纤维素-三(3,5-二甲基苯基氨基甲酸酯)手性柱的制备及应用

以微晶纤维素和(3,5-二甲基)苯基异氰酸酯为原料合成了纤维素-三(3,5-二甲基苯基氨基甲酸酯),经红外光谱和元素分析知微晶纤维素已酯化完全.用不同的方法(沉积法和蒸发法)将其涂敷于氨基丙烷化硅胶上制得了纤维素-三(3,5-二甲基苯基氨基甲酸酯)手性柱,对柱进行了评价,并在正己烷-异丙醇(体积比为90∶10)为流动相,流速为1.0mL·min-1,柱温25℃下拆分了几种手性物质.     

α-苯乙醇的高效液相色谱手性拆分研究

本文用实验室自制的纤维素三(3,5-二甲基苯基氨基)甲酸酯和纤维素三(4-甲基苯)甲酸酯涂敷于硅胶上,分别制成OD柱和OJ柱.在OD柱和OJ柱上对外消旋体α-苯乙醇进行了拆分,分别考察了流动相中异丙醇的含量对α-苯乙醇手性拆分的影响,还分别考察了流动相中1%(V/V)的正丙醇、异丙醇、正丁醇、叔丁醇对α-苯乙醇拆分的影响.我们选择了最佳的拆分方法,并将此方法应用于苯乙酮不对称催化还原产物的光学纯度的鉴定中,将苯乙酮在NaBH4为还原剂下,在自制的手性聚合物金属络合物PMA-QN-PdCl2催化剂作用下被还原,取得了满意的结果.     

纤维素-三（苯基氨基甲酸酯）手性固定相的制备及多种手性化合物的拆分

以微晶纤维素和苯基异氰酸酯为原料,合成了纤维素-三(苯基氨基甲酸酯),并以经3-氨丙基-三乙氧基硅烷修饰的硅胶为裁体,制备了涂敷型纤维素-三(苯基氨基甲酸酯)液相色谱固定相,对该固定相进行了表征,并在正相条件下对14种对映异构体进行了拆分,其中8种得到了分离,该柱表现出良好的手性分离性能.     

高效液相色谱法测定1-三甲基硅基-1-炔-3-癸醇对映体纯度

以苯甲酰氯试剂衍生1-三甲基硅基-1-炔-3-癸醇,得到具有强紫外吸收的1-三甲基硅基-1-癸炔-3-苯甲酸酯.考察流动相中不同醇调节剂、乙醇含量和柱温对外消旋1-三甲基硅基-1-癸炔-3-苯甲酸酯对映体在Chiralcel OD-H手性柱上色谱分离的影响,建立测定1-三甲基硅基-1-炔-3-癸醇对映体纯度的色谱分析方法.结果表明:以正己烷-乙醇(99.95:0.05,体积比)为流动相,检测波长为228 nm,外消旋苯甲酰氯衍生对映体在Chhalcel OD-H柱上得到很好的分离,保留时间分别为6.94 min和8.11 min,分离因子和分辨率分别为1.41和3.75.本法灵敏度高,方法简便,适合于手性1-三甲基硅基-1-炔-3-癸醇样品的对映体纯度分析.     

用三-(3,5-二硝基苯甲酰基)纤维素薄层分离对映体

采用超声方法合成了三_(3,5_二硝基苯甲酰基 )纤维素 (CTNB) ,并用红外光谱、元素分析对CTNB进行了表征。将CTNB用于薄层分离对映体 ,CTNB和微晶纤维素 (MC)按等比例混合 ,制备成薄板的手性固定相。采用合适的展开剂系统 ,使 6种手性药物得到完全分离 ,相对比移值α≥ 1 79。     

高取代度淀粉苯甲酸酯的水相法制备及其性质

以玉米淀粉为原料,苯甲酰氯(BC)为酯化剂,在水相中制备了淀粉苯甲酸酯(SB),并对其理化性质进行了系统研究.实验结果表明,最佳的反应条件为:BC与AGU摩尔比为3. 0,NaOH与BC摩尔比为1. 95,反应时间1 h,反应温度24℃,此时,取代度(DS)可达到0. 66. FTIR分析表明淀粉分子上成功接入了苯甲酰基团,羟基峰随取代度增大不断减弱; SEM测试显示淀粉苯甲酸酯基本保留原有的颗粒型态,颗粒表面形貌遭到了一定程度的破坏; XRD测试表明淀粉苯甲酸酯的结晶结构被破坏,微晶区已经完全消失,亚微晶区相对完整;接触角的变化表明淀粉苯甲酸酯与原淀粉相比具有更强的疏水性;同时淀粉苯甲酸酯具有优良的乳化性能且当取代度为0. 30时性能最佳;热重分析表明淀粉苯甲酸酯的持水力比原淀粉弱,耐温性较差.     

纤维素三（4-三氟甲氧基苯基氨基甲酸酯）手性固定相的制备及其手性识别能力

制备了基于纤维素三(4-三氟甲氧基苯基氨基甲酸酯)衍生物的涂敷型手性固定相(CSP1),并考察了其手性识别能力。研究表明:与商品化Chiralcel OD柱相比,CSP1显示出较低的手性识别能力。CSP1的手性识别能力随流动相中异丙醇含量的降低而升高。与以乙醇为流动相添加剂相比,使用异丙醇为添加剂更有利于对映体的分离。此研究拓展了多糖类衍生物手性固定相的种类。     

纤维素-三(苯基氨基甲酸酯)复合膜的制备及对(±)-1-萘乙醇的初步拆分

以微晶纤维素和苯基异氰酸酯为原料,合成了纤维素-三(苯基氨基甲酸酯)(CTPC)手性高分子.并以CTPC为膜材料用无纺布做支撑,制备了CTPC复合膜.讨论了浓度、操作压力对膜的性能的影响,并测试了复合膜的机械性能.将CTPC复合膜初步应用于对映体(±)-1-萘乙醇的分离.结果表明:当使用质量浓度为12%的复合膜,操作压力为0.25MPa时,该膜对(±)-1-萘乙醇具有明显的选择性,此时复合膜的抗张强度和断裂伸长率分男δb=45MPa,εb=54%.     

手性二噁唑啉铜不对称催化烯丙基氧化酰化反应的密度泛函研究

用密度泛函理论(DFT)研究了手性二嗯唑啉铜(I)催化过苯甲酸异丁酯与丁烯不对称烯丙基氧化酰化反应的机理．分别在B3LYP／6—31G,B3LYP／6—31G(d)水平上优化了反应中间体和过渡态的结构．结果表明,该反应是放热的．其中催化剂-苯甲酸丁烯酯手性加合物的生成是反应产物的手性决定步骤．理论预测的主要产物是s型苯甲酸-3-丁烯-2-酯,与实验吻合．     

纤维素三苯甲酯手性固定相的制备及对映体的拆分

用微晶纤维素和苯甲酰氯的超声反应合成了纤维素三苯甲酯 ( CTB) ,并将其涂敷于硅胶上 ,用作液相色谱手性固定相。在正相条件下 ,用此手性固定相对一系列外消旋缩水甘油芳香基醚类化合物进行了拆分 ,并对拆分机理进行了探讨。考察了流动相中添加不同的醇对缩水甘油间甲基苯基醚对映体拆分的影响     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

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.     

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