Dehydra-decyclization of 2-methyltetrahydrofuran to pentadienes on boron-containing zeolites

Kumar, Gaurav; Liu, Dongxia; Xu, Dandan; Ren, Limin; Tsapatsis, Michael; Dauenhauer, Paul J.

doi:10.1039/d0gc00136h

Cited by 28 publications

(82 citation statements)

References 83 publications

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“…The reported samples vary from purely microporous (P-MFI and P-BEA), purely mesoporous (P-MCM-41), micro-and mesoporous (P-SBA-15 and P-SPP) to non-porous (P-Stöber); the bulk phosphorous content was held relatively constant across all materials (Si/P ~ 30). Correponding data for the aluminosilicate zeolite samples has been previously reported in our prior works: ZSM-5 (Si/Al 40 and 140)), 5,24 Al-BEA (Si/Al 12.5), 5 and Al-SPP (Si/Al 62) 25 and not discussed here for brevity.…”

Section: Synthesis and Characterization Of P-zeosilssupporting

confidence: 62%

“…1,2,4 One strategy to address these issues has involved the tuning of solid Brønsted site strength in zeolites to selectively promote desirable pathways, and has relied on the catalytic investigations of trivalent-atom-substituted ([Ga], [Fe], and [B]) zeolites. 5,6 Alternatively, our recent work on exploring selective dehydration catalysts has led to the development of phosphoric-acid supported on all-silica zeolites (with Si/P >10). [7][8][9] For example, phosphoric acid impregnated on selfpillared pentasil (P-SPP) 10 led to the suppression of undesired alkylation and oligomerization reaction products in the Diels-Alder cycloaddition of ethylene to dimethyl furan, leading to 97% p-xylene yield.…”

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confidence: 99%

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On the Acid Sites of Phosphorous Modified Zeosils

Kumar¹,

Ren²,

Pang³

et al. 2021

Preprint

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The acid sites of phosphorus-containing zeosils were probed through a combination of solid acid characterization, density functional theory calculations, and kinetic interrogations, establishing their weakly Brønsted acidic character. Due to the disparity in acid-site strength, P-zeosils catalyzed the probe chemistry of isopropanol dehydration slower than aluminosilicate zeolites by an order of magnitude on an active site basis. Propene selectivity during isopropanol dehydration remained 20-30% higher than that of aluminosilicates, illustrating the distinct nature of the weakly acidic phosphorus active sites that favored unimolecular dehydration routes. Regardless of the confining siliceous environment, the nature of phosphorous active sites was unchanged, indicated by identical apparent uni- and bi-molecular dehydration energy barriers. Kinetic isotope experiments with deuterated isopropanol feeds implicated an E2-type elimination to propene formation on phosphorus-containing materials. Comparison of KIEs between phosphorus-containing zeosils and aluminosilicates pointed to an unchanged isopropanol dehydration mechanism, with changes in apparent energetic barriers attributed to weaker binding on phosphorous-active sites that lead to a relatively destabilized alcohol dimer adsorbate. Both ex-situ alkylamine Hofmann elimination and in-situ pyridine titration characterization methods exhibited phosphorous acid site counts dependent on probe molecules identity and/or concentration, underpinning the limitations of extending common characterization techniques for Brønsted-acid catalysis to weakly acidic materials.

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Section: Synthesis and Characterization Of P-zeosilssupporting

confidence: 62%

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confidence: 99%

On the Acid Sites of Phosphorous Modified Zeosils

Kumar¹,

Ren²,

Pang³

et al. 2021

Preprint

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“…It was observed that mesopores were detrimental to dienes production. In the same paper, the authors show that introducing boron into the framework of the all‐silica zeolites MWW, BEA and MFI yield selective materials for 2‐MTHF dehydra‐decyclization as a consequence of the weak acidity of the boron sites . The phosphoric acid impregnated zeosils were not extensively investigated for dehydra‐decyclization of 2‐MTHF, but the related reaction of 3‐MTHF to pentadienes and isoprene.…”

Section: Resultsmentioning

confidence: 99%

“…In the same paper,t he authors show that introducing boron into the framework of the all-silica zeolites MWW, BEA and MFI yield selective materials for 2-MTHF dehydradecyclization as ac onsequence of the weak acidity of the boron sites. [39] Thephosphoric acid impregnated zeosils were not extensively investigated for dehydra-decyclization of 2-MTHF,b ut the related reaction of 3-MTHF to pentadienes and isoprene.T he Al-free phosphorus-containing zeolites were all active and relatively selective to isoprene (30 % < S < 70 %), especially compared with regular aluminosilicates like ZSM-5 and FAU(5-40 %selective). [40] Thec atalytic activities and selectivities to products for different P-UiO-66 materials and different reaction conditions are summarized in Table S6.…”

Section: Methodsmentioning

confidence: 99%

Phosphonate‐Modified UiO‐66 Brønsted Acid Catalyst and Its Use in Dehydra‐Decyclization of 2‐Methyltetrahydrofuran to Pentadienes

et al. 2020

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Phosphorus‐modified all‐silica zeolites exhibit activity and selectivity in certain Brønsted acid catalyzed reactions for biomass conversion. In an effort to achieve similar performance with catalysts having well‐defined sites, we report the incorporation of Brønsted acidity to metal–organic frameworks with the UiO‐66 topology, achieved by attaching phosphonic acid to the 1,4‐benzenedicarboxylate ligand and using it to form UiO‐66‐PO3H2 by post‐synthesis modification. Characterization reveals that UiO‐66‐PO3H2 retains stability similar to UiO‐66, and exhibits weak Brønsted acidity, as demonstrated by titrations, alcohol dehydration, and dehydra‐decyclization of 2‐methyltetrahydrofuran (2‐MTHF). For the later reaction, the reported catalyst exhibits site‐time yields and selectivity approaching that of phosphoric acid on all‐silica zeolites. Using solid‐state NMR and deprotonation energy calculations, the chemical environments of P and the corresponding acidities are determined.

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“…Other typical side products are propene and large aromatics (C6+ fraction). 45 In the case of alcohol dehydration, the kinetic preference to unimolecular/biomolecular dehydration pathways was found to be temperature dependent. Increasing temperature consistently led to unimolecular dehydration being favored over the bimolecular pathway for all three alcohols.…”

Section: Reaction Kinetics Measurementsmentioning

confidence: 99%

Catalysis-in-a-Box: Robotic Screening of Catalytic Materials in the Time of COVID-19

Kumar¹,

Bossert²,

McDonald³

et al. 2020

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The emergence of a viral pandemic has motivated the transition away from traditional, labor-intensive materials testing techniques to new automated approaches without compromising on data quality and at costs viable for academic laboratories. Reported here is the design and implementation of an autonomous micro-flow reactor for catalyst evaluation condensing conventional laboratory-scale analogues within a single gas chromatograph (GC), enabling the control of relevant parameters including reactor temperature and reactant partial pressures directly from the GC. Inquiries into the hydrodynamic behavior, temperature control, and heat/mass transfer were sought to evaluate the efficacy of the micro-flow reactor for kinetic measurements. As a catalyst material screening example, a combination of four Brønsted acid catalyzed probe reactions, namely the dehydration of ethanol, 2-propanol, 1-butanol, and the dehydra-decyclization of 2-methyltetrahydrofuran on a solid acid HZSM-5 (Si/Al 140), were carried out in the temperature range 403-543 K for the measurement of apparent reaction kinetics. Product selectivities, proton-normalized reaction rates, and apparent activation barriers were in agreement with measurements performed on conventional packed bed flow reactors. Furthermore, the developed micro-flow reactor was demonstrated to be about ten-fold cheaper to fabricate than commercial automated laboratory-scale reactor setups and is intended to be used for kinetic investigations in vapor-phase catalytic chemistries, with the key benefits including automation, low cost, and limited experimental equipment instrumentation.

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Dehydra-decyclization of 2-methyltetrahydrofuran to pentadienes on boron-containing zeolites

Abstract:
1,3-Pentadiene (piperylene) is an important monomer in the manufacturing of adhesives, plastics, and resins. This study utilizes fundamental insights gained from the dehydra-decyclization of biomass-derived 2-methyltetrahydrofuran to achieve high piperylene yields.

Cited by 28 publications

References 83 publications

On the Acid Sites of Phosphorous Modified Zeosils

On the Acid Sites of Phosphorous Modified Zeosils

Phosphonate‐Modified UiO‐66 Brønsted Acid Catalyst and Its Use in Dehydra‐Decyclization of 2‐Methyltetrahydrofuran to Pentadienes

Catalysis-in-a-Box: Robotic Screening of Catalytic Materials in the Time of COVID-19

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Dehydra-decyclization of 2-methyltetrahydrofuran to pentadienes on boron-containing zeolites

Abstract: 1,3-Pentadiene (piperylene) is an important monomer in the manufacturing of adhesives, plastics, and resins. This study utilizes fundamental insights gained from the dehydra-decyclization of biomass-derived 2-methyltetrahydrofuran to achieve high piperylene yields.

Cited by 28 publications

References 83 publications

On the Acid Sites of Phosphorous Modified Zeosils

On the Acid Sites of Phosphorous Modified Zeosils

Phosphonate‐Modified UiO‐66 Brønsted Acid Catalyst and Its Use in Dehydra‐Decyclization of 2‐Methyltetrahydrofuran to Pentadienes

Catalysis-in-a-Box: Robotic Screening of Catalytic Materials in the Time of COVID-19

Contact Info

Product

Resources

About

Abstract:
1,3-Pentadiene (piperylene) is an important monomer in the manufacturing of adhesives, plastics, and resins. This study utilizes fundamental insights gained from the dehydra-decyclization of biomass-derived 2-methyltetrahydrofuran to achieve high piperylene yields.