Mesoporous Zeolite Catalysts for Biomass Conversion to Fuels and Chemicals

Triantafyllidis, Konstantinos S.; Iliopoulou, Eleni F.; Karakoulia, Stamatia A.; Nitsos, Christos; Lappas, Angelos A.

doi:10.1002/9783527673957.ch15

Cited by 4 publications

(5 citation statements)

References 148 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Finally, the potential of hierarchical zeolites as catalysts for the production of fuels and chemicals from biomass and the pyrolysis of polyethylene have been explored. 53 Notable recent examples are studies on glucose and lactose isomerization by Tsapatsis and co-workers 54 and epoxidation of biodiesel by Gla ¨ser and co-workers. 55 These reactions are very complex and a challenging topic and not well suited as standard test reaction systems for the evaluation of hierarchical zeolites although certainly of practical importance.…”

Section: Catalytic Crackingmentioning

confidence: 99%

See 1 more Smart Citation

Catalytic test reactions for the evaluation of hierarchical zeolites

2016

View full text Add to dashboard Cite

Catalytic test reactions for the evaluation of hierarchical zeolitesStudies on the synthesis, characterization and catalytic performance of hierarchical zeolites and related porous materials are currently revitalizing the mature field of zeolite research. This review discusses the challenges in evaluating the catalytic performance of a hierarchical zeolite catalyst compared to its parent zeolite. zeolites and the facilitated access and transport in the additional meso-or macropore system. In this tutorial review, we discuss several test reactions that have been explored to show the benefit of the hierarchical pore system with respect to their suitability to prove the positive effects of hierarchical porous zeolites. It is important to note that positive effects on activity, stability and less frequently selectivity observed for hierarchically structured catalysts not necessarily are only a consequence of the additional meso-or macropores but also the number, strength and location of active sites as well as defects and impurities. With regard to these aspects, the test reaction has to be chosen carefully and potential changes in the chemistry of the catalyst have to be considered as well. In addition to the determination of conversion, yield and selectivity, we will show that the calculation of the activation energy and the determination of the Thiele modulus and the effectiveness factor are good indicators of the presence or absence of diffusion limitations in hierarchical zeolites compared to their parent materials. Key learning pointsHierarchical zeolites are an emerging technology in the mature field of industrial catalysts. Several test reactions are suggested to prove the advantage of their hierarchical structure. In addition to an increase in activity and selectivity suppression of coke formation is often observed. Concept of the Thiele modulus and the effectiveness factor is required to judge the presence of diffusion limitations in hierarchical catalysts.

show abstract

Section: Catalytic Crackingmentioning

confidence: 99%

Section: Catalytic Crackingmentioning

confidence: 99%

Catalytic test reactions for the evaluation of hierarchical zeolites

2016

View full text Add to dashboard Cite

show abstract

“…The X-ray diffractograms of the commercial and treated beta and mordenite zeolites are presented in Figure 1. The reaction conditions used in zeolite modification processes, such as dealumination and desilication, can affect their crystalline structure through the formation of amorphous phases and the partial destruction of the zeolites' framework [22,24,28]. The typical structure of beta zeolite (JCPDS 48-0074) and mordenite (JCPDS 06-0239) were preserved in both acid and alkali treatments.…”

Section: Crystalline Textural and Morphological Propertiesmentioning

confidence: 99%

“…In this setting, hierarchical zeolites (containing micro-and mesopores) emerge as an alternative to this diffusional limitation [22][23][24][25][26][27]. They are obtained by incorporating mesopores into their structure via pre-synthetic or post-synthetic methods.…”

Section: Introductionmentioning

confidence: 99%

Selective Synthesis of Levulinic Ester from Furfural Catalyzed by Hierarchical Zeolites

et al. 2022

View full text Add to dashboard Cite

Furfural is a platform molecule that can be catalytically converted using a cascade series of reactions into levulinic esters, essential compounds used as fuel additives. Bifunctional catalysts containing Lewis and Brønsted acid sites such as zeolites are commonly used for these conversions. However, microporous zeolites often present diffusional restriction due to the size similarity of furfural and other molecules to the zeolites’ micropores. Thus, incorporating mesopores in these materials through post-synthetic protocols is a promising pathway to circumventing these limitations. This study presents the creation of hierarchical beta and mordenite using Si or Al removal and their employment in the furfural conversion to isopropyl levulinate (PL). Mordenite zeolite did not produce satisfactory mesopores, while the beta was more efficient in generating them by both acid and alkaline treatments. Beta zeolite treated in an alkaline solution presented larger mesopores (14.9 and 34.0 nm), maintaining a total acidity value close to its parent zeolite and a higher Lewis/Brønsted ratio. The combination of these features led to an improved diffusion of bulkier products and the highest furfural conversion (94%) and PL selectivity (90%), suggesting that a post-modification of beta zeolites produced efficient catalysts for upgrading abundantly available furfural.

show abstract

“…For the utilization of zeolites as a heterogeneous catalyst for a target reaction, many studies have been performed to improve their activity, stability, and selectivity. In this regard, recent studies achieved significant advances in two major directions: one direction is the development of a hierarchically structured zeolite that exhibited an improved catalytic performance, because of its enhanced diffusivity, especially for bulky molecules, − and the other direction is the understanding of the effect of the framework Al (Al F ) site on reaction pathways to eventually modulate product selectivity. − …”

Section: Introductionmentioning

confidence: 99%

Control of Hierarchical Structure and Framework-Al Distribution of ZSM-5 via Adjusting Crystallization Temperature and Their Effects on Methanol Conversion

et al. 2019

View full text Add to dashboard Cite

Incorporating mesoporosity into zeolite catalysts has been regarded as an innovative technology that improves diffusivity and catalytic lifetime. Here, we propose a facile synthesis of the hierarchically structured ZSM-5 with accompanying intracrystalline mesopores, which was achieved by controlling the growth rate of the zeolite nanocrystals without using extra additives. As the crystallization temperature is strongly related to the formation of primary nanocrystals and their further growth, which fills gaps between those nanocrystals, the hierarchically structured ZSM-5 zeolite was synthesized at low crystallization temperatures (<140 °C). 27 Al MAS NMR and UV-vis-DRS analyses revealed that the hierarchically structured ZSM-5 prepared in the present study contained Al located in the straight channel at a higher proportion than the conventional microporous ZSM-5. The substitution of Al was calculated to be more difficult at the channel intersection than at other T-sites, supporting the experimental results. The hierarchically structured ZSM-5 exhibited excellent stability as well as selectivity for a methanol-to-olefin reaction. Reaction free energies calculated along the hydrocarbon pool mechanism pathway revealed that the Al located in the straight channel drives the reaction through the alkene-based cycle, which is responsible for the high olefin selectivity of the hierarchically structured ZSM-5.

show abstract

Mesoporous Zeolite Catalysts for Biomass Conversion to Fuels and Chemicals

Cited by 4 publications

References 148 publications

Catalytic test reactions for the evaluation of hierarchical zeolites

Catalytic test reactions for the evaluation of hierarchical zeolites

Selective Synthesis of Levulinic Ester from Furfural Catalyzed by Hierarchical Zeolites

Control of Hierarchical Structure and Framework-Al Distribution of ZSM-5 via Adjusting Crystallization Temperature and Their Effects on Methanol Conversion

Contact Info

Product

Resources

About