Different diluents including 1-decanol, 1-octanol and 2-ethyl-1-hexanol and kerosene have been evaluated in extracting acetic acid from the treated prehydrolysis liquor (TPHL) by triisooctylamine (TIOA) or trioctylamine (TOA). Diluent played an important role in recovering acetic acid from the TPHL, thus affecting the extraction equilibrium and extraction efficiency. Polar diluent like 1-decanol, 1-octanol and 2-ethyl-1-hexanol showed better performance than the nonpolar diluent kerosene. The maximum extraction efficiency was 68.79%, which was from 2-ethyl-1-hexanol. The organic solvent was regenerated and extracted HAc was recovered by aqueous sodium hydroxide. The regeneration efficiency can be improved by increasing molar ratio of sodium hydroxide to HAc. (C) 2013 Elsevier B.V. All rights reserved.