CrCl_3/PVP纳米纤维催化葡萄糖制备5-羟甲基糠醛的研究

通过静电纺丝制备CrCl_3/PVP纳米纤维作为催化剂,在四乙基氯化铵(TEAC)反应体系中,考察催化剂、反应温度、反应时间等条件对葡萄糖制备5-羟甲基糠醛(HMF)产率的影响。实验结果表明,CrCl_3/PVP纳米纤维作为催化剂具有良好的催化效果,以TEAC为溶剂,当反应温度为120℃、反应时间20min,催化剂用量为葡萄糖质量10%时,果糖制备HMF的产率可达65.6%。     

乙醇中镧盐催化果糖脱水制备5-羟甲基糠醛的研究

以乙醇为反应溶剂,镧盐为催化剂催化果糖制备5-羟甲基糠醛(5-HMF)进行了初步研究.乙醇作为反应溶剂时,5-HMF产率远高于以水作为反应溶剂.氯化镧与硝酸镧相比具有更好的催化活性.提高催化剂浓度可以增大果糖转化为5-HMF的速率,但是对5-HMF的最大产率影响较小.随着反应温度的提高,果糖转化为5-HMF的速率增大,...     

改性分子筛催化果糖脱水制5-羟甲基糠醛

采用离子交换法制备Sn、Cu、Fe改性的SAPO-34分子筛,通过扫描电子显微镜(SEM)、X线衍射仪(XRD)、N_2物理吸附、NH_3程序升温脱附(NH_3-TPD)和X线荧光光谱仪(XRF)对改性后的催化剂进行形貌和结构表征。将改性前后的催化剂用于果糖脱水制5-羟甲基糠醛(5-HMF)反应中,考察反应时间、反应介质、催化剂使用量对产物产率的影响。结果表明:改性后的样品表面聚集了无定形颗粒,结晶度、孔容和酸性有所下降;以Sn-SAPO-34作为催化剂,在30 mL二甲基亚砜溶剂中添加0.25 g催化剂、1 g果糖,反应1 h后,转化率可达99.5%,5-HMF的产率为47.7%。在最优条件下将催化剂重复使用5次,产率有所下降,经过分离焙烧后再使用,产率可恢复至原来的水平。     

双相体系中催化碳水化合物水解制备5-羟甲基糠醛（英文）

采用廉价催化剂硅酸铝盐与痕量的盐酸组合,在双相体系中催化碳水化合物有效地转化制备5-羟甲基糠醛(HMF)。葡萄糖在水/正丁醇两相体系中在453 K下反应30min达到了100%的转化率,并可以获得61.5%产率的HMF。同时,在双相体系中在453 K下反应40min能有效地转化多糖(蔗糖、麦芽糖、淀粉和纤维素)制备HMF。此外,硅酸铝盐可以多次重复使用,试验中重复5次以上其活性没有明显下降。本催化体系在碳水化合物转化制备生物燃料和化学品领域具有很好的成本效益和商业应用潜力。     

纳米二氧化钛光催化降解硝基甲苯类废水的试验研究

采用纳米TiO2悬浮体系在循环式光催化反应器中处理硝基甲苯类废水,考察了TiO2投加量,H2O2投加量和pH值对光催化降解效率的影响.结果表明:2,6-二硝基甲苯和4-硝基甲苯的初始浓度分别为100mg/L和60mg/L,TiO2投加量为0.1g/L,H2O2投加量为0.1ml/L,pH值为3时,光催化反应2h,2,6-二硝基甲苯和4-硝基甲苯的去除率最高,分别为58.8%和68.6%.硝基甲苯浓度不高时,光催化降解反应符合准一级动力学方程.     

TiO_2悬浆体系光催化降解苯酚的研究

以高压汞灯为光源,研究了TiO2悬浆体系光催化降解苯酚的动力学规律,并考察了苯酚初 始质量浓度、催化剂投加量、溶液pH值、光强等对苯酚光解速率的影响.研究结果表明:该反应过 程可以用Langmuir-Hinshelwood(L-H)动力学方程描述;在一定条件下,催化剂的投加量、溶液 pH值均存在一最佳值;各因素对光催化降解苯酚反应影响的重要性排列顺序是,光照时间>pH 值>光照强度>TiO2投加量.     

TiO2悬浆体系光催化降解苯酚的研究

以高压汞灯为光源,研究了TiO2悬浆体系光催化降解苯酚的动力学规律,并考察了苯酚初始质量浓度、催化剂投加量、溶液pH值、光强等对苯酚光解速率的影响.研究结果表明该反应过程可以用Langmuir-Hinshelwood(L-H)动力学方程描述;在一定条件下,催化剂的投加量、溶液pH值均存在一最佳值;各因素对光催化降解苯酚反应影响的重要性排列顺序是,光照时间＞pH值＞光照强度＞TiO2投加量.     

纳米TiO2光催化氧化苯甲酸

采用DegussaP-25 TiO2悬浮体系,以紫外灯(λmax=254 nm)为光源,考察苯甲酸光催化氧化中溶液初始pH值、催化剂质量浓度、初始苯甲酸质量浓度、H2O2投加量对光催化氧化速率的影响,并对苯甲酸的光催化氧化过程进行了动力学分析.结果表明:苯甲酸的光催化氧化过程可采用准一级动力学模型;在pH=3.5时光催化氧化效果最佳,当催化剂质量浓度为0.05 g/L时,总有机碳去除率为87.2%;催化剂质量浓度大于0.1 g/L时,在反应初始阶段吸附作用为主要控制因素,但是随着反应的进行,传质和光源的利用率成为主要控制因素;随着苯甲酸质量浓度的增加,反应由一级向零级过渡;外加H2O2能够提高反应速率,其最佳投加量为1.5 mg/L.     

水相中离子液体[ADPQ][BF_4]催化“一锅法”合成四氢苯并[b]吡喃

目的:制备1种以4-氨基奎宁为基础的离子液体,催化3组分一锅法制备四氢苯并吡喃的反应.方法:以水为溶剂,反应底物为芳香醛、活性亚甲基化合物和双甲酮.结果:最佳反应条件为:催化剂用量为芳香醛摩尔量的15%,反应温度为60℃,以水做溶剂.在此条件下,尝试的底物反应时间均在2 h内,收率为83%~96%.结论:该催化体系反应条件温和,时间短,收率高,反应后处理简单,催化剂重复使用4次催化效果变化不大.     

相转移催化法合成4-羟甲基二苯甲酮

以4-甲基二苯甲酮为原料,经卤代、相转移催化水解反应合成有机中间体4-羟甲基二苯甲酮,并对其反应的工艺条件进行研究.研究结果表明:N-溴代丁二酰亚胺为较好的卤化剂,生成4-溴甲基二苯甲酮的产率为70.7%;4-溴甲基二苯甲酮以三乙基苄基氯化铵作相转移催化剂在碱性条件下水解,反应5 h后,目标化合物产率为84.4%;初产品用四氢呋喃重结晶后,最终产品纯度可达99%;经元素分析以及红外光谱、质谱和氢核磁共振谱表征,其结构为4-羟甲基二苯甲酮.     

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

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     

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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