Alkylphosphoric acid

Dapex [Di-alkylphosphoric acid extraction] A process for the solvent extraction of uranium from sulfuric acid solutions using di-(2-ethylhexyl) phosphoric acid (HDEHP). The HDEHP is dissolved in kerosene containing 4 percent of tributyl phosphate. The uranium is stripped from the organic phase by aqueous sodium carbonate and precipitated as uranyl peroxide (yellow cake). The process was no longer in use in 1988. See also Amex. 

In the example shown in Fig. 7.6, using an alkylphosphoric acid, about 60 stages are required to give a Co/Ni ratio of about 100. So many stages would be too many for mixer-settler operation, and other types of contactors would have to be considered. In this particular example, a sieve plate pulsed column has been shown to be very effective [3]. Flowever, with the development of the alkylphosphonic and alkylphosphinic acids, the separation of cobalt and nickel can be achieved in very few stages, owing to the high rejection of nickel (see Chapter 11). 

Soluble loss of a reagent (extractant, modifier, or diluent) from the solvent phase is an inherent part of the solvent extraction process, since all organic compounds are soluble, to some extent, in water. The conditions prevailing in the system can also promote solubility, which can be a particular problem if the composition and properties of the aqueous phase are inflexible. For example, the solubility of alkylphosphoric acid and carboxylic acid extractants is dependent on temperature, pH, and salt concentration in the aqueous phase. 

Phosphate and phosphonate molecules have a very high affinity for calcium carbonate surfaces, as shown by their influence on the precipitation and growth of calcite [164-166]. Accordingly, organophosphorus compounds such as alkylphosphoric acids [167-169] and phosphonic acid-terminated polyoxyethylene [170, 171] have been used to modify the surface of CaCOs powders. 

Dialkyl peroxyphosphates 67 or monoperoxy phosphates 68 react with phenyhnagnesium bromide to afford tcrt-butyl phenyl ether in high yield together with dialkylphosphoric acid or alkylphosphoric acid in moderate yields (equation 102). 

Leclerc, E., Guillaumont, D., Guilbaud, P., Berthon, L. 2008. Mass spectrometry and theoretical investigation of di-alkylphosphoric acid-lanthanide complexes. Radiochimica... 

Diethyl difluoro(trimethylsilyl)methylphosphonatc (42) with arenecarbaldehydes and aryl methyl ketones in the presence of cesium fluoride gives alkylphosphoric acid derivatives. ... 

Alkyl phosphoric acids. Perhaps the largest single group of extractants for actinides are the alkylphosphoric acids of three main types dialkylphosphoric acids, dialkylphosphonic acids, and... 

Gallium has been extracted from HCl media into chloroform in the presence of N-benzylaniline [3,4], n-octylaniline [5], and crown ethers (e.g., dicyclohexyl-18-crown-6) [6], and into o-dichlorobenzene in the presence of the tetraphenylarsonium ion [7]. Gallium has been separated from In and other metals by extraction into non-polar solvents in the form of its chelates with cupferron [8], HTTA [9], BPHA, p-diketones [10], and alkylphosphoric acids [11]. Gallium has been extracted also, from citric acid solutions of pH 2-3.5, into xylene solutions of Amberlit LA-2 [12] and Aliquat 336S [13]. 

Titanium has been extracted from hydrochloric acid medium by HTTA (mixed with TBP) [7]. Titanium has been extracted from salicylate medium by using Aliquat 336 in xylene [8]. Solutions of HDEHP and other alkylphosphoric acids in benzene or other solvents have also been used for separation of Ti [9]. 

Zirconium (hafnium) have been separated from other metals with the use of TOPO (in cyclohexane or toluene) [11,12], TBP (in benzene) [13], or alkylphosphoric acids (toluene, benzene) [14,15] from HNO3, HCl, or H2SO4 solutions. 

Alkylphosphoric acids are acidic extractants sometimes called liquid cation exchangers due to exchange of H+ ions for the extracted cations. They have been used for many metal ions. Examples include mono-(2-ethylhexyl)phosphoric acid (MEHP), dibutylphosphoric acid (DBP), and di-(2-ethylhexyl)phosphoric acid (DEHP). 

Comparison of Amine and Alkylphosphoric Acid Extractants for the Recovery of Uranium from Sulfate Solution... 

To prepare the [m-(acetylpyridinio)-n-alkyl]adenosine pyrophosphates, 10 mmoles of acetylpyridinio-n-alkylphosphoric acid and 10 mmoles of adenosine 5 -phosphoromorpholidate (as salt of 4-morpholine iV,iV -dicyclohexylcarboxamidine) are dissolved in 20 ml of freshly distilled o-chlorophenol. The mixture is stored at room temperature for 7 days. Progress of the condensation reaction is checked daily by paper electrophoresis (0.1 M Tris chloride at pH 8.1, 30 V/cm). After the reaction is completed, 60 ml of water are added to the mixture and the suspension is extracted 3 times, each with 200 ml of ethyl ether. The first ether extract obtained is reextracted with 30 ml of water. The combined aqueous phases are reduced to a volume of 5 ml under reduced pressure and are charged on to a Dowex 1X8 column (formate form, 2 X 50 cm, 100-200 mesh). The column is washed with 6.5 liters of water, and the coenzyme analogs are eluted from the resin with a convex gradient of formic acid ... 

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