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1.
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   

2.
以正丁醇和冰乙酸为原料,采用硫酸铝钾作催化剂合成醋酸正丁酯.考察了催化剂用量、原料配比和反应时间等因素对反应的影响.确定了硫酸铝钾催化合成乙酸正丁酯的较优条件:酸醇摩尔比为1:1,催化剂用量为乙酸质量的8.33%,反应时间1h,酯化率可达97.7%.  相似文献   

3.
二氧化硅负载硫酸镧催化合成乙酸正丁酯的研究   总被引:1,自引:0,他引:1  
以二氧化硅负载硫酸镧为催化剂.催化合成了乙酸正丁酯.研究了原料比例、催化剂用量、反应时问、催化剂重复使用效果等冈索对酯化率的影响,确定了较佳的工艺条件.结果表明,反应的最佳条件为:酸醇摩尔比(mol/mol)为1.0:2.0,催化剂的用量为冰乙酸用量的2.0%(质量比),反应温度为110~115℃.反应时间为2.0h,乙酸的转酯化率为95%以上.  相似文献   

4.
乙酸苄酯合成新工艺研究   总被引:3,自引:0,他引:3  
用强酸性阳离子交换树脂负载Fe3 制备的催化剂用于合成乙酸苄酯,研究了在不分离产物的条件下,醇酸比,催化剂用量,反应温度等因素对乙酸转化率的影响.当催化剂用量为15%(以乙酸加入的质量计),酸醇摩尔比为1∶1,反应温度为100℃,反应时间为2.5小时,乙酸转化率为69.30%.经负载Fe3 的树脂在选择的反应条件下催化合成乙酸苄酯,其催化活性比原树脂的催化活性提高了16.66%.催化剂经8次重复使用,其催化性能未见明显降低.  相似文献   

5.
强酸性阳离子树脂催化合成乙酸乙酯研究   总被引:1,自引:0,他引:1  
以D072强酸性阳离子树脂为催化剂, 乙酸和乙醇为原料,在常压下合成乙酸乙酯.该文研究了树脂种类、树脂用量、酸醇比、反应温度和反应时间等因素对酯化反应过程的影响.在不分离产物的情况下,合成乙酸乙酯的反应条件为:醇与酸摩尔比为1∶1, 反应时间100 min,催化剂用量6 g, 沸腾状态下反应,乙酸的单程转化率可达65.53%,催化剂可重复使用.  相似文献   

6.
固体超强酸催化反应合成丙二醇甲醚乙酸酯   总被引:4,自引:0,他引:4  
开发了以固体超强酸硫酸钛为催化剂精馏反应合成丙二醇甲醚乙酸酯的新工艺,考察了原料醇与酸的摩尔比、催化剂用量、带水剂用量、反应时间等因素对反应转化率的影响,得到了原料醇完全转化的适宜反应条件原料乙酸与醇的摩尔比1.60,带水剂环己烷与醇的摩尔比5.16,催化剂用量为反应物总质量的3.5%,反应时间3.5h。  相似文献   

7.
SO2-4改性铝层柱粘土固体酸催化合成乙酸正丁酯   总被引:1,自引:0,他引:1  
以SO2-4改性铝层柱粘土固体酸催化剂催化合成了乙酸正丁酯,考察了催化剂主要制备条件对乙酸转化率的影响.实验得乙酸正丁酯的最佳合成条件为酸醇摩尔比11.4,催化剂用量0.5 g,反应时间3 h,反应温度115~122 ℃.在此条件下,乙酸转化率可达90.2%以上,催化剂可重复使用.  相似文献   

8.
以柠檬酸和正丁醇为原料,对甲苯磺酸为催化剂合成无毒增塑剂柠檬酸三丁酯(TBC).探讨了酸醇物质的量比、催化剂用量、反应时间、反应温度、带水剂等对反应的影响,并对催化剂进行了重复利用研究,产品经气相色谱和红外光谱分析.确定的最佳工艺条件为:酸醇物质的量比为1∶4,催化剂用量为柠檬酸质量的3%,反应时间4 h,产率达96.3%.  相似文献   

9.
采用复合催化剂Hβ沸石/TiO2合成了乙酸辛酯.确定反应的最佳条件为:酸醇物质的量比1∶1.1、催化剂用量3.0g/mol乙酸、催化剂中TiO2的质量百分比10%、环己烷用量20mL/mol乙酸、反应时间3.5h.与其它单一固体酸催化剂比较,复合催化剂的催化性能更优越,乙酸的转化率更高.  相似文献   

10.
合成了硼钨杂多酸H5[BW12O40]·30H2O,将其用于乙酸正丁酯合成反应中,考察了催化剂用量、反应温度、反应时间及酸醇摩尔比对反应性能的影响.结果表明,硼钨杂多酸H5[BW12O40]·30H2O是乙酸正丁酯合成反应的理想催化剂,反应最佳条件:催化剂用量为0.1g,酸醇摩尔比为4∶1,反应温度为120℃,反应时间为3h,正丁醇的转化率为82%左右,乙酸正丁酯的选择性在95%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.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

15.
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   

16.
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   

17.
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   

18.
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   

19.
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   

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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