Phosphinodithioic acids reactions

Flotation Reagents. Only one sulfide mineral flotation collector is manufactured from phosphine, ie, the sodium salt of bis(2-methylpropyl)phosphinodithioic acid [13360-78-6]. It is available commercially from Cytec Industries Inc. as a 50% aqueous solution and is sold as AEROPHINE 3418A promoter. The compound is synthesized by reaction of 2-methyl-1-propene [115-11-7] with phosphine to form an iatermediate dialkylphosphine which is subsequently treated with elemental sulfur [7704-34-9] and sodium hydroxide [1310-73-2] to form the final product (14). The reactions described ia equations 10 and 11... 

Phosphinodithioic acids, R2P(S)SH, (9.433a) can be made in up to 90% yields by the action of secondary phosphines on sulphur in dilnte ammonia. The ammonium salts so obtained can then be converted into the corresponding acids with HCl (9.434). Phosphinodithioic adds can in some instances be obtained from phosphinothioic halides and sodium hydrosulphide (9.435). They may also be made by a Friedel-Crafts-type reaction with benzene (9.436). Metal salts may be produced directly by the action of sulphur and alkali sulphide, or sulphur and metal, on diphosphine disulphides (Figure 9.23). 

Many compounds of the types in Table 9.6 can be made by adding sulphur to the appropriate phosphine. Diphosphine disulphides are thus derived from biphosphines, bis(phosphinodthioic) acids from di-secondary biphosphines (9.584), alkylene bis(alkylphosphine sulphides) and aUcylene bis(phosphinodithioic)acids (Table 9.6) from secondary alkylene biphosphines (9.585, 9.586), and alkylene bis(dialkylphosphine sulphides) from alkylene diphosphines. Reaction (9.583) can also be noted. 

Both (R)-(-t-)- and (S)-(-)-tertiarybutylphenylphosphine sulphides (6) have been synthesised in high optical purity from (S)-(-)- and (R)-(+)-tertiarybutylphosphinothioic acids, respectively, by formation of the mixed anhydride (5) followed by borohydride reduction (Scheme 2). Reactions of the product (6) have been used to provide routes to optically active phosphinothioic iodides, phosphinodithioates and thioselenophosphinic acids of known configurations. A new method for the asymmetric synthesis of tertiary phosphine oxides has been reported.5 An Arbusov reaction of the optically active 1,3,2-... 

Oxidation with hydrogen peroxide or iodine will give rise to a mixture of phosphinodithioic and phosphinic acids (9.418). With carbon tetrachloride in the presence of triethylamine a vigorous exothermic reaction occurs, giving the chloride (9.419). 

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