hydroxide solution until it reaches pH 6-6.5, separating the aqueous solution containing dialkoxydithiophosphoric acid sodium salt from the organic phase and adding concentrated sulfuric acid to the aqueous solution, whereby acid is released yalkokciditi6focfofJna 3.

However, this method only reduces the amount of impurities to 5%. In addition, the method does not have a sufficiently high degree of purification of dialkoxydithiophosphoric acids,

The aim of the invention is to increase the purity of dimethoxy or diethoxydithiophosphoric acids or their sodium salts.

The goal is achieved by the method of separating dimethoxy or diethoxydithiophosphoric acids or their sodium salts from the reaction mixture obtained by reacting phosphorus pentasulfide with methanol or ethanol in a water-immiscible solvent when heated, the reaction mixture is treated with an aqueous solution of caustic soda at a dosage rate of 250 parts / per 100 parts the reaction mixture until reaching a pH

equal to 2, followed by a dosing rate of 50 parts by weight per hour per 100 parts by weight. the reaction mixture until the pH of the medium is 3, and the desired product is isolated as the sodium salt or converted to the appropriate acid.

The proposed sposs (allows the amount of impurities to be reduced to

by treating the reaction mixture with sodium hydroxide solution at a certain dosing rate to a pH value of 3. In the event that the pH exceeds 3, the amount of impurities increases. If this pH value is not reached, the yield of sodium salts of dialkoxydithiophosphoric acids is reduced. The method is technologically simple, the consumption of raw materials is less than in the known methods, and the corrosion protection of the installations used is not a problem.

Dimethoxy- and diethoxydithiophosphoric acids are obtained from various phosphorus pentasulfides differing from each other in their degree of contamination. Raw reaction mixtures obtained from various phosphorus pentasulfides are indicated in Examples L and B.

PRI me R 1. Obtaining dimethoxydithiophosphoric acid.

333 g (1.5 mol) phosphorus pentasulfide and 375 ml of toluene are introduced into a 2000 ml round-bottomed flask equipped with a stirrer, a thermometer, a reflux condenser and an additional funnel. The resulting suspension is heated to 80 ° C. At this temperature, g

(6.73 mol) of methanol. After the end of the methanol feed, the mixture is kept for 1 hour. Then the crude reaction mixture is cooled to room temperature. The parameters of the crude reaction mixture are presented in

tabl, t.

a b and c a. one

Dimethoxydithiophosphoric Concentration 5 Isolation of dimethoxy thiophosphoric acid sodium salt. Equipped with a stirrer, an additional funnel, an electrical device measuring the pH value, and a 1000 ml round-bottom flask with a 1000 ml indicator flask were placed 300 ml of the crude reaction mixture. With stirring at a rate of 250 parts by weight per hour, sodium hydroxide solution is dosed. After reaching a pI value of 2, the dosing rate is reduced to 35–50 parts by weight per hour and an aqueous solution of sodium hydroxide is supplied to a pH value of 3- Then the mixture divided into phases in a separatory funnel. The aqueous phase contains the pure sodium salt of dimethoxydithiophosphoric acid, the characteristics of which are presented in table. 2. Table 2 Quality of applied phosphate phosphorus peitasulfide 82 Table 3 Parameters Quality of phosphorus pentasulfide used Diethoxydithiophosphoric acid concentration 58-60, 0 lots, g / 100 ml Impurities% 6-10 L Diethoxythiophosphoric acid sodium salt excretion. into a 1000 ml round-bottom flask with a stirrer, an additional funnel, an electrical device measuring the pH value, and an indicator device, reduce 300 ml of the reaction mixture. With stirring, a 20-in aqueous caustic soda solution is added at a dosing rate of i 250 wt. h / h After reaching a pH of 2, the dosing rate is reduced to weight./h. The dosage is continued until the pH is 3. The mixture is then divided into two phases in a separatory funnel. The aqueous phase contains pure sodium salt of diethoxydithiophosphoric acid, its characteristics are shown in Table. k, table

Example 2. Getting diethoxydithiophosphoric acid.

A 2000-ml round-bottomed flask equipped with a stirrer, a thermal meter, a reflux condenser and an additional funnel is added with ZbO g (1.6 mol) of phosphorus pentasulfide and 00 ml of toluene. The resulting suspension is heated to 80 ° C. At this temperature, 313 g (.6.8 mol of ethanol is added over 1 hour. After the end of the ethanol feed, the mixture is kept for 1 hour. Then the reaction mixture is cooled to room temperature. The parameters of the crude reaction mixture are presented in Table 359-6t58 -61 99.0-99.5 98.9-93.7

0.5-1.0 1.3-2.0

3. Getting dimetic acid. The process is carried out analogously to example 1. The parameters of the crude reaction of the NOI mixture are presented on Table. 5 "Table 06382 The isolation of the sodium salt of diethoxydithiophosphoric acid is carried out as in Example 2. The parameters of the solution are listed in Table. 8. Table В

Claims (1)

Claim The method of separation of dimethoxy or riethoxy dithiophosphoric acids or their sodium salts from a reaction mixture obtained by reacting phosphorus pentasulfide with methanol or ethanol in a water-immiscible solvent * by heating, by treating the reaction mixture with a sodium hydroxide solution, characterized in that, in order to increase the degree purity of the target products, use a 5 ~ 20% aqueous solution of caustic soda, the process is conducted at a rate of dosing a solution of caustic soda 250 wt.h. / / h per 100 wt.h. the reaction mixture until a pH of 2 is reached, with a subsequent dosing rate of 50 parts by weight per hour per 100 parts by weight the reaction mixture until a pH of 3 is reached, and the desired product is isolated in the form of a sodium salt or transferred to the corresponding acid.