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1.
 为了合成高效的固体催化剂,离子液体被引入到介孔分子筛中。采用水热合成法制备了Al-MCM-41介孔分子筛,并浸渍离子液体制备出一种固载化催化剂。通过FT-IR、TG、N2吸附-脱附等方法进行表征,分析其晶型结构,成功将离子液体固载到Al-MCM-41介孔分子筛上。通过对工艺条件的考察和正交实验设计,确定了最佳反应条件。当苯烯摩尔比为8:1、反应温度为200℃、空速1.5h-1、压力3MPa时,反应的转化率和选择性综合达到最佳,Al-MCM-41固载离子液体催化剂的烯烃转化率为95.32%。  相似文献   

2.
该文对二苄叉丙酮的制备实验进行了改进。用分子筛固载氟化钾代替氢氧化钠作催化剂,研究了醛酮物质的量之比、催化剂用量和溶剂对产率的影响,确定了最佳合成条件。  相似文献   

3.
对苄叉丙酮(4-苯基-3-丁烯-2-酮)的合成实验进行了改进。用分子筛固载氟化钾代替氢氧化钠作催化剂,研究了醛酮物质的量之比、催化剂用量和溶剂对产率的影响;确定了最佳合成条件:醛酮物质的量之比为1:4,催化剂(以KF计)与苯甲醛物质的量之比为0.6:1。以甲苯为溶剂于25℃~30℃下反应2h,苄叉丙酮的产率可达80.5,并用同样方法成功地合成了其他的4-芳基-3-丁烯-2-酮。催化剂可回收再生重复使用。  相似文献   

4.
探索氧化锌固载四(4-羟基)苯基锰卟啉的催化性能.用混合溶剂法直接合成四(4-羟基)苯基卟啉(H2 THPP),采用研磨法合成四(4-羟基)苯基锰卟啉[Mn(Ⅲ)THPP].将Mn(Ⅲ)THPP固载到新生成的氢氧化锌沉淀上,经烘焙制得氧化锌固载四(4-羟基)苯基锰卟啉催化剂.用紫外和红外光谱对它进行表征.研究固载催化剂...  相似文献   

5.
李秉正  黎演明  吴学众  黄日波 《广西科学》2013,20(2):158-161,164
以酸性沸石为催化剂,催化葡萄糖脱水制备5-羟甲基糠醛(5-HMF).沸石催化剂采用固载磷钨酸(PW)和脱铝两种方法制备,固载PW方法用3种类型沸石:HY、MCM-41和HMOR,脱铝方法用HY型沸石,共制得产物PW/MCM-41、PW/HMOR、PW/HY、HY-D0.2和HY-D1.0,考察沸石结构、反应温度、葡萄糖与水质量比、催化剂与葡萄糖质量比对制备5-HMF的影响.结果表明,沸石固载PW后5-HMF的产率均有所提高,其中,以Y型沸石(HY)固载PW后(PW/HY)作为催化剂时5-HMF产率最高,为27.9%;HY特殊的结构对提高5-HMF的产率具有重要的作用.另外,提高反应温度有利于加快5-HMF的生成;葡萄糖与水质量比为3.0∶100时5-HMF产率最高,反应2.5h时达到30.4%,说明适当的葡萄糖与水质量比有利于5-HMF的制备.  相似文献   

6.
用TiO2/S2O2-8-沸石分子筛作催化剂,由硬脂酸和正丁醇发生酯化反应来合成硬脂酸正丁酯.考察了各种因素对酯化反应的影响,得到了反应的最佳条件:当醇和酸的物质的量之比为3:1、TiO2/S2O2-8-沸石分子筛的用量为反应物质量的2.0%、反应温度为85℃时,反应仅需约2.5h,酯化率可达到98.7%,酯的纯度>99.1%.  相似文献   

7.
用TiO2/S2O2-8 -沸石分子筛作催化剂,由硬脂酸和正丁醇发生酯化反应来合成硬脂酸正丁酯。考察了各种因素对酯化反应的影响,得到了反应的最佳条件:当醇和酸的物质的量之比为3∶1、TiO2/S2O2-8 沸石分子筛的用量为反应物质量的2.0%、反应温度为85 ℃时,反应仅需约2.5 h,酯化率可达到98.7%,酯的纯度>99.1%。  相似文献   

8.
以煅烧煤系高岭土为原料,采用氢氧化钠溶液水热合成制备NaA分子筛.以NaA分子筛晶体的生长过程为基础,利用XRD、SEM对NaA分子筛晶体生长规律进行表征, 并对其结晶机理进行了分析.结果表明,煤系高岭土制备NaA分子筛的最佳工艺条件是:煅烧温度为725 ℃;配料比 m(Na2O)/m(SiO2)为3,m(H2O)/m (Na2O)为40;胶化条件为70 ℃×2 h;晶化条件为100 ℃×6 h.所制NaA分子筛的钙离子交换量为316.55 g CaCO3/g.在NaA分子筛的碱液合成过程中,在晶化条件下,凝胶固相中的硅铝酸根骨架解聚重排晶化成沸石晶体骨架.  相似文献   

9.
用固体超强酸TiO2 /SO2 -4 -沸石分子筛催化合成对羟基苯甲酸酯 ,对催化剂的制备条件和酯的合成反应条件进行了研究 .结果表明 ,该催化剂具有较高的活性 ,并具有一定重复使用性 ,是合成对羟基苯甲酸酯的良好催化剂 ,具有较好的应用前景  相似文献   

10.
固载化PW_(12)/SiO_2催化剂及其催化合成DOTP的研究   总被引:1,自引:0,他引:1  
用 1 2 -钨磷杂多酸和硅酸钠 ,通过凝胶法制备固载化杂多酸催化剂 PW12 /Sio2 ,并对所制备的催化剂进行了红外光谱、差热、电子能谱以及酸强度测定。以对苯二甲酸和 2 -乙基乙醇为原料 ,用自备的 PW12 /Si O2 催化酯化合成增塑剂对苯二甲酸二辛酯 ,通过正交化实验确定了最佳反应条件。  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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