2-Bromolauric acid

Extraction of sulfuric acid by an extractant comprising a tertiary amine and a-bromolauric acid is very efficient (see curve A in Fig. 17) but not very reversible. As fatty acids are much weaker acids than H2SO4, the distribution curve is quite similar to that for extraction by an amine alone (curve C in Fig. 17). Dinonylnaphthalenesulfonic acid, on the other hand, is too strong an HA in combination with tertiary amines and the extraction is too low (see Table 8). Extractants comprising a tertiary amine and mixtures of a-bromolauric acid with the sulfonic acid were tested. As expected, increasing the proportion of the stronger acid decreases the total extraction power of the extractant (see Table 8). 

Table 8 H2SO4 Extraction by ABC Extractants Comprising Trilauryl Amine (TLA) and Dinonylnaphthalenesulfonic Acid (DNNSA) or Mixtures of DNNSA and a-Bromolauric Acid (ABL)...

Figure 19 presents the curves for phosphoric acid distribution between water (pure solution) and extractants comprising a quaternary amine and a sulfonic acid. The extraction is proportional to the concentration of the active components and decreases slightly on elevation of the temperature. The distribution curves show that these extractants, found suitable for sulfuric acid extraction, are not sufficiently basic for the extraction of HsPO i, which is a much weaker acid (free acid concentrations of about 6 M are required to reach loading of 1 mole of acid per mole of amine). An extractant comprising a long-chain tertiary amine (trilauryl amine, TLA, Alamine 304, produced by Henkel) and a-bromolauric acid (ABL, Miles Yeda) was tested. The distribution curves for phosphoric acid extraction from pure solutions are shown in Fig. 20. The extraction is proportional to the concentration of the active components and depends on the temperature. Note that whereas the extraction decreases on elevation of the temperature at the lower concentration range, it increases with temperature at concentration ranges at which the H PO /amine molar ratio is greater than one. Similar reverses in the effects of various parameters at about stoichiometric extraction were noted in the past. They are explained by shifting from the ion-pair formation mechanism to the H-bonding one [58,59].

A rather outstanding example of acidic extractants is that of alkyl phosphoric acid, in particular die-2-ethyl hexylphosphoric acid (DEHPA) which has been used in the extraction of uranium, nickel, zinc, cobalt, chromium and many other metals (46). Dodecyl phosphoric acidics also used in uranium extraction (46). A large number of carboxylic acids may be used to extract a variety of metals these include naphtenic acids for base metals and rare earth metals, a-bromolauric acid, pivalic acid etc. Versatic acids (which is a trade mark of Shell Co.) have a general formulae of ... 

---