Patent GB-740444-A (GB)
Title: Manufacture of sulphur derivatives of organic phosphorus compounds
Inventor: PERREN EDWARD ARTHUR
IPC: C07F9/40
Filed: 1951-11-12
Abstract: Organic phosphorus compounds containing sulphur are obtained by reacting a complex compound of an organic chloride of the formula RCl (in which R is as defined below), phosphorus trichloride or tribromide, and anhydrous aluminium chloride or bromide, with hydrogen sulphide at elevated temperature and subjecting the resulting sulphur-containing complex compound to controlled hydrolytic decomposition to form an organic monothiophosphonyl compound, e.g. ethyl thiophosphonyl dichloride, or a dithiophospho compound, e.g. dithiophosphoethane, or a monothiophospho compound. In a modification the product of the reaction with hydrogen sulphide is dissolved in an inert solvent, e.g. methylene chloride, and treated with an alkyl alcohol, e.g. ethyl alcohol and the product decomposed with water to form an alkyl ester of an R-substituted dithiophosphonic acid, e.g. O-ethyl ethyl dithiophosphonate.  The radical R is defined as an alkyl, cycloalkyl, or aralkyl radical, or an alkenyl radical containing at least three carbon atoms, or a chloroalkyl radical, which term includes polychlorinated methyl but only includes higher radicals above methyl containing one chlorine atom. Examples of the radical R are methyl, ethyl, n-propyl, isopropyl, n-, iso-, secondary- and tertiary-butyl, cetyl, benzyl, and cyclohexyl.  The formula RCl also includes chlorinated paraffins of indefinite composition such as chlorinated white spirit or chlorinated paraffin wax.  The hydrolytic decomposition may be effected by treatment with water and when it is continued at raised temperature various products may be formed, thus by warming dithiophosphoethane (C2H5PS2) with water it is converted to monothio phosphoethane (C2H5.POS).  In an alternative method for decomposing the complex compound obtained by the hydrogen sulphide treatment the product is dissolved in an inert solvent, e.g. methylene chloride, and decomposed by concentrated hydrochloric acid to produce an organic dithiophospho compound.  In examples, an ethyl chloride-phosphorus trichloride-aluminium chloride 1 : 1 : 1-complex is treated with (1) hydrogen sulphide at 90-100 DEG  C. for 200 hours and the product dissolved in methylene chloride and then decomposed with cold water at 15 DEG  C. to yield dithiophosphoethane; (2) with hydrogen sulphide at 140-145 DEG  C. for four hours and the product dissolved in methylene chloride and treated with cold water to form ethylthiophosphonyl dichloride (C2H5.P(S)Cl2); (3) with hydrogen sulphide at 130 DEG  C. for 72 hours, the product being dissolved in methylene chloride and the solution divided into two parts, one of which is hydrolysed with concentrated hydrochloric acid to yield dithiophosphoethane, while the second part is treated with ethyl alcohol, the solvent and alcohol distilled off, and the residue dissolved in methylene chloride and treated with cold water to yield O-ethyl ethyl dithiophosphonate-C2H5PS(SH) (OC2H5).  In another example, (4) a methyl chloride - phosphorus trichloride - aluminium chloride 1 : 1 : 1 complex is treated with hydrogen sulphide at 130 DEG  C. for 100 hours and the product is dissolved in methylene chloride and hydrolysed with cold water to yield monothiophosphomethane (CH3POS).