Crucial Role of Weak Acid Sites for Catalytic Performance of Zeolites in Ethyl <i>tert</i>-butyl Ether Synthesis

Vlasenko, N. A.; Kochkin, Yu. N.; Puziy, Alexander M.; Strizhak, P. E.

doi:10.1080/00986445.2017.1328411

Cited by 7 publications

(11 citation statements)

References 30 publications

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“…Using CONTIN method allows to calculate the ammonia adsorption energy for acid sites of studied zeolites. 78,83 The corresponding ammonia adsorption energy distribution proles for H-BEA samples are shown in Fig. 4, highlighting the energetic heterogeneity of acid sites.…”

Section: Acid Capacity and Strengthmentioning

confidence: 99%

“…Acid properties of samples were investigated by Quasi-Equilibrium Thermodesorption (QETD) of ammonia. 78,83 Experiments were carried out at 50-500 C under vacuum (constant pressure 0.133 Pa was maintained by vacuum pump) using thermogravimetric apparatus with quartz spring balance of McBain type. Prior to the experiment, the sample was outgassed at the temperature of its calcination during a time sufficient to reach a constant weight of the sample (typically 1.5-2 h).…”

Section: Acidity Measurementmentioning

confidence: 99%

“…The concentration of each type of acid sites was calculated from the amount of ammonia sorption (mmol g À1 ) in a certain temperature range determined by the form of the QETD curve. The total concentration of the acid sites (acid capacity) was determined as a quantity of ammonia adsorbed on a sample surface at 50 C. 78,83 The obtained QETD data allows one to estimate not only the total acid capacity as an amount of ammonia adsorbed in all temperature range but also amounts of weak and strong sites of various strength. The acidity of all zeolites was investigated by adsorption of pyridine used as a probe molecule followed by FTIR spectroscopy.…”

Section: Acidity Measurementmentioning

confidence: 99%

“…The ammonia QETD studies show that zeolites H-BEA may contain three types of acid sites, which are typical for zeolites. 21,83 The strong acid sites, apparently, can be assigned to the Lewis sites representing three-coordinated aluminum atoms. The sites of medium strength can be assigned to the "classic" Brønsted acid sites represented by the bridging hydroxyl groups, Si(OH)Al.…”

Section: The Nature Of Active Sites Of Zeolite H-beamentioning

confidence: 99%

“…In our previous work, we have established a crucial role of the weak acid sites of zeolites for their catalytic behavior in the ETBE synthesis. 83 However, the nature of these sites was not clear. In this study we present the results to highlight the nature of the weak acid sites of H-BEA zeolites which are active in the etherification of isobutylene with ethanol.…”

Section: Introductionmentioning

confidence: 99%

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Insight into the active site nature of zeolite H-BEA for liquid phase etherification of isobutylene with ethanol

et al. 2019

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Section: Acid Capacity and Strengthmentioning

confidence: 99%

Section: Acidity Measurementmentioning

confidence: 99%

Section: Acidity Measurementmentioning

confidence: 99%

Section: The Nature Of Active Sites Of Zeolite H-beamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Insight into the active site nature of zeolite H-BEA for liquid phase etherification of isobutylene with ethanol

et al. 2019

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Hybrid organic‐inorganic acid catalysts: The effect of active sites localization on catalytic characteristics in the processes of alcohols' etherification. A review

Vlasenko

Strizhak

2021

J of Applied Polymer Sci

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This article reviews the various types of hybrid organic–inorganic resin catalysts: mixed and co‐precipitated composites, loaded, and tailored systems. The review gives a generalization of the authors' results in the field of synthesis and research of organic–inorganic resin catalysts, in the context of the main trends in the development of this field of science. Based on a comparison of the productivity of organic–inorganic and commercial sulfonic resins, the role of acid sites localization for determining the catalytic characteristics of sulfonic resin catalysts in ethanol and isopropanol etherification with isobutylene is discussed. Studies showed that acid sites of loaded sulfonic resins, localized on the external surface, have the highest productivity. The effect of morphology on the differences in the activity of different types of sulfonic resins in the etherification reactions is more pronounced for materials with limited accessibility of acid sites due to internal diffusion. With an increase in the accessibility of acid sites, the polarity and molecule size of the reacting alcohols become the predominant factors. These findings have an impact on the design of organic–inorganic resin catalysts with high performance.

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Glycerol Oligomerization over Titania‐Based Catalyst Compositions

Vlasenko,

Yanushevska,

Didenko

et al. 2023

Chemistry A European J

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The possibility of using TiO2‐based compositions: individual and sulfated titania, and their composites with carbon nanotubes as catalysts for glycerol oligomerization has been displayed. The effect of modification of TiO2 with sulfur and carbon nanotubes on acid‐base and catalytic characteristics in the glycerol conversion was investigated. The activation of glycerol on the catalysts has been studied using attenuated total reflectance Fourier transform infrared (ATR‐FTIR) spectroscopy. Only the samples based on sulfated titania are active over glycerol transformation, showing up to 58.7% conversion. This is explained by the presence of strong base sites. Glycerides up to pentaglycerides, both linear and nonlinear structure are formed by glycerol oligomerization over TiO2‐S. The addition of nanotubes to the catalyst`s reduces both the glycerol conversion (up to 10.5%) and the yield of glycerides. However, the spectrum of the resulting products is significantly narrowed, increasing the selectivity for short‐chain glycerides: the portion of diglycerides reaches 72%, and triglycerides 21%. Herewith, glycerides of a linear structure only formed.

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Crucial Role of Weak Acid Sites for Catalytic Performance of Zeolites in Ethyl tert-butyl Ether Synthesis

Cited by 7 publications

References 30 publications

Insight into the active site nature of zeolite H-BEA for liquid phase etherification of isobutylene with ethanol

Insight into the active site nature of zeolite H-BEA for liquid phase etherification of isobutylene with ethanol

Hybrid organic‐inorganic acid catalysts: The effect of active sites localization on catalytic characteristics in the processes of alcohols' etherification. A review

Glycerol Oligomerization over Titania‐Based Catalyst Compositions

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