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Synthesis and Heterogenous Catalytic Applications of Noble Metal Nanoparticles/Carbon Nanotubes Nanocomposites
Published in Ann Rose Abraham, Soney C. George, A. K. Haghi, Carbon Nanotubes, 2023
Mamatha Susan Punnoose, Beena Mathew
PdNP/SWCNTs exhibit higher catalytic activity than palladium-activated carbon (Pd/C) for the Heck reaction of styrene and iodobenzene and also for the Suzuki coupling of phenylboronic and iodobenzene. The activity of the palladium catalyst for C-C bond forming reactions including hydrogenation and oxidation are deeply influenced by their particle size (Fig. 6.1).95,96 Efficient Suzuki-Miyaura coupling of arylbromides are efficiently catalyzed by Pd/CNT under ligandless and additive-free conditions in aqueous media.97 The effective hydrodehalogenation of aryl halides was promoted by Pd/CNT nanocomposites at a very low Pd content (~2.3%) and in the absence of any ligands. Thiol groups were used as linkers to anchor the PdNPs on the CNTs surface without agglomeration.98
Palladium-Catalyzed Suzuki–Miyaura Cross-Coupling in Continuous Flows
Published in Ahindra Nag, Greener Synthesis of Organic Compounds, Drugs and Natural Products, 2022
Remi Nguyen, Virinder S. Parmar, Christophe Len
Suitable solid supports having Pd(II) species precursors to Pd(0) catalysts are currently available commercially but researchers prefer to design their own, home-made catalysts. Monguchi and Sajiki reported palladium on carbon-catalyzed Suzuki–Miyaura coupling reaction sequence in tandem using an efficient and continuous flow system (Scheme 7.7).102 To investigate the scope of the reaction, a range of arylboronic acids and halogenobenzene derivatives were tested under mild conditions for 20 sec during a single-pass (Figure 7.5), the authors have reported the detection of little or no leaching (< 1 ppm).
m-Aminophenol
Published in John R. Kosak, Thomas A. Johnson, Catalysis of Organic Reactions, 2020
Hydrogenolysis of the C—N bond to form ammonia was a major source of by-products in the dehydrogenation of 3-ACO to MAP. Cyclohexanone was the major organic by-product detected by GC when the low-boiling products were removed in the early stages of the dehydrogenation. Although only small amounts of phenol (1–2%) were detected, 3-hydroxy-diphenylamine and 3-hydroxyphenylcyclohexylamine were both detected in significant quantities by GC-MS (although not quantitated). These products were apparently formed by condensation of cyclohexanone with 3-ACO or MAP followed by hydrogen exchange. The palladium on carbon catalyst is known to be active for carbon-heteroatom hydrogenolysis [9].
Surface modified nanoparticles: a green catalyst for the reduction of ketones
Published in Inorganic and Nano-Metal Chemistry, 2022
In general, secondary alcohols constitute indisputable applications in many fields for the production of valuable life products and are used as key intermediates for the production of fine chemicals.[1] Synthesis of secondary alcohols via the reduction of keto compounds is a promising route for the production of various substrates of secondary alcohols.[2–7] Conventionally, the reduction of ketones was done using common reducing agents like sodium borohydride,[8] lithium aluminum hydride [9] and ammonia borane in neat water [10] for the synthesis of secondary alcohols. Also, noble metals such as Raney Ni, platinum oxide, palladium on carbon, rhodium on alumina were used for the hydrogenation of ketones.[11] But these chemicals have noticeable limitations for large scale synthesis due to their high cost and also they possess less selectivity and high sensitivity that can’t be implemented under simple laboratory conditions.
Molecular packing handedness dominated by the chirality of the lactic acid residue near the liquid crystalline core
Published in Liquid Crystals, 2021
Xiaoqing Wu, Baining Ni, Limin Wu, Yongmin Guo, Yi Li, Baozong Li, Yonggang Yang
4-Iodobenzoic acid (≥99%) was purchased from Shanghai Dibo Chemical Technology Co., Ltd. Heptadecafluoro-1-iodooctane (≥98%) was purchased from Aladdin Industrial Co., Ltd. Methyl (R)-(+)-lactate and methyl (S)-(-)-lactate (≥98%) was purchased from Beijing HWRK Chem. Co., Ltd. L-Lactic acid and D-lactic acid (≥98%) was purchased from 9 Ding chemistry (Shanghai) Co., Ltd. 1-Hexanol was purchased from Shanghai Macklin Biochemical Co., Ltd. DCC (≥99%) was purchased from Shanghai Titan scientific Co., Ltd. DMAP (≥99%) was purchased from Adamas Reagent Co., Ltd. Triphenylphosphine (PPh3) (≥98%) was purchased from Sinopharm Chemical Reagent Co., Ltd. Diethyl azodicarboxylate (DEAD) was purchased from Shanghai Darui Fine Chemical Co., Ltd. THF was obtained from Chinasun Speciality Products Co., Ltd. Before use, THF was treated with sodium and then redistilled. Ethanol, CDCl3 and dimethyl sulphoxide-d6 (DMSO-d6) were purchased from Sinopharm Chemical Reagent Co., Ltd. Palladium on carbon hydrogenation (Pd/C, 10 wt%) was purchased from Sinopharm Chemical Reagent Co., Ltd.
Influence of multifluorophenyloxy terminus on the mesomorphism of the alkoxy and alkyl cyanobiphenyl compounds in search of new ambient nematic liquid crystals and mixtures
Published in Liquid Crystals, 2021
Kunlun Wang, Mohammad S. Rahman, Tibor Szilvási, Jake I. Gold, Nanqi Bao, Huaizhe Yu, Nicholas L. Abbott, Manos Mavrikakis, Robert J. Twieg
Commercial-grade solvents were used without further purification. PdCl2 was bought from Pressure Chemical (Pittsburgh, PA). Palladium on carbon (5%), diisopropylamine, ether and copper iodide were purchased from Acros. The precursor 4ʹ-cyano-4-iodobiphenyl was prepared using a literature method [23]. The poisoned catalyst required for preferential alkyne reduction in the presence of a nitrile was also prepared using a literature method [24]. Triphenylphosphine and ethylenediamine were bought from Sigma-Aldrich. The pentafluoropyridine, pentafluorobenzonitrile, hexafluorobenzene, bromopentafluorobenzene chloropentafluorobenzene and pentafluorostyrene were purchased from Oakwood Products (Columbia, SC). The decafluorobiphenyl and pentafluorobenzene were purchased from Matrix Scientific (Columbia, SC). The terminal hydroxyacetylenes were purchased from GFS Organic Chemicals (Columbus, OH). The compressed hydrogen was bought from Linde Gas. Sythesis of all precursors can be accessed in supplemental information. The products were purified by column chromatography using silica gel (60–120 mesh) and/or by recrystallisation from analytical grade solvents.