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411.
廉价易得且对环境友好无毒的氯化铵作为Lewis酸催化剂,表现出较高的催化活性,已经成为有机合成中的一个重要方法,近年来一直是有机化学和催化化学的研究热点之一。本文按照反应类型的不同对近年来氯化铵催化的有机反应研究进展进行了综述。 相似文献
412.
THF-FER沸石的系列研究IV.固体酸性及C5烯烃骨架异构化催化性能 总被引:2,自引:0,他引:2
在四氢呋喃(THF)-Na2O-SiO2-Al2O3-H2O体系中水热合成的THF-FER沸石,经酸交换/焙烧或焙烧/酸交换处理可制得H-FER-1和H-FER-2两种H型沸石.红外光谱及NH3-TPD等实验结果表明,两者的强酸位主要是对烯烃骨架异构化反应有贡献的Bronsted酸位.1073K/10h的高温水蒸汽处理会导致沸石骨架脱铝,但并未产生过多的末端硅羟基.两者比较,H-FER-1沸石的结构缺陷较少,Bronsted酸位较多,骨架更完美.由THF-FER沸石制备的H-FER催化剂,对C5正构烯烃骨架异构化反应显示了优良的催化活性、选择性及稳定性. 相似文献
413.
Jie Yin Xuejing Liu Lin Fan Jiazhen Wei Guohang He Shaozhen Shi Junxue Guo Cang Yuan Ning Chai Can Wang Jiawen Cui Xiaojun Wang Huawei Zhou Dongxu Tian 《应用有机金属化学》2019,33(4)
Lead‐free and organic–inorganic hybrid (CH3NH3)2CoCl4 [(MA)2CoCl4] single crystal and thin film are prepared. The single crystal diffraction data of (MA)2CoCl4 are assigned to monoclinic, P2(1)/C space group (7.6590 × 12.6908 × 10.89350 Å, 90.0 × 96.5320 × 90.000). The absorption edge of (MA)2CoCl4 reaches 730 nm. The band gap for (MA)2CoCl4 is determined to be approximately 1.63 eV. To the best of our knowledge, this is the first study on (MA)2CoCl4 for optoelectronic applications. A low‐cost photodetector based on (MA)2CoCl4 thin film is efficient under different monochromatic light from 330 nm to 400 nm with different chopping frequencies (1.33–60 Hz). The strongest photoresponse (Ion ? Ioff) is under 330 nm monochromatic light with 1.33 Hz according to our optimal condition. The calculational results by density functional theory show that the narrow valence bands and conduction bands are derived from the 3p orbitals of Cl and 3d orbitals of Co. 相似文献
414.
Mingliang Ma Yuying Yang Dili Liao Ping Lyu Jinwei Zhang Jianli Liang Lizhi Zhang 《应用有机金属化学》2019,33(2)
A strategy has been developed for the synthesis, characterization and catalysis of magnetic Fe3O4/P(GMA‐EGDMA)‐NH2/HPG‐COOH‐Pd core‐shell structure supported catalyst. The P(GMA‐EGDMA) polymer layer was coated on the surface of hollow magnetic Fe3O4 microspheres through the effect of KH570. The core‐shell magnetic Fe3O4/P(GMA‐EGDMA) modified by ‐NH2 could be grafted with HPG. Then, the hyperbranched glycidyl (HPG) with terminal ‐OH were modified by ‐COOH and adsorbed Pd nanoparticles. The hyperbranched polymer layer not only protected the Fe3O4 magnetic core from acid–base substrate corrosion, but also provided a number of functional groups as binding sites for Pd nanoparticles. The prepared catalyst was characterized by UV–vis, TEM, SEM, FTIR, TGA, ICP‐OES, BET, XRD, DLS and VSM. The catalytic tests showed that the magnetic Fe3O4/P(GMA‐EGDMA)‐NH2/HPG‐COOH‐Pd catalyst had excellent catalytic performance and retained 86% catalytic efficiency after 8 consecutive cycles. 相似文献
415.
基于水平管式反应器气化条件,结合化学吸收-分光光度法和X射线光电子能谱(XPS)分析,研究了四种富氮生物质(豆秆(SBS)、稻秆(RS)、玉米秆(CS)和中密度纤维板(MDF))气化过程NOx前驱物生成特性及规律,对比考察了燃料特性(燃料N官能团、N含量)及气化条件(温度、气化介质)的影响。结果表明,NH3-N为主要NOx前驱物并伴随一定量的HCN-N,绝大部分形成于初次裂解和二次反应同时进行的挥发分析出阶段。各因素通过影响NOx前驱物组分生成路径而改变其产率:燃料特性对产率的影响主要体现在N官能团(胺类-N(N-A)类型)稳定性方面,与N含量关系不大,因不稳定N-A在初次裂解中的关键作用,MDF总产率高达74.7%(质量分数),比秸秆类平均总产率高出15%(质量分数);温度和气化介质会影响二次反应中与NOx前驱物相关的反应路径(特别是加氢氢化反应),秸秆SBS气化,温度从800℃到1000℃,NH3-N产率从38.9%(质量分数)增加至47.7%(质量分数),HCN-N产率先增加后减少,峰值为18.3%(质量分数),源于各反应路径受温度影响的平衡性;气化介质改变加氢氢化反应,CO2主要影响HCN-N,起一定抑制作用,H2O主要影响NH3-N,起促进作用,因此,通过调节气化介质比例可一定程度改变NOx前期物组分的选择性。 相似文献
416.
采用以太阳光为能源、半导体材料为催化剂的催化体系将胺类化合物转化为相应的亚胺类化合物的方法是一种理想的有机合成手段.为了探索这类反应更温和的反应条件及更清晰的反应机理,本工作以NH2-MIL-68(In)和硫脲为前驱体制备了In2S3分级纳米管,并进一步采用热离子交换的方法制备了In2S3/CdIn2S4纳米管复合材料.采用粉末X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、高分辨透射电子显微镜(HRTEM)、紫外-可见漫反射光谱(UV-vis DRS)、荧光光谱(PL)和电化学阻抗谱(EIS)等分析手段对催化剂的结构、形貌、光电性质等进行了表征.实验结果显示,In2S3和CdIn2S4间有效异质结降低了In2S3/CdIn2S4复合材料的光生载流子的复合效率,使In2S3/CdIn2S4具有较高的催化活性.催化剂的活性测试实验结果证明,In2S3和CdIn2S4间有效异质结和分级结构间的协同作用使In2S3/CdIn2S4纳米复合材料可作为一种有效的光催化剂催化氧化苯甲胺的偶联反应.活性物种捕获实验证明该反应是由光生空穴(h+)引发的.此外,此研究发现苯甲胺的氧化偶联反应同时可以在氧气或氮气条件下发生,打破了该反应必须要有氧气参与的束缚,拓展了苯甲胺氧化偶联反应的适用范围.循环实验结果显示,催化剂可循环使用五次,证明该催化剂具有较好的稳定性. 相似文献
417.
Shasha Li Jianping Pan Xiaoxue Wu Yanghe Fu Qiang Xiao Fumin Zhang Weidong Zhu 《应用有机金属化学》2019,33(12)
Metal–organic frameworks (MOFs) have recently been identified as versatile sacrificing templates to construct functional nanomaterials for heterogeneous catalysis. Herein, we report a thermal transformation strategy to directly fabricate metal Pd nanoclusters inlaid within a ZrO2@nitrogen‐doped porous carbon (Pd/ZrO2@CN) composite using Pd@NH2‐UiO‐66(Zr) as a precursor that was pre‐synthesized by a one‐pot hydrothermal method. The developed Pd/ZrO2@CN as a robust catalyst delivered remarkable stability and activity to the catalytic hydrogenation of 2,3,5‐trimethylbenzoquinone (TMBQ) to 2,3,5‐trimethylhydroquinone (TMHQ), a key reaction involved in vitamin E production. The hydrogenation was carried out at 110 °C with 1.0 MPa H2, and it resulted in 98% TMHQ yield as the sole product over five consecutive cycles, outperforming the analogue Pd/ZrO2@C without nitrogen doping templated from Pd@UiO‐66(Zr). The excellent catalytic properties of Pd/ZrO2@CN likely originated from the highly stable ultrafine Pd nanoclusters inlaid within ZrO2@CN matrix on account of the strong interaction between N and Pd, as well as on the Lewis acidity of ZrO2, which was beneficial to the hydrogenation. 相似文献
418.
Reza Tayebee Mojtaba Fattahi Abdizadeh Nasrin Erfaninia Amirhassan Amiri Mehdi Baghayeri Roya Mohammadzadeh Kakhki Behrooz Maleki Effat Esmaili 《应用有机金属化学》2019,33(8)
Phosphotungstic acid (H3PW12O40, PTA) supported on ZIF‐9(NH2) was synthesized for the first time and performed as an effective and environmental friendly catalyst in the one‐pot three component Biginelli condensation of different substituted benzaldehydes with ethyl acetoacetate and urea to afford the corresponding 3,4‐dihydropyrimidin‐2‐(1H)‐ones under solvent‐free conditions. ZIF‐9(NH2) and the prepared nanocatalyst PTA@ZIF‐9(NH2) were characterized by XRD, FESEM, TEM, EDX, BET, AAS, TGA, UV–Vis, and FT‐IR. After reaction, the nanocatalyst can be easily separated from the reaction mixture by centrifuge and the recovered catalyst can be reused for at least five times with a 14% reduction in yield after the fifth run. This study showed that ZIF‐9(NH2) can be utilized as a promising support for PTA and developed a highly active, stable and reusable heterogeneous catalyst under easy reaction condition in the multi‐component organic synthesis. 相似文献
419.
Ning Yu Siwen Tao Jiawen Cui Huawei Zhou Yan Chen Shuting Cui Xiaorui Gao Jie Yin Xuejing Liu Xianxi Zhang 《应用有机金属化学》2020,34(12):e5982
At present, developing new organic–inorganic hybrid materials (OIHM) and studying their photoelectric properties is an important research field. In this work, the OIHM (CH3NH3)2HgCl4 (MA2HgCl4) single crystal and thin film are prepared. The results show that the crystal structure of MA2HgCl4 has a monoclinic crystal system with P21/c (14) space group (unit cell dimensions 7.776 × 12.917 × 10.993 Å, 90.00 × 96.366 × 90.00) by solving the single crystal diffraction data. The band gap of MA2HgCl4 is calculated to be approximately 3.21 eV. To the best of our knowledge, this is the first study on MA2HgCl4 for optoelectronic application. The photodetector based on MA2HgCl4 thin film is highly selective for ultraviolet (UV) light (369 nm), and has a poor response for visible light. The electrochemical impedance spectrum shows that the impedance value (2 kΩ) of the device under 369 nm UV light is four magnitudes lower than that (107 Ω) under dark. Thus, MA2HgCl4 has the nature of a photoconductor. The density functional theory indicates that the valence band maximum (VBM) of MA2HgCl4 is mainly derived from Cl-3p state, Hg-5d state and organic CH3NH3+ state also participate in the formation of the VBM band. The electron states of VBM and the conduction band minimum of MA2HgCl4 come from inorganic HgCl42− clusters. 相似文献
420.
The reversible reaction NH3 + H ⇌ H2 + NH2, which plays an important role in NH3 fuel combustion, is studied with a theoretical approach that combines the high-accuracy extrapolated ab initio thermochemistry (HEAT) protocol with semiclassical transition state theory (SCTST). The calculated forward reaction is endothermic by 11.8 ± 1 kJ/mol, in nearly perfect agreement with the active thermochemical tables (ATcT) value of 11.5 ± 0.2 kJ/mol. Using this improved thermochemistry yields better rate constants, especially at low temperatures. Experimental rate constants available from 400 to 2000 K for the forward and reverse reaction pathways can be reproduced (within 20%) by the calculations from first principles. 相似文献