Separation of fatty acid esters and fatty acid ester derivatives using preparative scale sequential gas-liquid chromatographic equipment

Summary

A sequential continuous chromatographic refiner (SCCR-2) for preparative-scale GLC up to 200°C is described. The separating capabilities and other characteristics of the SCCR-2 unit have been investigated using fatty acid ester mixtures of different separation difficulty and volatility. The feed mixtures selected had separation factors (α) between 1.1 and 1.5 and required operating temperatures between 110 and 200°C, while using FFAP (free fatty acid phase) on Chromosorb W or OV-275 (a cyanosilicone) on Chromosorb P. Initially the separation of a 50/50 v/v mixture of methyl chloroacetate/ethyl lactate (α≃1.5) was studied and the ability of the SCCR-2 unit to separate the mixture into two products with purities in excess of 99.8% has been demonstrated at feedrates up to 80 cm³h⁻¹ and temperatures between 110 and 130°C. For the more difficult system ethyl chloroacetate/ethyl lactate (α≃1.2) the column was too short for successful separation, although purities of about 95% for one product stream were obtained at feedrates of 33 cm³ h⁻¹ at 125°C. Preliminary studies on the recovery of γ-linolenic acid from fungal oil, at temperatures of 200°C are reported. Although this equipment has been demonstrated on the laboratory scale it is amenable to scale up to production levels. Partition coefficient data for several fatty acid solutes were determined using a comerical analytical scale GLC and some of the most favoured stationary phases for the GLC of fatty acids.