Understanding of potassium promoter effects on oxychlorination of ethylene by operando spatial-time resolved UV–vis–NIR spectrometry

Rout, Kumar Ranjan; Baidoo, Martina Francisca; Fenes, Endre; Zhu, Junwu; Fuglerud, Terje; Chen, D.

doi:10.1016/j.jcat.2016.12.026

Cited by 24 publications

(43 citation statements)

References 37 publications

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“…However, the second one is seemingly more puzzling as there is a general agreement in the literature that the oxidation step is rate determining, [17] a result we have also previously confirmed experimentally. [9] However, the activation energy of the oxidation step is lower than the reduction step (Table 1), but the pre-exponential factors (Table 1) for the oxidation step (A 1,I , A 1,II ) are much smaller than the one of the reduction step (A 2,I , A 2,II ). It implies a more significant entropy loss during the oxidation step compared to the reduction step since oxygen is incorporated into the catalyst lattice and loses all the entropy of the gas phase.…”

Section: Transient Kinetics Of the Oxidation Stepmentioning

confidence: 97%

“…(5)] [8] . The regeneration step is faster than the redox steps and assumed kinetically irrelevant in the overall reaction [8d,9] . CuCl is not only inactive towards ethylene at the given temperatures but also highly volatile.…”

Section: Transient Kinetics Of the Reduction Of Cucl2mentioning

confidence: 99%

“…(3)], CuCl 2 was reduced by C 2 H 4 [10] . The ethylene conversion and the accumulative removed Cl from CuCl 2 was measured as a function of time [8d,9,11] . Only EDC and no CO x were detected as the product.…”

Section: Transient Kinetics Of the Reduction Of Cucl2mentioning

confidence: 99%

“…Details regarding the experimental procedure and setup can be found elsewhere [9] . In short, the catalyst was prepared through incipient wetness impregnation (CuCl 2 ⋅ 2H 2 O, 5 wt % Cu) on γ ‐Al 2 O 3 .…”

Section: Transient Kinetics Of the Reduction Of Cucl2mentioning

confidence: 99%

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Prediction and Tuning of the Defects in the Redox Catalysts: Ethylene Oxychlorination

Fenes

et al. 2020

ChemCatChem

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The defect plays a significant role in tuning the electronic structure of metal compounds such as oxides, chlorides, sulfides and nitrides, which is frequently used to explain the enhanced catalytic activity. However, the dynamic change of defect relating to the oxidation state change during the reaction is rarely addressed, and it is still not able to be appropriately predicted since the kinetic modeling of the redox reaction involving the in‐situ formation of defects is challenged by the dynamic evolution of the active sites and the complex kinetic phenomena. Here, for the first time, we present a general method to build a new kinetic model of the redox reaction cycle by combined kinetics of reduction‐ and oxidation steps to predict the time and spatially resolved formation of defects of solid catalysts and the reaction products in ethylene oxychlorination on CuCl2/Al2O3 catalyst. The defect concentration can be tuned by manipulating the relative rates of the reduction‐ and oxidation steps.

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Section: Transient Kinetics Of the Oxidation Stepmentioning

confidence: 97%

Section: Transient Kinetics Of the Reduction Of Cucl2mentioning

confidence: 99%

Section: Transient Kinetics Of the Reduction Of Cucl2mentioning

confidence: 99%

Section: Transient Kinetics Of the Reduction Of Cucl2mentioning

confidence: 99%

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Prediction and Tuning of the Defects in the Redox Catalysts: Ethylene Oxychlorination

Fenes

et al. 2020

ChemCatChem

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“…9 and 10), thus forming complex compounds on the surface, which subsequently catalyze the reaction of OCE in 1.2-DCE as shown earlier by [6]. At the same time, relatively large amounts of K and La do not positively influence the work of the catalyst X1 Harshow [13][14]. The figures below show the EDX spectra of the dispersive x-ray fluorescence spectrometer of the industrial catalyst of the EOC process of the impregnated type MEDC-B with their decoding of the mass content of the elements (Fig.…”

Section: Methodsmentioning

confidence: 89%

Features of the structure active centers of industrial catalysts for the oxidative chlorination of ethylene

Kurta¹,

Mykytyn²,

Ribun³

et al. 2018

IJET

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The active phase of CuCl2, HСuСl2, H2СuСl4 and two grades of industrial ethylene oxidation chlorination catalysts (EOC) such as deposited catalyst X1 (Harshow), with copper chlorides supported on an alumina surface, and a permeated MEDC-B catalyst immobilized in the internal pores of the firm of the company Sud-Chemie. Catalyst were analyzed by the method of thermoemission electronic raster (VEGA3NTSCAN) microscopy and X-ray fluorescence energy dispersion spectroscopy (EDX-7000). It is shown that the active catalyst centers of CuCl2 have different crystalline structure from the amorphous active phase of H2CuCl2, H2CuCl4 on the surface of the catalysts. On the surface of X1 Harshow copper chlorides are uniformly distributed throughout the volume of the carrier catalyst γ-Al2O3 in the form of amorphous portions [CuCl4]-2, [CuCl2]-1. At the same time, on the surface of the catalyst MEDC-B, the active centers have a separate cluster immobilized crystalline structure of the active phase, which differs from the composition of the carrier γ-Al2O3.

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Nitrogen‐Doped Carbon‐Assisted One‐pot Tandem Reaction for Vinyl Chloride Production via Ethylene Oxychlorination

et al. 2020

Angewandte Chemie

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Abifunctional catalyst comprising CuCl 2 /Al 2 O 3 and nitrogen-doped carbon was developed for an efficient one-pot ethylene oxychlorination process to produce vinyl chloride monomer (VCM) up to 76 %y ield at 250 8 8Ca nd under ambient pressure,whichishigher than the conventional industrial two-step process (% 50 %) in as ingle pass.Int he second bed, active sites containing N-functional groups on the metal-free N-doped carbon catalyzed both ethylene oxychlorinationa nd ethylene dichloride (EDC) dehydrochlorination under the mild conditions.Benefitting from the bifunctionality of the Ndoped carbon, VCM formation was intensified by the surface Cl*-looping of EDC dehydrochlorination and ethylene oxychlorination. Both reactions were enhanced by in situ consumption of surface Cl* by oxychlorination, in which Cl* was generated by EDC dehydrochlorination. This work offers ap romising alternative pathwayt oV CM production via ethylene oxychlorination at mild conditions through asingle pass reactor.

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Understanding of potassium promoter effects on oxychlorination of ethylene by operando spatial-time resolved UV–vis–NIR spectrometry

Cited by 24 publications

References 37 publications

Prediction and Tuning of the Defects in the Redox Catalysts: Ethylene Oxychlorination

Prediction and Tuning of the Defects in the Redox Catalysts: Ethylene Oxychlorination

Features of the structure active centers of industrial catalysts for the oxidative chlorination of ethylene

Nitrogen‐Doped Carbon‐Assisted One‐pot Tandem Reaction for Vinyl Chloride Production via Ethylene Oxychlorination

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