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1.
相转移催化法制备环己酮   总被引:4,自引:0,他引:4  
以次氯酸钠作为氧化剂,用不同的相转移催化剂,选择出最合适的条件,进行氧化环己酮制备环己酮的反应。结果表明:以四丁基碘化铵为催化剂制备环己酮的收经最高,可达87.9%,制备环己酮收率的高低取决于所用的相转移催化剂的种类,选用的溶剂,环己醇与次氯酸钠的比例,反应时间和反应温度。  相似文献   

2.
研究了聚乙二醇(PEG—600)作为相转移催化剂催化KMnO4氧化对硝基甲苯合成对硝基苯甲酸的反应,考察了相转移催化剂用量、反应温度、反应时间、KMnO4用量和反应体系酸碱性对反应的影响.PEG—600用量为反应底物摩尔数的5%,KMnO4与对硝基甲苯摩尔比为3∶1,反应温度为95℃,反应时间为3 h,在中性条件下进行反应,产物收率达51.6%.实验表明,PEG—600对于KMnO4氧化对硝基甲苯合成对硝基苯甲酸的反应是一种优良的相转移催化剂.  相似文献   

3.
于固-液相转移催化条件下,以PEG-400为催化剂,通过苯酚与氯乙酸乙酯反应合成了苯氧基惭酸乙酯(Ⅰ),(Ⅰ)与85%的水合肼作用得到相应的酰肼(Ⅱ)(Ⅱ)分别与乙酰丙酮和2-噻吩甲酰三氟丙酮反应,得到1-苯氧基乙酰基-3,5-二甲基吡唑(Ⅲ)-1-苯氧基乙酰基-3-三氟甲基-5-(噻吩-2-基)吡唑(Ⅳ),产物结构通过元素分析和光谱鉴定已得到证实。  相似文献   

4.
2,5-二甲氧基苯甲醛是重要、不易合成的药物中间体。以对甲氧基苯酚为原料,经聚乙二醇10000催化的Reiman-Tiemann反应及甲氧基化制备而得。通过比较不同相转移催化剂对Reimer-Tiemann反应产率的影响,选择效果最佳的聚乙二醇-10000(PEG-10000)作为该反应的相转移催化剂。把2-羟基-5-甲氧基苯甲醛的甲氧基化放在缓冲溶液中进行,产物的收率和品质有明显提高。就影响产率的各种因素进行了探讨,并从机理上作了简要解释。通过反应条件改进,总收率达68%。  相似文献   

5.
磷钼杂多酸盐催化作用下的SBS环氧化反应   总被引:2,自引:0,他引:2  
用磷铝杂多酸盐为反应控制相转移催化剂,以30%H2O2为氧源,对SBS进行环氧化反应.实验表明:其适宜条件为反应时间2h,反应温度70℃,SBS溶液浓度为100g/L.n(磷钼酸盐):n(过氧化氢)=1.72,过氧化氢(相对于SBS)质量百分用量为27.2%,所得产物的环氧化程度最高为7.63%,催化剂可回收再利用.  相似文献   

6.
用聚乙二醇-400作为相转移催化剂合成2-(三氯甲基)-2-丙醇,反应在碱性介质中进行,条件温和,反应温度控制在5~10℃原料的摩尔配比为丙酮:氯仿:氢氧化钠:聚乙二醇-400=10:10:7:1.产率为30.4%。  相似文献   

7.
聚乙二醇用作改善亲核取代反应的相转移催化剂   总被引:2,自引:0,他引:2  
研究了将聚乙二醇用作相转移催化剂及其对亲核取代反应的改善,先将雌二醇经溴化制得2-或4-溴雌二醇,再分别氯仿中以聚乙二醇(PEG-400)作相转移催化剂(PTC)进行亲核取代反应制备2-呈4-甲氧基雌二醇,发现其适条件为:反应温度6-65℃,搅拌反应时间1.5h,试剂比例底物为甲醇:KOH:PEG=1:20:80:0.8,获得较高亲核取代产率;2-氧基雌二醇66.7%及4-甲氧基雌二醇70.3%,  相似文献   

8.
以4-苯氧基苯酚,环氧丙烷为原料合成1-(4-苯氧基苯氧基)-2-丙醇,考察了物料比、反应时间、反应温度等因素对其收率的影响,得到最佳工艺条件。规(4一苯氧基苯酚):规(环氧丙烷):规(氢氧化钾)=1:3.0:0.3,反应温度40℃,反应时间3.5h,1-(4-苯氧基苯氧基)-2-丙醇收率最高达93.7%。以液相色谱法,采用LiChrospher100 RP~18柱、甲醇+水为流动相、紫外检测器、外标法对1-(4-苯氧基苯氧基)-2-丙醇进行了高效液相色谱分析研究。方法标准偏差0.20%,变异系数0.23%,回收率在99.57%~100.52%之间。  相似文献   

9.
在微波辐射和相转移催化剂的条件下,采用Henry反应,快速合成β—甲基—β—硝基对甲氧基苯乙烯.考察了微波辐射功率、微波辐射时间、不同的相转移催化剂、反应物的物料比等因素对反应收率的影响.结果表明:在微波辐射功率为130w、微波辐射时间为8min,以PEG—1000做相转移催化剂,反应物的用量为:对甲氧基本甲醛:硝基乙烷:PEG—1000为1:2.5:0.08.在冰乙酸/醋酸铵条件下,产物收率达48.9%。  相似文献   

10.
在相转移催化剂存在的条件下,以1,2,4-三氮唑和2-氯-2’,4’-二氟苯乙酮为原料合成2’,4’-二氟-2-(1H-1,2,4-三唑-1-基)苯乙酮,分别讨论了原料配比、反应时间、缚酸剂、溶剂对合成反应的影响,确定了最佳合成工艺条件,产物收率可达82.6%。  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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