离子液体萃取脂肪酸甲酯性能研究

以咪唑型离子液体为萃取剂萃取长链脂肪酸甲酯。研究了离子液体阴离子的结构、相比和改性剂对萃取率的影响。Bmim]Cl,Bmim]Ac对脂肪酸甲酯有一定的萃取能力,但萃取率远远低于路易斯酸型离子液体Bmim]Cl-xAlCl_3。对于Bmim]Cl-xAlCl_3,萃取率随离子液体中AlCl_3比例的增加而增加。离子液体对脂肪酸甲酯的萃取能力与脂肪酸甲酯的分子结构有关,并受相比和改性剂影响。脂肪酸甲酯分子中双键个数越多、碳链长度越短,离子液体与石油醚的体积比越大,萃取率越高,当以x=1.35的咪唑型氯铝酸盐离子液体为萃取剂,离子液体与石油醚相比为1:2时,EPA的萃取率可以达到97.23%。萃取体系中加入乙酸乙酯或乙醇,将降低离子液体对脂肪酸甲酯的萃取能力。体系中200μL乙醇,EPA的萃取率由99.06%降低到15.10%。

The extraction performance of ionic liquids for fatty acid methyl ester

The extraction of fatty acid methyl ester (FAME) by imidazole ionic liquids was studied in this paper. The influences of the structure of the ionic liquid, phase ratio and modifier on the extraction rate were investigated. Bmim]Cl and Bmim]Ac have weak extraction ability for FAME. The extraction ability was far lower than lewis acidic ionic liquid, such as Bmim]Cl-xAlCl3. For Bmim]Cl-xAlCl3, the extraction rate increased with the increase of AlCl3 proportion in the ionic liquid, the ratio of ionic liquid to petroleum ether. The extraction rate was related to the molecular structure of FAMEs. The FAMEs with more double bonds and shorter carbon chain have higher extraction rate. Furthermore, the addition of the modifiers, such as ethyl acetate and ethanol, could dereace the extraction rate. When imidazole chloride aluminate ionic liquid with the Bmim]Cl and AlCl3 mole ratio of 1:1.35 was used as extractant, the phase ratio of ionic liquid to petroleum ether was 1:2, the extraction rate of EPA could reach 97.23%. When 200 ul ethanol was added into the extraction system, the extraction rate of EPA was reduced to 15.10%.