Selected properties and electronic spectra for a series of copper(II) alkali, alkaline earth, and lanthanide metal chloride oxyhydrochlorination catalysts on alumina

Dotson, Ronald L.

doi:10.1016/0021-9517(74)90265-6

Cited by 23 publications

(13 citation statements)

References 25 publications

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“…They proposed that the ethylene oxychlorination reaction did not go through the Deacon reaction, instead, it went through the reduction (eq ) and oxidation as well as hydrochlorination (eqs and ) reactions . Later a three-step mechanism (eqs –) was proposed on CuCl 2 catalysts based on a Mars-van Krevelen (MvK) mechanism, where the lattice Cl participates in the reaction evidenced by the direct reduction of CuCl 2 by ethylene. ,, Lamberti et al confirmed the three-step redox reaction mechanism on CuCl 2 /γ-Al 2 O 3 -based catalysts by using operando X-ray absorption spectroscopy, as shown in Figure . ,, The XANES spectroscopy is found to be a powerful tool to measure both oxidation and coordination states of copper, which could be measured by the shift of the Cu K-edge Figure a indicates that interaction with ethylene leads to a redshift of the edge.…”

Section: Cu-based Catalysts For Ethylene Oxychlorinationmentioning

confidence: 99%

“…Besides, the interaction between CuCl 2 and the support plays a virtually important role in the mobility of the Cu species. The strong adsorption on γ-Al 2 O 3 reduced significantly the mobility and enhanced stability. ,, …”

Section: Cu-based Catalysts For Ethylene Oxychlorinationmentioning

confidence: 99%

“…Therefore, the industrial catalysts are typically promoted to maintain and enhance the activity and stability of CuCl 2 /γ-Al 2 O 3 . Based on the promoter chemical identity, the promoters can be classified into alkali metals (K, Na, Li, and Cs), ,,,,, alkali-earth metals (Mg, Ca, Sr, etc. ), ,,, and rare-earth metals such as La, Ce, Pr, etc. ,,,,,,− Based on the number of promoters employed in one catalyst, the promoters can be classified as mono-, bi-, and multipromoters.…”

Section: Cu-based Catalysts For Ethylene Oxychlorinationmentioning

confidence: 99%

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Critical Review of Catalysis for Ethylene Oxychlorination

Wang

et al. 2020

ACS Catal.

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Ethylene oxychlorination is the key technology in vinyl chloride (VCM, the monomer of PVC, polyvinyl chloride) production to close the chlorine loop by consuming the HCl released from the former cracking step. Due to the high demand for PVC, this leads to ethylene oxychlorination being one of the most important processes in the industry. This Review covers an indepth analysis of the dynamic nature of active sites for the main and side reactions involved in ethylene oxychlorination, featuring the findings and viewpoints from the dynamic kinetics study and analysis under industrial operating conditions. A unified picture of the mechanism of the surface reactions, and the effect of supports and promoters, has been presented based on the decoupled redoxcycle experiments, which leads to a significantly better understanding of the mechanism and provides valuable guidelines for effective catalyst design. Operando techniques and kinetic tools of the rate-diagram, as well as their application to the study of the redox-cycle in ethylene oxychlorination and kinetic models on both the main product and byproduct, are also reviewed. Perspectives on challenges and new process development and future research focus for better study of the VCM production chemistry are also proposed.

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Section: Cu-based Catalysts For Ethylene Oxychlorinationmentioning

confidence: 99%

Section: Cu-based Catalysts For Ethylene Oxychlorinationmentioning

confidence: 99%

Section: Cu-based Catalysts For Ethylene Oxychlorinationmentioning

confidence: 99%

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Critical Review of Catalysis for Ethylene Oxychlorination

Wang

et al. 2020

ACS Catal.

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“…without additives) for the oxychlorination reaction only. Due to its relevant industrial impact, several papers have been devoted to its study [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. From these studies, the existence, on base catalyst, of two different Cu compounds is clearly emerging.…”

Section: Introductionmentioning

confidence: 99%

The CuCl2/Al2O3 Catalyst Investigated in Interaction with Reagents

Lamberti

Prestipino

Capello

et al. 2001

IJMS

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Alumina supported CuCl2, the basic catalyst for ethylene oxychlorination, has been investigated by UV-Vis spectroscopy, EPR, EXAFS and XANES in a wide range (0.25-9.0 wt%) of Cu concentration. We have evidenced that, at low Cu content, the formation of a surface aluminate species takes place. The formation of this surface copper aluminate stops at 0.95 wt% Cu / 100 m2; at higher Cu concentrations excess copper chloride precipitates directly from solution during the drying step forming an highly dispersed CuCl2.H2O, phase, overlapping progressively the surface aluminate. Depletion tests and IR spectroscopy of adsorbed NO have demonstrated that the latter is the only active phase. A complete catalytic cycle has then been performed on CuCl2/Al2O3 catalyst. EPR, XANES and EXAFS, have been used to demonstrate that the ethylene oxychlorination reaction: C2H4 + 2HCl + Ã‚Â½ O2 --> C2H4Cl2 + H2O follows a three steps mechanism: (i) reduction of CuCl2 to CuCl (2CuCl2 + C2H4 --> C2H4Cl2 + 2CuCl), (ii) oxidation of CuCl to give an oxychloride (2CuCl + Ã‚Â½ O2 --> Cu2OCl2) and (iii) closure of the catalytic circle by rechlorination with HCl, restoring the original CuCl2 (Cu2OCl2 + 2HCl --> 2CuCl2 + H2O). Finally, we have shown that time resolved, in situ, spectroscopy is a very promising technique to investigate the interplay between catalyst activity and oxidation state of copper

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“…However, the exact form of this influence is unknown. The current discussion is concerned with the presence of monovalent copper inside the active phase of catalysts of type carrier-CuCl2, KC1 [6][7][8][9], and the effects of the carrier surface on the active phase and structure of the catalyst [10][11][12]. Thus, little is known about the exceptional applicability of the natural carrier with the trade-name "Florida" for the production of a catalyst for the process of ethene oxychlorination [13].…”

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confidence: 99%

DTA analysis of the system carrier-CuCl2, KCl. part I

Żurowski¹

1990

Journal of Thermal Analysis

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DTA analysis of carrier-CuCl2, KCI catalysts with total active salt contents of from 17.68 to 33.27%, and with Cu:K molar ratios of from 0.691 to 0.922, revealed a number of r dothermic processes within the temperature range 293-773 IL The extents of these processes depended on the total salt content and the Cu:K molar ratio. The influence of the carrier on the active phase constitution was observed.

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Selected properties and electronic spectra for a series of copper(II) alkali, alkaline earth, and lanthanide metal chloride oxyhydrochlorination catalysts on alumina

Cited by 23 publications

References 25 publications

Critical Review of Catalysis for Ethylene Oxychlorination

Critical Review of Catalysis for Ethylene Oxychlorination

The CuCl2/Al2O3 Catalyst Investigated in Interaction with Reagents

DTA analysis of the system carrier-CuCl2, KCl. part I

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