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Halide moieties are essential structures of compounds in organic chemistry due to their popularity and wide applications in many fields such as natural compounds, agrochemicals, and pharmaceuticals. Thus, many methods have been developed to introduce halides into various organic molecules. Recently, visible-light-driven reactions have emerged as useful methods of organic synthesis. Particularly, halogenation strategies using visible light have significantly improved the reaction efficiency and reduced toxicity, as well as promoted reactions under mild conditions. In this review, we have summarized recent studies in visible-light-mediated halogenation (chlorination, bromination, and iodination) with photocatalysts. 相似文献
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Ni-B/SiO2非晶态催化剂应用于硝基苯液相加氢制苯胺 总被引:26,自引:1,他引:26
考察了Ni-B/SiO2非晶态催化剂在高压液相硝基苯加氢制苯胺反应中的催化活性和选择性.研究表明,该催化剂不仅具有很高的催化活性,而且对苯胺的选择性较高,优于RaneyNi以及其它Ni基催化剂.晶化导致催化剂失活.载体的存在不仅能提高催化剂的分散度,而且能对非晶态结构起稳定化作用;将催化剂保存在乙醇中可保持其活性不变.结合催化剂的表征,讨论了Ni-B/SiO2非晶态催化剂的催化性能与其结构的关系. 相似文献
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以自制的漆原镍作催化剂,在45℃常压下将间硝基三氟甲苯氢化还原为间三氟甲基苯胺,收率达98%,催化剂能重复使用9次。 相似文献
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Pd/C催化剂用于苯胺氧化羰基化 总被引:4,自引:0,他引:4
研究了催化剂制备条件、助催化剂对负载型Pd/C催化剂性能的影响及氧分压、原料苯胺中硝基苯的加入对苯胺氧化羰基化反应的影响;用X光电子能谱(XPS)、程序升温还原(TPR)和现场红外(IR)表征钯催化剂;根据实验结果提出在Pd/C-NaI催化剂体系、醇介质中,苯胺氧化羰基化可能的反应机理. 相似文献
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Chang Yuan HU Feng Yi LI Rong Bin ZHANG Li HUA 《中国化学快报》2006,17(1):109-112
Carbon nanotubes (CNTs) are severely bundled and essentially insoluble in solvent. These properties are generally considered as a significant barrier toward the practical uses of CNTs. Therefore, the functionalization and solubilization of CNTs have recei… 相似文献
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Ajda Podgoršek Dr. Marko Zupan Jernej Iskra Prof. 《Angewandte Chemie (International ed. in English)》2009,48(45):8424-8450
It is difficult to imagine organic chemistry without organo‐halogen compounds and the molecular halogens needed for their preparation. The halogens have very different reactivity, with iodine usually requiring some form of activation, while others are reactive and hazardous chemicals. To avoid their use, various modified reagents have been discovered (N‐bromo‐ and N‐chlorosuccinimide, Selectfluor…?), but halogens are used to prepare these reagents and when they are used the atom economy is poor. A better approach, which is based on biomimetric research on oxidative halogenation in nature, consists of generating the halogenating reagent in situ under acidic conditions from a halide salt. The result of such a reaction has been halogenation with 100 % halogen atom economy. Suitable oxidants for the oxidation of halides are hydrogen peroxide and oxygen. 相似文献
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Dr. Gang Li Dr. Andrew K. Dilger Dr. Peter T. Cheng Dr. William R. Ewing Prof. Dr. John T. Groves 《Angewandte Chemie (International ed. in English)》2018,57(5):1251-1255
The selective C?H functionalization of aliphatic molecules remains a challenge in organic synthesis. While radical chain halogenation reactions provide efficient access to many halogenated molecules, the use of typical protocols for the selective halogenation of electron‐deficient and strained aliphatic molecules is rare. Herein, we report selective C?H chlorination and fluorination reactions promoted by an electron‐deficient manganese pentafluorophenyl porphyrin catalyst, Mn(TPFPP)Cl. This catalyst displays superior properties for the aliphatic halogenation of recalcitrant, electron‐deficient, and strained substrates with unique regio‐ and stereoselectivity. UV/Vis analysis during the course of the reaction indicated that an oxo‐MnV species is responsible for hydrogen‐atom abstraction. The observed stereoselectivity results from steric interactions between the bulky porphyrin ligand and the intermediate substrate radical in the halogen rebound step. 相似文献
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茂金属催化剂催化烯烃齐聚与环化的研究进展 总被引:1,自引:0,他引:1
本文介绍近年来国内外在茂金属催化剂催化烯烃齐聚与环化方面的研究进展, 主要侧重于茂金属催化剂催化烯烃齐聚, α, ω-二烯的环化及应用前景。 相似文献
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Ni-B非晶态合金催化剂用于卤代硝基苯液相加氢制卤代苯胺 总被引:31,自引:2,他引:31
用化学还原法制备了Ni-B非晶态合金催化剂,并将其用于4种卤代硝基苯的液相加氢反应. 采用X射线衍射和透射电子显微镜研究了催化剂的非晶性质. 在373 K下处理2 h后催化剂保持非晶态结构,在773 K下处理2 h后催化剂完全晶化. 讨论了Ni-B非晶态合金催化剂的催化性能与其结构之间的关系,并与其它Ni基催化剂进行了比较. Ni-B非晶态合金催化剂不仅具有较高的催化活性,而且对卤代芳胺的选择性较高,脱卤率小于4%,优于其它Ni基催化剂. 相似文献