2.2. Separation scheme
Distillation is the most commonly used method to separate liquid mixtures, but it is not suitable for complete separation of mixed alcohols and mixed alkanes due to their similar volatilities. A hybrid separation scheme is proposed here to accomplish the separation. It includes three steps: (1) the raw material is pre-separated by fractional distillation into four fractions according to normal boiling points; (2) appropriate extractants and operating conditions are selected to separate the primary alcohols from the saturated alkanes and then extraction is performed on each fraction; and (3) the extractants are recovered by azeotropic distillation and the primary alcohols in the extract phase are purified. The separation process is given in Fig. 1.