JPH0477751B

PURPOSE:To purify the titled compound useful for solidification, gelatinization, and thickening of organic liquid substance, useful as a nucleating agent of polymer, etc. industrially in high purity, by using a fluid in a subcritical or supercritical state as an extraction solvent for impurities in a dibenzylidine sorbitol. CONSTITUTION:A dibenzylidene sorbitol shown by the formula (R is alkyl, alkoxy, halogen, or nitro; m and n are 0-5; p is 0-1) is treated with a fluid (preferably CO2 at 60-300kg/cm pressure at 25-70 deg.C, more preferably blended with an organic solvent such as methanol, etc.) in a subcritical or supercritical state.