| 摘要 |
The distillation residue (normally discarded) is extracted with a 0.1-40 wt. % aq. soln of an organic acid (e.g. acetic acid) at 50-200 degrees C (pref. 85-105 degrees C) in a continuous or discontinuous manner, the ratio of the organic phase to the aq. phase being 1:8 to 8:1. |
