F. Temelli et al., CONVERSION OF OILS TO MONOGLYCERIDES BY GLYCEROLYSIS IN SUPERCRITICALCARBON-DIOXIDE MEDIA, Journal of the American Oil Chemists' Society, 73(6), 1996, pp. 699-706
Glycerolysis of soybean oil was conducted in a supercritical carbon di
oxide (SC-CO2) atmosphere to produce monoglycerides (MG) in a stirred
autoclave at 150-250 degrees C, over a pressure range of 20.7-62.1 MPa
, at glycerol/oil molar ratios between 15-25, and water concentrations
of 0-8% (wt% of glycerol). MG, di-, triglyceride, and free fatty acid
(FFA) composition of the reaction mixture as a function of time was a
nalyzed by supercritical fluid chromatography. Glycerolysis did not oc
cur at 150 degrees C but proceeded to a limited extent at 200 degrees
C within 4 h reaction time; however, it did proceed rapidly at 250 deg
rees C. At 250 degrees C, MG formation decreased significantly (P < 0.
05) with pressure and increased with glycerol/oil ratio and water conc
entration. A maximum MC content of 49.2% was achieved at 250 degrees C
, 20.7 MPa, a glycerol/oil ratio of 25 and 4% water after 4 h. These c
onditions also resulted in the formation of 14% FFA. Conversions of ot
her oils (peanut, corn, canola, and cottonseed) were also attempted. S
oybean and cottonseed oil yielded the highest and lowest conversion to
MG, respectively. Conducting this industrially important reaction in
SC-CO2 atmosphere offered numerous advantages, compared to conventiona
l alkali-catalyzed glycerolysis, including elimination of the alkali c
atalyst, production of a lighter color and less odor, and ease of sepa
ration of the CO2 from the reaction products.