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ARS Home » Research » Publications at this Location » Publication #72619


item Sahle Demessie, Endalkachew
item King, Jerry

Submitted to: Supercritical Fluids International Symposium
Publication Type: Abstract Only
Publication Acceptance Date: 5/11/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Supercritical CO2 was used to fractionate a mixture of monoacylglycerides (MAGs), diacylgylcerides (DAGs) and triacylglycerides (TAGs) using an eight-foot packed column that was kept under thermal gradient conditions and operated simi-continuously. The feed material used, approximating a feed stream used in the industrial enrichment of MAGs, was composed of 48.7 wt% MAG, 46.3 wt% DAG, and 5 wt% TAG having main acyl chain compositions of 6 wt% C16:0, 23 wt% C18:0 and 59 wt% C18:1. The resultant top product had MAG concentrations a high as 90 wt% and no TAG, which is comparable to that produced by molecular distillation. Increasing column pressure from 172 bars to 344 bar, or density of CO2 from 420 to 720 kg/m**3, increased yields of the top product. However, with this increase the supercritical fluid became less selective, with the MAGs concentration decreasing from 84 wt% to 56 wt%. At 207 bars a linear temperature gradient from bottom to top of the column varying from 65 deg C to 95 deg C gave the best selectivity. As the MAGs concentrations in the feed mixture increased from 48.7 wt% to 63 wt%, the MAGs concentration in the top product (at 207 bars, 65-95 deg C) increased from 79.4 wt% to ? wt%.