MCM-41固载席夫碱钴配合物在环己烷氧化反应中的应用

制备γ-氨丙基三乙氧基硅烷修饰的MCM-41分子筛固载型双水杨醛缩乙二胺合钴(Cosalen)配合物,采用傅里叶变换红外光谱、X线衍射、比表面积测定、热重-差热(TG-DSC)、紫外-可见光光谱(UV-Vis)、透射电镜等方法对分子筛固载型配合物Cosalen/MCM-41的结构进行表征,并对比Cosalen/MCM-41与Cosalen/NaY的催化性能。研究结果表明:Cosalen已进入分子筛孔道内;在以氧气为氧源的环己烷氧化反应中,Cosalen/MCM-41催化剂具有较好的活性和对环己醇、环已酮的选择性。该催化反应产物中环已基过氧化氢(CHHP)的量很少,表明Cosalen/MCM-41催化剂能加速环已基过氧化氢的分解;以Cosalen/MCM-41为催化剂,在初始氧气压力为0.80 MPa,温度为130℃,环己烷与催化剂的质量比为100,叔丁基过氧化氢0.06 g的相对温和条件下反应2 h,环己烷的转化率达到5.96%,醇酮选择性87.03%。     

锡修饰MCM-41的合成、表征及催化应用

以硅酸钠为硅源,十六烷基三甲基溴化铵为模板剂,锡酸钠为金属源,水热法直接合成一系列不同含量Sn掺杂的MCM-41分子筛,采用XRD、N2吸脱附、FTIR和ICP对材料的结构和物化性质进行表征。以乙腈为溶剂,H2O2为氧化剂,70℃考察了所合成的材料对环己烷液相氧化的催化活性和选择性的影响。结果表明:随着锡含量的增加,环己烷的转化率增加趋缓,环己醇的选择性减小而环己酮的选择性增大。     

希夫碱锰催化氧化环己烯合成环己烯酮

以MCM-41型介孔分子筛为载体,制备出固载型金属希夫碱锰催化剂,并用红外、紫外漫反射对其结构进行了表征.以固载型金属希夫碱锰为催化剂,对分子氧氧化环己烯制备环己烯酮的工艺条件进行了探索,结果表明,在催化剂用量:0.2g,温度:60℃,时间:9h,溶剂:乙腈的条件下,环己烯转化率可达90.9%,环己烯酮的选择性可达55.8%,催化剂重复使用4次后活性略有下降.     

H6P2Mo9W9O62/MCM-41催化合成环己酮乙二醇缩酮

目的合成环己酮乙二醇缩酮。方法采用浸渍法制备了H_6P_2Mo_9W_9O_(62)/MCM-41催化剂,并采用FT-IR、XRD对其进行了表征。以环己酮和乙二醇为原料,催化合成环己酮乙二醇缩酮,采用FT-IR表征手段来表征合成产物。结果经反应条件优化,在酮醇摩尔比为1∶1.3,带水剂环己烷用量为8 mL,催化剂用量为反应物总质量的0.8%,反应时间为60 min的条件下,缩酮收率可达82.6%。催化剂重复使用5次后收率仍有73.5%。结论催化剂H_6P_2Mo_9W_9O_(62)/MCM-41对合成环己酮乙二醇缩酮具有反应时间短、催化剂用量少、产品收率高等优点。     

Cr-MCM-41分子筛的合成、 表征及其催化性能[HT][HT4F]

合成了一系列掺杂Cr的MCM-41分子筛， 并用XRD, IR和EXAFS等手段表征了催化剂. 实验结果表明， 一部分Cr离子进入到MCM-41骨架， 另一部分Cr离子以其他Cr化合物形式存在且这部分铬可通过NH₄Ac溶液洗去. Cr-MCM-41和Cr-MCM-41-t催化剂在十八醇选择 氧化反应的几个循环中表现了稳定的十八醇转化率和十八酸选择性.     

甲基修饰Au/MCM-41催化环己烷选择氧化

介绍了一种提高环己烷氧化制备环己酮/环己醇催化效率的方法.通过对Au/MCM-41催化剂进行甲基化修饰以提高其表面的疏水性,从而提高环己烷催化氧化的效率.结果表明,在相同反应条件下,甲基化修饰的催化剂Au/CH3-McM-41比未修饰的催化剂Au/MCM-41表现出更高的催化效率,Au/CH3-McM-41优异的催化性能是由于甲基的引人改变了Au活性位的周围环境引起的.     

纳米氧化铁的制备及其对环己烷氧化性能的影响

采用超声波方法在不同浓度的五羰基铁溶液中制备得到纳米氧化铁,并将其为催化剂用于环己烷催化氧化反应。在反应体系中,考察了反应时间、温度、催化剂用量、引发剂用量、空气量对催化氧化反应的影响。结果表明,以叔丁基过氧化氢为引发剂,空气为氧化剂在70℃,常压下反应3h,环己烷转化率可以达到23.8%,环己醇、环己酮和环己基过氧化氢的选择性可达94.5%.     

含过渡金属分子筛催化环己醇与空气氧化制备环己酮

分别采用离子交换法、水热合成法和干胶转化晶化法,将非贵过渡金属引入到分子筛中合成出含过渡金属的分子筛催化剂,并将其应用于以空气为氧化剂、多相催化环己醇合成环己酮的反应中,探索高效、环保、廉价的绿色催化氧化反应体系.研究结果表明,采用水热合成法制备的含钴分子筛(CoAlPO-5)在催化空气氧化环己醇制备环己酮的反应中表现出优异的催化活性,通过考察反应温度、空气流速、反应时间、催化剂用量等探索了最佳催化反应条件是:反应温度为100℃、空气流速为40mL/min、反应时间为8h、催化剂用量为100mg时,环己醇转化率可达到38.2%,环己酮选择性达到95.8%.     

Al-MCM-41固载离子液体催化-合成长链烷基苯

 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%。     

NHPI复合体系催化氧化环己烷的研究进展

环己烷氧化制备环己酮和环己醇是一个重要的工业过程,但目前满足绿色环保和便于工业化应用的催化剂或反应工艺很少,N-羟基邻苯二甲酰亚胺(NHPI)催化剂因其能在温和条件下有效地催化烃类自由基氧化而受到广泛关注.本文综述了近年来NHPI复合催化体系催化氧化环己烷的实验路线.分析表明NHPI复合催化剂能明显地提高环己烷的转化率和环己酮的选择性,但普遍存在反应时间长,热稳定性差,可回收率低等缺点.因而开发更高效的NHPI复合催化剂,对环己烷氧化工艺及其工业化应用具有重要的现实意义.     

Markedness and its Interpretation in Language Use

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.     

Features of Women's language

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.     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

On Tragic Consciousness In The Works By Ernest Hemingway

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.     

Achieving Unusual States of Matter Under High Pressure

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-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

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-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

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     

Call for Papers

<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     

Journal of Donghua University ( English Edition) Contents of Volume 31

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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has