Effect of water treatment on Sn-BEA zeolite: Origin of 960 cm−1 FTIR peak

Courtney, Timothy D.; Chang, Chun‐Chih; Gorte, Raymond J.; Lobo, Raúl F.; Fan, Wei; Nikolakis, Vladimiros

doi:10.1016/j.micromeso.2015.02.012

Cited by 72 publications

(78 citation statements)

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“…The nature of Zr/BEA active sites was further investigated in subsequent studies [49,70]. Ivanova et al argued that the configuration of Zr(IV) within the zeolite framework influenced the activity of the Lewis acid sites-a phenomenon comparable to the well-documented cases of Ti/BEA and Sn/BEA in which distinguishable "open" and "closed" Lewis acid sites have been demonstrated to exist [71][72][73][74][75]. The term open site refer to partially hydrolyzed metal ion sites linked by three M-O-Si bonds to the zeolite framework with one M-OH linkage ( Figure 9) compared to closed sites fully coordinated in the zeolite framework by four M-O-Si bonds ( Figure 9).…”

Section: Catalysts For the One-step Processmentioning

confidence: 99%

Recent Breakthroughs in the Conversion of Ethanol to Butadiene

et al. 2016

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1,3-Butadiene is traditionally produced as a byproduct of ethylene production from steam crackers. What is unusual is that the alternative production route for this important commodity chemical via ethanol was developed a long time ago, before World War II. Currently, there is a renewed interest in the production of butadiene from biomass due to the general trend to replace oil in the chemical industry. This review describes the recent progress in the production of butadiene from ethanol (ETB) by one or two-step process through intermediate production of acetaldehyde with an emphasis on the new catalytic systems. The different catalysts for butadiene production are compared in terms of structure-catalytic performance relationship, highlighting the key issues and requirements for future developments. The main difficulty in this process is that basic, acid and redox properties have to be combined in one single catalyst for the reactions of condensation, dehydration and hydrogenation. Magnesium and zirconium-based catalysts in the form of oxides or recently proposed silicates and zeolites promoted by metals are prevailing for butadiene synthesis with the highest selectivity of 70% at high ethanol conversion. The major challenge for further application of the process is to increase the butadiene productivity and to enhance the catalyst lifetime by suppression of coke deposition with preservation of active sites.

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Section: Catalysts For the One-step Processmentioning

confidence: 99%

Recent Breakthroughs in the Conversion of Ethanol to Butadiene

et al. 2016

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“…Lewis acid strength 12,[17][18][19][20]33 . In most cases, the adsorption of deuterated acetonitrile is monitored by FTIR spectroscopy.…”

Section: Adsorption Of Acetonitrilementioning

confidence: 99%

“…In most cases, the adsorption of deuterated acetonitrile is monitored by FTIR spectroscopy. Additionally, some reports on the application of temperature programmed desorption (TPD) techniques are also available 17,20 . Application of this probe molecule allows for the differentiation between framework and extraframework tin sites 12,20 .…”

Section: Adsorption Of Acetonitrilementioning

confidence: 99%

“…Among the different approaches, the application of probe molecules was shown to be the most fruitful for characterization of tin sites and their local environment 8,11,12,14,[17][18][19][20]23,[25][26][27][28][29][30] . Besides that, probe molecules were particularly useful in deducing the catalytic behavior by providing insights into the interaction of the active site with solvents, reactants, intermediates and products in reactions catalyzed by Sn-BEA.…”

mentioning

confidence: 99%

“…It should be noted that most studies involving probe molecules has been monitored by FTIR and TPD techniques 8,12,[17][18][19][20]26,[28][29][30] . Both these techniques provide comprehensive information on the state of the adsorbed probe molecule, indirectly providing information on the nature of the Sn-sites.…”

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¹¹⁹Sn MAS NMR Study of the Interaction of Probe Molecules with Sn-BEA: The Origin of Penta- and Hexacoordinated Tin Formation

et al. 2016

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Zeolite (In)Stability under Aqueous or Steaming Conditions

et al. 2020

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zeolites, modification of zeolite acidity for use as fluid catalytic cracking (FCC) catalysts or even for the preparation of novel zeolite frameworks. [1] Considering the significance of zeolite applications at the industrial level, a thorough understanding of zeolite (in)stability under aqueous conditions has been identified as a very important problem in catalysis and zeolite science. Zeolite (in)stability in water or under steaming conditions has been investigated by a number of experimental techniques, in particular magic angle spinning (MAS) NMR, IR, powder X-ray diffraction (PXRD), calorimetry and adsorption. Experimental studies have often been augmented by computational modeling and a large number of relevant theoretical papers can be found in the literature. While the main focus of this review is on reactive interactions of water with zeolites, it is also important to review the most important observations obtained for nonreactive water adsorption in zeolites. It is not surprising that all-silica zeolites, which exhibit negligible water uptake are stable even under conditions where Alcontaining zeolites lose crystallinity: the effective framework hydrolysis can only take place when sufficient water is present in the zeolite channel system. The amount of water inside the zeolite channels depends critically on the concentration of heteroatoms and/or framework defects, such as silanol nests, which show much higher affinity toward water than hydrophobic SiOSi bridges. Zeolite hydrophobicity increases with increasing Si/Al ratio and incomplete pore filling by water is commonly observed for zeolites with high Si/Al at standard pressure. It has been suggested already in the 1950s by Young that water can only adsorb on surface silanol groups, while the parts of the silica surfaces formed by SiOSi bridges are hydrophobic. [2] Both water adsorption in zeolites and zeolite (in)stability under aqueous conditions depend on the zeolite composition (Si/Al ratio, charge-compensating cations, and defect concentration in particular). Our primary goal is to review the most critical aspects of zeolite (in)stability for a broad range of temperature and partial water pressure (p 0), focusing on the framework zeolite composition (Si/Al ratio and presence of Ge, Sn, and Ti heteroatoms) and defect concentration. Zeolites (in)stability in water is discussed for increasing extent of framework degradation, starting from the nonreactive interaction with water, reversible hydrolysis of TO bonds, mild zeolite demetallation, mesopore formation, and total amorphization (Figure 1). Zeolites are among the most environmentally friendly materials produced industrially at the Megaton scale. They find numerous commercial applications, particularly in catalysis, adsorption, and separation. Under ambient conditions aluminosilicate zeolites are stable when exposed to water or water vapor. However, at extreme conditions as high temperature, high water vapor pressure or increased acidity/basicity, their crystalline framework can be destroyed....

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Effect of water treatment on Sn-BEA zeolite: Origin of 960 cm−1 FTIR peak

Cited by 72 publications

References 46 publications

Recent Breakthroughs in the Conversion of Ethanol to Butadiene

Recent Breakthroughs in the Conversion of Ethanol to Butadiene

¹¹⁹Sn MAS NMR Study of the Interaction of Probe Molecules with Sn-BEA: The Origin of Penta- and Hexacoordinated Tin Formation

Zeolite (In)Stability under Aqueous or Steaming Conditions

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Effect of water treatment on Sn-BEA zeolite: Origin of 960 cm−1 FTIR peak

Cited by 72 publications

References 46 publications

Recent Breakthroughs in the Conversion of Ethanol to Butadiene

Recent Breakthroughs in the Conversion of Ethanol to Butadiene

119Sn MAS NMR Study of the Interaction of Probe Molecules with Sn-BEA: The Origin of Penta- and Hexacoordinated Tin Formation

Zeolite (In)Stability under Aqueous or Steaming Conditions

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Product

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¹¹⁹Sn MAS NMR Study of the Interaction of Probe Molecules with Sn-BEA: The Origin of Penta- and Hexacoordinated Tin Formation