Solvent-free selective hydrogenation of chloronitrobenzene to chloroaniline over a robust Pt/Fe3O4 catalyst

Lian, Chang; Liu, Hongquan; Xiao, Chao; Yang, Wen; Zhang, Kai; Liu, Yan; Wang, Yuan

doi:10.1039/c2cc16620h

Cited by 72 publications

(43 citation statements)

References 34 publications

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“…reported a series of colloidal monodisperse so‐called “unprotected” noble metal nanocrystals that are stabilized by ethylene glycol and simple ions (including OH − , Cl − , glycolate, oxalate, and acetate ions) . Although these unprotected nanocrystals are not really naked, the solvents and simple anions adsorbed on the surface of metal nanoparticles can be easily washed or replaced by organic ligands to acquire metal nanocrystal catalysts with various modified shells of protective agents . As the structures and morphologies of the unprotected nanocrystals do not change after surface modification, suitable model catalysts to study the effect of protective agents upon the intrinsic catalytic property of nanocrystals can be obtained by modifying the surface of unprotected nanoparticles with different protective agents.…”

Section: Introductionmentioning

confidence: 99%

Effect of Protective Agents upon the Catalytic Property of Platinum Nanocrystals

Yan

Chen

et al. 2018

ChemCatChem

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“Unprotected” Pt nanocrystals were modified with triphenylphosphine (PPh3), octadecylamine (ODA), poly(vinylpyrrolidone) (PVP), poly(vinyl alcohol) (PVA), and dodecanethiol (DT) to investigate the effect of protective agents on the intrinsic catalytic property of Pt nanocrystals. By evaluating the catalytic performance of these model catalysts for the hydrogenation of para‐chloronitrobenzene (p‐CNB), it was found that direct or indirect interaction between nanocrystals and protective agents imposed a great impact on the catalytic performance of the nanocrystals. Protective agents with different electron‐donating ability (PPh3, ODA, PVP, and PVA) directly altered surface electronic state of Pt nanocrystals to bring the surface Pt atoms into an electron‐rich state, which would exert influence on the hydrogenation course by changing the adsorption and the reactivity of reactant, intermediates, and products. In contrast, DT exerted an indirect influence on the Pt nanocrystals. The coordinated Pt atoms were oxidized by DT to generate cationic Pt species on the surface of nanocrystals, and the cationic species would simultaneously improve the hydrogenation rate and selectivity to para‐chloroaniline by polarizing the N=O bond in the −NO2 group of p‐CNB and altering the electronic state of Pt nanocrystals, respectively. This work provided further insights into nanocatalysis, which is helpful for further design and application of highly efficient nanocrystal catalysts.

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Section: Introductionmentioning

confidence: 99%

Effect of Protective Agents upon the Catalytic Property of Platinum Nanocrystals

Yan

Chen

et al. 2018

ChemCatChem

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“…[1][2][3][4][5][6][7][8][9][10] However, these catalysts are not qualied to catalyse the selective hydrogenation of organic compounds with multiple reducible functionalities because of their very high activity. [1][2][3][4][5][6][7][8][9][10] However, these catalysts are not qualied to catalyse the selective hydrogenation of organic compounds with multiple reducible functionalities because of their very high activity.…”

Section: Introductionmentioning

confidence: 99%

Preparation of supported core–shell structured Pd@Pd_xS_y/C catalysts for use in selective reductive alkylation reaction

Zhang

Feng

et al. 2015

RSC Adv.

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Supported noble-metal sulphide catalysts have attracted extensive scientific interest for their good selectivity in selective hydrogenation. However, the application of noble-metal catalysts is limited due to their lower activity, leading to harsh reaction conditions and poor conversion during hydrogenation reactions. In this study, Pd/C was sulphidized by H 2 S to prepare a series of core-shell structured Pd@Pd x S y /C catalysts, which were characterized by BET, EDS, XPS, XRD and CO chemisorption to investigate the influences of sulphidation temperature, sulphidation time and sulphidation atmosphere on the structure of the resulting catalysts. The sulphidation of Pd/C at low temperatures resulted in a core-shell structured catalyst, Pd@Pd x S y /C; with increasing sulphidation temperature, the size of Pd 0 as the core decreased, and the thickness of palladium sulphides as the shell increased correspondingly.When the sulphidation temperature reached 150 C, the resulting catalyst transformed to a complete palladium sulphide catalyst, Pd x S y /C. The structure of Pd@Pd x S y /C sulphidized at 30 C was independent of sulphidation time and sulphidation atmosphere. The sulphidized catalysts were applied to the reductive alkylation of PADPA and MIBK to DBPPD. The sulphidized catalysts presented a much higher selectivity for DBPPD compared with Pd/C, and Pd@Pd x S y /C showed higher activity than Pd x S y /C; moreover, the greater amount of Pd x S y content in the resulting catalyst led to a lower activity.

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“…In the catalytic reaction, the catalyst plays a very important part. Catalysts based on noble and non-noble metals, such as Pt, [5][6][7] Pd, 8,9 Rh, [10][11][12] Au, [1][2][3]13 Ni, [14][15][16][17][18][21][22][23][24][25][26][27][28] and Fe, 19,20 have been widely studied. Even though the noble metal catalysts show a good catalytic performance under mild conditions, their rather rare resource and high cost limit practical applications.…”

Section: -4mentioning

confidence: 99%

Metal fluoride promoted catalytic hydrogenation of aromatic nitro compounds over RANEY® Ni

Liu

et al. 2015

RSC Adv.

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The catalytic hydrogenation reactivity of aromatic nitro compounds over RANEY® Ni was substantially improved when a moderate amount of metal fluoride (NaF, KF, MgF 2 , and CaF 2 ) was added into the reaction system.Aromatic amines (ANs) are commercially important for the large scale production of many ne chemicals, such as dyes, herbicides, whiteners, pharmaceuticals, and agrochemicals. [1][2][3][4] Liquid-phase hydrogenation of nitro aromatic compounds (NBs) over metal catalysts is recognized as an efficient and environmentally friendly procedure to produce ANs as no other harmful effluents are produced except water. In the catalytic reaction, the catalyst plays a very important part. Catalysts based on noble and non-noble metals, such as Pt, 5-7 Pd, 8,9 Rh, 10-12 Au, 1-3,13 Ni, [14][15][16][17][18][21][22][23][24][25][26][27][28]19,20 have been widely studied. Even though the noble metal catalysts show a good catalytic performance under mild conditions, their rather rare resource and high cost limit practical applications. Actually, in industrial production, Ni is usually chosen as catalyst rather than noble metals for the hydrogenation of NBs owing to its abundant resources and low price. 14-18,21-28 Therefore, the utilization of Ni catalyst has received considerable attention in the hydrogenation of NBs.Recently These two methods which introduced inorganic uoride into metal catalysts obviously improved the catalytic performance. Whether could it achieve the same promoting effect for catalytic hydrogenation of NBs over RANEY® Ni by adding a small amount of metal uoride into the liquid phase reaction system? Herein, various metal uorides (NaF, KF, CaF 2 , and MgF 2 ) were explored to investigate the effect of these metal uorides on the hydrogenation of NBs to ANs over RANEY® Ni catalyst.The simplied reaction route of p-chloronitrobenzene (p-CNB) hydrogenation to p-chloroaniline (p-CAN) is displayed in Scheme 1. 2,32 The target product is p-CAN and the main intermediate product is p-chlorophenylhydroxylamine (p-CHB). As shown in Scheme 1, the process involves two steps that p-CNB is hydrogenated to produce p-CHB, and then p-CHB is further hydrogenated to form p-CAN. Generally, the hydrogenation of p-CNB over RANEY® Ni catalyst is slowly under mild conditions. The hydrogenation of p-CNB over original RANEY® Ni was repeated three times to guarantee that every batch of RANEY® nickel could perform similarly Scheme 1 Simplified reaction route of p-CNB hydrogenation to p-CAN.

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Solvent-free selective hydrogenation of chloronitrobenzene to chloroaniline over a robust Pt/Fe3O4 catalyst

Cited by 72 publications

References 34 publications

Effect of Protective Agents upon the Catalytic Property of Platinum Nanocrystals

Effect of Protective Agents upon the Catalytic Property of Platinum Nanocrystals

Preparation of supported core–shell structured Pd@Pd_xS_y/C catalysts for use in selective reductive alkylation reaction

Metal fluoride promoted catalytic hydrogenation of aromatic nitro compounds over RANEY® Ni

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Solvent-free selective hydrogenation of chloronitrobenzene to chloroaniline over a robust Pt/Fe3O4 catalyst

Cited by 72 publications

References 34 publications

Effect of Protective Agents upon the Catalytic Property of Platinum Nanocrystals

Effect of Protective Agents upon the Catalytic Property of Platinum Nanocrystals

Preparation of supported core–shell structured Pd@PdxSy/C catalysts for use in selective reductive alkylation reaction

Metal fluoride promoted catalytic hydrogenation of aromatic nitro compounds over RANEY® Ni

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Preparation of supported core–shell structured Pd@Pd_xS_y/C catalysts for use in selective reductive alkylation reaction