Diethyldithiophosphoric acid

Metal dithiophosphate complexes are involved in a wide variety of analytical methods for metals. Diethyldithiophosphoric acid reportedly 13-1 is) fonns complexes with thirty-five elements, mainly metals, in various oxidation states which are useful for solvent extraction. No attempt is made here to detail all the applications to solvent extraction methods which have been described since these ate summarized in the texts listed. Dithiophosphoric... 

The reaction of 1-allylsilatrane (76) with 0,0-diethyldithiophosphoric acid in CHCI3 at room temperature gave 0,0-diethyl S-(silatran-l-yl)dithiophosphate (81) in low yield (15%) instead of the terminal adduct (equation 116)109. 

Other reagents which have occasionally been used to cleave hydrazides include diborane (which also reduces the carbonyl groups), sodium naphthalenide, 0,0-diethyldithiophosphoric acid, (EtO)2PS2H, - and sulfur monochloride. Nickel-aluminum alloy in aqueous methanolic potassium hydroxide is a good reagent for reductively cleaving a number of N—N bonded compounds, such as A -methyl-A -phenylhydrazine and Af/Z-dimethylnitrosamine. - Nitrosamines have also been cleaved with titanium(IV) chloride-sodium borohydride and lithium aluminium hydride. 

When the potassium salts of thiolacetic acid or 0,0-diethyldithiophosphoric acid are used, the 3-0-acetate or 3-0,0-diethyldithiophosphate derivative is obtained. Thioepichlorohydrin was believed to be an intermediate, and, in fact, treatment of thioepichlorohydrin with the above-mentioned salts in aqueous media gives similar results. In absolute ethanol or in 1-propanol, the reaction with the dithiophosphate salt gives mainly the thiirane derivative 38 instead of the thietane, 37. Reactions of thioepichlorohydrin with oxygen nucleophiles (H20, 172,178,179a, 179b phCOj, ClCHjCOa, CH2=C(R)C02, ... 

Antimony was also extracted as the complex with cupferron [12] or BPHA [13]. Sb(III) and As(in) can be extracted with bis(2-ethylhexyl)dithiophosphoric acid (0.1 M) in heptane from 2-4 M HCl in the presence of iodide. Only Sb(III) is re-extracted with 12 M HCl [14]. The reagent has been applied for isolation of Sb in partition chromatography [15]. Also diethyldithiophosphoric acid has been recommended for the separation of Sb(III) and As(III) [16]. In the presence of Bi and Sn, antimony was determined after extraction (CHCI3) with cyclic thiourea derivatives [17]. Sb(III) was also extracted with the use of the crown ether 18-crown-6 [18]. 

A chloroform solution of diethylammonium DDTC (formula 4.37) extracts As(III), Sn(II), and Sb(III) from 1-5 M H2SO4 medium. Arsenic(V), Sn(IV), and Sb(V) do not react with DDTC. After Cu, Bi, and Hg have been extracted, iodide and ascorbic acid are added to the aqueous solution and As(III) is extracted. The DDTC method enables to separate As from Ge in the presence of oxalic acid. Pyrrolidinedithiocarbamate is also recommended for separation of As [7-9]. A hexane solution of diethyldithiophosphoric acid extracts As and Sb from 1-2 M H2SO4, but only Sb is extracted at pH 1.3-2.5 [10]. 

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