共查询到15条相似文献,搜索用时 93 毫秒
1.
2.
3.
4.
5.
6.
7.
以微波辐射辅助的方法合成溴化1-辛基-3-甲基咪唑[OMIM]Br。实验证明微波辐射能促进N-甲基咪唑与1-溴代辛烷反应。经正交试验分析,确定微波辐射反应最佳条件如下:N-甲基咪唑与1-溴代辛烷物质的量比为1:1.1,反应时间150s,微波功率500W,反应温度70℃,收率为96.39%。经1HNMR确定目标产物。 相似文献
8.
微波法合成溴化1-丁基-3-甲基咪唑,通过正交试验,对微波反应条件进行优化研究。考察原料配比、微波照射时间、微波功率对该反应的影响。结果表明:该反应以1∶1.3原料摩尔比、在200 W微波功率下照射180 s为较佳的微波反应条件,收率可达98.9%。 相似文献
9.
10.
11.
12.
《分离科学与技术》2012,47(5):673-681
Artemisinin is a compound extracted from Artemisia annua L. with a remarkable curative effect against malaria. It can be extracted using ultrasound-assisted extraction (UAE) and then detected via HPLC. In this study, response surface methodology (RSM) was used to optimize UAE conditions for obtaining the maximum yield of artemisinin. Three independent variables (ratio of solvent to material, extraction temperature, and ultrasonic power) were evaluated using the Box-Behnken experimental design, with the yield of artemisinin as a response variable. Experimental data were highly fitted to a mathematical-regression model using multiple linear regression (MLR). Based on response surface plots, the three independent variables exhibited interactive effects on the yield of artemisinin. The optimal extraction conditions were as follows: 42.71 mL/g ratio of solvent to material, 41.86°C extraction temperature and 120 W ultrasonic power. The predicted yield of artemisinin by model was 0.7848%, whereas the actual yield in the extracts was 0.7826% ± 0.0790% in adjusted optimal conditions, with a relative error of 0.28%. The results undoubtedly demonstrated that RSM could be used to explore the optimum conditions of artemisinin extraction. 相似文献
13.
14.
考察了碱性离子液体1-乙基-3-甲基咪唑磷酸二乙酯盐{[Em im]+[(EtO)2(PO)O]-}催化一系列醛与活性亚甲基类化合物的Knoevenagel反应,比较了该离子液体在有溶剂存在及无溶剂条件下的催化性能。结果表明,该离子液体在乙醇作溶剂条件下对芳香醛的反应具有较高的催化活性,采用摩尔分数为20%的离子液体来催化该反应,于室温反应即可顺利完成,产率达73.2%~97%,生成相应的取代烯烃化合物。在无溶剂条件下采取机械研磨的方法进行反应,该离子液体表现出更高的催化活性,采用摩尔分数为10%的离子液体进行反应,在1~10 m in即可使产率达90%以上,所得产物均为E式构型。而且在无溶剂条件下,不仅可催化芳香醛的反应,亦可催化脂肪醛的反应。所用离子液体可重复使用,第5次使用时产率仍能达到85.9%。 相似文献