The role of different types of acid site in the cracking of alkanes on zeolite catalysts

Corma, Avelino; Planelles, Josep; Sánchez‐Marín, José; Tomás, F.

doi:10.1016/0021-9517(85)90148-4

Cited by 220 publications

(72 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…However, catalytic degradation of PE is known to proceed by a carbenium-ion mechanism [43][44][45]. The initial step is considered to occur either by the abstraction of the hydrid ion (by Lewis acid sites) from the PE molecule or by addition of a proton (by Brönsted acid sites) to the C C bonds of the PE molecule.…”

Section: Resultsmentioning

confidence: 99%

Catalytic pyrolysis of polyethylene: A comparison between pillared and restructured clays

Stefanis

Cafarelli

Gallese

et al. 2013

Journal of Analytical and Applied Pyrolysis

View full text Add to dashboard Cite

Section: Resultsmentioning

confidence: 99%

Catalytic pyrolysis of polyethylene: A comparison between pillared and restructured clays

Stefanis

Cafarelli

Gallese

et al. 2013

Journal of Analytical and Applied Pyrolysis

View full text Add to dashboard Cite

“…However, if the strength and density of Brønsted acid sites in zeolitic micropores are sufficiently high, alkene intermediates can undergo cracking due to increased surface residence time and probability of beta scission. 29,30 The high selectivity observed for Pt/Al-MCF-17 is primarily due to milder acid sites generated by post-synthetic doping of amorphous silica with aluminum ( Figure 2a). The Brønsted acid sites of Al-MCF-17…”

Section: Aluminum Modified Mesoporous Silica Vs Mesoporous Zeolitesmentioning

confidence: 99%

Hydroisomerization of n-hexadecane: remarkable selectivity of mesoporous silica post-synthetically modified with aluminum

Sabyrov

Musselwhite

Melaet

et al. 2017

Catal. Sci. Technol.

View full text Add to dashboard Cite

As the impact of acids on catalytically driven chemical transformations is tremendous, fundamental understanding of catalytically relevant factors is essential for the design of more efficient solid acid catalysts. In this work, we employed post-synthetic doping method to synthesize highly selective hydroisomerization catalyst and to demonstrate the effect of acid strength and density, catalyst microstructure, and platinum nanoparticle size on reaction rate and selectivity. Aluminum doped mesoporous silica catalyzed gas-phase n-hexadecane isomerization with remarkably high selectivity, producing substantially higher amount of isomers than traditional zeolite catalysts. The main reason for its high selectivity was found to be mild acidic sites generated by post-synthetic aluminum grafting. The flexibility of post-synthetic doping method enabled us to systematically explore the effect of acid site density on reaction rate and selectivity, which has been extremely difficult to achieve with zeolite catalysts. We found that higher density of Brønsted acid sites leads to higher cracking of n-hexadecane presumably due to increased surface residence time. Furthermore, regardless of pore size and microstructure, hydroisomerization turnover frequency linearly increased as a function of Brønsted acid site density. In addition to strength and density of acid sites, platinum nanoparticle size affected catalytic activity and selectivity. Smallest platinum nanoparticles produced the most effective bifunctional catalyst presumably because of higher percolation into aluminum doped mesoporous silica, generating more 'intimate' metallic and acidic sites. Finally, aluminum doped 2 silica catalyst was shown to retain its remarkable selectivity towards isomers even at increased reaction conversions.

show abstract

“…In addition, the protonation of the C-C bond between two secondary carbon atoms was approximately 50 kJ mol -1 more stable than protonation of a C-C bond involving a primary carbon atom [32,35].…”

Section: Hydrocarbon Cracking Mechanismmentioning

confidence: 96%

“…Increasing the chain length of the hydrocarbon increases the number of possible C-H or C-C bonds that can interact with the catalyst [32]. However, cracking rates of alkanes increase non-linearly with carbon chain length, shown in Table 1-4 [33].…”

Section: Hydrocarbon Cracking Mechanismmentioning

confidence: 99%

Solid Acid Catalysts for Endothermic Fuels

Huang

View full text Add to dashboard Cite

Vehicles traveling at high supersonic and hypersonic flight speeds experience high thermal heat loads from aerodynamic heating that exceed the heat sink capacity of existing thermal management systems. Conventional thermal management systems are limited by the physical heat sink capacity of hydrocarbon fuels. One method to increase the heat sink capacity of hydrocarbon fuels is to carry out endothermic reactions on the hydrocarbon fuel near the heat load. The breaking of C-C bonds over a catalyst, otherwise known as catalytic cracking, is an endothermic reaction that can provide a substantial heat sink for so called endothermic fuels. Understanding the effects of catalyst porosity and hydrocarbon molecular structure for catalytic cracking under supercritical conditions is necessary for the rational design of catalyst/fuel pairings for endothermic fuels. In this study, reactions of linear, branched, and cyclic hydrocarbons were performed over micro-and mesoporous solid acid catalysts under supercritical conditions. Measurements of intrinsic rate parameters were used to develop a fundamental understanding of the reaction mechanism under supercritical conditions.

show abstract

The role of different types of acid site in the cracking of alkanes on zeolite catalysts

Cited by 220 publications

References 23 publications

Catalytic pyrolysis of polyethylene: A comparison between pillared and restructured clays

Catalytic pyrolysis of polyethylene: A comparison between pillared and restructured clays

Hydroisomerization of n-hexadecane: remarkable selectivity of mesoporous silica post-synthetically modified with aluminum

Solid Acid Catalysts for Endothermic Fuels

Contact Info

Product

Resources

About