Patent GB-870005-A (GB)
Title: Dithiophosphinic acid compounds and preparation thereof
IPC: C07F9/30
Filed: 1959-10-26
Abstract: The invention comprises products of the formula:  <FORM:0870005/IV (b)/1> wherein Y is a salt or ester-forming group and R is an organic group directly attached to the phosphorus atom through a carbon atom. Y may be a substituted or unsubstituted ammonium group other than a quaternary ammonium group, e.g. a pyridinium, anilinium, guanidinium or triethylammonium group, an alkali metal e.g. Li, Na or K or a multivalent metallic cation radical in which at least one of the metal valencies forms a salt with the substituted dithiophosphinic acid.  Specified multivalent metals are the alkaline earth metals, Cu, Hg, Ni and Al.  The groups Y and R can be a substituted or unsubstituted, saturated or unsaturated, branched or straight chain alkyl radical, a substituted or unsubstituted saturated or unsaturated alicyclic radical or a substituted or unsubstituted aryl radical.  The groups R and Y may be substituted by e.g. cyano, alkoxy, halogen, aryloxy, aralkoxy, alkaryloxy, amino, nitro, ureido, hydroxyl, carbamyl, acyloxy, carbalkoxy, carboxy, and aryl.  The products may be obtained by (a) contacting a 2-cyanoethyl secondary phosphine of the formula: NCCH2CH2,PH(R) with sulphur and pyridine, guanidine, aniline, or triethylamine in an inert atmosphere under substantially anhydrous conditions to produce a compound of the first given formula in which Y is a pyridinium, guanidinium, anilinium or triethylammonium group, (b) if required, treating the product of step (a) with a metal alkoxide in an inert atmosphere free of moisture to produce the product in which Y is a metallic cation in which at least one of the metal valencies forms a salt with the 2-cyanoethyl substituted secondary dithiophosphinic acid, (c) and further if required, treating the salt formed in step (b) with a halogen derivative of the formula A-X wherein X is halogen and A is a substituted or unsubstituted ammonium group other than a quaternary ammonium group or A is an organic group as defined above for R having a carbon atom bounded to the halogen to form the compound of the first given formula in which Y is a substituted or unsubstituted ammonium group other than a quaternary ammonium group or in which Y is R as defined above. Suitable reaction temperatures in step (a) are from about 10 DEG C. to 115 DEG C. preferably 25 DEG  to 60 DEG  C., in step (b) from 0 DEG C. to 70 DEG C. and in step (c) from 25 to 150 DEG C.  Examples are given for the production of products of the first given formula in which R is NC,CH2,\CH2 and Y is pyridinium, sodium, -CH2C(O)NH C(O)NH2, 2,4-dinitrophenyl, cyclopentyl and NH4 respectively.  The products are useful as lubricant additives, insecticides and flotation agents.  The compound pyridinium bis(2-cyanoethyl) dithiophosphinate is also useful as a flame-proofing agent.  The following compounds which may be used as starting materials are prepared as follows:- 2-cyanoethylcyclohexyl phosphine by heating 2-cyanoethyl phosphine with cyclohexene in a nitrogen atmosphere in the presence of a ,a 11-azobisisobutyronitrile as initiator; n-octyl-2-cyanoethylphosphine by heating 2cyanoethyl phosphine with 1-octene in a nitrogen atmosphere in the presence of ditertiary-butylperoxide; and 2-cyanoethyl phenylphosphine by adding acrylonitrile dropwise to a stirred mixture of phenylphosphine, acetonitrile and aqueous KOH solution in an atmosphere of nitrogen.