Study On Preparation Of Transesterification/Esterification With Double Acidity Properties And Bifuncitonal Catalyst

Biodiesel fuel, an alternative to classic diesel fuel, belongs to ecological fuelsbecause it consists of methyl esters of fatty acids, derived from vegetable oils oranimal fats. It is a renewable, and non-toxic biodegradable. The preparation ofbiodiesel is by esterification and transesterification in commom, so looking for thecatalyst of effective, recycled and reused as a target for researchers.12-tungstophosphoric acid H₃PW₁₂O₄₀（HPW） as a Br nsted acid has highest acidstrength and metal salts of PW12O403-potentially show Lewis acidity originating fromthe metal cation as well as Br nsted acidity generated from HPA moleculesdissociation. Both Br nsted acidity and Lewis acidity are active for the esterificationand transesterification reaction in one-pot. In this thesis, The catalysts ofMx/nH3-xPW12O40and nano-heterpolyanions containing acidic sites and basic siteshad been prepared, characterize and the catalytic activity of these catalysts wasstudied1、Some salts of H₃PW₁₂O₄₀M_x/nH_3-xPW₁₂O₄₀（abbreviated as Mx/nH3-xPW,M=Ti, Fe, In, Sn, Zr, Ce, La, Al, and Zn） are prepared and used as acid catalysts fortransesterification and esterification reactions. These catalysts possess double acidityproperties, i.e. Lewis acidity and Br nsted acidity, which are suitable for theconversion of waste cooking oil into biodiesel. The highest efficiency was59.2%and94.7%corresponding to transesterification and esterification reaction by Ti0.6H0.6PWwith moderate Lewis acidity. The relationship between the acidic properties andcatalytic activity is discussed in detail.2、The nano-heterpolyanions containing acidic sites and basic sites had beendesigned and prepared by amion acid as a template. This bifunctional heteropolyacid((C₆H₁₅O₂N₂)₂HPW₁₂O₄₀) had been characterized by IR、XPS、XRD、TEM andTGA/DTA. And it was found that it exhibited nanosphere morphology and had thebest catalytic performance, which exhibited higher catalytic activities forsimultaneous esterification and transesterification at one pot compared to the typicalacid catalyst12-tungstophosphoric acid H₃PW₁₂O₄₀, and gave markedly enhancedyield of methylesters in converting Eruca Sativa Gars （ESG） to biodiesel. The catalystwas recycled and reused with negligible loss in activity for about five times. Thenanocatalyst (C₆H₁₅O₂N₂)₂HPW₁₂O₄₀is proved to be an excellent acid-tolerant, water-tolerant, and highly suitable for various feedstock and environmentally benignheterogeneous catalyst for the production of biodiesel from low quality feedstocks.