Use of the Product from Low Pressure Extraction (Crambe Seed Oil and Methyl Acetate) for Synthesis of Methyl Esters and Triacetin Under Supercritical Conditions

Abstract

AbstractMethyl esters (ME) and triacetin production from the supercritical interesterification of the product from low pressure extraction (crambe seed oil and methyl acetate) are evaluated. Reactions are conducted at 300–375 °C for different residence times, at 20 MPa, and under these conditions the thermal stability of triacetin is evaluated. The effect of the free fatty acid (FFA) concentration (in oil) is determined. An increase in temperature favors the formation of ME and triacetin at shorter reaction times. At 375 °C, after 15 min a drop in the ME yield is observed and triacetin is not detected. A reduction in the triacetin concentration (reaching ≈99%) is observed at 375 °C. High FFA concentration (in oil) initially provided higher product generation, however, after 15 min no influence is observed. The highest ME yield (≈60%) is obtained at 300 °C, along with 1.22 wt% triacetin and ≈5.0 wt% unreacted compounds.Practical Applications: This paper reports new experimental data on an integrated process for the production of methyl esters from low pressure extraction (crambe seeds and methyl acetate) and supercritical reaction of the extraction mixture. The technique used allows the removal of a high quantity of oil from good quality crambe seeds. The viability of applying the integrated process to obtain oils with a high content of free fatty acids is verified, promoting the obtainment of relatively simple methyl esters. The procedure does not require oil purification and solvent recovery prior to the reaction.