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1.
丙烯酸酯化反应中固体酸催化剂的应用   总被引:2,自引:0,他引:2  
制备并研究了多种用于合成丙烯酸酯的固体酸催化剂,以代替浓硫酸,初步探索了负载型固体酸以及锆基固体酸CZ催化剂的不同制备方法对催化剂性能的影响。结果表明:在反应温度为110~120℃,酸醇质量比为105~11∶1的条件下,以对甲苯磺酸为活性组分负载到分子筛上制得催化剂对丙烯酸二乙二醇酯有较好的催化活性,丙烯酸的转化率达到939%。锆基固体酸催化剂CZ对多种丙烯酸酯合成均有很高的活性,丙烯酸的转化率可达到978%。用于三羟甲基丙烷三丙烯酸酯(TMPTA)合成,产物中其二酯和三酯的比例为1比66。  相似文献   

2.
制备固体超强酸23-24-Fe O SO催化壬二酸和2-乙基己醇合成了壬二酸二辛酯.通过实验对催化剂种类、催化剂用量、壬二酸和2-乙基己醇物质的量比、反应温度和反应时间进行对比,研究各实验因素对合成壬二酸二辛酯产率的影响.经过实验优化,当催化剂固体超强酸23-24-Fe O SO用量为壬二酸质量的0.4%、壬二酸和2-...  相似文献   

3.
合成了固体酸催化剂,应用该催化剂合成了三乙酸甘油酯。实验表明,Zr:Ti=2:1、活化温度为450℃时催化剂活性最高。酸强度和酸量分布表明中强酸位有利于酯化反应。  相似文献   

4.
三氧化二钕催化合成尼泊金丁酯   总被引:4,自引:0,他引:4  
研究了以三氧化二钕作固体催化剂合成尼泊金丁酯,通过正交实验讨论了影响催化酯化反应的各种因素,确定了该酯化反应最佳条件。催化剂用量仅为尼泊金酯重量的5% ,醇酸摩尔比为4∶1,反应时间为4h,温度为12℃,酯收率达812%  相似文献   

5.
五氧化二铌催化酯化制备 DOP 的研究   总被引:2,自引:0,他引:2  
用固体酸五氧化二铌作酯化催化剂,由苯酐和2-乙基己醇制备了邻苯二甲酸二(2-乙基己酯)(DOP)。反应先快速生成中间产物邻苯二甲酸单(2-乙基己酯),然后再酯化成双酯DOP。由单酯转化成双酯的反应为典型的二级反应,测定了二级反应的速率常数和活化能。研究了催化剂的循环使用,探讨了反应时间、反应温度和催化剂用量等因素对粗产品酸度和外观质量的影响。  相似文献   

6.
用固体酸五氧化二铌作酯化催化剂,由苯酐和2-乙基己醇制备了邻苯二甲酸二(2-乙基己)(DOP)。反应先快速生成了中间产物邻苯二甲酸单(2-乙基己酯)然后再酯化双酯DOP。由单酯转化成双酯的反应为典型的二级反应,测定了二级反应的速率常数和活化能,研究了催化剂的循环使用,探讨了反应时间,反应温度和催化剂用量等因素以粗产品酸度和外观质量的影响。  相似文献   

7.
研究了以三氧化二钕为固体催化剂,由冰乙酸和异丁醇合成乙酸异丁酯,讨论了影响酯化反应的因素,找出了合成乙酸异丁酯的最佳工艺条件。本工艺特点是:催化剂用量少,是异丁醇的5%,反应时间短(3h),温度为110℃,酯收率可达80%。  相似文献   

8.
本文利用共沉淀法制备的超细Al2O3粉末催化合成了增塑剂偏苯三酸三异辛酯。在考究了催化剂用量,酸醇比,反应温度等因素对偏苯三酸酐转化经影响的基础上,测定了TOTM的催化反应动力学方程。结果表明,当催化剂浓度为0.4,酸醇比为1:4,反应温度为190℃-220℃时,反应活化胡Eα=42.4kJ/mol。  相似文献   

9.
在催化剂的作用下,以亚磷酸三甲酯和对二氯苄为原料,合成一种高效无卤阻燃剂——对二苄基双膦酸四甲酯.当反应温度为130℃,物质的量比(亚磷酸三甲酯:对二氯苄)为2.8:1,反应时间为6h,催化剂用量为原料总质量的3%时,产率可达80%.通过高分辨质谱仪、红外光谱仪、核磁共振仪对产品结构进行了表征,通过热重分析仪对其热稳定...  相似文献   

10.
一缩二乙二醇二苯甲酸酯的合成   总被引:1,自引:0,他引:1  
用自制的高分子固载化螯合钛酸酯催化合成一缩二乙二醇(俗称二甘醇)二苯甲酸酯(DEDB)。通过试验确定了合成DEDB的适宜的工艺条件为:n(一缩二乙二醇):n(苯甲酸)=1.0:2.1,催化剂用量为0.41%,反应时间3h,反应温度210℃,产率达96.5%。催化剂的催化活性高,易与产品酯分离,可重复使用。  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.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

18.
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   

19.
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   

20.
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   

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