硫化MoO3／Al2O3甲烷化催化剂上不同吸附物种的作用

运用加压动态分析装置研究了硫化MoO_3/A1_2O_3,甲烷化催化剂上CO和H_2的吸附及反应。结果表明,在给定反应条件下催化剂上吸附的CO和H_2可分为可逆与不可逆两类,且对甲烷化反应有着不同的贡献。甲烷的生成是可逆吸附氢和不可逆吸附CO共同作用的结果。不可逆吸附氢与CO不生成甲烷,可逆吸附的CO加氢则与副产物乙烷等的生成密切相关。结合前人的动力学考察结果,解释了Mo系甲烷化催化剂与Ni系甲烷化催化剂要求不同反应压力的实质性原因。     

Selective Metallation of 3-Halothiophenes: Practical Methods for the Synthesis of 2-Bromo-3-formylthiophene

Selective lithiation of 3-bromothiophene was accomplished under controlled conditions without formation of undesired thienyllithium compounds. A thienyl Grignard reagent derived from 2-bromo-3-iodothiophene was transformed into 2-bromo-3-formylthiophene in high selectivity by formylation with dimethylformamide (DMF) at optimal reaction temperature.     

Synthesis of 3-substituted 3H-indol-3-ols by the reaction of 2-isocyanophenyl ketones with Grignard reagents

A facile method for the synthesis of 3-substituted 3H-indol-3-ols has been developed. Thus, 2-isocyanophenyl ketones are allowed to react with various Grignard reagents to give the corresponding desired indolol derivatives in generally fair to good yields. The formation of 3-aryl-2,3-dimethylindolin-3-ols by the reaction of 2-isocyanobenzophenones with 2 M amounts of methylmagnesium bromide is also reported.     

Synthesis of 4,5‐Dihydrofuran‐3‐carbonitrile Derivatives with Electron‐Rich Alkenes in the Presence of Manganese(III) Acetate

Radical cyclization reactions mediated by manganese(III) acetate were carried out with ν‐excessive alkenes ( 2a‐d ) and 3‐oxopropanenitriles ( 1a‐f ) resulting in the formation of 3‐cyano‐4,5‐dihydrofuran derivatives in poor to high yields. A mechanism was proposed for the cyclization reaction. The significance of the study is the formation of the 3‐cyano‐4,5‐dihydrofuran derivatives resembling terfuran, 2‐(2‐thienyl)furan and 2‐(2‐benzofuryl)furyl compounds having the fluorescent properties due to a conjugated ν‐electron system particularly containing the cyano moeity.     

激光烧蚀La~2O~3产生的等离子体的发光光谱研究

用发光光谱法研究了355nm脉冲激光在真空和O~2气氛中烧蚀La~2O~3产生的等离子体的组成和形成过程。对等离子体中La^+离子和LaO的空间和时间分辨发光光谱分析表明,在O~2气氛中LaO有两个生成通道:一是在靶附近的等离子体内直接生成的,另一是由La,La^+与O^2发生氧化反应而生成的。测定了激光能量密度,离靶表面的距离和O~2压力对产物发光的延迟时间和发光强度的影响。此外,还讨论了激光烧蚀La~2O~3诱导产生等离子体的形成和演化机理。     

Hydration of C3a in the presence of CaCO3

The hydration of C₃A with and without CaCO₃ was studied. The techniques used were X-ray diffraction, thermogravimetry, differential thermogravimetry and calorimetry.In the presence of CaCO₃, the hydration of C₃A is accelerated. The hexagonal hydrates are formed first. They react with CaCO₃ to form calcium carboaluminate hydrate. This reaction blocks formation of the cubic hydrate. The latter appears when CaCO₃ is completely consumed.     

3‐Formylpyrroles from 3‐Furfurylamines by Bromine Oxidation Reaction

Oxidation of 3‐furfurylamines 3a‐e with bromine in acetone‐water solution gave N‐substituted 3‐formylpyrroles 4a‐e in good yields. A reaction mechanism via the Clauson‐Kaas reaction followed by the cis‐trans isomerization of the 2‐ene‐1,4‐diones 13 and 14 was proposed to account for the formation of the pyrroles 4a‐e .     

An Efficient Synthesis of Some New Isolated and Fused Triazole Derivatives

A facile and efficient route to 5‐hydrazinyl‐3‐phenyl‐3H‐[1,2,4]triazole 2 from the reaction of triazol‐3‐one 1 and hydrazine hydrate is described. In addition, the formation of isolated and fused triazole derivatives was prepared via reaction of 2 with some selected electrophilic reagents in basic medium.     

负载型钙钛矿La0.8Sr0.2MnO3/SBA-15催化燃烧甲苯的研究

采用逐层负载-孔道内氨/水蒸气原位羟化法制备了一系列负载型钙钛矿La_0.8Sr_0.2MnO₃/SBA-15催化剂,用XRD、BET、TG-DTG、XPS、H₂-TPR等手段对催化剂的物性结构等进行了表征,并在常压连续流动固定床反应器上评价了该催化剂对甲苯催化燃烧的催化性能。结果表明,逐层负载-孔道内氨/水蒸气原位羟化法的使用有助于活性组分La_0.8Sr_0.2MnO₃进入SBA-15的孔道,并在SBA-15上形成钙钛矿结构。La_0.8Sr_0.2MnO₃/SBA-15上钙钛矿结构的形成和晶格氧的出现,可为催化剂提供较多的活性中心,有利于其催化燃烧甲苯的活性。     

Synthesis of Arylidene Derivatives of 1-Aryl-3H-pyrrol-2-ones

The aminolysis of 5-aryl-3-arylidene-3H-furan-2-ones by the action of aromatic amines leads to the formation of substituted amides of 4-oxo acids, the subsequent azacyclization of which in the presence of acetic anhydride leads to the formation of 1,5-diaryl-substituted 3-arylidene-3H-pyrrol-2-ones. The mechanism of the occurring and alternative transformations is discussed.     

Pd-catalyzed synthesis of 3-(diarylmethylene)-2-oxindoles and 3-(arylmethylene)-2-oxindoles

An efficient method for the stereoselective synthesis of 3-(diarylmethylene)-2-oxindoles and 3-(arylmethylene)-2-oxindoles via carbopalladation is described. In this approach, an Ugi-4-component reaction (4-CR) adduct was used as the starting material. A one-pot sequence involving intermolecular carbopalladation C-H activation/C-C bond formation efficiently afforded the oxindole derivatives.     

Pu3M和PuM3 (M=Ga,In, Sn,Ge)化合物的电子结构和形成热

采用全势线性缀加平面波(FPLAPW)方法, 在广义梯度近似(GGA)+自旋轨道耦合(SOC)+自旋极化(SP)下计算了具有AuCu3构型的Pu3M和PuM3 (M=Ga, In, Sn, Ge)化合物的平衡结构、电子结构和形成热. 计算的晶格常数与实验值符合得很好; 态密度分析表明Pu 和M 原子轨道间的杂化作用决定于Pu 6d-Pu 5f、Mp-Pu 6d和Msp-M sp轨道杂化之间的竞争, 而这种竞争又依赖于M的含量; 电负性差和电子杂化效应是影响Pu3M和PuM3化合物形成热和稳定性的两个重要因素, 电负性差越大, M的s、p带中心距费米能级越远, Pu3M(PuM3)化合物的形成热越负, 稳定性越高.     

Numerical Investigation on 1,3-Butadiene/Propyne Co-pyrolysis and Insight into Synergistic Effect on Aromatic Hydrocarbon Formation

A numerical investigation on the co-pyrolysis of 1,3-butadiene and propyne is performed to explore the synergistic effect between fuel components on aromatic hydrocarbon formation.A detailed kinetic model of 1,3-butadiene/propyne co-pyrolysis with the sub-mechanism of aromatic hydrocarbon formation is developed and validated on previous 1,3-butadiene and propyne pyrolysis experiments.The model is able to reproduce both the single component pyrolysis and the co-pyrolysis experiments,as well as the synergistic effect between 1,3-butadiene and propyne on the formation of a series of aromatic hydrocarbons.Based on the rate of production and sensitivity analyses,key reaction pathways in the fuel decomposition and aromatic hydrocarbon formation processes are revealed and insight into the synergistic effect on aromatic hydrocarbon formation is also achieved.The synergistic effect results from the interaction between 1,3-butadiene and propyne.The easily happened chain initiation in the 1,3-butadiene decomposition provides an abundant radical pool for propyne to undergo the H-atom abstraction and produce propargyl radical which plays key roles in the formation of aromatic hydrocarbons.Besides,the 1,3-butadiene/propyne co-pyrolysis includes high concentration levels of C3 and C4 precursors simultaneously,which stimulates the formation of key aromatic hydrocarbons such as toluene and naphthalene.     

Novel 5,6-bis-(4-substitutedphenyl)-2H(3)-pyridazinones: Synthesis and reactions

A series of 5,6-bis(4-substitutedphenyl)-2H(3)-pyridazinones 2a–f have been synthesized from the condensation of the corresponding benzil monohydrazones 1 either with ethyl cyanoacetate or diethyl malonate in ethanol. The synthesized pyridazinones were converted to the corresponding 3-chloro derivatives 3a–f by the action of phosphoryl chloride. Reaction of the latter halogenated pyridazines with various aromatic amines led to the formation of new 3-aminoaryl pyridazines (4) in moderate yield. The structures of all new compounds 2b,c,e,f, 3b–e, 4 were fully identified by the analysis of their ¹H and ¹³C NMR and mass spectra. Some of these synthetic heterocyclic compounds were screened for their antimicrobial activities but they were almost negative.     

3-Halotetrahydropyran-4-one Derivatives from Homopropargyl Acetal

A gold(I)-catalyzed regioselective method for the preparation of 3-bromo/iodo-tetrahydropyran-4-one derivatives from homopropargyl acetal is reported. A one-pot procedure based on a gold(I)-catalyzed Petasis–Ferrier rearrangement/cyclization and subsequent electrophilic halogenation was developed. Corresponding hemiacetals were not suitable substrates for the formation of the 3-halo-pyran derivatives. The present transformation is a useful method to readily afford highly substituted 3-halo-tetrahydropyran-4-ones, which are suitable substrates in a variety of reactions in further synthesis.     

Controlled Growth of CH3NH3PbBr3 Perovskite Nanocrystals via a Water–Oil Interfacial Synthesis Method

Fundamental insights into the reaction kinetics of organic–inorganic lead halide perovskite nanocrystals (LHP NCs) are still limited due to their ultrafast formation rate. Herein, we develop a water–oil interfacial synthesis of MAPbBr₃ NCs (MA=CH₃NH₃⁺), which prolongs the reaction time to tens of minutes. This method makes it possible to monitor in situ the formation process of MAPbBr₃ NCs and observe successive spectral evolutions from 438 to 534 nm in a single reaction by extending reaction time. The implementation of this method depends on reducing the formation rate of PbBr₆^4? octahedra and the diffusion rate of MA. The formation of PbBr₆^4? is a rate‐determining step, and the biphasic system offers a favorable reaction condition to control the mass transfer of MA. The effects of temperature and concentration of precursor and ligand are investigated in detail.     

Synthesis and Molecular Structure of 1,5-Diphenyl-3-phenacylthio-1H-1,2,4-triazole

1 INTRODUCTION 1,2,4-Triazole and its derivatives are very useful compounds due to their broad spectrum of pharmacological activities, such as antitumor[1], antiviral[2 ～ 4], antibacterial[5] and antifungal[6] activities. Moreover, they can be used as ver- satile ligands for transition metals. Particularly, they exhibit a strong and typical property of act- ing as bridging ligands between two metal cen- ters[7, 8]. 3-Substituted thio-1H-1,2,4-triazole is the important 1,2,4-triazole deri…     

一种不含胶凝剂的凝胶电解质在准固态染料敏化太阳能电池中的应用

报道了一种不含胶凝剂的凝胶电解质的制备及在准固态染料敏化太阳能电池中的应用.这种新型凝胶电解质仅含有机溶剂和碘盐,即3-甲氧基丙腈、苯胺、三碘化铝和碘.上述混合物通过路易斯酸性三碘化铝离子导体和路易斯碱性苯胺有机溶剂间的路易斯酸-碱相互作用形成凝胶,无需额外添加传统凝胶电解质的关键组分—胶凝剂.形成的三碘化铝-苯胺复合物在凝胶电解质中能同时发挥离子导体和胶凝剂的作用.红外光谱图中苯胺的氨基和苯环特征峰的变化证实了三碘化铝-苯胺复合物的形成.含这种新型凝胶电解质的准固态染料敏化太阳能电池光电性能和稳定性与含三碘化铝-3-甲氧基丙腈液体电解质的染料敏化太阳能电池相比有很大提高.     

NH3和SO3对硫酸氢铵和硫酸铵生成的影响

通过建立具有更精确的SO₃组分的实验室模拟烟气系统,同步研究了反应物浓度对硫酸氢铵和硫酸铵生成率和生成进度（生成速率）的影响。在实验浓度范围内,硫酸氢铵的开始生成温度为230-270℃,峰值温度为180-240℃,硫酸铵开始生成温度及峰值温度总体上比硫酸氢铵低40℃左右。硫酸氢铵的生成率明显高于硫酸铵,根据NH₃和SO₃浓度与物质的量比不同,烟温到120℃时,硫酸氢铵的生成率为64%-90%,硫酸铵的生成率为6%-15%,硫酸氢铵的生成率为硫酸铵的6-10倍。反应物浓度的增加会促进硫酸氢铵和硫酸铵的生成,且SO₃较NH₃更有利于硫酸氢铵的生成。硫酸氢铵和硫酸铵生成份额随温度的变化呈单峰状,且随着反应物浓度的增加,其峰值所在的温度区间逐渐升高。     

The Baylis-Hillman chemistry in aqueous media: elucidation of mechanism for synthesis of ether side-product leads to an efficient approach to C-O bond formation

The formation of an ether from the Baylis-Hillman (BH) adduct during the BH reaction of 5-isoxazolecarboxaldehydes is a common phenomenon if the reaction is allowed to proceed for longer periods. The amount of formation of such ethers depends on the acrylates used and is most significant for tert-butyl acrylates. A study of the plausible mechanism for the formation of these side-products led to reactions of acetates of BH adducts with phenol in aqueous media to yield the corresponding 3-phenoxy alk-2-enoates in good yields. The successful translation of solution phase methodology to solid phase for application towards combinatorial chemistry is discussed.