Solubility of 2-tert-butylanthraquinone in binary solvents

The solubilities of 2-tert-butylanthraquinone (TBAQ) in three binary solvents 1,3,5-trimethylbenzene (TMB) + 2,6-dimethyl-4-heptanol (diisobutylcarbinol, DIBC) with 3:1, 3:2, 1:1 and 2:3 in the volume ratio of TMB to DIBC (solvent ratio) were determined in the temperature range from 303.15 to 333.15 K by the equilibrium method. As a comparison, the solubilities of TBAQ in solvent mixtures TMB + 2-methylcyclohexyl acetate (MCA) and TMB + trioctylphosphate (TOP) were also determined. The solubilities of TBAQ in all the binary solvents always increased with rising temperature and solvent ratio. At the same temperature and solvent ratio, the solubilities of TBAQ in TMB + DIBC were close to those in TMB + MCA and much higher than those in TMB + TOP. Two activity coefficient models NRTL equation, Wilson equation and modified λ–h equation were applied to correlate and predict the solubilities of TBAQ in mixed solvents. The satisfactory correlation were obtained using all three equations and the NRTL equation gave relatively good prediction with the average and maximum relative deviation of 1.87% and 5.06%, respectively.