A liquid phosphine oxide has been developed with a phosphoryl concentration of 2.3M, twice the maximum that can be reached in TOPO solvents at 50°C. Distribution coefficients are increased by 2mwhere m relates to mols phosphoryl in the extracting complex. The value of m is 1.6 for phenol, 1.0 for acetic acid and 0.9 for ethanol. Kinetics are unchanged. Costs of extracting phenol with the new extractant and with isopropyl ether are compared. Extraction coefficient and separation factor for ethanol are compared with other potential extractants.