Enrichment of decanoic acid in cuphea fatty acids by molecular distillation

The introduction of a new crop often requires the development of new products and purification techniques of either the oil or fatty acids. Most new crops enter the cosmetic market first due to their high rates of return. However, the cosmetic market often demands highly pure and colorless materials. A molecular distillation unit is a powerful method of separation; separation occurs at extremely low pressures, and therefore at reduced temperatures compared with normal distillations and makes it very suitable for cuphea germplasm line PSR-23 (C. lanceolta × C. viscosissima) fatty acids. Refined cuphea fatty acids, which are mainly short-chain saturated fatty acids such as decanoic acid (C-10), were distilled using a lab-scale centrifugal molecular distillation unit to yield a distillate that was colorless (Gardner color = 1−). The optimal distillation conditions were explored by varying the rotor temperature and flow rate onto the rotor. As the conditions were varied, the distillate and residue were monitored for Gardner color, fatty acid composition, and mass split rate between the distillate and residue. Under a high flow rate (2.23 g/min), enrichment of C-8 and C-10 in the distillate was increased to 96% in a single-pass distillation (rotor temperature = 65 °C) with no unsaturation in the distillate while maintaining a split ratio of 1.5. A high flow, multiple-pass distillation (rotor temperature = 70 °C) of a distillate fraction produced a distillate that was 99.8% saturated fatty acid and 0.2% unsatured with very high split flow ratios. Overall, laboratory distillation of cuphea fatty acids successfully demonstrated the ability to achieve either high quantities of C-8 and C-10 or total saturated samples.