Extraction equilibria of rare earths by a new reagent (2-ethylhexyl-3-pentadecylphenyl) phosphoric acid

A new reagent (2-ethylhexyl-3-pentadecylphenyl) phosphoric acid (EPPA = HR) was synthesized from cardanol (I, 37300-39-5) and was used to investigate the extraction behaviour of lanthanum(III), europium(III) and lutetium(III) from hydrochloric acid solutions. The species extracted were found to be Ln(HR(2))(3) (where Ln = La(III) or Eu(III) or Lu(III)). The extraction behaviour of the above lanthanides has also been compared with yttrium and other rare earths. It was observed that the extraction increases with increase in atomic number of rare earths. In addition, the extraction efficiency of EPPA has also been compared with well known acidic organophosphorus extractants like di-2-ethylhexyl phosphoric acid (DEHPA), 2-ethylhexyl-mono-2-ethylhexyl phosphoric acid (EHEHPA).