The separation of intermediate using distillation under vacuum was replaced by extraction method. It was convenient and reliable.

Compared with the raw material, soy fatty acid mixture obtained by the distillation under vacuum had lower content of unsaturated fatty acid, but higher content of saturated one.

The molecular distillation (short-path distillation or unobstructed distillation) is a special separation technique of liquid-liquid and a special distillation technique under the high vacuum.