微波辅助组合离子液体直接制备微藻生物柴油

采用小球藻、甲醇为原料,离子液体组合物作为提取催化剂,微波辅助原位一步法催化制备微藻生物柴油。考察微波功率、离子液体类型、离子液体用量、反应温度、反应时间、醇油物质的量之比等因素对酯交换率的影响,并与传统水浴加热机械搅拌法比较。结果表明:微波和离子液体对生物柴油的制备有协同促进作用,离子液体具有催化、提取与增溶的作用,能较好地消除醇油界面接触,微波的引入可强化传质传热过程,与传统加热方式水浴加热机械搅拌法相比,可缩短酯交换反应的时间,降低反应温度,减少离子液体、甲醇用量。离子液体BMIM]HCOO]为提取剂,微藻油脂提取率最高;酸性离子液体催化效果明显高于碱性离子液体,离子液体SO₃H-BMIM]HSO₄]为催化剂,微藻油脂转化率最高。在甲醇用量和藻粉质量比为6∶1,离子液体组合物和藻粉质量比为5∶1,BMIM]HCOO]与SO₃H-BMIM]HSO₄]体积比12∶1,微波功率400 W,反应温度为60℃,反应时间40 min条件下,生物柴油转化率可达93.3%。该方法将离子液体溶解提取性能、催化性能及微波的热效应相结合,将油脂的提取与油脂的酯化合二为一,能够实现微藻生物柴油的一步转化制备。

PREPARATION OF MICROALGAE BIODIESEL BY DIRECT TRANSESTERIFICATION UNDER MICROWAVE-ASSISTED IONIC LIQUID COMPOSITE CONDITIONS

In this paper,biodiesel from Chorella was prepared via in-situ microwave assisted transesterification method using ionic liquids as extraction agent and catalyst.The effects of mass ratio of methanol to microalgae powder,reaction temperature,reaction time and ionic liquid dosage,microwave power on the transesterification were investigated.Under the conditions that mass ratio of methanol to micro algae powder is 6∶1,mass ratio of ionic liquid to micro algae powder is 5∶1,BMIM]HCOO]toSO₃H-BMIM]HSO₄]volume ratio at 12∶1,microwave power is 400 W,reaction temperature is 60℃and reaction time is 40 is min,the conversion of fatty aid methyl ester reached 93.3%.Preparation of biodiesel from microalgae by direct transesterification under microwave assisted ionic liquid conditions do not need to extract oil from micro algae powder,thus reducing the process cost,shorten the process time,which can realize oil micro algae directly esterified into biodiesel.