Simultaneous characterization of acidic and basic properties of solid catalysts by a new TPD method and their correlation to reaction rates

Tago, Teruoki; Okubo, Yoshihito; Mukai, Shin R.; Tanaka, Tsunehiro; Masuda, Toshio

doi:10.1016/j.apcata.2005.05.010

Cited by 17 publications

(13 citation statements)

References 29 publications

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“…Additionally, the acidity of the obtained samples was also evaluated by the NH 3 -TPD method [25]. In the TPD experiment, the carrier gas was 1.0% NH 3 (balance He), the heating rate was 5 K min -1 , and the temperature range was 373 -823 K. The desorption of NH 3 molecules from the acid sites of the zeolite was measured under a 1.0% NH 3 -He atmosphere so that the TPD profile could be measured under complete adsorption equilibrium conditions, referred to as the ac-NH 3 -TPD method.…”

Section: Characterizationmentioning

confidence: 99%

Kinetics of n-hexane cracking over ZSM-5 zeolites – Effect of crystal size on effectiveness factor and catalyst lifetime

Konno

Okamura

Kawahara

et al. 2012

Chemical Engineering Journal

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163

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The catalytic cracking of n-hexane over ZSM-5 zeolite (MFI-type zeolite, Si/Al = 150 and 240) catalysts was examined at reaction temperatures ranging from 823 to 923 K under atmospheric pressure. The reaction rate constants and activation energies of n-hexane cracking over ZSM-5 zeolites with various crystal sizes and Si/Al ratios were evaluated. The catalytic cracking of n-hexane was first order with respect to the n-hexane concentration, and the activation energies of n-hexane cracking over ZSM-5 zeolites were found to be approximately 123-128 kJmol -1 . Compared with the macro-sized zeolite, the nano-sized zeolites exhibited high n-hexane conversion with stable activity for 50 h. This is because the cracking reaction with nano-sized zeolite proceeded under reaction-limiting conditions, whereas the reaction with macro-sized zeolite proceeded under transition conditions between reaction-and diffusion-limiting conditions. As a result, the application of nano-zeolite to the catalytic cracking of n-hexane was effective and gave light olefins with high yield and excellent stable activity.

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Section: Characterizationmentioning

confidence: 99%

Kinetics of n-hexane cracking over ZSM-5 zeolites – Effect of crystal size on effectiveness factor and catalyst lifetime

Konno

Okamura

Kawahara

et al. 2012

Chemical Engineering Journal

Self Cite

163

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“…The distribution of sites is mainly caused by the phase composition of a compound. Acid sites are Brønsted-type (terminal or bridge surface hydroxyl groups) and Lewis (coordination-unsaturated aluminum cations) centers [24,25]. Both types of acid sites are identified by various methods one of which is the TPD of NH 3 method.…”

Section: Resultsmentioning

confidence: 99%

Influence of the Obtaining Method on the Properties of Amorphous Aluminum Compounds

et al. 2019

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Amorphous aluminum compounds are formed during the synthesis of the γ-Al2O3 catalyst precursor. Amorphous compounds influence on the alumina catalyst variously due to different physicochemical properties, which depend on the method of their preparation. In this research, the comparative analysis of physicochemical properties of amorphous aluminum compounds that were obtained by the precipitation method, the thermal decomposition of aluminum nitrate, and alcoxide hydrolysis product were studied. It is the first time that a new method for calculating of quantitative phase composition of amorphous aluminum compounds using the X-ray powder diffraction, thermogravimetric and differential scanning calorimetry analysis, mass-spectrometry, and CHN-analysis was described. Properties of obtaining samples were studied using scanning electron microscopy, low-temperature nitrogen adsorption, and temperature programmed desorption of ammonium analyses. The methods of precipitation and thermal decomposition of aluminum nitrate allows for obtaining non-porous samples consisting of a mixture of amorphous phases (hydroxide and basic salt) that contain the metals impurities and have low acidity of the oxides obtained from them. The highly porous amorphous alumina formed by the thermal decomposition of the alcoxide hydrolysis product with the least amount of impurities and a high acidity of the surface was observed.

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“…A Acidity of Oxide Catalysts Ammonia TPD has been employed to characterize the acidity of a variety of zeolites including MFI (ZSM-5) [35,[47][48][49][50], MOR (mordenite) [35], FAU (faujasite) [48,49,51], BEA (beta) [49,52], MAZ (mazzite) [53] and MWW (MCM-22) [54]. Pyridine TPD has also been used to study the acid properties of zeolites (e.g.…”

Section: 2423mentioning

confidence: 99%

Thermochemical Characterization

Cardona-Martı́nez¹,

Dumesic²

2008

Handbook of Heterogeneous Catalysis

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The sections in this article are Introduction Principles of Temperature‐Programmed Desorption Applications of Temperature‐Programmed Desorption Principles of Adsorption Microcalorimetry Applications of Adsorption Microcalorimetry Conclusions

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Simultaneous characterization of acidic and basic properties of solid catalysts by a new TPD method and their correlation to reaction rates

Cited by 17 publications

References 29 publications

Kinetics of n-hexane cracking over ZSM-5 zeolites – Effect of crystal size on effectiveness factor and catalyst lifetime

Kinetics of n-hexane cracking over ZSM-5 zeolites – Effect of crystal size on effectiveness factor and catalyst lifetime

Influence of the Obtaining Method on the Properties of Amorphous Aluminum Compounds

Thermochemical Characterization

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