367-25-9Relevant articles and documents
Synthesis of carbon-supported Pd/SnO2 catalyst for highly selective hydrogenation of 2,4-difluoronitrobenzene
Zhao, Jia,Ma, Lei,Xu, Xiao-Liang,Feng, Feng,Li, Xiao-Nian
, p. 1137 - 1140 (2014)
Halogenated anilines have a wide range of applications in the production of pharmaceuticals and agrochemical substances, and thus it is of great importance to develop highly active and selective catalysts for the hydrogenation of halogenated nitrobenzenes. We approach this challenge by probing noble metal/non-noble metal oxide nanoparticles (NPs) catalysts. Carbon-supported Pd/SnO2 catalysts were synthesized by the chemical reduction method, and their catalytic activity was evaluated by the hydrogenation reaction of 2,4-difluoronitrobenzene (DFNB) to the corresponding 2,4-difluoroaniline (DFAN), showing a remarkable synergistic effect of the Pd and SnO2 NPs. The as-prepared Pd/SnO2/C catalysts were characterized using TEM, XRD, H2 TPD and XPS techniques. Modifications to the electronic structure of the Pd atoms through the use of SnO2 led to the suppression of the hydrogenolysis of the CF bond and the acceleration of nitrosobenzene (DFNSB) conversion and consequently, resulted in the inhibition of the formation of reactive by-products and may be responsible for the enhancements observed in selectivity.
Novel preparation method of 2, 4, 5-trifluorophenylacetic acid
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, (2021/06/23)
The invention discloses a novel preparation method of 2, 4, 5-trifluorophenylacetic acid, which belongs to the technical field of preparation of medical intermediates, and comprises the following preparation steps: carrying out nitration reaction on sulfuric acid and m-dichlorobenzene to obtain an intermediate II; adding the intermediate II, a phase transfer catalyst and potassium fluoride into an aprotic solvent to obtain an intermediate III; performing hydrogenation reaction on the intermediate III to obtain an intermediate IV; carrying out diazotization reaction on the intermediate IV, nitrosyl sulfuric acid and sodium fluoborate to obtain an intermediate V; performing cracking reaction on the intermediate V to obtain an intermediate VI; carrying out reduction reaction on the intermediate VI, and then carrying out bromination reaction on the intermediate VI and liquid bromine to obtain an intermediate VII; subjecting the intermediate VII to a substitution reaction with diethyl malonate, and obtaining 2, 4, 5-trifluorophenylacetic acid after hydrolysis and purification. A novel synthesis route is provided, the problem that technological operation is tedious is solved, the requirements for reaction and operation conditions are low, anhydrous and oxygen-free reaction conditions are not needed, the method is suitable for industrial production, and the yield and purity are greatly improved.
Highly selective hydrogenation of halogenated nitroarenes over Ru/CN nanocomposites by: In situ pyrolysis
Yue, Shengnan,Wang, Xueguang,Li, Shaoting,Sheng, Yao,Zou, Xiujing,Lu, Xionggang,Zhang, Chunlei
, p. 11861 - 11869 (2020/07/28)
A highly chemoselective and recyclable ruthenium catalyst for the hydrogenation of halogenated nitroarenes has been prepared via the simple in situ calcination of a mixture of melamine, glucose and ruthenium trichloride. Superfine Ru particles (2.3 ± 0.3 nm) were obtained and highly dispersed in the nitrogen-doped carbon matrix. The Ru/CN catalyst smoothly transforms a variety of halogenated nitroarenes to the corresponding haloanilines with high intrinsic activity (e.g. TOF = 1333 h-1 for p-chloronitrobenzene) and selectivity of more than 99.6percent. Furthermore, through an analysis of the products in the reaction process, it was concluded that there are two parallel reaction pathways (a direct pathway and an indirect pathway) for the hydrogenation of aromatic nitro compounds over the Ru/CN catalyst, and the direct pathway was proved to be dominant in catalyzing the intermediates. This journal is
