The Study On Using Functionalized Quaternary Ammonium Ionic Liquids As Catalyst For The Synthesis Of Biodiesel With Gutter Oil In One-step Process

Energy is an important and indispensable material resource for human survival,economic development and social progress, which is also the relationship betweennational economy and national security an important strategic material. In today’senergy shortage, the development of renewable biological diesel oil to make up forthe shortage of fossil energy become more and more attention of thecountries.However, about80%production cost of biodiesel is from feedstock.Therefore relatively inexpensive gutter oil becomes an ideal raw material forbiodiesel production. Currently the gutter oil to produce biodiesel has someadvantages, such as adequate waste oil source, low prices and environmental friendly.Biodiesel is a term of fatty acid methyl ester with Long chain，derived from thetransesterification of used vegetable oils or animal fats with alcohols. Biodiesel needsan efficient, safe and environmental friendly production route. As a novel greencatalytic and solvent Ionic liquids have aroused increasing interest because theyplayed a positive role in the chemical reaction. Studies show that the SO3H-functionalionic liquids are the most acidic Bronzed ionic liquids. They are excellent catalystsused in transesterification synthesis of biodiesel that can solve the problem ofenvironmental pollution, equipment corrosion and the high cost, which showed agood industrial prospect.In this paper, biodiesel is made through one step from high acid value gutter oilcatalyzed by a quaternary ammonium salt ionic liquid. The main contents aresummarized as follows:(1)Ionic liquid [(CH3CH2)3N(CH2)3SO3H][C7H7O3S] was synthesized withdiethylamide, propane sultone and p-toluenesulfonic acid. Using IR and NMR tocharacterize their structure, the analysis results show that the ionic liquid in line withits theoretical structural features, but also that this synthesis method is feasible.(2)The TGA analysis of the [(CH3CH2)3N(CH2)3SO3H][C7H7O3S] ionic liquidshows that the thermostability of ionic liquid is good, their decompositiontemperature are all higher than280℃, they can be used as the catalyst for biodiesel synthesis.(3) After simple cleaning, bleaching and dehydration, the pretreatment of gutter oilwas esterified to detect the type and content of fatty acid methyl esters by GC-MS.The results showed that: the methyl oleate content of37.25%,methyl linoleatecontent of24.41%, methyl palmitate content of32.08%. These three components ofbiodiesel are total of93.74%. Simultaneously the other physical and chemicalproperties of the gutter oil were measured. Acid value was120.37mg KOH/g.Saponification value was251.94mg KOH/g. Iodine value was76.75gI/100g.Peroxide value was3.023.The average relative molecular weight of gutter oil was499.25g/mol. Because of high acid value and peroxide value, gutter oil was easily torancidity and not suitable as edible oil, but as a raw material for biodiesel synthesis.Besides the large saponification value indicated that the gutter oil contains much fattyacid, which also indicated that gutter oil was suitable as feedstock for biodieselsynthesis.(4) Under atmospheric condition，using [(CH3CH2)3N(CH2)3SO3H][C7H7O3S] ionicliquids as catalyst for the synthesis of biodiesel with untreated gutter oil.The productwas analyzed by gas chromatography to investigate the effect on the reaction time,the amount of ionic liquid and oil to alcohol ratio of the production of biodiesel.Theresults showed that: sulfopropyl triethyl ammonium p-toluenesulfonate ionic liquidsat atmospheric pressure (reaction temperature70℃) under simultaneous catalyticwaste oil triglycerides and free fatty acids and esters transesterification occursrespectively reaction, to achieve one-step production of biodiesel, at a temperature of70℃,n (Oil): n (MeOH): n (IL)=1:8:0.063, the optimal reaction conditions reactiontime20h, the biodiesel yield was93.80%. Compared with the results of other rawmaterials in the literature, with high acid value waste oil as raw material, the shorterthe time required for the reaction, the desired amount of ionic liquid oil and alcohol issmaller than the ionic liquids catalyzed esterification described herein the effect ofbetter response than the transesterification reaction.(5) The synthesis of biodiesel was catalyzed by ionic liquid[(CH3CH2)3N(CH2)3SO3H][C7H7O3S] with untreated gutter oil in one-step process in a1L autoclave.The results show that: While increasing the reaction temperature in theautoclave,the reaction time can be shortened considerably due to the reaction ratehasten.At a reaction temperature of120℃, n (Oil): n (MeOH): n (IL)=1:10:0.063,the reaction time1h, the yield of biodiesel was up to95.32%. While the ionic liquidcould be repeated6times after recovered, the biodiesel yield was no significantlydecreasing. The further amplification experiments was made in the reactor of10Lautoclave as the optimum conditions obtained in1L autoclave. The results alsoshowed that: the biodiesel yield dropped about10%, and three times compared awaylarge. Because it migjt not be long enough reaction time and the reaction of methanolto oil ratio was not big enough. Specific reasons and process improvement needfurther study.(6) Eight kinds of quality indicators of biodiesel were measured. The resultsshowed that: the density, flash point, cold filter plugging point, sulfur content,mechanical impurities, copper corrosion and acid are combined in line with nationalstandards GB/T20828-2007"diesel fuel transfer biodiesel (BD100)", only thekinematic viscosity of non-compliance.This may be the trace amounts of ionic liquidin the product of biodiesel.