DE1198374B - Process for the preparation of thionophosphoric acid-O-phenyl-O, O-dialkyl esters with lower alkyl groups - Google Patents

Description

Process for the preparation of thionophosphoric acid O-phenyl-O, O-dialkyl esters With lower alkyl groups There are various processes for the preparation of thionophosphoric acid-O-aryl-O, O-dialkyl esters known with lower alkyl groups. Following one of these methods, these compounds are made by reacting a dichlorothionophosphoric acid O-aryl ester with a lower one Alcohol in the presence of a hydrochloric acid acceptor such as pyridine. According to another method, these compounds are prepared by reacting a dichlorothionophosphoric acid-O * aryl ester made with an alkali alcoholate. In such procedures, the implementation participants brought together at a temperature between about 15 and 80OC. After implementation the reaction mixture can be used for the purpose of separating off alkali metal chloride or pyridine hydrochloride be filtered, the thionophosphoric acid-O-aryl-O, O-dialkyl ester in the filtrate can be obtained. When carrying out such processes, however, the thionophosphoric acid-O-aryl-O, O-dialkyl esters with a lower alkyl group in unsatisfactory yield and purity obtain. This is due to the fact that triester thionophosphate compounds in the presence of alkali metal alcoholates, such as sodium ethylate, and in the presence of tertiary ones Bases such as pyridine are subject to rapid conversion or decomposition (cf. G. S c h r a d e r, The development of new insecticidal phosphoric acid esters «, Verlag Chemie GmbH, Weinheim / Bergstr., 1963 pp. 227, 228 and 244, and Y. N i s h i z a w a in Agricultural and Biological Chemistry, 25, pp. 820 to 828 [1961]).

According to the new and improved method of the present invention are thionophosphoric acid-O-phenyl-O, O-dialkyl ester with lower alkyl groups in better purity and in higher yield than by the previously known processes obtain.

The invention relates to a process for the preparation of thionophosphoric acid O-phenyl-O, O-dialkyl esters with lower alkyl groups by reaction of excess aliphatic monovalent Alkanols with 1 to 3 carbon atoms with chlorothionophosphoric acid phenyl esters at a temperature at which hydrogen chloride is formed, which is characterized is that dichlorothionophosphoric acid O-phenyl ester or monochlorothionophosphoric acid as starting materials -0 - phenyl - 0- alkyl ester, whose alkyl group has 1 to 3 carbon atoms, are used, the reaction temperature does not exceed 65 "C and 4 mol of des used alkanol with an amount of the mono- or dichlorothionophosphoric acid ester not more than 1 gram atom of phosphorus-bound chlorine corresponds, the thionophosphoric acid ester, if it is in an amount corresponding to more than 0.8 gram atom of phosphorus-bound chlorine is used, the alkanol is added in part, while the hydrogen chloride is continuously added to the extent is deducted as it is formed.

When the reaction with the formation of hydrogen chloride is practically complete, the reaction mixture can be partially distilled off under reduced pressure for the purpose of separating off low-boiling constituents, the desired O-aryl thionophosphoric acid O-aryl-O, O-dialkyl ester having lower alkyl groups being obtained as the residue. These products are obtained as crystalline solids or as viscous liquids, which are somewhat soluble in many organic solvents and very sparingly soluble in water.The conversion can be explained by the following equations: 5 excess s ~~~~~~~ MOX R-0-P-Cl + 2H-OX H-0-X ROP¼ + 2HCl (a) ox 5 ROP \ excess RO -F \ + HCl ROP + HOX HOX ox (b) R = phenyl, optionally substituted by chlorine, bromine, an alkyl, alkoxy, nitro, cyclohexyl, benzyl or phenyl group; X = alkyl group with 1 to 3 carbon atoms.

If you work in part, the partial addition takes place under reduced pressure or while an inert gaseous flushing agent is being passed through through the conversion mixture. Under such conditions the will be uninterrupted Removal of the formed hydrogen chloride from the reaction mixture effected. to Suitable gaseous purging agents include nitrogen, methyl chloride, carbon dioxide and air.

According to a preferred embodiment, at least 5 moles of the Alkanol reacted with an amount of the mono- or dichlorothionophosphoric acid ester, which corresponds to 1 gram atom of chlorine bound to phosphorus.

It is essential that the reaction of the invention take place at a temperature of not above 65 "C and preferably at a temperature between 15 and 45" C is carried out. The reaction proceeds smoothly under these temperature conditions to form the desired product and hydrogen chloride. Temperatures above 65 ° C are not used because it reduces the yield and purity of the desired Products is reduced.

The reaction is somewhat exothermic, so that the temperature through Regulation of the additional speed of one implementation participant and / or through Bringing the reactants into contact in an inert solvent and through external cooling can be set. Suitable solvents include hydrocarbon and halogenated hydrocarbon solvents such as methylene chloride, ethylene dichloride, Ethylene dibromide, carbon tetrachloride, chloroform, benzene and toluene.

The rate of conversion is determined by the temperature used and also determined by the implementation participants used in each case. The speed of implementation decreases z. B. with increasing chain length of the alcohol used.

On the other hand, the dichlorothionophosphoric acid O-aryl esters react and the chlorothionophosphoric acid-O-aryl-O-alkyl esters, the halogen or nitro substituents carry on the O-aryl group, with lower alcohols far faster than the others Chlorothionophosphoric acid ester: The reaction usually takes place within 1 up to 3 hours, after which the reaction is practically complete.

When carrying out the implementation according to the invention, the necessary Amounts of the reactants mixed with one another and below those given above Conditions kept. When the formation of the hydrogen chloride formed during the reaction is practically complete, the reaction mixture can under reduced pressure at temperatures gradually rising up to 65 ° C for the purpose of separating off the low-boiling ones Components such as the excess alcohol and - if used - the solvent, are distilled, the desired thionophosphoric acid-O-aryl-O, O-dialkyl ester with lower alkyl groups than liquid or crystalline residue is obtained. -In another method, the reaction mixture is placed in water, wherein the desired product is deposited as a liquid or as a solid material.

The compounds produced by the process according to the invention are used as preservatives for paper, paints and wood and as pesticides to destroy bacteria, fungi, mites and insects such as aphids, the Southern army worm and flies, usable.

The following examples explain the process according to the invention.

Example 1 Dichlorothionophosphoric acid - 0 - (2,4,5 - trichlorophenyl) ester (165.2 g; 0.5 mol) was added in part and with stirring over the course of 10 minutes Given 3200 g (100 mol) of methanol. The addition took place at the boiling point of the methanol (65 "C), whereupon after the addition the same temperature with stirring Was maintained for 30 minutes. The reaction mixture was then reduced under reduced pressure Distilled pressure to recover some of the methanol. The remaining methanol was removed by evaporation, leaving the thionophosphoric acid - 0 - (2,4,5 - trichlorophenyl) -O, O-dimethyl ester was obtained as a white, crystalline residue. This product was made with petroleum ether (Boiling range 30 to 60 "C) washed and dried. The dried product was obtained in a yield of 96.5%. Thionophosphoric acid - 0 - (2,4,5 - trichlorophenyl) - O, O-dimethyl ester melts at 39 to 41 "C.

Example 2 Dichlorothionophosphoric acid - 0 - (2,4,5 - trichlorophenyl) ester (66 g, 0.2 mol) was partially and with stirring to 160 over 25 minutes given g (5 mol) of methanol. The reaction was carried out with cooling and at one temperature from 25 to 30 "C. With stirring, the reaction mixture was turned on for 6 hours Maintained temperature of 28 to 32 "C. It was then kept under reduced pressure of 10 mm at temperatures gradually increasing to 30 "C to remove partially distilled unreacted methanol. The residue was in cold water poured, whereby the -TChionophosphoric acid-0- (2,4,5-trichlorophenyl) -O .O-dimethyl ester parted as a crystalline solid substance.

This product was separated by filtration and dried. The dried product was obtained in a yield of 95.6% and melted at 39 to 40 "C.

Example 3 Dichlorothionophosphoric acid - 0 - (2,4,5 - trichlorophenyl) ester (0.2 mol) was added partially and with stirring to 96 g (3.0 Mol) given methanol. The addition took place at a temperature of 22 to 410 C, whereupon the reaction mixture is stirred for 23/4 hours at one temperature of 31 to 45 "C. The excess methanol was then kept under reduced pressure partially distilled off, whereupon the residue was poured into cold water. Of the Thionophosphoric acid 0- (2,4,5-trichlorophenyl) -O, O-dimethyl ester which separates out in water as a product was separated and dried. The dried product was in a yield of 93 ° / 0 obtained.

Example 4 Chlorothionophosphoric acid 0- (2,4,5-trichlorophenyl) -O-methyl ester (32.6 g; 0.1 mol) was added to 640 g (20 mol) of methanol, whereupon the obtained The mixture was heated to boiling temperature (63 to 65 "C) for 45 minutes. The excess Methanol was then removed by evaporation, the product being thionophosphoric acid 0- (2,4,5-trichlorophenyl) -O, O-dimethyl ester was obtained in a yield of 890 / o.

Example S Dichlorothionophosphoric acid -0- (4-methylphenyl) -ester (48.2 g; 0.2 mol), which boils at a pressure of 6 to 8 mm at 122 to 128 ° C, was with stirring to 1280 g (40 mol) of methanol at the boiling point of methanol given, whereupon the resulting mixture 21/2 hours with stirring at this temperature was held. The methanol was then partially distilled off under reduced pressure, whereupon the residue is diluted with water and methylene chloride and the resulting mixture washed with water. The washed mixture was then reduced under a Print 15 mm at temperatures gradually increasing to 60 "C for removal distilled from methylene dichloride. The product of thionophosphoric acid O- (Pmethylphenyl) -O, O-dimethyl ester obtained as a viscous liquid in a yield of 860 / o. This product had at 25 ° C a density of 1.278 and a refractive index n25 1.5258.

Example 6 Dichlorothionophosphoric acid 0- (2-bromo-4-biphenyl) ester (38.2 g; 0.1 mol; boiling between 175 and 180 ° C at a pressure of 0.2 to 0.5 mm) was added to 160 g (5 mol) of methanol with stirring, whereupon the resulting mixture was added Was heated to boiling temperature (64 to 65 "C) for 20 minutes. After evaporation of the excess methanol was the product, thionophosphoric acid-0- (2-bromo-4-biphenyl) -0, 0-dimethyl ester, obtained in a yield of 91 0 / o. This product was one crystalline solid substance with a melting point of 65 to 66.50 C.

Example 7 Dichlorothionophosphoric acid 0- (2,4-dichlorophenyl) ester (15.5 g; 0.052 mol; boiling at 154 "C at a pressure of 10 mm) became 46 g (1 Mol) ethanol, whereupon the resulting mixture for 5 hours with stirring on a Temperature of 32 to 48 "C. The reaction mixture was then heated with methylene dichloride diluted, whereupon the diluted mixture was washed with water and then for the purpose of Separation of excess solvent was partially distilled. It was of thionophosphoric acid-0- (2, 4-dichlorophenyl) -O, O-diethyl ester- as a viscous liquid Example 8 gives 1 mol of dichlorothionophosphoric acid in a yield of 87.5% - 0 - (2,4,5 - tri-chlorophenyl) ester was partly within 4 hours and added to 10 moles of methanol with stirring. The addition was made gradually from 19 to 38 "C increasing temperatures and under a pressure of 250 mm. After the addition was continued for an additional 3 hours at a temperature of 38 to 40 "C and below stirred at a pressure of 245 mm. The reaction mixture was then washed with water washed, whereupon the washed product by partial distillation under a reduced pressure of 30 mm and gradually increasing temperatures up to 65 "C concentrated and thereby the thionophosphoric acid 0- (2,4, 5-trichlorophenyl) -O, O-dimethyl ester was obtained as a crystalline residue in a yield of 86.5%.

Example 9 1 mole of dichlorothionophosphoric acid 0- (2,4-dichlorophenyl) ester was within 4 hours with stirring and partially to a mixture of 8 moles of ethanol and 3 moles of ethylene dichloride are added. The addition took place at one Temperature from 24 to 400 C and under a pressure of 250 mm. After the addition was the reaction mixture for 3 hours at a temperature of 35 to 40 "C and below one Pressure held at 250 mm. It was then washed with water, whereupon the washed product under a reduced pressure of 30 mm and at gradually up was partially distilled to 65 "C increasing temperatures. The thionophosphoric acid-0- (2,4-dichlorophenyl) - O, O-diethyl ester as a colorless, liquid residue in one 83% yield obtained.

Example 10 Dichlorothionophosphoric acid-0- (3-chloro-4-nitrophenyl) ester (38.5 g; 0.125 mol; refractive index n2o0 = 1.6063) was within one hour partly to a mixture of 1.25 mol of methanol and 0.375 mol of ethylene dichloride given. The addition was carried out under reflux and at a temperature of 34 to 38 "C and a pressure of 245 mm. After the addition, the reaction mixture was 4 hours kept with stirring at a temperature of 38 to 41 "C at a pressure of 240 mm. The reaction mixture was then washed with water, followed by the solvent removed by evaporation and the thionophosphoric acid O- (3-chloro-4-nitrophenyl) O-, O-dimethyl ester was obtained as a liquid residue. This product was in a yield of 84.5% and was a lightly colored, water-insoluble oil.

Example 11 1 mole of chlorothionophosphoric acid 0- (2,4,5-trichlorophenyl) -O-methyl ester was partially and with stirring to 9.5 mol of n-propanol within one hour given. The addition took place at a temperature of 30 to 40 "C while through the reaction mixture was passed through a stream of air. That Was stirring continued and the implementation mix to complete the implementation below kept the same conditions for 4 hours.

The reaction mixture was then washed with water, whereupon the washed product under a reduced pressure of 30 mm and at gradually up concentrated to 65 ° C increasing temperatures by partial distillation and the thionophosphoric acid O- (2,4,5-trichlorophenyl) -0-methyl O-n-propyl ester was obtained as a liquid residue in a yield of 85%. This product had a density of 1.4081 at 25 ° C and a refractive index nD25 = 1.5525, in the same The process according to the invention can also be used to prepare other 8-phenyl-O, O-dialkyl thionophosphoric acid can be used in very high yields as follows: thionophosphoric acid-O- (4-benzylphenyl) -O, O-diethyl ester (Yield 99%; nD25 = 1.5689; density of 1.195 at 25 ° / 4 ° C) by reacting ethanol with dichlorothionophosphoric acid O- (4-benzylphenyl) ester.

Thionophosphoric acid O- (2-chloro-4-tert-butylphenyl) -O, O-dimethyl ester (Yield 98%; liquid product with a sulfur content of 1001o and a chlorine content of 11.8 0 / o) by reacting methanol with dichlorothionophosphoric acid 0- (2-chloro-4-tert-butylphenyl) ester.

Thionophosphoric acid O- (2,4-dichlorophenyl) -O, O-dimethyl ester (yield of 96%; nD25 = 1.5338; Density of 1.247 at 25 ° / 4 ° C) by reacting methanol with dichiorthionophosphate-O- (2,4-dichloro ester.

Thionophosphoric acid O- (4-methoxyphenyl) -O, O-dimethyl ester (yield 970 / o; n25 1.5311; density of 1.237 at 25a / 4OC) by reacting with methanol Dichlorothionophosphoric acid O- (4-methoxyphenyl) ester.

Claims (2)

Claims: 1. Process for the preparation of thionophosphoric acid-O-phenyl-O, O-dialkyl esters with lower alkyl groups by reaction of excess aliphatic monovalent Alkanols with 1 to 3 carbon atoms with chlorothionophosphoric acid phenyl esters at a temperature at which hydrogen chloride is formed, d u r c h g ek It is noted that the starting materials used are dichlorothionophosphoric acid - O - phenyl ester or monochlorothionophosphoric acid O-phenyl-O-alkyl ester, the alkyl group of which is 1 to 3 carbon atoms are used, the reaction temperature 65 ° C is not exceeds and 4 moles of the alkanol used with an amount of the mono- or. Dichlorothionophosphoric acid ester not more than 1 gram atom of phosphorus-bound chlorine corresponds, the thionophosphoric acid ester, if it is in an amount corresponding to more than 0.8 gram atom of phosphorus-bound chlorine is used, the alkanol is added in part, while the hydrogen chloride is continuously added to the extent is deducted as it is formed. 2. The method according to claim 1, characterized in that at least 5 mol of the alkanol with an amount of the mono- or dichlorothionophosphoric acid ester which corresponds to 1 gram atom of the chlorine bound to phosphorus.