The catalytic transformation of chlorofluorocarbons in hydrogen on metal-based catalysts supported on inorganic fluorides

Coq, Bernard; Medina, Françesc; Tichit, Didier; Morato, A.

doi:10.1016/j.cattod.2003.11.008

Cited by 19 publications

(13 citation statements)

References 40 publications

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“…Recently, various types of Ni catalysts, including RANEY® Ni, 21,22 29 Gao et al also had similar report that uorine-modied Cu/Zn/Al catalysts showed much better catalytic properties for CO 2 hydrogenation to methanol. 30,31 These two methods which introduced inorganic uoride into metal catalysts obviously improved the catalytic performance.…”

Section: -4mentioning

confidence: 85%

“…Therefore the difference in catalytic activity could not be explained by the difference in surface area. The possible reason of the promoting effect of these metal uorides could be referred to the literature, 29 which proposed that the good hydrodechlorination performance of Pd/uoride catalyst came from an electronic modication of Pd by uo-ride species in decoration onto the metal particles. The electron withdrawing effect of these species favored the desorption of Pd-substrate to yield the target compounds.…”

Section: 32mentioning

confidence: 99%

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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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Section: -4mentioning

confidence: 85%

Section: 32mentioning

confidence: 99%

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

Liu

et al. 2015

RSC Adv.

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“…Higher selectivity to CH 2 F 2 over Pd supported on AlF 3 than on other supports studied is ascribed to the interaction of Pd with AlF 3 supports as in the case of hydrodehalogenation of CCl 2 F 2 and CCl 2 FCF 3 over fluorinated supports [123]. As mentioned previously, the strong Lewis acidity of the fluoride species could induce electron deficiency (Pd d+ ) in Pd atoms located in the vicinity of the fluorinated support.…”

Section: Catalytic Hydrodehalogenation Of Halon 1211 Withmentioning

confidence: 90%

“…Coq et al suggest that the interaction of support with Pd plays an important role for the higher selectivity to CH 2 F 2 observed [123]. During the hydrodehalogenation, the migration of halogen species from metal to fluoride supports occur, which then prevents the diffusion of halogen into the Pd bulk, thus refreshing the Pd surface and maintaining the high activity of Pd.…”

Section: Factors Influencing Catalytic Hydrodehalogenationmentioning

confidence: 95%

A review of CFC and halon treatment technologies – The nature and role of catalysts

Kennedy

Adesina

et al. 2006

Catal Surv Asia

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The purpose of this review article is to provide readers with an account of CFC and halon treatment technologies as depicted in the patent and open literature. Destruction technologies, in which halons and CFCs are converted into species such as CO 2 , HX or X 2 (X = Br, Cl, F), are treated less extensively. Emphasis has been placed on conversion processes, which aim at transforming (rather than destroying) CFC or halon into environmentally benign and useful products. It has been found that catalytic hydrodehalogenation over transition metal based catalysts, Pd in particular, has great potential for conversion of CFCs and halons to hydrofluorocarbons. In this regard, the focus of this review is on catalytic hydrodehalogenation, including an assessment of reaction mechanisms, catalytic activity, selectivity and durability.

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“…Palladium supported on metal fluorides (AlF 3 or MgF 2 ) can be regarded as a new type of catalysts for the process of hydrodechlorination of CHCs (Hina and Al-Fayyoumi 2004). Coq and others (Coq et al 2004) demonstrated the efficiency of Pd supported on inorganic fluorides catalysts for the process of hydrotransformation of chlorofluorocarbons. They also described exceptional properties of Pd/AlF 3 .…”

Section: Introductionmentioning

confidence: 98%

Hydrodechlorination of Carbon Tetrachloride and 1,2-Dichloroethane on Palladium Nanoparticles Supported on Metal Fluorides

Machynskyy

Śrębowata

Kemnitz

et al. 2014

International Journal of Green Energy

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Catalytic activity of palladium supported on strongly acidic aluminum fluoride or on much less acidic magnesium fluoride has been the subject of current research. Both catalysts were synthesized by non-aqueous sol-gel method with subsequent two-stage activation: post-fluorination and reduction. The catalytic behavior of prepared Pd/HS-AlF 3 and Pd/HS-MgF 2 in the hydrodechlorination reactions of chlorinated hydrocarbons was investigated. It was found that differences in support acidity and catalyst's activation protocol strongly effect the catalytic performance.

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The catalytic transformation of chlorofluorocarbons in hydrogen on metal-based catalysts supported on inorganic fluorides

Cited by 19 publications

References 40 publications

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

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

A review of CFC and halon treatment technologies – The nature and role of catalysts

Hydrodechlorination of Carbon Tetrachloride and 1,2-Dichloroethane on Palladium Nanoparticles Supported on Metal Fluorides

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