Study On Esterification Of Fatty Using Ionic Liquid As Catalyst Acid With Ultrasonic-microwave Assisted

Fatty acid methyl ester is a kind of clear yellow liquid with a stable chemical structure, a mild scent, and no corrosion, and was prepared by esterification and ester exchange reaction between vegetable oils, or animal fats, or waste cooking oil with lower alcohol. Fatty acid methyl ester has a good osmosis, emulsification, a solubilization and other properties, is widely used in the filed of--food, chemical, pharmaceutical, etc. It also can be used as a green and alternative biomass fuel. The traditional preparation process of fatty acid methyl ester is not accord with the requirement of green food processing and green chemical process due to the use of inorganic acid and alkali. Therefore, it has important significance to the develop a green preparation for fatty acid methyl ester.In this paper, using oleic acid or fats as raw materials and the synthesized acidic ionic liquid as catalyst, the green and highly efficient preparation of fatty acid mehyl ester was investigated under the ultrasonic microwave assisted. The major contents are included as follows:(1) Fatty acid methyl ester was prepared by esterification of oleic acid with methanol using H2SO4 as catalyst. The effects of various parameters such as reaction time, temperature, mole ratio of alcohol/oleic acid, catalyst dosage on the conversion rate of oleic acid were investigated. On the base of single factor experiments, the preparation process was optimized by using Response Surface Methodology (RSM). The results showed that the interactions among temperature, time and molar ratio of methanol to oleic acid have a great influence on the conversion rate of oleic acid. The optimum reaction conditions were obtained:the reaction time of 3.5 h, the reaction temperature of 65℃, the mole ratio of alcohol/oleic acid of 9:1, and the catalyst dosage of 4%. Under the optimal condition, the highly conversion rate of oleic acid of 97.5% was achieved.(2) Using 1-(4-sulfopropyl)-3-methylimidazole hydrosulfate ionic liquid as catalyst, fatty acid methyl ester was prepared via esterification reaction of oleic acid with methanol in this paper. The effects of some parameters such as reaction time, temperature, mole ratio of alcohol/oil and catalyst dosage on the conversion rate of oleic acid were studied. On the base of single factor experiments, the preparation process was optimized by response surface methodology. The results showed that the influence of the investigated factors on the conversion rate of oleic acid was similar to that in the conventional process using sulphuric acid as catalyst. The ionic liquid catalyst exhibits a good catalytic activity similar to sulfuric acid, and after reused four times, the conversion rate of oleic acid remained more than 90%. The obtained optimum conditions were 3.5 h of the reaction time,60℃ of reaction temperature,9:1 of the mole ratio of alcohol/oil,10% of the catalyst dosage, and the conversion rate of oleic acid reached 98.3% under these conditions.(3) The four kind of ionic liquids had been synthesized, characterized and used as catalyst for preparation of fatty acid methyl ester with ultrasonic-microwave assisted using oleic acid as raw materials. Their catalytic properties had been researched and the esterification process was optimized by using response surface experiment design method based on the single factor experiments. The results showed that [Bsmim]HSO4 has a good catalytic property and the introduction of ultrasonic-microwave can obviously shorten the reaction time and decrease the product cost to obtain a good gain. The optimmal reaction conditions for esterification reaction model were as follows:microwave power 118 W, reaction time 17 min,cohol/oil 22:1, ionic liquid dosage of 11%. The conversion rate ws 97.32% under the above conditions.(4) Three kinds of temperature-sensing single ether-based ionic liquids with different molecular weight were synthesized and characterized by FT-IR, NMR and TG-DTA. And the temperature-sensitive and catalytic properties of the ionic liquids were investigated in this paper.The results showed that the snthesized ionic liquids with toluene/cyclohexane can form into a temperature sensitive catalytic system to be used to the catalyzed esterification of fatty for producing fatty acid methyl ester. The temperature-sensitive ionic liquid exhibited their excellent catalytic properties in toluene/cyclohexane and can be used in esterifciaion reaction as the substitution of sulfuric acid.