DD234426A1 - PROCESS FOR THE PREPARATION OF CHLOROSULPHANOPHOSPHORIC ACID O, O-DIALKYL ESTERS - Google Patents

Abstract

The invention relates to a novel process for the preparation of Chlorsulfanphosphorsaeure-0,0-dialkyl esters, which are used as intermediates for the synthesis of pesticides. The aim of the invention is to enable a technically simple use of the products obtained. This object is achieved in accordance with the invention by reacting thiophosphoric acid-0,0,0-trialkyl esters in a halohydrocarbon as solvent with sulfuryl chloride to the Chlorsulfanphosphorsaeure 0,0-dialkyl esters at 20-60C so that the gaseous reaction products are removed quickly and completely and thereby the formation of by-products is largely suppressed. The resulting products can immediately without further purification for the synthesis z. B. used by crop protection agents.

Description

_/ P - * SCl, R ² O

in which R ¹ and R ^{2 may be} identical or different straight-chain or branched alkyl radicals (C 1 -C 4), is obtained by reacting appropriately substituted trialkylthiophosphoric acid esters and sulfuryl chloride in a molar ratio of 1: 1 to 1: 0.8 in a halohydrocarbon at temperatures between 20 ⁰ C and the boiling point of the solvent used within 60-90 minutes with gradual increase in temperature until the completion of gas evolution. The target products are obtained in high yield and satisfactory purity and without thermal rearrangement products.

Conveniently, the procedure is to submit the trialkyl phosphate in a halohydrocarbon, preferably methylene chloride, the sulfuryl chloride is added dropwise and during the reaction, the temperature slowly first, then more rapidly from 20 ⁰ C to 6O ⁰ C (when working in methylene chloride of 20 ° to 40 °) and thus achieved a nearly complete conversion and at the same time the resulting by-products of the reaction (sulfur dioxide and allyl chloride) removed.

By this technically easily practicable procedure, depending on the chain length of the alkyl radicals of the trialkyl ester used, yields of more than 90% can be achieved on the target product. Thermal rearrangements the Chlorsulfanphosphate (eg with sulfur separation to Ο, Ο-Dialkylphosphorsäureesterchloriden) are largely suppressed by the rapid mode of operation and the purity of the solutions obtained for the subsequent reactions without further workup (eg degassing in vacuo or by Purging with inert gas, removal of the solvent, distillation, etc.) satisfactory. Although isolation of the target products is readily possible, but generally not necessary. The following examples serve to explain the method according to the invention.

embodiments example 1

Chioresulfanic acid-0,0-dimethyl ester To a solution of 15,6 g (0,1 mol) of 0,0,0-trimethyl-Tiophosphate in 50 ml abs. Dichloromethane is added dropwise with stirring at 20 ⁰ C, a solution of 13.5 g (0.1 mol) of sulfuryl chloride in 10ml abs. Dichloromethane in about 20min under water cooling so that the internal temperature does not rise above 20 ° C. After completion of the addition, the mixture is stirred for 10 min at the same temperature and then raises the internal temperature in the course of 1.5 to 2 hours gradually to 4O ⁰ C is stirred for a further 15 min at boiling temperature (42-44 ⁰ C). The content of the solution of Chlorsulfanphosphorsäure OjO dimethyl ester can be determined by ³¹ P NMR spectroscopy. The sample of a representative batch showed a signal with a chemical shift of δ = 23.0 ppm. By quantitative evaluation of the phosphorus-containing products, a content of 93% chlorosulfan phosphate was determined. Another representative batch was worked up and distilled in vacuo. There were obtained 13.4 g (76% of theory) of target product. Molecular Formula: C ₂ H ₆ CIO ₃ PS Molar weight: 176.56 KP ₀ , ₅ : 49-5O ⁰ C ng ⁰ : 1.4820

Example 2

To a solution of 15.6 (0.1 mol) of thiophosphoric acid 0,0,0-trimethyl ester in 50 ml abs. Dichloromethane is added dropwise with stirring at 20 ⁰ C, a solution of 11.5 g (0.085 mol) of sulfuryl chloride in 10 ml of abs. Add dichloromethane in about 15 minutes. Further procedure analogous to Example 1. According to ³¹ P NMR spectroscopy, the reaction product contained 80.2% of 0.03-chlorophosphorus acid ester (5 = 23.0 ppm) and 16.8% of starting material (δ = 73.8 ppm). The thiophosphoric acid 0,0,0-trimethyl ester still present in the solution according to this example, in contrast to sulfuryl chloride, does not interfere in many subsequent reactions. In the procedure of Example T may still unreacted SO ₂ CI _{2 be present} in the reaction mixture.

Example 3

To a solution of 15.6 g (0.1 mol) of thiophosphoric acid-0,0,0-trimethyl ester in 50 ml abs. Chloroform is added dropwise with stirring at 20 ⁰ C, a solution of 13.5 g (0.1 mol) of sulfuryl chloride in 10 ml of abs. Chloroform in about 15 min with water cooling at 20 ° C and stirred for a further 15 min at the same temperature. Then, the internal temperature is gradually increased in the course of 110 min to 6O ⁰ C, so that there is always a moderate evolution of gas and then stirred for 10 min at boiling temperature (approx.

According to ³¹ P-NMR spectroscopy, the reaction product contained 90% Chlorsulfanphosphorsäure OjO dimethyl ester.

δ = 23.0 ppm ng ⁴ = 1.4850

Example 4

Procedure analogous to Example 1 19.8 g (0.1 mol) of thiophosphoric acid 0,0,0-triethyl ester were used. According to ³¹ P-NMR-Sprektroskopie the reaction product contained 95% ChlorosulfanphosphorsäureHXO diethyl ester.

Example 5

Procedure analogous to Example 1 were used 24.0 g (0.1 mol) of thiophosphoric OAO tripropyl ester. According to ³¹ P-NMR spectroscopy, the reaction product contained 77.4% Chlorsulfanphosphorsäure OO dipropylester.

Example 6

Procedure analogous to Example 1 were used 24.0 g (0.1 mol) of thiophosphoric acid 0,0,0-triisopropylester. According to ³¹ P NMR spectroscopy, this contained:

Reaction product 73.2% Chlorsulfanphosphorsäu, t -0,0-di-isopropyl ester.

Example 7

Procedure analogous to Example 1 were used 17.0 g (0.1 mol) of thiophosphoric acid-0,0-dimethyl-0-ethyl ester. According to ³¹ P NMR spectroscopy, the reaction product contained 73% chlorosulfanphosphoric acid 0-methyl-O-ethyl ester (δ = 21.0 ppm) and 22.8% chlorosulfan phosphoric acid CO 2 dimethyl ester fo = 23.0 ppm).

Example 8

Procedure analogous to Example 1 were used 18.4 g (0.1 mol) of thiophosphoric acid 0,0-dimethyl-0-propyl ester. According to ³¹ P-NMR spectroscopy, the reaction product contained 75% chlorosulfanphosphoric acid 0-methyl-0-propyl ester (δ = 20.9 ppm) and 20% chlorosulfanphosphoric acid-0,0-dimethyl ester (δ = 23.0 ppm).

Example 9

Procedure analogous to Example 1 were used 19.8 g (0.1 mol) of thiophosphoric acid-0,0-dimethyl-0-butyl ester. According to ³¹ P-NMR spectroscopy, the reaction product contained 64.9% chlorosulfanphosphoric acid 0-methyl-O-butyl ester (δ = 21.3 ppm) and 12.5% chlorosulfanphosphoric acid-0,0-dimethyl ester (δ = 23.0 ppm). ,

Claims (1)

Invention claim: Process for the preparation of chlorosulfan phosphoric acid C ^ O-dialkyl esters of the general formula 0. P - SCI, in which R ¹ and R ^{2 may be} identical or different straight-chain or branched alkyl radicals (C ₁ -C ₄ ), from trialkylthiophosphoric acid esters and sulfuryl chloride, characterized in that the phosphoric acid esters and the sulfuryl chloride are in a molar ratio of 1: 1 to 1: 0.8 in a halohydrocarbon at temperatures between 2O ⁰ C and the boiling point of the solvent used within 60-90 minutes with gradual increase in temperature until the completion of gas evolution. Field of application of the invention The present invention relates to a novel, advantageous process for the preparation of Chlorsulfanphosphorsäure-0,0-dialkyl esters, which may be used as intermediates u. a. can be used for the synthesis of pesticides. Characteristic of the known technical solutions It is known that can be obtained by reaction of thiophosphoric acid 0,0-diesters or thiophosphoric 0,0,0-triesters with sulfuryl chloride chlorosulfanphosphoric acid-0,0-diester, hereinafter referred to as chlorosulfan phosphate. (See "Organic Phosphorus Compounds", edited by GM Kosolapoff and L. Meier, Wiley and Sons, New York / London / Sydney / Toronto 1975, Vol. 7, p. 573.) Such compounds provide useful intermediates for synthesis however, the techniques described so far have not found application in the art, although it would be desirable for the synthesis of the compounds which are difficult or impossible to prepare in other ways. However, the known methods have a number of disadvantages. Thus, the preparation of the Chlorsulfanphosphorsäure-CO diesters generally at temperatures below 10 ⁰ C, which is carried out in most cases in an inert solvent. The exclusively used benzene (PoIn.Pat., 87 321 and DE-AS 2012272), however, in addition to the considerable fire hazard also has a high toxicity. In addition, the sufficient removal of the resulting in the reaction with resulting gaseous reaction products is difficult. However, since this is absolutely necessary for the success of the reaction and the avoidance of undesired side reactions, work is carried out using reduced pressure (see PoIn., Pat., 87321) or high vacuum (see US Pat. No. 4,111,2024). Finally, the isolation of the chlorosulfanophosphates by fractional vacuum distillation described in many cases represents an expensive and lossy operation which is not necessary for technical further processing. Object of the invention The object of the invention is to obtain by a simplified process low-toxic by-products and clean chlorosulfanophosphoric acid-0,0-diesters and also to allow versatile use of Chlorsulfanphosphate as intermediates. Explanation of the essence of the invention The task was to carry out the reaction of thiophosphoric acid 0,0,0-trialkyl with sulfuryl chloride so that the reaction proceeds as completely as possible, the formation of by-products is largely suppressed and can be easily remove the inevitably forming by-products. The object is achieved in that chlorosulfanphosphorsäure 0,0-dialkyl ester of the general formula