Zeolite Characterization

Bradley, Steven; Broach, Robert W.; Mezza, Thomas M.; and, Sesh Prabhakar; Sinkler, W.

doi:10.1002/9783527629565.ch4

Cited by 9 publications

(9 citation statements)

References 209 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In contrast, the small-probe ammonia (ca. 3 Å) was able to penetrate into the small 8-MR channel of non-dealuminated MOR . As a result, the total acid sites of recrystallized MOR (H-R) were higher compared to dealuminated MOR in the NH 3 -TPD analysis (Table ).…”

Section: Resultsmentioning

confidence: 96%

“…3 Å) was able to penetrate into the small 8-MR channel of non-dealuminated MOR. 34 As a result, the total acid sites of recrystallized MOR (H-R) were higher compared to dealuminated MOR in the NH 3 -TPD analysis (Table 2). We can conclude that acid dealumination on MOR has opened access to the acid sites on the side-pocket 8-MR channel of MOR, which contains SAS.…”

Section: Energy and Fuelsmentioning

confidence: 95%

See 1 more Smart Citation

Selective Isomerization of n-Butane over Mordenite Nanoparticles Fabricated by a Sequential Ball Milling–Recrystallization–Dealumination Route

et al. 2017

View full text Add to dashboard Cite

For the first time, a sequential fabrication step involving mechanochemistry, recrystallization, and dealumination was developed to convert low-cost natural zeolites to mordenite (MOR) nanoparticles. Natural zeolites are mostly found having poor textural properties and a high aluminum content, which are not suitable for most industrial catalytic reactions. The parent natural zeolites within the size of 1−10 μm were treated by ball milling to obtain nanosized particles with size in the range of 20− 160 nm. The nitrogen physisorption study revealed that the external surface area and intercrystalline mesopore volume of the milled nanoparticles increased by 4-and 7-fold, respectively. Recrystallization by hydrothermal treatment in basic silicate solution was applied to recover the MOR crystallinity at 170 °C for 6 h. The recrystallized MOR samples were further subjected to acid dealumination treatment over different periods. The H-MOR samples were evaluated in a fixed-bed reactor for n-butane isomerization. The isobutane selectivity increased from 11 to 28% when the parent microparticle was substituted by the recrystallized nanoparticles. Moreover, the catalyst stability improved over the recrystallized nanoparticles. The dealuminated− recrystallized nanoparticle exhibited the highest selectivity of ca. 58% to isobutane and less deactivation rate as a result of low acid site density and small nanoparticle size.

show abstract

Section: Resultsmentioning

confidence: 96%

Section: Energy and Fuelsmentioning

confidence: 95%

Selective Isomerization of n-Butane over Mordenite Nanoparticles Fabricated by a Sequential Ball Milling–Recrystallization–Dealumination Route

et al. 2017

View full text Add to dashboard Cite

show abstract

“…As pyridine is relatively small (kinetic diameter = 5.7 Å), it can access most of the acid sites in our POPs and Amberlyst controls. In contrast, the bulkier bases 2,6-lutidine (kinetic diameter = 6.7 Å) and 2,4,6-collidine (kinetic diameter = 7.4 Å) will not sample the most sterically hindered sites. The fact that these bulkier bases sample about 90–95% of the acid sites for S1 and S2 but only 80–90% for S3 and the Amberlyst controls is consistent with the observed trends in our catalysis data (Figure ): S3 , A15 , and A15c are qualitatively less effective than S1 and S2 for reaction .…”

Section: Resultsmentioning

confidence: 99%

“…The difference in accessibility of the acid sites in our POPs can be qualitatively delineated through titration with pyridine, 2,6-lutidine, and 2,4,6-collidine (Figure 5). As pyridine is relatively small (kinetic diameter = 5.7 Å), 83 it can access most of the acid sites in our POPs and Amberlyst controls. In contrast, the bulkier bases 2,6-lutidine (kinetic diameter = 6.7 Å) 83 and 2,4,6-collidine (kinetic diameter = 7.4 Å) 83 will not sample the most sterically hindered sites.…”

Section: Acs Sustainable Chemistry and Engineeringmentioning

confidence: 99%

“…As pyridine is relatively small (kinetic diameter = 5.7 Å), 83 it can access most of the acid sites in our POPs and Amberlyst controls. In contrast, the bulkier bases 2,6-lutidine (kinetic diameter = 6.7 Å) 83 and 2,4,6-collidine (kinetic diameter = 7.4 Å) 83 will not sample the most sterically hindered sites. The fact that these = 1 mol % (0.0062 M).…”

Section: Acs Sustainable Chemistry and Engineeringmentioning

confidence: 99%

See 1 more Smart Citation

Matching the Activity of Homogeneous Sulfonic Acids: The Fructose-to-HMF Conversion Catalyzed by Hierarchically Porous Sulfonic-Acid-Functionalized Porous Organic Polymer (POP) Catalysts

Agrawal

Chakraborty

et al. 2019

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

Three HO3S-functionalized porous organic polymers (HO3S-POPs) with high surface areas (500–700 m2/g) and a broad range of porosity profiles were synthesized and tested against homogeneous-acid analogs and commercially available acid resins to evaluate their relative catalytic activities in the acid-catalyzed conversion of fructose to HMF. Comparison of fructose conversions and HMF yields demonstrates that the sulfonated POPs with hierarchical porosity can achieve catalytic activities that rival those of their homogeneous counterparts. The associated HMF selectivities represent optimized values that increase with higher temperature and faster heating, both of which can reduce the reaction time and limit product decomposition. Due to their intrinsically high mesoporosity and number of accessible acid sites, these HO3S-POPs also outperform the commercially available Amberlyst 15 resin catalyst and its crushed variant.

show abstract

Zeolites

Broach¹,

Jan²,

Lesch³

et al. 2012

Ullmann's Encyclopedia of Industrial Chemistry

View full text Add to dashboard Cite

The article contains sections titled: 1. Introduction 2. Nomenclature 3. History 4. Structure, Composition, and Properties 4.1. Framework Structure 4.2. Nonframework Cations 4.3. Chemical and Physical Properties 4.3.1. Physical Properties 4.3.2. Chemical Properties 5. Characterization 6. Occurrence, Mining, and Processing of Natural Zeolites 7. Production of Synthetic Zeolites 7.1. Chemistry of Zeolite Synthesis 7.2. Composition of Reaction Mixtures 7.3. Raw Materials 7.3.1. Synthesis Conditions 7.3.2. Examples of Industrial Zeolite Syntheses 7.3.3. Post Synthesis Treatments 7.3.4. Environmental Aspects 8. Commercial Applications and Importance 8.1. Natural Zeolites 8.2. Synthetic Zeolites 8.2.1. Adsorption 8.2.2. Membranes 8.2.3. Catalysis 8.2.4. Other Uses 9. Toxicology Zeolites are hydrated aluminosilicates with a three‐dimensional framework structure constructed of SiO 4 and AlO 4 tetrahedra linked through oxygen atoms. They contain regular channels or interlinked voids whose aperture diameters are in the micropore range. The regular nature of the channels and apertures, whose dimensions are of the same order of magnitude as molecular diameters, enables the zeolites to function as molecular sieves and gives them value as selective adsorbents for separating substances and as shape‐selective catalysts. This article gives an overview of history, structure, properties, occurrence, production, and applications of zeolites.

show abstract

Zeolite Characterization

Cited by 9 publications

References 209 publications

Selective Isomerization of n-Butane over Mordenite Nanoparticles Fabricated by a Sequential Ball Milling–Recrystallization–Dealumination Route

Selective Isomerization of n-Butane over Mordenite Nanoparticles Fabricated by a Sequential Ball Milling–Recrystallization–Dealumination Route

Matching the Activity of Homogeneous Sulfonic Acids: The Fructose-to-HMF Conversion Catalyzed by Hierarchically Porous Sulfonic-Acid-Functionalized Porous Organic Polymer (POP) Catalysts

Zeolites

Contact Info

Product

Resources

About