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．     

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.     

二羰基茂铁二聚体光反应产物的二维红外光谱

利用二维红外光谱研究了二羰基茂铁二聚体([CpFe(CO)₂]₂)在非极性溶剂CCl4中的平衡态光反应产物．时间分辨的二维红外光谱结果证实了一种可能的可见光驱动的光反应路径,其光反应产物为CpFe(CO)₂Cl,存在两个相互耦合的羰基基团,即对称和反对称羰基伸缩振动．这是主要的光产物,其光反应路径包括自由基形成以及氯加成过程．量化计算支持上述实验结果,结果表明,二维红外光谱方法可用来原位地检测凝聚相反应的化学物种的结构及其动力学     

31P NMR在阻燃剂DOPO合成中的应用

9,10-二氢-9氧杂-10-膦杂菲-10-氧化物(DOPO)的合成涉及酯化、酰基化、水解和脱水环化反应.通过核磁共振磷谱(~(31)P NMR)对各步反应得到的产物进行表征,分析各反应产物的组成,由此得出各步反应规律,并找出了影响DOPO的产率和纯度的一些关键因素.     

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.     

Effect of Potassium Addition on Coprecipitated Iron Catalysts for Fischer-Tropsch Synthesis Using Bio-oil-syngas

以生物油基合成气的模拟气H2/CO/CO2/N2(62/8/25/5，体积比)为原料，采用固定床反应器，在1.5 MPa、300 o C、W=F=12.5 gcath/mol的条件下，研究了钾助剂及钾的添加量对沉淀铁催化剂费托合成催化活性及产物选择性的影响．生物油基合成气是通过生物油催化蒸汽重整得到．研究发现，钾的添加促进了沉淀铁催化剂费-托反应及逆水气变换反应的活性．此外，钾的加入增加了碳氢产物的平均分子量(链长)．结果表明，随着钾助剂含量的增加，甲烷的选择性降低，液相碳氢产物(C5+)的选择性增加．通过多种方法，例如X射线衍射、X射线光电子能谱及比表面等对不同钾含量的费托合成催化剂进行了表征．通过费托合成实验和催化剂的表征，选出100Fe/6Cu/16Al/6K(质量比)作为生物油基合成气费-托合成最适宜的催化剂．     

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。     

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.     

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.     

O，O—二（2—乙基已基）二硫代磷酸合成过程的~（31）PNMR谱研究

报道了不同反应条件下所制得Ｏ，Ｏ—二（２—乙基己基）—二硫代磷酸的３１ＰＮＭＲ谱．研究了其合成产物组成分的变化及其反应机理．