541-73-1Relevant articles and documents
Exploiting a silver-bismuth hybrid material as heterogeneous noble metal catalyst for decarboxylations and decarboxylative deuterations of carboxylic acids under batch and continuous flow conditions
?tv?s, Sándor B.,Fül?p, Ferenc,Kónya, Zoltán,Kukovecz, ákos,Márton, András,Mészáros, Rebeka,Pálinkó, István,Szabados, Márton,Varga, Gábor
, p. 4685 - 4696 (2021/07/12)
Herein, we report novel catalytic methodologies for protodecarboxylations and decarboxylative deuterations of carboxylic acids utilizing a silver-containing hybrid material as a heterogeneous noble metal catalyst. After an initial batch method development, a chemically intensified continuous flow process was established in a simple packed-bed system which enabled gram-scale protodecarboxlyations without detectable structural degradation of the catalyst. The scope and applicability of the batch and flow processes were demonstrated through decarboxylations of a diverse set of aromatic carboxylic acids. Catalytic decarboxylative deuterations were achieved on the basis of the reaction conditions developed for the protodecarboxylations using D2O as a readily available deuterium source.
Facile Synthesis of a Fully Fused, Three-Dimensional ?-Conjugated Archimedean Cage with Magnetically Shielded Cavity
Han, Yi,Jiao, Tianyu,Li, Zhengtao,Ni, Yong,Wu, Jishan,Wu, Shaofei,Zhang, Qiuyu,Zhu, Jun
supporting information, p. 14314 - 14321 (2021/09/13)
The synthesis of molecular cages consisting of fully fused, ?-conjugated rings is rare due to synthetic challenges including preorganization, large strain, and poor solubility. Herein, we report such an example in which a tris-2-aminobenzophenone precursor undergoes acid-mediated self-condensation to form a truncated tetrahedron, one of the 13 Archimedean solids. Formation of eight-membered [1,5]diazocine rings provides preorganization and releases the strain while still maintains weak ?-conjugation of the backbone. Thorough characterizations were performed by X-ray, NMR, and UV-vis analysis, assisted by theoretical calculations. The cage exhibits a rigid backbone structure with a well-defined cavity that confines a magnetically shielded environment. The solvent molecule, o-dichlorobenzene, is precisely encapsulated in the cavity at a 1:1 ratio with multiple ?···?, C-H···?, and halogen···πinteractions with the cage skeleton, implying its template effect for the cage closing reaction. Our synthetic strategy opens the opportunity to access more complex, fully fused, three-dimensional ?-conjugated cages.
Controllable synthesis of ultrasmall Pd nanocatalysts templated by supramolecular coordination cages for highly efficient reductive dehalogenation
Jiang, Wei-Ling,Peng, Zhiyong,Shen, Ji-Chuang,Shi, Xueliang,Wu, Gui-Yuan,Yang, Hai-Bo,Yin, Guang-Qiang
supporting information, p. 12097 - 12105 (2020/07/09)
Supported ultrasmall noble metal nanocatalysts (UNMNs) are one of the most important classes of solid materials for heterogeneous catalysis. Herein, a simple and efficient supramolecular coordination cage (SCC) template-strategy has been developed to synthesize UNMNs with controllable size and size distribution. A series of SCCs, including M2L4, M4L2, M6L4 and M12L24, with well-defined sizes and shapes as well as different numbers of Pd ions were designed and synthesized as templates. Subsequently, the corresponding Pd nanocatalysts M2&at;CMC, M4&at;CMC, M6&at;CMC and M12&at;CMC were prepared by an impregnation-reduction method on carboxymethylcellulose (CMC) hydrogel supports. It was found that the employment of SCCs as templates could not only significantly reduce the aggregation tendency of Pd nanoparticles but also play an important role in regulating their size and size distribution. For example, the analysis of the catalyst size distribution indicated that the greater the number of Pd ions the cage possesses, the bigger the size of the catalyst. Moreover, with the decrease of the concentration of the template, the size of the Pd nanocatalyst also decreased obviously. Particularly, the resultant catalyst with a nano-Pd loading as high as 12.63percent could still maintain a narrow size distribution. Furthermore, the as-prepared Pd nanocatalyst could serve as a highly efficient polychlorinated biphenyl (PCB) degrader both in a stirred vessel and a continuous flow reactor because of its excellent catalytic efficiency in the reductive dehalogenation reaction under mild conditions. In a word, the SCC template-strategy employed in this study provides new guidelines for the preparation of size-controllable UNMNs on a variety of supports, along with high noble metal loading and catalytic activity. This journal is
Hydrodebromination of Aromatic Bromides Catalyzed by Unsupported Nanoporous Gold: Heterolytic Cleavage of Hydrogen Molecule
Bao, Ming,Feng, Xiujuan,Yamamoto, Yoshinori,Zhang, Sheng,Zhao, Yuhui
, p. 4951 - 4957 (2020/09/09)
Unsupported nanoporous gold (AuNPore) is a highly efficient, practically applicable, and recyclable catalyst for hydrodebromination of aromatic bromides. The AuNPore-catalyzed hydrodebromination of aromatic bromides proceeded smoothly at relatively low hydrogen pressure and temperature to achieve good to excellent yields of the corresponding non-bromine variants. The selective hydrodebromination reaction occurred exclusively in the coexistence of chlorine atom. For the first time, a mechanistic study revealed that the H?H bond splits in a heterolysis manner on the surface of AuNPore to generate Au?H hydride species.
Direct Stereoselective β-Arylation of Enol Ethers by a Decarboxylative Heck-Type Reaction
Hachem, Mahmoud,Hoarau, Christophe,Schneider, Cédric
, (2020/04/15)
Despite remarkable advances to promote regio- and stereoselective decarboxylative arylation of inactivated olefins with benzoic acid derivatives, methodologies involving hetero-substituted alkenes are still lacking. Herein, PdII-catalyzed decarboxylative Heck coupling of α-alkoxyacrylates with (hetero)aryl carboxylic acids for the stereocontrolled production of (Z)-β-heteroarylated vinyl ethers is reported. This methodology offers a rational and step-economical route to the synthesis of attractive β-arylated α-alkoxy α,β-unsaturated carboxylates family which emerged as a relevant class of building blocks with different applications. Mechanistically, whereas electron rich benzoic acids undergo a PdII-catalyzed decarboxylation, electron-deficient substrates proceed through silver(I)-mediated decarboxylation, explaining thus the formation of stereoisomers (E) and (Z) of β-arylated vinyl ethers in presence of these latter.
Efficient synthesis method of meta-fluoranisole (by machine translation)
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Paragraph 0026; 0030; 0036; 0040; 0046; 0050; 0056; 0060, (2020/06/05)
The method is characterized by comprising the following steps: taking m-chloronitrobenzene as a raw material, carrying out high-temperature chlorination reaction, nitration reaction and fluorination reaction to obtain 2,4 - 2,4 -difluorobenzene and carrying out a methoxylation reaction with m-difluorobenzene as a raw material and carrying out methoxylation reaction to obtain m-fluorobenzyl ether; and the hydrogenation catalyst is a porous alumina loaded NiO-Co222O3-MoOO3 composite catalyst. The method disclosed by the invention is simple in process and high in product yield. (by machine translation)
Copper-Mediated Fluorination of Aryl Trisiloxanes with Nucleophilic Fluoride
Dorel, Ruth,Boehm, Philip,Schwinger, Daniel P.,Hartwig, John F.
supporting information, p. 1759 - 1762 (2020/02/05)
A method for the nucleophilic fluorination of heptamethyl aryl trisiloxanes to form fluoroarenes is reported. The reaction proceeds in the presence of Cu(OTf)2 and KHF2 as the fluoride source under mild conditions for a broad range of heptamethyltrisiloxyarenes with high functional group tolerance. The combination of this method with the silylation of aryl C?H bonds enables the regioselective fluorination of non-activated arenes controlled by steric effects following a two-step protocol.
Synthesis method of m-dichlorobenzene
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Paragraph 0025; 0029-0035; 0039-0045; 0049-0054, (2019/12/25)
The invention relates to the technical field of organic synthesis, in particular to a synthesis method of m-dichlorobenzene, and aims to improve the yield and purity of a product. According to the technical scheme, the method comprises the following steps: mixing benzene and concentrated nitric acid, and performing catalytic reaction by taking potassium permanganate as a catalyst to obtain nitrobenzene; mixing nitrobenzene with concentrated nitric acid, and carrying out secondary catalytic reaction to obtain a mixed nitrobenzene solution; mixing and stirring the mixed nitrobenzene, sodium hydrogen sulfite and sodium hydroxide to obtain m-dinitrobenzene; introducing chlorine into m-dinitrobenzene to obtain a crude m-dichlorobenzene solution; carrying out impurity removal treatment on the m-dichlorobenzene solution with a hydrophobic silicalite molecular sieve; crystallizing, rectifying to remove impurities, and carrying out secondary chlorination to obtain pure m-dichlorobenzene; and finally, condensing to obtain a finished product and collecting.
Synthesis method of m-dichlorobenzene
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Paragraph 0024-0044, (2020/01/03)
The invention relates to a synthesis method of m-dichlorobenzene, which is obtained by translocation reaction with dichlorobenzene as a raw material under the action of a catalyst, wherein the catalyst is an ionic liquid including Lewis acid and onium salt chloride. The synthesis method of the present invention uses an ionic liquid composed of a Lewis acid and an onium salt chloride as a catalyst,the selectivity of the reaction is above 90%, the yield can be significantly increased to above 60%, no under-pressure reaction is required, the reaction conditions are mild, the requirements for equipment are low, the catalyst can be reused many times, the amount of the three wastes is small, the environment is friendly, and the industrial production is suitable.
Multiphase Hydrodechlorination of 1,3,5-Trichlorobenzene on Palladium Catalysts Supported on Alumina: Effect of the Support Properties and Modification by Heteropoly Acid Based on Silicon and Tungsten
Golubina,Lokteva,Gurbanova,Kharlanov,Egorova,Lipatova,Vlaskin,Shkol’nikov
, p. 297 - 314 (2019/06/24)
Abstract: Catalytic systems 2 wt % Pd/Al2O3 were prepared using noncalcined boehmite (NC) and two types of alumina support: one was prepared by the calcination of boehmite at 600°C (C) and the other produced by Engelhard (E). To prepare 2 wt % Pd/HPC–Al2O3 samples, these supports were modified by impregnation by a heteropoly compound (HPC) (20 wt % Н8[Si(W2O7)6] ? 6Н2О). The effect of the Al2O3 structure and its modification by the heteropoly compound on the physicochemical properties, activity, selectivity and stability of catalysts in the reaction of multiphase hydrodechlorination of 1,3,5-trichlorobenzene (TCB) was studied. All catalysts showed activity in the considered reaction with the predominant formation of benzene but were deactivated in the reaction medium. Modification by the heteropoly compound resulted in increased stability and was especially effective for catalyst supported on Al2O3(E). The method of scanning electron microscopy (SEM) was used to determine the morphological differences of supports. According to the data of transmission electron microscopy, all catalysts contained palladium in the form of particles less than 20 nm in size. The particle size and width of the size distribution increases in the series Pd/Al2O3(NC) 2O3(C) 2O3(E). Modification by the heteropoly compound was favorable for the decrease in the size of palladium particles. The method of temperature-programmed reduction with hydrogen (TPR-H2) showed that all catalysts included in their composition palladium hydride along with more strongly surface-bound metal forms that are reduced at elevated temperatures, and their content decreases after modification by the heteropoly compound and increases after catalytic tests. According to diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), the deposition of a heteropoly compound leads to a change in the type of Lewis acid sites on the alumina surface and in the electronic state of palladium. According to the results of infrared spectroscopic studies of adsorbed CO, the relatively large particles of Pd0 are the main form on the surface of nonmodified catalysts. The catalysts modified by the heteropoly compound contain single Pd+ and Pd2+ cations, and the fraction of Pd0 is substantially smaller. The specific features of the Lewis acidity of the catalyst surface determine the possibility of 1,3,5-trichlorobenzene adsorption and activation on the support and the spillover of hydrogen from Pd0. An increase in the catalyst stability as a result of support modification by the heteropoly compound can be explained by the appearance of new active sites in the interaction of palladium with the heteropoly compound or its thermal decomposition products.
