The Study Of Applyication Of Ionic Liquid In Synthesising Of Medium-chain Triglycerides

Medium-chain triglycerides are a family of triglycerides,predominantly containing caprylic and capric fatty acids with feweramounts of caproic and lauric fatty acids, which are widely used innutraceuticals, cosmetics and pharmaceuticals. One of medium-chaintriglycerides, tricaprylin was synthesized from esterification of caprylicacid and glycerol chemically and biologically.A Br nsted acidic ionic liquid,[BMIm（CH₂）4SO₃H][HSO₄] wasselected as a chemical catalyst according to conversion and selectivity. Theoptimum conditions obtained through single factor test and orthogonalexperiment were caprylic acid/glycerol molar ratio3.5:1, the catalystamount1ï¼…based on the reactant employed in the reacting system，reacting at160℃for6hours．Under these conditions, conversion of85% and tricaprylin percentage of80ï¼…were obtained．The activity of two immobilized lipases, Lipozyme RM IM andNovozym435in various imidazolium ionic liquids were investigated.Among these ten types, both lipases showed good activity in [C4MIM]PF6,which could be separated from product when the reaction finished.[C₄MIM]PF₆was chosen as media for enzymatic synthesis.5%amount ofLipozyme RM IM, caprylic acid/glycerol molar ratio3:1, open system at45℃for48hours, conversion of78%and tricaprylin percentage of44ï¼…were achieved. Lipozyme RM IM displayed low efficiency in this process.However, Novozym435was found as the most effective enzyme foresterification. The optimum conditions were obtained through responsesurface method. When the6.1%amount of Novozym435were added,caprylic acid/glycerol molar ratio4.5:1, react at66.7℃for24hours,conversion and selectivity of MCT amounted to92.4%and90.1%,respectively. The models obtained by response surface method could beused to predict the conversion and selectivity of tricaprylin with satisfiedeffectiveness.Biological method was compared with chemical method in threeways, including the reaction process along with time, product appearanceand product composition. The product obtained biologically was muchbetter than chemically both in color and odor. Biological method wassuperior to chemical method in this process. There were no absorption peak in amideâ… region in the infraredspectra of [C₄MIM]PF₆,[C4MIM]BF4and [C₄MIM]Tf₂N. It was feasible tofitting amideâ… region to obtain the information of secondary structure.Deconvolution and fitting the amideâ… region of Novozym435pretreatedwith different medias, the changes found in content of each element couldroughly explain the different in activity in various medias.