The separation of indole from a model mixture comprising four kinds of nitrogen heterocyclic compounds [indole (In), quinoline (Q), iso-quinoline (iQ), quinaldine (Qu)], three kinds of bicyclic aromatic compounds [1-methylnaphthalene (1MN), 2-methylnaphthalene (2MN), dimethylnaphthalene (DMN)], biphenyl (Bp) and phenyl ether (Pe) was examined by batch cocurrent 4 stages equilibrium extraction. The model mixture used as a raw material in this work was prepared according to the components and compositions contained in coal tar fraction (the temperature ranges of fraction: 240∼265 ℃). An aqueous solution of formamide was used as a solvent. Indole was recovered more than 99% through 4 stages of the equilibrium extraction. The range of selectivity of indole in reference to DMN obtained through the 5 stages equilibrium extraction was found to be 63∼118. The process for separation and recovery of indole contained in coal tar was studied by using the experimental results obtained from this work and the previous work.

회분 병류 5단 평형추출에 의해 4종류의 질소고리화합물[indole(In), quinoline(Q), iso-quinoline(iQ), quinaldine(Qu)], 3종
류의 2환 방향족화합물[1-methylnaphthalene(1MN), 2-methylnaphthalene(2MN), dimethyl naphthalene(DMN)], biphenyl과
phenyl ether로 구성된 모델 혼합물로부터 In의 분리를 검토했다. 본 연구의 원료로서 사용된 모델 혼합물은 콜타르
유분(유출온도범위: 240∼265 ℃)을 구성하고 있는 성분 및 조성을 고려하여 작성했다. 추출용매로서는 Formamide 수
용액을 사용했다. 4단 평형추출을 통해 In을 99% 이상 회수할 수 있었다. 5단 평형추출을 통해 얻어진 DMN을 기준성
분으로한 In의 선택도는 63∼118의 범위를 나타냈다. 본 연구를 통해 얻어진 실험적 결과와 이전의 연구결과를 이용
하여 콜타르 중에 함유된 In의 분리 및 회수공정을 검토했다.