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Br (?) Nsted acidic ionic liquid is not easy volatile with the reactivity of the high density of the liquid acid and solid acid corrosion of equipment, is a class of new environment-friendly, recyclable catalyst. Therefore become a hot research at this stage. Each of N-methyl imidazole, pyridine, triethylamine, and the industrial-grade 1,3 - propanesultone, 1,4 - D-sultone, synthesized in the microwave reactor for six kinds of water and air-stable good, since the cation-anion intermediate of a functional group of the belt-S03H, and then with sulfuric acid, phosphoric acid, respectively, the reaction of methyl benzenesulfonate, synthesis of the 11 kinds of BR (?) nsted acidic ionic liquid. By infrared, 1H NMR to characterize its structure, the use of automatic potentiometric titrator a Wilhelmy plate method its the acidic surface tension measured, were used to characterize the strength of its acidic dissociation constant pKa, and its surface tension measured under the conditions of microwave heating, the ionic liquid in the herein as a catalyst for ester exchange reaction, examine different kinds of ionic liquids and the transesterification conversion rate of different microwave conditions. [MimN (CH2) 4SO3H] [HSO4] Synthesis for example, under the premise of the same yield, microwave hydrothermal synthesis time is greatly reduced. The synthesis of ionic liquids IR and 'H NMR by comparison with literature values, and its structure can be determined. By automatic potentiometric titrator acidic ionic liquid, and the structure of the ionic liquid affect its acidity. The same cation, with the weakening of the anionic acidic ionic liquid acidic gradually weakened. With the growth of the cationic carbon chain, the acid will be increased accordingly. Ionic liquid as a catalyst of the ester exchange reaction, the catalytic effect is related to the acidity of the ionic liquids, the stronger the acidity, the higher the conversion rate. In the case of the same carbon chain length and the anion, the catalytic effect of the pyridine type ion liquid better than the imidazole and triethylamine. For the same nitrogen-containing functional group, the longer the carbon chain of ionic liquids, the higher the catalytic activity. This thesis by examining [MimN (CH2) 4SO3H] [HSO4] in the ester exchange reaction, to obtain the optimal catalytic conditions: The catalyst is added in an amount of 5% of the quality of soybean oil, and the methanol to oil ratio of 12:1, in the heating The power of 700W, and a temperature of 70 ℃, reaction 4h yield is higher, gas chromatography measured yield of 94.38% of the fatty acid methyl esters, glycerol yield of 89.23%, through the reuse of ionic liquids recovered found that without processing conditions, can be reused six times.
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