1993 Volume 26 Issue 2 Pages 153-158
Supercritical fluid extraction was applied to the separation and purification of indole. Indole is important as a feedstock for tryptophan, which is used in the field of biotechnology.
Supercritical fluid extraction of coal tar oil including indole was conducted using CO2 and C2H4. Not much indole was extracted, but it was concentrated in the raffinate. To concentrate high-purity indole in the rafflnate, ethylene glycol and mono ethanol amine (MEA) were used as additives for supercritical fluid extraction by C2H4. After distiflation of the raffinate with MEA was conducted, high-purity indole was obtained. On the basis of these results, a newly developed process was proposed that uses combined supercritical fluid extraction to separate high-purity indole from coal tar oil.
