Design Of Ionic Liquids Based On Heteropolyacids And Investigation In Esterification And Transesterification

Esterificaiton and transesterification are the best way to prepare the estercompounds, especially in the production of biodiesel. Liquid acid and base catalystsare usually used in esterificaiton and transesterification. However, there are someproblems, such as equipment corrosion, environment pollution, difficult pretreatmentfor high acid value and high water content of feed. The development ofenvironmental-friendly, high performance catalysts are very important.Heteropolyacids (HPA) is one of a kind of important candidate.This work is devoted to prepare the catalysts with high Br nsted acid strength,water-tolerance and effectivity for simultaneous esterification and transesterification.Ionic liquids (ILs) are used as the precursor to prepare the HPA-ILs catalysts. Theperformance of catalysts is estimated by esterification and transesterification. Themain results are as follows:1. The dendritic [HMTABS]3[PW12O40]4has been prepared and characterized byElemental analysis?FT-IR?NMR?TEM and so on. It is proved that the originalstructure of H3PW12O40was obtained in the catalyst. The catalyst sites were suppliedby the group of–SO3H. The optimized reaction conditions of esterification weremethanol/palmitic acid/catalyst8667:667:1, reaction time5h, and temperature65°C. The highest conversion was97%. The best results of transesterification wereobtained at the molar ratio of methanol/Eruca sativa Gars. Oils/catalyst1800:36:1,reaction time24h, and reaction temperature65°C. The highest yield was86%. Thecatalyst was recycled for six times and the leaching of the catalyst after six runs inesterification and transesterification was7%and10%, separately.2. ChH2PW12O40was prepared by chloride (ChCl) and H3PW12O40, andcharacterized by Elemental, FT-IR?CMC and so on. It was proved that ChH2PW12O40was temperature controlled self-separation catalyst with Br nsted cites and Kegginstructure. The optimism reaction conditions are the molar ratio of methanol/palmiticacid/catalyst520:40:1, reaction time50min and temperature65°C under microwaveassistance. The highest conversion was obtained by97%under the condition. Thereuse activity of catalyst was still very good after six times with the leaching of6.5%.The heterogeneous ChH2PW12O40could be used in esterification of differentsubstrates instead of H3PW12O40.3. Several catalysts were synthesized by the combination of ILs and HPAsaccording to different molar ratio. The performance of catalyst was evaluated byesterification of methanol and palmitic acid, oleic acid (OA) and trimethylolpropane(TMP). The highest conversion (98.3%) of methyl palmitate was obtained at themolar ratio of methanol/palmitic acid11:1,the amount of [MIMPS]H2PW12O400.06 mmol, reaction time8h, reaction temperature65°C. The highest conversion (87.6%)of trimethylolpropane trioleate was obtained at the molar ratio of TMP/OA3.6:1, theamount of [MIMPS]H2PW12O404wt%, reaction time5h, reaction temperature110°C. The high activity and reuse activity were due to the Br nsted acid sites derivedfrom the group of–SO3H and H2PW12O40-.