Studies on Reactive Extraction of Meta‐Aminophenol Using Trialkylphosphine‐Oxide

Distribution of meta‐aminophenol (MAP) between water and trialkylphosphine oxide (TRPO), dissolved in different diluents (1‐octanol and kerosene), as well as a comparison with the extraction equilibrium of pure diluent alone has been studied. The influence of the pH value of aqueous solutions, the TRPO concentration and diluents on the distribution ratio D has been discussed. The results indicate that the pH value and the TRPO concentration are the key factors that affect D. The non‐polar diluent (kerosene) is favorable for extracting MAP when TRPO is used as extractant. MAP can be extracted with both acidic and neutral extractants (Di(2‐ethylhexyl)phosphoric and TRPO) efficiently in kerosene while the basic one (Alamine 336) in 1‐octanol, and their efficient pH region is 2.5–3.5, 4.5–6.5, and 6.5–7.8, respectively. The extraction ability shows the order of TRPO/kerosene ≥Di(2‐ethylhexyl)phosphoric/kerosene>Alamine 336/1‐octanol. The best selection is TRPO/kerosene with initial pH at 5.5–9.5.