二苯并-18-冠-6的合成及其光谱性质

通过改变溶剂的极性、离子性、离去基团的活性及反应温度等方法,对传统的Pedersen冠醚合成法进行了优化,使目标产物的最高产率可达71%以上,速率增加,而且反应条件温和.产物通过IR、1H NMR及元素分析等方法进行结构表征.同时对目标产物的荧光及紫外可见光谱性质也进行了初步的研究,结果表明:目标产物不仅具有较好的光谱性质,而且一些金属离子能使其荧光强度发生改变.因此我们期望目标化合物能够用于一些离子的检测、生物分子的分析.     

石墨烯固体酸催化转化葡萄糖为化学品

利用氢化钠和丙磺酸内酯合成出了磺化石墨烯催化剂,采用XPS、FT-IR、TEM等方法对其进行了表征,并且对此催化剂催化葡萄糖的转化反应进行了研究．探究此催化剂在纯水中、没有添加任何有机溶剂下催化转化葡萄糖制备高附加值化学品方面的催化活性,在最优的反应条件下, 5-羟甲基糠醛(HMF)最高产率可达28.8%,产物甲酸、乳酸和HMF的总产率可达51.94%．经过5次催化反应,催化剂仍表现出相对高的催化活性,三种产物的产率依然较高,表明此种固体酸催化剂有很好的热稳定性．     

费托合成工艺热力学性质的计算化学研究

本文采用高精度的G4方法,全面计算了不同反应条件下费托合成工艺中可能的1287个产物的热力学数据,然后用这些数据得到的热力学量用于分析实际化工生产的热力学和分析费托合成的产物分布.结果表明:降温、加压和增大氢碳比(H_2/CO)时,热力学上可能生成的产物数目增多.在低温、高压和高碳氢比下,很多产物都在热力学上可以生成,其中产物的选择性主要由动力学因素控制.另一方面,升温或者降压可以提高小分子产物的选择性.值得注意的是在降温、加压和增大碳氢比到一定条件时,产物的平衡产率会达到最大值并且不随条件改变而变化,这说明优化条件改变产率是有一定限度的.热力学分析同样对设计和评价费托合成的反应机理有重大意义,其中甲醛的平衡产率很低,可以排除含有甲醛的反应路径.近期有一些采用金属氧化物-分子筛双功能催化剂高选择性获得C_(2-4)烯烃和芳烃的报道,其中有很多可能进入分子筛孔道的中间体,分析结果显示乙烯酮、甲醇和二甲醚是可能的中间体.     

铂催化3-炔-1-醇分子内加氢烷氧基化反应的理论研究

用密度泛函理论(DFT) M06-2X方法对铂催化的3-炔-1-醇分子内加氢烷氧基化反应机理和区域选择性进行了计算研究.计算结果表明:(1)通过羟基氧原子分别进攻分子内不同的炔烃碳原子形成两种竞争机制;(2)反应的关键步骤是分子内成环过程和氢迁移得到目标产物并释放催化剂的过程;(3)对于5-外切形成五元环产物的反应路径,具有相对较低的活化自由能;(4)两个竞争通道有一定的能量差,表明反应具有选择性但也会有副产物.计算研究结果与实验合成一致,并对实验报道给予了很好的补充和解释.     

费托合成工艺热力学性质的计算化学研究（英文）

本文采用高精度的G4方法,全面计算了不同反应条件下费托合成工艺中可能的1287个产物的热力学数据,然后用这些数据得到的热力学量用于分析实际化工生产的热力学和分析费托合成的产物分布.结果表明:降温、加压和增大氢碳比(H_2/CO)时,热力学上可能生成的产物数目增多.在低温、高压和高碳氢比下,很多产物都在热力学上可以生成,其中产物的选择性主要由动力学因素控制.另一方面,升温或者降压可以提高小分子产物的选择性.值得注意的是在降温、加压和增大碳氢比到一定条件时,产物的平衡产率会达到最大值并且不随条件改变而变化,这说明优化条件改变产率是有一定限度的.热力学分析同样对设计和评价费托合成的反应机理有重大意义,其中甲醛的平衡产率很低,可以排除含有甲醛的反应路径.近期有一些采用金属氧化物-分子筛双功能催化剂高选择性获得C_(2-4)烯烃和芳烃的报道,其中有很多可能进入分子筛孔道的中间体,分析结果显示乙烯酮、甲醇和二甲醚是可能的中间体.     

溶剂热法制备Cd(OH)_2和CdO纳米盘研究性实验

利用溶剂热法设计了合成Cd(OH)2和CdO纳米盘的研究性实验.以Cd(CH3COO)2等为镉源,与NaOH在水和乙二醇的混合溶剂中反应得到Cd(OH)2纳米盘(中间镉产物),后在高温下煅烧中间产物分解得到CdO纳米盘.该实验有助于理解溶剂热法中各实验参量的作用以及如何通过调节各实验参量最终得到目标产物.     

N,N′-二芳基乙二胺的一锅法绿色合成

以芳胺、乙二醛和硼氢化钠为原料,一锅法合成了3种N,N′-二芳基乙二胺,以高于80%的产率得到相应产物,结构均通过核磁氢谱和碳谱表征。与分步法相比,该方法具有操作简单、反应产率高、对环境友好无污染等优点,是一种绿色高效的合成方法。     

光诱导液相中BPEB的[2+2]环加成反应

环加成反应是在光或热的条件下,两个或多个不饱和分子通过双键相互加成生成环状化合物的反应。本研究以1,4-二[2-(4-吡啶)乙烯基]苯(BPEB)为前驱体,通过二甲基亚砜(DMSO)液相光诱导反应获得了BPEP二聚体。与在晶体固相中制备方法相比,该方法不需要模版剂或培养特定结构的晶体、能耗少、操作简单。同其他液相中2+2环加成反应相比,该方法不需要使用催化剂。该研究通过核磁以及红外光谱对环加成产物进行表征,此方法获得的目标产物特异性好及产率高等特点。     

[Bmim]Br3与β-二羰基化合物的选择性溴化反应研究

研究离子液体三溴化1-丁基-3-甲基咪唑[Bmim]Br3对乙酰丙酮、乙酰乙酸乙酯、丙二酸二乙酯等羰基化合物的α-溴化反应。在无催化剂、溶剂条件下,[Bmim]Br3对以上几种羰基化合物溴化,高产率、高选择性地得到α-溴化产物,产率为93%—96%。实验结果表明,在离子液体[Bmim]Br3存在下,溴化反应不仅速度较快、温度缓和、操作简便,而且产物的产率高、易分离、对环境更友好。本方法提供了一个区域选择性好、简单、方便合成α-溴化β-二羰基化合物的方法。     

系列甲基苯基卟啉-5-氟尿嘧啶化合物的合成与表征

设计合成了6种甲基苯基卟啉-5-氟尿嘧啶化合物。通过红外光谱、紫外-可见光谱、核磁共振谱和质谱对所合成的化合物结构进行了确认。探索出了合成反应的最佳条件和目标化合物的分离纯化方法。实验结果表明,选择DMF为溶剂,反应温度在115℃,反应时间2h,产率较高,A1、A2,B1、B2、C1和C2分别为25.66%、25.02%,24.89%、26.17%、28.43%和24.19%;采用硅胶G(粒径为48—75μm)柱层析,分离效果较好。     

Fabrication of nanoporous AuPt nanoparticles modified indium tin oxide electrode and their electrocatalytic effect

This paper describes the synthesis of nanoporous AuPt nanoparticles (np-AuPt NPs) by galvanic replacement reactions that involve large-sized silver nanoparticles (Ag NPs) electrodeposited upon an indium tin oxide (ITO) film glass as a sacrificial template. Compared to a previous synthetic route based on the formation and dealloying of Ag/Au alloy nanoparticles, this method can easily fabricate nanoporous Au nanoparticles (np-Au NPs), as well as nanoporous AuPt nanoparticles. Structural characterization indicated that the products had a particle size of ～170 nm with a ligament size of tens of nanometers. The fabricated np-Au NPs/ITO and np-AuPt NPs/ITO electrode were also tested and compared for the oxidation of hydrogen peroxide in a phosphate buffer solution (pH 7.0). The np-AuPt NPs/ITO electrode showed a much higher electrocatalytic efficiency and detection sensitivity to hydrogen peroxide than the np-Au NPs/ITO electrode.     

三氧化硫低温磺化法合成聚苯乙烯磺酸新工艺

利用三氧化硫在低温条件下与聚苯乙烯合成聚苯乙烯磺酸,反应速度快,副反应少,后处理简单,是一种绿色合成新工艺.实验结果发现,最佳的反应条件为:常压下-20℃时,以氯仿为溶剂,三氧化硫与聚苯乙烯按0.8∶1的质量比混匀,低速搅拌反应时间30min,老化30 min.溶剂与产物分离后,测定纯净产品的磺化度为92.45%.通过...     

New, fast and green procedure for the synthesis of gold nanoparticles based on sonocatalysis

An easy, cheap and green synthetic route, using high-power ultrasounds and sodium citrate dihydrate as non-toxic reducing and stabilizer agent, produces gold nanoparticles in aqueous solution, and at ambient conditions. The time required for the synthesis is 5.5 min. The spherical nanoparticles obtained by this route show a homogeneous size distribution, within the range 5-17 nm, with an average diameter of 10±1 nm. Moreover, 90% of the particles have a diameter ranging from 7 to 13 nm, and their half-life is more than 30 days. The gold nanoparticles synthesized following this route are known as sononanoparticles. Gold sononanoparticles have been characterized by TEM and XRD and their stability has been studied by UV-Vis spectroscopy. Alternative experimental designs are compared to optimize the proposed synthesis procedure.     

A reaction route network for hydrogen combustion

The 20 elementary reactions comprising the mechanism of hydrogen oxidation in the gas phase have been assembled into a so-called a reaction route (RR) network, i.e., a road map showing explicitly how a stoichiometric mixture of reactants (2H₂+O₂) is transformed into products (2H₂O) via various sequences of elementary reactions such that the intermediate species are canceled resulting in the overall reaction (OR). The RR network is thermodynamically and kinetically balanced in that the nodes satisfy the quasi-steady state mass balance conditions while the affinities of the reactions in any cycle add up to zero. The network also possesses two unusual topological features that have not been observed so far. First, the nodes and cycles in the RR network may be balanced only assuming that the network is infinite. Second, for every “entry” in the network, there exists two and only two “exits”.     

Oxygen nonstoichiometry of nanosized ceria powder

Oxygen nonstoichiometry of nanocrystalline ceria powder with a particle size of about 12 nm was measured by thermogravimetric techniques as a function of temperature, oxygen partial pressure and synthetic route. The measured oxygen release/uptake from the samples under isothermal or isobaric conditions applied in this study are found to be predominantly due to variations in the surface nonstoichiometry. Its oxygen partial pressure dependence indicates the presence of surface oxygen vacancies in different ionization states in addition to segregated impurities.     

Micro‐Raman investigations of early stage silver corrosion products occurring in sulfur containing atmospheres

Silver is a soft, lustrous metal with the highest electrical and thermal conductivity. Due to these properties, it has many applications as a precious material both in pure and alloy form (ornaments, jewellery, utensils, coins), but also in several technological fields, considering silver compounds (e.g. photography, electric and electronic industry). As a consequence of this, silver and its by‐products are regularly exposed to different atmospheres where a wide spectrum of agents (e.g. moisture, temperature, air pollutants, UV light) may cause metal corrosion and alteration of their surface characteristics and properties. The aim of this research is to deepen the potential and applicability of micro‐Raman spectroscopy as a surface‐sensitive technique to investigate the initial steps of atmospheric corrosion throughout the identification of surface chemical reactions and corrosion products formed on silver substrates. In a previous study, micro‐Raman analysis was carried out on pure silver powder compounds, selected among the most expected corrosion products occurring on silver substrates, in order to optimize experimental conditions and to obtain reference spectra ^[1]. Subsequently highly pure silver samples were exposed for 24 h to different controlled laboratory atmospheres (synthetic air, relative humidity, SO₂, H₂S), particularly focusing on sulfur containing gases, and the resulting surface reactions. The experiments highlight micro‐Raman spectroscopy as a highly surface‐sensitive technique enabling to detect both adsorbed chemical species and crystalline corrosion products of only several monolayers of thickness. Furthermore, these investigations could show the trends of primary and secondary corrosion mechanisms and their mutual interaction occurring on silver substrates. Copyright © 2013 John Wiley & Sons, Ltd.     

Synthesis of $$\upalpha $$-amino-1,3-dicarbonyl compounds via Ugi flow chemistry reaction: access to functionalized 1,2,3-triazoles

The Ugi multicomponent reaction has been used as an important synthetic route to obtain compounds with potential biological activity. We present the rapid and efficient synthesis of \(\upalpha \)-amino-1,3-dicarbonyl compounds in moderate to good yields via Ugi flow chemistry reactions performed with a continuous flow reactor. Such \(\upalpha \)-amino-1,3-dicarbonyl compounds can act as precursors for the production of \(\upalpha \)-amino acids via hydrolysis of the ethyl ester group as well as building blocks for the synthesis of novel compounds with the 1,2,3-triazole ring. The \(\upalpha \)-amino acid derivatives of the Ugi flow chemistry reaction products were then used for dipeptide synthesis.     

基于ReaxFF模拟的正戊烷热分解机理研究

采用密度泛函理论和ReaxFF力场对正戊烷的热分解机理进行研究,分析了热分解的起始反应路径、温度对热分解的影响,并对正戊烷热分解进行了一级动力学研究。结果表明正戊烷热分解的起始反应主要分为两类:一类为碳碳单键断裂,另一类为碳氢键断裂,其中C2-C3键断裂是主要的起始反应路径。正戊烷热分解的主要产物为氢气、甲烷、乙烷、乙烯、乙炔、丙烷和丙烯。经过一级动力学计算得到表观活化能和指前因子分别为224.4 kJ·mol^-1和3.1324×10^14 s^-1。     

油酰柠檬酸三乙酯的合成及红外光谱研究

以柠檬酸和乙醇为原料,在磷酸和苯磺酸混合催化剂作用下,加热回流,酯化生成柠檬酸三乙酯。以油酸与氯化亚砜为原料,通过酰化反应合成油酰氯。再使柠檬酸三乙酯与油酰氯在吡啶作用下,通过酰基化反应合成油酰柠檬酸三乙酯。采用红外光谱法对原料、中间体、产物进行了红外光谱测试,并进行了红外谱图的分析与比较,证明了各步产品为目的产物。根据原料、中间体、产物红外谱图中相应特征吸收峰的消失或是出现,证明了所选择的合成工艺路线是可行的。     

Ring opening of epoxides with <Emphasis Type="Italic">C</Emphasis>-nucleophiles

Ring opening of epoxides has been an area of interest for organic chemists, owing to their reactivity toward nucleophiles. Such reactions yield important products depending on the type of nucleophiles used. This review article covers the synthetic approaches (1991–2015) used for the ring opening of epoxides via carbon nucleophiles.