Study On Production Of Biodiesel With Basic Ionic Liquids

Biodiesel as fuel is renewable, biodegradable and non-toxic, etc, andcan be mixed use with petroleum diesel in any proportion. Biodiesel can notonly reduce dependence on foreign oil, but also can reduce the emissions ofgreenhouse gases. Ionic liquids as an environmentally friendly green solventsand novel catalytic material, and it has many characteristics, such as lowmelting point, high chemical and thermal stability, varieties and can bedesigned and so on. The advantage of combining these two substances,studies of two substances have been concerned by the world.In this paper two new ionic liquid was synthesized from N-methylmorpholine, Morpholine, Butyl bromide, Acetonitrile, potassium hydroxideand Anhydrous methanol by a two-step reaction. Firstly, Intermediates wassynthesized, then the target ionic liquids1-butyl-3-methyl-morpholine cationand morpholine anion ([Hnmm]Im) and1-butyl-3-methyl-morpholinemorpholine hydroxide [Hnmm]OH was synthesized by anion exchange withthe intermediates. Their structures and thermal stabilities were characterizedby FT-IR、1H-NMR and TGA respectibely. It was found that ionic liquidswere in good agreement with those expected; and displayed high thermalstability; and they can be dissolved in polar solvents, but not nonpolarsolvents or weakly polar solvents; and they showed a strong alkaline.(1) Biodiesel is produced by transesterification using preparation ofbiodiesel from soybean oil and methanol catalyzed by alkaline ionic liquids.The catalytic activity of the two ionic liquids were investigated.[Hnmm]OHexhibited more higher catalytic performance than [Hnmm]Im. By performingthe various reactions factor experiments and orthogonal test, the optimumreaction conditions were found as [Hnmm]OH amount of4%wt(massfraction), Methanol amount of30%wt, temperature70℃andreaction time1.5h, the yields of biodiesel reached97.03%, and exhibits high stabilityupon reusage, it still remained highly active even after being reused for fivetimes.By the study on kinetics of transesterification, the reaction series of transesterification is1, activation energy is73.3kJ/mol.(2) The pre-esterification were conducted from acidification of waste oiland methanol and with concentrated Fe2(SO4)3and NaHSO4as catalyst.Through orthogonal analysis, the optimal reaction conditions for theesterification catalyzed by Fe2(SO4)3and NaHSO4were achieved. The formerwas carried out at130℃, with methanol dosage30%wt,and0.5%wtcatalystfor80min，the acid value falled from146.47mgKOH/g to12.70mgKOH/g.The latter was carried out at120℃, with methanol dosage35%wt, and1.4%wt catalyst for80min, the acid value falled from146.47mgKOH/g to11.56mgKOH/g. The solid acid catalyst was synthesized by complextechnology and it produced the highest conversion at mass ratio Fe2(SO4)3/NaHSO4=3（accounting for1%wt of the reactant in the raw material oil totalquality），the reaction was carried out at at130℃, with methanol dosage40%for60min, the acid value from146.47mgKOH/g to7.06mgKOH/g. Usingthe composite solid acid catalyst for second esterification and throughorthogonal experiment， the optimum conditions were obtained foresterification as follows: Composite catalyst total mass is4%wt (mass ratioFe2(SO4)3/NaHSO4=3),30%wt methanol dosage, reaction temperature120℃, reaction time40min, the acid value falled from20.14mgKOH/g to1.69mgKOH/g, The performance meet the main index of transesterification.During the optimal conditions, the biodiesel was synthesized fromsecondary esterification products and methanol by transterification withKOH(as a constrast agent) and [Hnmm]OH respectively. The results show:KOH amount of1%wt, Methanol amount of25%wt, temperature66℃, andreaction time2h, the yields of biodiesel reached96.56%;[Hnmm]OH amountof7%wt, methanol of25%wt, temperature60℃, and reaction time1.5h, theyields of biodiesel reached91.70%. we can know that the ionic liquids bysynthesis have a high catalytic activity.