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1.
异佛尔酮是丙酮的衍生物之一,丙酮在碱性催化条件下发生羟醛缩合反应后,经脱水、环化、脱酮而得。现有异佛尔酮的合成方法主要可以分为异亚丙基丙酮法和丙酮缩合法两种。通过对合成现状的分析与研究,为进一步展开研究工作奠定了基础。  相似文献   

2.
异佛尔酮合成反应动力学模型   总被引:1,自引:0,他引:1  
研究以丙酮为原料液相法合成异佛尔酮的液相缩合反应动力学.考察NaOH为催化剂,催化剂用量、压力、温度、反应时间对反应的影响.结果表明,反应温度215~225 ℃、丙酮与水质量比3∶1、0.13 mol NaOH、压力3.8~4.5 MPa为最优反应条件,其表观活化能51.31 kJ/mol,对丙酮消耗速率的动力学方程-rA=0.953×103e-51 310/RTCA,经统计检验,所得反应速率方程是可信的,可用于反应器的模拟计算.  相似文献   

3.
用同时蒸馏萃取方法对海南地区白胡椒中挥发油组分进行了提取,测得白胡椒挥发油质量分数为5.5%,并用GC/MS法对挥发油进行了分离和鉴定,确认出25种化合物;用峰面积归一法通过G1701BA化学工作站数据处理系统得出各化学成分在挥发油中的峰面积相对质量分数为80.6%.  相似文献   

4.
2-庚酮的合成研究   总被引:1,自引:0,他引:1  
以NaOH为缩合催化剂,ZnCl2为助催化剂,Pd/C为加氢催化剂,用丁醛和丙酮经交叉羟醛缩合、脱水、催化加氢制得2-庚酮,利用气相色谱和红外光谱对产品进行了表征。研究了催化剂用量等因素对缩合的影响,考察了脱水、催化加氢的条件。结果表明:以质量分数为12%的NaOH溶液作为催化剂,ZnCl2为助催化剂,反应温度为15℃,加料时间3h,n(丁醛):n(丙酮)=1:3为最佳缩合条件;脱水温度90℃、酸性条件下进行;催化加氢的温度和压力以70℃、0.7MPa为宜。  相似文献   

5.
用同时蒸馏萃取方法对海南地区白胡椒中挥发油组分进行了提取 ,测得白胡椒挥发油质量分数为5 5 % ,并用GC MS法对挥发油进行了分离和鉴定 ,确认出 2 5种化合物 ;用峰面积归一法通过G170 1BA化学工作站数据处理系统得出各化学成分在挥发油中的峰面积相对质量分数为 80 6 %  相似文献   

6.
针对固定床反应器模拟过程难以形成其模型完整通用的计算模块且编程工作量大的问题,提出了一种稳态下固定床反应器中反应物和产物温度及浓度分布的通用计算方法.该方法以关键组分的摩尔分数作为变量,推导出关键组分在物料与热量衡算中的偏微分方程组中的通式,并利用正交配置法求解.同时考虑固定床反应器内气相流速的变化,将其描述为关键组分摩尔分数的函数进一步实现模型的通用性.对于特定的反应,只需提供目标反应的动力学方程及操作条件即可求解.最后利用所提出的方法实现乙苯催化脱氢制苯乙烯与乙炔法制氯乙烯反应过程的模拟,结果表明该方法具有通用性和高效性.  相似文献   

7.
在以丙酮为溶剂、以V2O5/SiO2为催化剂、8-羟基喹啉为助剂的催化条件下,以过氧化氢水溶液为氧化剂,对环己烯催化氧化制备环己烯酮的催化反应体系进行了研究。考察了V2O5的负载量以及8-羟基喹啉的用量及反应温度对环己烯氧化反应的影响,发现适当的负载量有利于V2O5催化性能的提高。结果表明,当V2O5负载量(质量分数)为5%、催化剂的量和8-羟基喹啉的质量相等、反应温度为30℃时环己烯的转化率和环己烯酮的选择性较好。这源于V2O5高度分散于SiO2载体上,增大了活性组分V2O5的表面积,从而增加了其活性中心的个数及活性组分与反应物的接触面积,从而增加了催化活性。  相似文献   

8.
采用光照内环流反应器,研究了邻、对氯甲苯分别侧链光氯化制备对、邻氯氯苄,对、邻氯苄叉二氯,对、邻氯三氯甲苯,考察了氯气流量、温度对光氯化反应的影响,实测了各组分质量分数随时间的变化关系,得到了各组分的最高质量分数与时间的对应关系,得出了制备各产物的适宜工艺条件.通过对对、邻氯甲苯光氯化的比较,发现邻氯氯苄的最高质量分数稍高于对氯氯苄的最高质量分数,140℃时分别达72.2%和69.2%,邻氯苄叉二氯的最高质量分数显著高于对氯苄叉二氯的最高质量分数,140 ℃时分别达88.5%和74.2%.经过充分氯化,对、邻氯三氯甲苯质量分数均能达到99%以上.  相似文献   

9.
以天然氨基酸为原料合成了一种脯胺酰胺衍生物,并研究了它在催化芳香醛与丙酮的不对称羟醛缩合反应中的应用。酸的添加能够提高反应速率及产物的对应选择性。  相似文献   

10.
假紫罗酮合成方法的研究   总被引:1,自引:0,他引:1  
研究了以固体Ba(OH) 2 作为催化剂,使柠檬醛与丙酮醛醇缩合反应制备假紫罗酮的方法。发现在体系中加入少量乙醇可以加快缩合反应的速度;加入微量的添加剂可以有效地提高反应的选择性,成功地抑制副反应的发生。  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   

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