Quantifying the dominant factors in Cu catalyst deactivation during glycerol hydrogenolysis

Rajkhowa, Tapas; Marin, Guy; Thybaut, Joris W.

doi:10.1016/j.jiec.2017.05.040

Cited by 17 publications

(22 citation statements)

References 53 publications

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“…A decreasing activity as a function of time on stream at constant operating conditions is then caused by catalyst deactivation. The specific evolution in the catalyst activity can then be used to gain more insight into the mechanism responsible for this deactivation [24]. Hence, the assessment of catalyst stability is preferably done in a continuous-flow reactor as opposed to a batch reactor.…”

Section: Continuous-flow Reactor For the Assessment Of Catalyst Deactmentioning

confidence: 99%

“…Kinetically, this leads to a rate which not only depends on the operating conditions, but also depends on the historical evolution of operating conditions the catalyst has been subjected to. A common approach to deactivation kinetics results in a "separable" rate expression [24,26], written as a time-on-stream independent kinetics term, and a time-on-stream dependent deactivation term. Hence, to determine the catalyst activity free of any deactivation phenomena, a function representative for the deactivation kinetics should be found [24,27,28].…”

Section: Continuous-flow Reactor For the Assessment Of Catalyst Deactmentioning

confidence: 99%

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Catalyst Stability Assessment in a Lab-Scale Liquid-Solid (LS)² Plug-Flow Reactor

et al. 2019

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A packed-bed plug-flow reactor, denoted as the lab-scale liquid-solid (LS)² reactor, has been developed for the assessment of heterogeneous catalyst deactivation in liquid-phase reactions. The possibility to measure intrinsic kinetics was first verified with the model transesterification of ethyl acetate with methanol, catalyzed by the stable commercial resin Lewatit K2629, for which a turnover frequency (TOF) of 6.2 ± 0.4 × 10−3 s−1 was obtained. The absence of temperature and concentration gradients was verified with correlations and experimental tests. The potential for assessing the deactivation of a catalyst was demonstrated by a second intrinsic kinetics evaluation where a methylaminopropyl (MAP)-functionalized mesoporous silica catalyst was used for the aldol reaction of acetone with 4-nitrobenzaldehyde in different solvents. The cooperative MAP catalyst deactivated as a function of time on stream when using hexane as solvent. Yet, the monofunctional MAP catalyst exhibited stable activity for at least 4 h on stream, which resulted in a TOF of 1.2 ± 0.1 × 10−3 s−1. It did, however, deactivate with dry acetone or DMSO as solvent due to the formation of site-blocking species. This deactivation was mitigated by co-feeding 2 wt % of water to DMSO, resulting in stable catalyst activity.

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Section: Continuous-flow Reactor For the Assessment Of Catalyst Deactmentioning

confidence: 99%

Section: Continuous-flow Reactor For the Assessment Of Catalyst Deactmentioning

confidence: 99%

Catalyst Stability Assessment in a Lab-Scale Liquid-Solid (LS)² Plug-Flow Reactor

et al. 2019

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“…However, crude glycerol from the biodiesel industry is always found at high concentrations (70-80 wt.%) and has impurities of a different nature [32][33][34]. Among those impurities, remnants of methanol and NaOH can come from the biodiesel synthesis [32] as well as NaCl [33] or Na 2 SO 4 [34] due to the neutralization of NaOH with inorganic acids, such as HCl or H 2 SO 4 respectively. Matter organic non-glycerol (MONG) such as mono, di-and triglycerides may also be present in crude glycerol [33].…”

Section: Introductionmentioning

confidence: 99%

“…Among those impurities, remnants of methanol and NaOH can come from the biodiesel synthesis [32] as well as NaCl [33] or Na 2 SO 4 [34] due to the neutralization of NaOH with inorganic acids, such as HCl or H 2 SO 4 respectively. Matter organic non-glycerol (MONG) such as mono, di-and triglycerides may also be present in crude glycerol [33]. In the case of NaOH, it was reported that the concentration of NaOH can lead to lactic acid formation, which is a degradation product [35].…”

Section: Introductionmentioning

confidence: 99%

“…In the case of NaOH, it was reported that the concentration of NaOH can lead to lactic acid formation, which is a degradation product [35]. With respect to the NaCl salt, the presence of Cl-can lead to a catalyst deactivation due to the incorporation of Cl-over the metallic particles [33]. As regards the MONG content, reports indicate that glycerides (mono, di, or triglycerides) make the catalyst surface dirty, block active sites, and even act as coke precursors [33].…”

Section: Introductionmentioning

confidence: 99%

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High Yield to 1-Propanol from Crude Glycerol Using Two Reaction Steps with Ni Catalysts

et al. 2020

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The objective of the present work is to achieve high yield to 1-propanol (1-POH) by crude glycerol hydrogenolysis in liquid phase and find an alternative to the use of noble metals by employing Ni catalysts. Two Ni catalysts with different supports, alumina (γ-Al2O3), and a phosphorous-impregnated carbon composite (CS-P) were studied and characterized in order to determine their acid properties and metallic phases. With the Ni/γ-Al2O3 catalyst, which presented small particles of metallic Ni interacting with the acid sites of the support, it was possible to obtain a complete conversion of crude glycerol with high selectivity towards 1,2-propylene glycol (1,2 PG) (87%) at 220 °C whereas with the Ni/CS-P catalyst, the presence of AlPOx species and the Ni2P metallic phase supplied acidity to the catalyst, which promoted the C-O bond cleavage reaction of the secondary carbon of 1,2 PG to obtain 1-POH with very high selectivity (71%) at 260 °C. It was found that the employment of two consecutive reaction stages (first with Ni/ γ-Al2O3 at 220 °C and then with Ni/CS-P at 260 °C) allows reaching levels of selectivity and a yield to 1-POH (79%) comparable to noble metal-based catalysts.

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Catalytic Conversion of Glycerol to Acetol and Acrolein Using Metal Oxides: Surface Reactions, Prospects and Challenges

Barbosa

Braga

2022

ChemCatChem

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Glycerol dehydration to acetol and acrolein is an interesting reaction pathway for conversion of biomass‐derived products. However, they undergo extensive deactivation due to coke deposition and sintering, requiring the design of stable catalysts. The oxides stand out due to their natural abundance, simple synthesis, low cost and tunable acidic, basic and redox properties. The different studies apply these oxides as pure phase, supported, mixed or doped. However, it is observed that despite the large number of applied oxides in glycerol conversion, few works describe in detail about more complex oxides such as ferrites, hexaferrites, perovskites, among others. This review reports different acid oxides in the glycerol dehydration to acetol and acrolein as well as basic and redox oxides, describing a historical perspective, showing the most important theoretical foundations of heterogeneous catalysis to comprehend surface reactions and mentioning the different possibilities to understanding the different reactional pathway, highlighting the proposal mechanisms that explain the participation of the different active sites on the surface reactions. Furthermore, the sequence of reactions which show the origin of the coke deposited on catalyst surface was presented, emphasizing the main challenges. The role of the Lewis and Brønsted acid‐base sites present in the metal oxides and their interactions on glycerol dehydration were described, providing a direction to design catalysts for selective dehydration reactions resistant against coke deposition and sintering.

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Quantifying the dominant factors in Cu catalyst deactivation during glycerol hydrogenolysis

Cited by 17 publications

References 53 publications

Catalyst Stability Assessment in a Lab-Scale Liquid-Solid (LS)² Plug-Flow Reactor

Catalyst Stability Assessment in a Lab-Scale Liquid-Solid (LS)² Plug-Flow Reactor

High Yield to 1-Propanol from Crude Glycerol Using Two Reaction Steps with Ni Catalysts

Catalytic Conversion of Glycerol to Acetol and Acrolein Using Metal Oxides: Surface Reactions, Prospects and Challenges

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