Study On The Hydrogenation Of Sunflower Oil With Pd Catalysts Supported On Mesoporous Silica And The Rule Reaction

In this paper, the hydrogenation catalysts were Palladium supported on mesoporous silica.Effect of sunflower oil hydrogenation activity and rule reaction with catalyst reductionmethods, different types and structure of catalyst support, loading conditions and metalloadings were discussed. In this study, rate of hydrogenation and content of trans fatty acids(TFA) were assessment objectives, low TFA and stearic producing catalyst was chose, andthen was used for the hydrogenation process of sunflower oil. The optimal conditions wereobtained by single factor and orthogonal experiments. In addition, three Pd magneticmesoporous silica catalysts were prepared and tested for the hydrogenation of sunflower oil.The effect of reaction activity and rule reaction with process conditions and the reuse ofcatalyst were studied as well.The catalyst which reduced by formaldehyde has a better catalytic performance. Thehydrogenated oil (I.V.=75) has a lower TFA with the catalyst which loading amount was3%wt and support was SBA-15(Type9-700). TEM and N2adsorption desorption isothermshowed that Palladium dispersed on the inner pores and the surface of support. The Pd metalpartical had a large size and distributed densely, and the catalyst had a better activity.The best load conditions were that SBA-15(Type9-700) was used as support, pH=2ofimpregnating solution,8h of impregnation time,4h of reduction time. Under the followingconditions:20g sunflower oil, hydrogenation temperature70℃,101.2mg Pd/SBA-15amount(5.0mg Pd/100g Oil) and hydrogen pressure1.0MPa, the TFA and stearic content ofhydrogenated product was19.8%and22.7%(I.V.=75). The hydrogenation rule under loadconditions was discussed. With pH of impregnating solution and impregnation time increased,hydrogenation rate increased firstly and then decreased. And maximum hydrogenationreaction rate was achieved when pH=2of impregnating solution and6h of impregnation timewere used.The best conditions of low trans fatty acid hydrogenation were obtained by single factorand orthogonal experiments:20g sunflower oil, reaction temperature of50℃, the reaction pressure of1.0MPa, the amount of catalyst was2.5mgPd/100gOil. Under the aboveconditions, the trans fatty acid content of the hydrogenation sunflower oil was14.1%(I.V.=75). When the loading amount was3%wt, the trans fatty acid content was12.6%(I.V.=75). The hydrogenation rule with load conditions was discussed. In a certain range, withthe temperature, stirring rate and catalyst amount increased, hydrogenation rate increased.The magnetic mesoporous silica catalyst3%-Pd/Fe3O4@nSiO2@mSiO2was selected forthe effect of hydrogenation parameters. Under the following conditions:20g sunflower oil,reaction temperature of50℃, the amount of catalyst was17.2mg, the reaction pressure of1.0MPa, the TFA and stearic content of hydrogenated product was19.2%and16.8%(I.V.=75).The magnetic mesoporous catalyst shows a good separation effect. The catalyst andhydrogenated oil can be separated easily by magnet. And the Pd/Fe3O4@nSiO2@mSiO2catalyst can be reused for six times. The hydrogenation rule with load conditions was alsodiscussed. In a certain range, with the temperature, stirring rate and catalyst amount increased,hydrogenation rate increased.