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1.
制备Dawson型磷钼钒杂多酸,用傅里叶变换红外光谱和X射线衍射进行表征.以环戊醇为反应底物,考察了催化剂用量、反应温度、反应时间和30%H2O2用量对氧化反应的影响及催化剂的重复使用.实验结果表明,杂多酸催化H2O2氧化环戊醇合成环戊酮的较佳条件为:H8[P2Mo16V2O62]:环戊醇:H2O2物质的量比为1:3826:8956、反应时间6h、反应温度80℃,环戊酮产率为85.75%,催化剂循环使用7次,环戊酮的产率在82%以上.在此条件下,催化氧化了苯甲醇、正丁醇、环己醇、异丙醇和仲丁醇合成苯甲醛、正丁醛、环己酮、丙酮和2-丁酮,其产率分别为 87.62%、35.64%、70.24 %、76.34 %和80.41 %.  相似文献   

2.
己二酸合成实验的改进   总被引:2,自引:0,他引:2  
在学生合成实验己二酸合成中采用相转移催化剂 ,用高锰酸钾碱性条件氧化环已醇使反应在较温和条件下 ,达到高产率并缩短反应时间 ,使己二酸合成实验成为可操作性及直观性较强的实验 ,同时也节省了实验原料和时间。  相似文献   

3.
以KX分子筛内原位合成的含CeO2助剂的酞菁钴为催化剂,考察了苯乙烯与过氧化氢的环氧化反应.研究表明该催化剂对苯乙烯的环氧化有一定的催化活性.对该条件下的环氧化反应机理进行了初步探讨.  相似文献   

4.
应用Baeyer-Villiger氧化反应,通过"一锅煮"的方法,以β-紫罗兰酮为原料,H2O2(30%)作氧化剂,经Lewis酸催化,合成β-环高柠檬醛.通过单因素实验法,详细研究了溶剂、催化剂、氧化剂、反应时间以及反应温度对β-环高柠檬醛合成反应的影响.确定了最佳反应条件,产率35%,产物结构通过GC-MS和NMR鉴定.  相似文献   

5.
研究了氧化钐为催化剂,乙酸和丁醇为合成原料合成乙酸丁酯,并考查了影响反应的因素,结果表明:酸醇物质的摩尔比为2:1,催化剂用量0.3g,反应时间3小时为最适应的反应条件,其产率可达67.0%。  相似文献   

6.
研究了氧化钐为催化剂,乙酸和丁醇为合成原料合成乙酸丁酯,并考查了影响反应的因素,结果表明:酸醇物质的摩尔比为2:1,催化剂用量0.3g,反应时间3小时为最适应的反应条件,其产率可达67.0%.  相似文献   

7.
相转移条件下杂多酸催化合成氧化苯乙烯   总被引:7,自引:0,他引:7  
为研究开发污染少、能耗低且对环境友好的催化剂和氧化剂,在相转移条件下,用新合成的杂多酸催化剂催化环氧化苯乙烯合成氧化苯乙烯,用15%的双氧水氧化苯乙烯,1,2 二氧乙烷作溶剂时,得出最佳的工艺条件为:反应时间3h,反应温度60℃,溶液的pH值2.00左右,催化剂由1mol钨酸与9mol钼酸组成,其催化选择性和催化活性高,用高压液相色谱分析氧化苯乙烯的产率为81.2%.在该条件下考察了催化剂的重复使用情况,效果较好.  相似文献   

8.
以肉桂酸和环己醇为原料,微波辅助催化合成肉桂酸环己酯。通过单因素实验和正交试验考察了催化剂种类、催化剂用量、肉桂酸与环己醇物质的量比、微波功率、微波时间对肉桂酸环己酯产率的影响。实验结果表明,合成肉桂酸环己酯最佳条件为:肉桂酸与环己醇物质的量比1∶4,以硫酸氢钠为催化剂,其用量为0.5 g,微波功率为600 W,微波时间为15 min,肉桂酸环己酯产率可达到96.5%。该工艺操作简单,反应条件温和,节约时间,产品纯度高,是一种高效环保的合成工艺。  相似文献   

9.
氮杂冠醚的合成   总被引:2,自引:0,他引:2  
报道了在酸性条件下,以丙酮和吡咯为原料合成大环氮杂冠醚--卟吩环的合成方法,反应时间为7 d,催化剂用甲磺酸,反应温度控制在5 ℃时,产率可达82%.  相似文献   

10.
利用水热法处理五水四氯化锡溶胶制备二氧化锡纳米粉,试验纳米二氧化锡纳米粉催化合成乙酰水杨酸的研究,并研究了酯化反应的优化条件,结果表明:纳米二氧化锡呈现出较高的催化活性,其催化合成乙酰水杨酸产率比以浓硫酸为催化剂的产率高,也明显高于普通的二氧化锡的产率,且纳米二氧化锡催化剂安全无毒,克服了浓硫酸的强腐蚀性、强氧化性、难于与产品分离、对环境污染大等缺点,纳米二氧化锡可望成为一种较好的能取代浓硫酸且对环境友好的催化剂。  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.
<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   

20.
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