硫酸铁催化合成氯乙酸异戊酯的研究

以硫酸铁为催化剂,正己烷为带水剂催化合成氯乙酸异戊酯,对反应过程中的酸醇摩尔比、反应时间、催化剂用量及催化剂重复使用等因素对反应收率的影响进行了考察,寻求氯乙酸异戊酯的最佳合成条件.结果显示,当酸醇摩尔(以0.1 mol为基准)比为1:1.3,催化剂用量为0.5 g,反应时间为0.5 h,带水剂正己烷为15 ml,反应温度100～110℃的条件下,氯乙酸异戊酯的收率可达到93.0%.该研究为氯乙酸异戊酯的工业合成提供了理论依据.     

十八水硫酸铝催化合成氯乙酸异戊酯

以Al2SO4318H2O为催化剂,氯乙酸和异戊醇反应合成了氯乙酸异戊酯,研究了醇酸物质的量比、催化剂的用量、带水剂的用量、催化剂反复使用次数及反应时间等因素对酯化率的影响.结果表明:Al2SO4318H2O对氯乙酸异戊酯的合成具有良好的催化活性,当氯乙酸为0.10mol,异戊醇为0.14mol,催化剂的用量为反应物总重量的1.5%,带水剂环己烷的用量为7mL,反应时间1.5h,反应温度105~118℃时,酯化率可达96.5%.     

硫氢酸钠催化合成氯乙酸异丙酯

以硫酸氢钠作为催化剂合成氯乙酸异丙酯,研究了醇酸摩尔比、催化剂种类、催化剂用量、带水剂种类以及带水剂用量对合成氯乙酸异丙酯的酯化反应的影响.在醇酸摩尔比1.2/1、催化剂用量1.0%(以酸的摩尔数计量)、反应时间2.5 h、反应温度为回流温度以及10 mL环已烷作为带水剂的反应条件下,酯化率可达97.1%.     

氯乙酸乙酯的合成研究

目的以自制的复合无机盐Fe2（SO4）3.Na2S2O8为催化剂,氯乙酸和乙醇为原料合成氯乙酸乙酯.方法研究了氯乙酸与乙醇的摩尔比、催化剂用量、环己烷的用量、反应时间等因素对产品收率的影响,并用红外光谱（IR）、元素分析对产物氯乙酸乙酯进行了表征.结果与结论复合无机盐Fe2（SO4）3.Na2S2O8是合成氯乙酸乙酯的良好催化剂,适宜的反应条件如下：氯乙酸与乙醇的摩尔比为1∶2.0,催化剂用量为反应物总质量的2.5%,环己烷用量12 mL,反应时间1.5 h,氯乙酸乙酯的收率可达85.61%.     

微波辐射硫酸氢钠催化合成氯乙酸正丁酯

在微波辐射下,以硫酸氢钠为催化剂,由氯乙酸和正丁醇合成氯乙酸正丁酯, 探讨了诸因素对收率的影响.结果表明:硫酸氢钠具有良好的催化活性,当微波功率为中火, 反应时间为15min, 氯乙酸0.1mol,正丁醇0.2mol,催化剂用量为1.0g,环己烷为带水剂用量为10mL时,酯收率可达83.1%,并且催化剂可重复使用.     

2-氯苯氧乙酸的催化合成研究

利用十六烷基三甲基溴化铵催化氯乙酸和2-氯苯酚合成2-氯苯氧乙酸,十六烷基三甲基溴化铵具有较高的催化活性,可以加快合成2-氯苯氧乙酸.反应过程考察了2-氯苯酚与氯乙酸摩尔比、催化剂用量、反应时间、反应温度对产率的影响以及催化剂的重复使用性能.反应的最佳条件为:在85℃下,2-氯苯酚和氯乙酸的摩尔比为1:4,催化剂质量为...     

氯乙酸碱性水解法合成聚合用羟基乙酸单体

本实验采用了氯乙酸碱性水解法合成羟基乙酸的工艺路线,以氯乙酸和氢氧化钠为主要原料,碘化钠为催化剂进行反应。本实验采用单因素法对单个影响因素(反应温度、反应时间、催化剂的量)进行研究,得到的最优化条件是:反应温度为90℃,反应时间为8小时,催化剂用量与氯乙酸的质量比为0.8%。该反应为亲核取代反应。反应时,反应物氢氧化钠与氯乙酸钠的物质的量的比为1.1:1。用酸碱滴定法来计算羟基乙酸的产率,首先用乙醚对产物进行萃取,除去未水解的氯乙酸,然后用标定好的氢氧化钠溶液进行滴定,计算得羟基乙酸的产率可达到73.1%。     

氯乙酸异丙酯的催化合成

以氯乙酸和异丙醇为原料，氯化亚锡为催化剂，合成了氯乙酸异丙酯．探索了酸醇摩尔比、反应时间、催化剂用量等因素对酯化反应的影响，优化出最佳工艺条件并得到较高的酯收率．     

用负载磷钨酸的SBA-15分子筛催化合成氯乙酸酯

制备了负载磷钨酸的介孔分子筛SBA-15复合物PW12/SBA-15,用X射线衍射、N2吸附-程序升温脱附、红外光谱等方法进行了表征,用正丁醇、异丁醇、正戊醇、异戊醇等和氯乙酸为原料在PW12/SBA-15催化反应下合成了氯乙酸系列酯,并考查了醇酸比、催化剂用量、磷钨酸负载量、反应时间和催化剂寿命等因素对酯化率的影响。实验结果表明:SBA-15负载磷钨酸催化剂活性好,且催化活性稳定,催化剂可重复使用30次以上。适宜的反应条件为:醇与氯乙酸的摩尔比1.3∶1,催化剂的用量为反应物料总质量的2.0%,磷钨酸负载量23%(质量分数),反应时间3~5h。酯化率最高可达98%以上。     

硫酸氢钾催化合成氯乙酸乙酯

采用自制的硫酸氢钾作为催化剂,由氯乙酸与无水乙醇为原料合成氯乙酸乙酯。最佳合成工艺条件为：以0．1mol氯乙酸为基准,酸醇物质的量比为1：3．5,环己烷15m1,催化剂用量为1．0g,反应时间150min,产品收率74．6％。该法具有后处理简便,不污染环境,不腐蚀设备,催化剂可重复使用等优点。     

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.     

Design and analysis of generic LBS application developing platform

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.     

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