The Separation of Mixtures of Fatty Acid Derivatives by Continuous Chromatographic Refining

Abstract

A review is given of the factors affecting the performance and the scale up of chromatographic columns. The industrial separation of fatty acid derivatives and the application of G.L.C. as a possible separation method for fatty acids are also reviewed. The design and construction of a sequential continuous 5 chromatographic refiner (SCCR-2) for high temperature (up to 210°C) preparative scale G.L.C. separation is described. Counter-current operation was simulated by sequencing a system of inlet and outlet port functions around twelve fixed, 2.21 an diameter and 61 cm long stainless steel columns. The separation capabilities of the SCCR-2 unit have been investigated using mixtures of different fatty acid esters. The feed mixtures selected had separation factors in the range of 1.44- 2.8 and required equipment operation in the range of 105-210°C, while using OV-275 (a cynosilicone liquid phase) on Chromosorb P, as chromatographic packing material. Fatty acid derivatives; ethyl caprylate/ethyl caprate (separation factor (S.F.) 1.9, 105°C), ethyl caprate/ethyl laurate (S.F. 1.44, 160°C), ethyl laurate/methyl myristate (S.F. 1.54, 185°C) and methyl myristate/methyl stearate (S.F. 2.8, 206°C) were separated on the SCCR-2 unit. Purities of greater than 99% have been achieved for both product streams at feed rates of up to 80 an’ h ~ and at an operating, temperature of 105°C. Lower throughputs; 50, 25 and 20 am"H ~ at operating temperatures 160, 185 and 205°C respectively were used to retain the purity in excess of 98.0% for both products. The experimental results of the separation of binary mixtures at different temperatures have been compared with the results of a plate model computation procedure. Results achieved from the theoretical study indicated partial agreement with the experimental findings.