多金属氧酸盐催化的水氧化研究进展

氢气以其清洁无污染、燃烧值高等优点成为未来最具潜力的可再生能源之一,而清洁生产氢气的最佳选择之一即为裂解水. 利用太阳能模拟光合作用实现水的全分解产生氢气和氧气是目前最为理想的能源转化方式,并且已经引起了众多研究者的关注. 水分解的半反应之一--水氧化反应由于其过程复杂,一直是制约水分解的瓶颈. 所以寻找高效、稳定的水氧化催化剂便成为了突破该瓶颈的关键. 多金属氧酸盐是一类以前过渡金属氧簇为基本单元形成的多金属氧簇化合物. 由于多金属氧酸盐在物理、化学性质方面具有无法比拟的特性,使得其在催化、药物、纳米科技和材料科学等方面已被广泛地应用. 多金属氧酸盐的全无机配体可很好地抵御水氧化反应的强氧化性环境,故将其作为水氧化催化剂越来越引起研究者们的注意,并且已有多种多金属氧酸盐被设计为水氧化催化剂. 本文详细介绍了各种不同过渡金属取代的多金属氧酸盐水氧化催化剂的研究进展.     

生物油蒸馏残渣理化性质及热失重研究

利用傅里叶变换红外光谱仪、激光共焦显微拉曼光谱仪和TGA Q500热分析仪对生物油蒸馏残渣及其在不同温度处理后的热解焦炭理化性质进行表征,并对其热失重特性进行分析。结果表明,生物油蒸馏残渣主要是由脂肪族、芳香族和低聚糖类等有机化合物组成;在氮气氛围下热解主要分为三个阶段:30-145℃为小分子物质挥发析出阶段145-550℃为大分子物质裂解和氧化阶段,550-750℃为焦炭产生阶段;热处理过程中各类物质逐步有序热解析出,同时固体产物石墨化程度随着热处理终止温度的升高而升高。     

Synthesis,Characterizations, Magnetism and Thermal Degradation of a 2‐Fold Interpenetrated 3D Cobalt‐Organic Framework

A new coordination polymer, [Co₂(L)₂(4,4′‐bipy)]_n·3nH₂O ( 1 ) based on 5‐(3‐methyl‐5‐phenyl‐4H‐1,2,4‐triazol‐4‐yl)isophthalic acid (H₂ L ) and 4,4′‐bipyridine (4,4′‐bipy) has been hydrothermally synthesized and characterized by single‐crystal X‐ray diffraction, XRPD, IR, and elemental analysis. Temperature‐dependent magnetic susceptibility and thermal degradation for 1 were also studied. The asymmetric unit of compound 1 consists of two crystallographically independent Co(II) ion, two L ^2? ligand, one 4,4′‐bipy ligand, and three lattice water molecules. The 2D triangle networks were linked by the bridging 4,4′‐bipy ligand to give rise to a 2‐fold interpenetrated 3D architecture. The simplest cyclic motif of the 2D networks is a triangle ring consisting of three Co(II) cations and three L ^2? ligands. So we can define Co(II) ions as 4‐connected nodes and the L ^2? ligands as 3‐connected nodes. Thus, the 3D structure can be described as a 2‐fold parallel interpenetrated ins InS 3,4‐conn topology.     

差示扫描量热法测定食用油脂的热氧化稳定性及氧化寿命

利用差示扫描量热法（DSC）测定了四种食用花生油的热氧化稳定性,用Ozawa法和Kissinger法计算了四种食用花生油热氧化反应的动力学参数,推算了不同温度下的氧化寿命。     

Cu[C5H3N(CCH3=N-C6H5)2]2(PF6)2配合物的合成、晶体结构和热分解反应动力学

The title complex Cu[C₅H₃N(CCH₃=N-C₆H₅)₂]₂(PF₆)₂ has been synthesized by reaction of Schiff base C₅H₃N(CCH₃=N-C₆H₅)₂ and cupric sulfate in toluene solution. The crystal structure was determined by X-ray diffraction method and the chemical formula weight of the complex is 1041.85. The crystal structure belongs to triclinic system with space group P1 and cell parameters: a=12.6470(10)?, b=14.123(2)?, c=15.613(2)?;α=66.150(10)°,β=79.470(10)°,γ=78.290(10)°, V=2481.6(5)?³, Z=2, D_c=1.394Mg·m^-3 and F(000)=1064. The final R[I >2σ(I)]:R₁=0.0668, wR₂=0.1927; R(all data): R₁=0.1133, wR₂=0.2357. The Cu(Ⅱ) was coordinated by six nitrogen, at the same time the Cu(Ⅱ) formed a distorted octahedron, besides the angles and planes of this compound were discussed . The result of kinetics of the thermal decomposition indicated that the first step of it is 2 series chemical reactions, the function of machanism is f(a)=(1-a)², and the activation energy is 144.64E/kJ. CCDC: 180872.     

Assessing contaminated hydrogen peroxide for safe storage and transportation using the FTAI

Hydrogen peroxide is a very versatile oxidizing agent, and it is also environmentally compatible considering that the products of its exothermic decomposition are oxygen and water.When kept in a clean temperature-controlled environment, the self-reaction (decomposition) rate is extremely low. However, it is well known that even a small amount of contamination will dramatically increase the reaction rate. This paper describes the use of the fast thermal activity interpreter (FTAI) instrument to examine the chemical reactivity of commercially available 50% hydrogen peroxide at two different temperatures (30 and 40°C) both with and without contamination. The results show that at 30°C a small amount of rust (330 ppm) increases the reaction rate of 50% hydrogen peroxide by a factor of 50. When the temperature is increased to 40°C, the reaction rate is further increased by almost a factor of four. The implication for reactivity management is that at this contamination level most practical vessel sizes would require emergency venting capability. An evaluation was then performed to determine the emergency venting requirement for the safe transportation or storage of the contaminated hydrogen peroxide. It was determined that for quantities of the material less than 5 gallons, conventional breather vents would be sufficient to accommodate the gas evolved. However, for larger quantities, a safety relief device would be needed. For example, for a 400-gallon tote bin at 40°C the required minimum vent area is estimated to be 4.3 in², corresponding to a minimum vent diameter of 2.3 inches.     

Influence of the thermal degradation on the dielectric properties of a thermoset

The thermal degradation of an epoxy system consisting of a diglycidyl ether of bisphenol A (DGEBA, n=0) and m-xylylenediamine (m-XDA) was studied by both thermogravimetric analysis (TG) and dielectric analysis (DEA). It has been checked a deviation of the typical behaviour in the Arrhenius plot expected for this kind of systems, owing to the thermal degradation. Both, structural relaxation time and conductivity values, were represented as a function of the mass loss, that allow a relationship to be obtained between characteristic relaxation time and the degree of degradation at the beginning of the degradation process.     

三苯基锡9-蒽甲酸酯的合成、表征、荧光、热稳定性及量子化学研究

在甲醇中三苯基氢氧化锡与9-蒽甲酸反应,合成了有机锡配合物[Ph₃Sn(O₂CC₁₄H₉)(MeOH)]₂·MeOH,经IR、¹H和¹³C-NMR、元素分析及X-射线单晶衍射表征结构。晶体结构分析表明:配合物中心锡原子为五配位畸变三角双锥构型。晶体中,配合物分子的羰基氧与近邻的甲醇氧、两相邻的甲醇氧间分别形成O-H…O氢键,组成一维S形链;经链内蒽环H与另一蒽环的C-H…π作用,进一步连接成梯状结构。两相邻梯状链间,通过配位甲醇的甲基H与另链苯环发生C-H…π作用扩展成二维网状。室温下,配合物在460nm处有较强的荧光发射(λ_ex=360nm)。热重分析表明,配合物在240℃以下能稳定存在。利用量子化学G03W软件,在LANL₂DZ基组对配合物的稳定性、前沿分子轨道组成及能量进行研究。     

两个基于4-羧酸-2,2':6',2"-三联吡啶的铜配合物的合成、晶体结构及性质

水热法合成了2个配合物{[Cu₂(L)₂(tp)]·2H₂O}_n(1)和[CuL(ClO₄)]_n(2)(L=4-羧酸-2,2':6',2"-三联吡啶,H₂tp=对苯二甲酸)。对其晶体结构进行了分析,结果表明配合物1和2都通过配体和金属离子组装成一维链结构;配合物1属于三斜晶系,P1空间群,并通过链间的氢键作用形成三维的网状结构;配合物2通过链与链间的氢键作用形成二维的层状结构。对其热稳定性和荧光性质进行了研究。     

Preparation and characterization of novel polyimide‐silica hybrids

Polyimide‐silica (PI‐SiO₂) hybrids were prepared from a novel polyimide (PI), derived from pyromellitic dianhydride (PMDA), 1,6‐bis(4‐aminophenoxy)hexane (synthesized) and 4,4′‐oxydianiline. SiO₂ networks (5–30 wt%) were generated through sol–gel process using either tetraethylorthosilicate (TEOS) or a mixture of 3‐aminopropyltriethoxysilane‐PMDA‐based coupling oligomers (APA) and TEOS. Thin, free standing hybrid films were obtained from the respective mixtures by casting and curing processes. The hybrid films were characterized using Fourier transform infrared, ²⁹Si nuclear magnetic resonance (NMR), field emission scanning electron microscopy (FE‐SEM), energy dispersive X‐ray spectrometry and atomic force microscopy (AFM) techniques. ²⁹Si NMR results provide information about formation of organically modified silicate structures that were further substantiated by FE‐SEM and AFM micrographs. Contact angle measurements and thermogravimetric thermograms reveal that the addition of APA profoundly influences surface energy, interfacial tension, thermal stability and the residual char yield of modified hybrids in comparison to those obtained by mixing only TEOS. It was found that reduced particle size, efficient dispersion and improved interphase interactions were responsible for the eventual property enhancement. Copyright © 2012 John Wiley & Sons, Ltd.