An ex situ methodology for characterization of coke by TGA and 13C CP-MAS NMR spectroscopy

Pradhan, Ajit; Wu, Jinfu; Jong, Sung-Jeng; Tsai, Tseng-Chang; Liu, S.B.

doi:10.1016/s0926-860x(97)00231-7

Cited by 40 publications

(19 citation statements)

References 22 publications

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“…We previously observed that coke precursors of disproportionation, such as diethylbenzene in ethylbenzene disproportionation and di-propylbenzene in cumene disproportionation, can be removed simply by vacuum evaporation [34,35]. As evidenced in Table 1, coke content reduced after nitrogen reactivation, dropping from 12.3% down to 10.1%, indicating the removal of coke precursors.…”

Section: Mechanism Of Reactivation In Hmentioning

confidence: 90%

Reactivation of acidic sites in mordenite used in toluene disproportionation

Tsai

2006

Applied Catalysis A: General

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Section: Mechanism Of Reactivation In Hmentioning

confidence: 90%

Reactivation of acidic sites in mordenite used in toluene disproportionation

Tsai

2006

Applied Catalysis A: General

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“…The DTA peak at ca. 673-873 K can be assigned to the combustion of "hard" coke, essentially located in the zeolite cavities [42]. In Fig.…”

Section: Characterization Of the Exhausted Catalysts By Tg-dtamentioning

confidence: 99%

Tuning of product selectivity in the conversion of ethanol to hydrocarbons over H-ZSM-5 based zeolite catalysts

Phung

Radikapratama

Garbarino

et al. 2015

Fuel Processing Technology

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Conversion of ethanol to hydrocarbons was investigated over H-ZSM-5 zeolite and its modification by addition of phosphorus, iron and nickel. Reaction is realized in a tubular flow reactor at atmospheric pressure. Catalyst characterization was performed by UV-vis, TG-DTA, XRD, NH3-TPD, and IR spectroscopy of the surface OH groups and of adsorbed pyridine. High P content enhances the selectivity to lower olefins, in particular ethylene, as also occurs in the case of Fe addition. Over Ni-modified zeolites, C4 and aromatic production is promoted. The role of acidity on the conversion path is briefly discussed

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“…The TGA results show that more coke is formed on the Cs-X and Ca-HA samples than on the Na-USY and Rb-USY zeolites. Based on the observed combustion temperature the weight loss has been presented as soft and hard coke as well as graphitic-like coke [50], according to the classification proposed by Pradhan et al [57]. The analysis of the coke composition indicates that the coke deposits on the Ca-HA sample correspond to a great extent to hard coke burning between 330 and 700 °C [49].…”

Section: Coke Amount and Composition Of Spent Catalyst Materialsmentioning

confidence: 99%

Operando Spectroscopy of the Gas-Phase Aldol Condensation of Propanal over Solid Base Catalysts

et al. 2017

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time. In particular, for Cs-X and Ca-HA the rapid formation of carbonaceous deposits was observed consisting of (poly-)aromatics and highly conjugated structures, respectively. The physicochemical properties of Ca-HA with strong basic sites and moderate acidity limit its deactivation despite the observed coke formation. On the other hand, both USY catalysts were more efficient in suppressing coke formation likely due to the moderate strength of their active sites.

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An ex situ methodology for characterization of coke by TGA and 13C CP-MAS NMR spectroscopy

Cited by 40 publications

References 22 publications

Reactivation of acidic sites in mordenite used in toluene disproportionation

Reactivation of acidic sites in mordenite used in toluene disproportionation

Tuning of product selectivity in the conversion of ethanol to hydrocarbons over H-ZSM-5 based zeolite catalysts

Operando Spectroscopy of the Gas-Phase Aldol Condensation of Propanal over Solid Base Catalysts

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