Fractionation of castor oil methyl esters by liquid‐liquid extraction

Summary and Conclusions A solubility diagram has been constructed for methanol‐castor oil methyl esters‐heptane at 8.4°C. and 24°C. A selectivity diagram has been prepared for methanol‐castor oil methyl esters‐heptane at 8.4°C. and 24°C. Castor oil methyl esters have been fractionated by continuous countercurrent liquid‐liquid extraction at 3°C. and at 6°C. with methanol‐heptane and heptane‐methanol as solvents, using an extraction column containing four equilibrium stages. The methyl ricinoleate fraction produced compared favorably with pure methyl ricinoleate with respect to hydroxyl value and optical activity. It should be noted that there were undoubtedly some mono‐ and diglycerides in the castor oil methyl esters used in this study. These go along with the methyl ricinoleate and cause discrepancies between hydroxyl value and optical activity (2). The column feeds ranged from 2.9 to 10.3% methyl esters by weight in methanol‐heptane. Solvent‐feed ratios were from 0.49 to 1.21 lb. per pound. The flow rates were from 706 to 1,020 lb. per hour per square foot of column cross section (based on the cross section of the empty column).