Patent GB-848485-A (GB)
Title: Process for the stabilising of esters of phosphorus-containing acids
IPC: C07F9/02
Filed: 1957-11-29
Abstract: A neutral ester of a dialkyl phosphoric acid or of a dialkyl mono-or di-thiophosphoric acid free of aliphatically bound halogen atoms and wherein the alkyl groups each contain 1 to 3 carbon atoms is stabilised by adding to the ester from 2% to 30% (calculated on the weight of the ester) of a compound having an epoxide group, e.g., epichlorhydrin, cyclohexene oxide, propylene oxide, or styrene oxide, as stabilising agent.  The esters to be stabilised may be pure or technical grade substances and they may be incorporated as such in solid, semi-solid or liquid concentrates which on dilution produce readyfor-use preparations (see Group XV).  Specified esters are thiophosphoric acid-[2-isopropyl-4-methyl-pyrimidyl-(6)]-,diethylester, phosphoric acid-[3-methylpyrazolyl-(5)]-diethyl ester, dithiophosphoric acid S-(3, 5-dichloro-phenylmercaptomethyl)-0, 0-dimethyl ester and dithiophosphoric acid S-(3-chloro-phenyl-mercaptomethyl)-0,0-dimethyl ester. Specification 713,278 is referred to.ALSO:A composition which may be used to provide an insecticide comprises a neutral ester of a dialkyl phosphoric acid or of a dialkyl dithiophosphoric acid free of aliphatically bound halogen atoms and in which the alkyl groups contain 1 to 3 carbon atoms and from 2 to 30% (calculated on the weight of the ester) of a compound having an epoxide group as stabilising agent.  The composition may also contain an emulsifying agent e.g. an alkyl p  phenol-ethylene oxide condensation product, an organic solvent such as xylene, benzene, diesel oil, kerosene, spindle oil or a petrolatum product.  Specified epoxide compounds are epichlorhydrin, cyclohexene oxide, propylene oxide and styrene oxide. Examples describe the following compositions (the parts being by weight) : (1) an emulsifiable solution for preparing an insecticidal emulsion comprising 20 parts of thiophosphoric acid-[2-isopropyl-4-methylpyrimidyl-(6)]-diethyl ester, 35 parts of an alkyl phenol-ethylene oxide condensation product obtained by condensing 1 mol of nonyl, octyl or iso-octyl phenol with 5 to 10 mols of ethylene oxide, 44 parts xylene and 1 part of epichlorhydrin; (2) as in (1) except that the ratio of the respective ingredients is 60:30:7:3; (3) an emulsifiable insecticidal composition comprising 20 parts of phosphoric acid-[3-methyl-pyrazolyl-(5)]-diethyl ester, 35 parts of emulsifying agent as in (1), 44 parts xylene and 1 part epichlorhydrin, (4) as in (3) except that the ratio of the respective ingredients is 20:8:71:1, (5) and (6) 80 parts of an ester as in (1), 16 parts of the same emulsifying agent and 4 parts of cyclohexene oxide or of propylene oxide, (7) 40 parts of the ester used in (1), 20 parts of the same emulsifying agent, 28 parts xylene and 12 parts styrene oxide, (8) 25 parts of the ester used in (1), 10 parts of the same emulsifying agent, 64,5 parts of benzene and 0,5 part of cyclohexene oxide, and (9) an insecticidal solution comprising 436 parts of the ester used in (1), 539 parts of kerosene and 25 parts of epichlorhydrin.  Other esters referred to are dithiophosphoric acid-S-(3,5-dichloro-phenylmercaptomethyl) 0,0-dimethyl ester and dithiophosphoric acid-S-(3-chlorophenylmercaptomethyl)-O,O-dimethyl ester. Specification 713,278 is referred to.