首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
微波辐射SnCl4·5H2O催化合成乙酸正丁酯   总被引:8,自引:1,他引:8       下载免费PDF全文
采用微波辐射技术,以SnCl4@5H2O为催化剂催化合成了乙酸正丁酯.最佳反应条件醇酸配比为l1.2,催化剂用量为1.4 g,微波功率为450 W,微波辐射时间为15 min,产率95%.实验结果表明适当的微波辐射可以加速乙酸正丁酯的合成反应,而且产率高,操作简便,腐蚀性小.  相似文献   

2.
以冰醋酸和无水乙醇为原料,氯化锌为催化剂,采用微波加热法合成乙酸乙酯.探讨了酸醇比、催化剂用量、微波功率和辐射时间对合成乙酸乙酯产率的影响.得出最佳的反应条件为酸醇摩尔比2∶1、催化剂质量百分数1.5%、辐射时间6 min和微波功率400 W,合成乙酸乙酯的产率为78.36%.  相似文献   

3.
在微波辐射下采用乳酸作为催化剂合成四(对硝基苯基)卟啉,考察了溶剂、催化剂、微波辐射时间、微波辐射功率对产率的影响.实验表明:硝基30 mL苯作溶剂,乳酸2.0 mL作催化剂,对硝基苯甲醛0.01 mol,吡咯0.01 mol,微波辐射功率280 W,辐射时间16 min,产率达到23.9%.  相似文献   

4.
对L-谷氨酸-γ-乙基酯的微波合成方法进行研究,采用HPLC法进行分析测定.实验表明,不同的微波辐射时间、温度及催化剂用量对合成反应的影响较大.经试验得到最佳的反应条件:微波辐射温度45℃,微波辐射时间为30 min,催化剂用量为1.1 mL,其产率可达80%以上.实验结果说明,微波技术可用于L-谷氨酸-γ-乙基酯的合成,方法操作简便、反应时间短、产率高,具有一定的实用价值.  相似文献   

5.
王彩霞  徐翠莲  樊素芳  杨国玉 《河南科学》2010,28(11):1396-1397
以水杨酸和乙酸酐为原料,选用不同催化剂,用微波法快速合成阿司匹林.通过实验考察了原料用量比、不同催化剂、微波辐射功率、辐射时间等因素对产率的影响,得到了最佳合成工艺条件:水杨酸和乙酸酐量的比为1∶1.5,微波功率为550 W,用乙酸钾作催化剂,辐射时间5 min时,纯化后产物产率高达81.46%.  相似文献   

6.
采用微波催化技术,以硫酸氢钠为催化剂合成尼泊金丁酯,并对催化剂用量、醇酸比、微波辐射时间、微波催化功率等因素对产物收率的影响进行了讨论.实验确定反应的最优化条件是对羟基苯甲酸:正丁醇:硫酸氢钠的摩尔比是1:2:0.036,微波功率700W条件下,辐射回流分水25min,经后处理和分析验证,白色晶体尼泊金丁酯收率可达89.70%.  相似文献   

7.
微波辐射纳米固体超强酸催化合成尼泊金庚酯   总被引:1,自引:0,他引:1  
以纳米固体超强酸SO42-/ZrO2为催化剂,以对羟基苯甲酸和正庚醇为原料,在微波辐射下合成了尼泊金庚酯。讨论了微波功率、微波辐射时间、催化剂用量、醇酸物质的量比等对合成尼泊金庚酯产率的影响。结果表明,微波功率450 W、微波辐射30 min、醇酸物质的量比3.0∶1、催化剂用量为酸质量的1.5%,尼泊金庚酯的产率可达96.0%。同时,考查了催化剂的重复使用性。  相似文献   

8.
微波辐射下固体酸催化合成异烟酸乙酯   总被引:2,自引:1,他引:1  
在微波辐射下,以异烟酸和乙醇为原料,以活性炭固载对甲苯磺酸作催化剂,合成了异烟酸乙酯.最佳工艺条件:醇酸物质的量比为8∶ 1,催化剂用量为 1.0 g,微波辐射时间为 10 min,微波辐射功率为 200 W,酯化产率达 97.18%.另外通过实验发现,微波辐射下,反应速率及产率都明显高于常规加热方式.  相似文献   

9.
微波辐射下硫酸铜催化合成苯甲醛乙二醇缩醛   总被引:1,自引:0,他引:1  
用无水硫酸铜作催化剂,在微波辐射下催化合成苯甲醛乙二醇缩醛.系统考察微波辐射功率、微波辐射时间、原料配比、催化剂用量、带水剂用量对产率的影响.实验结果表明:当微波输出功率为600 W,辐射时间为12 min,苯甲醛用量为0.075 mol,乙二醇用量为0.112 5 mol,无水硫酸铜用量为1.2 g,带水剂环己烷用量为12 mL时,产率可达77.9%.  相似文献   

10.
微波辐射下肉桂酸苄酯的相转移催化合成研究   总被引:2,自引:1,他引:2  
以肉桂酸钠和氯化苄为原料 ,二乙胺作催化剂 ,采用微波辐射技术 ,在常压下直接合成了肉桂酸苄酯 .讨论了催化剂用量、微波辐射功率和辐射时间对酯产率的影响 .实验结果表明 ,最适宜的反应条件为 :当n肉桂酸钠∶n氯化苄 =1∶3 4时 ,二乙胺的用量 1 0mL ,微波功率 4 5 0W ,辐射 12min ,产率达 85 3%以上 .  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

20.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号