The isomerization of S-carvone over the natural clinoptilolite as the catalyst: the influence of reaction time, temperature and catalyst content

Wróblewska, Agnieszka; Retajczyk, Monika

doi:10.1007/s11144-020-01781-0

Cited by 3 publications

(5 citation statements)

References 29 publications

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“…Reports on its use in catalytic reactions such as cracking, isomerization, alkylation, and methanol to olefin conversion remain restricted despite its low cost and wide availability. [12,14,22,[34][35][36][37][38][39] This study investigates the acetalization process of benzaldehyde with butanediol-1,3 employing Brønsted acid catalysis while also examining the impact of acidic modification on a natural zeolite sample and its catalytic activity. The research delves into the stability of aluminum and Brønsted acid sites within the tetrahedral framework concerning temperature, employing comprehensive analysis methods such as nitrogen adsorption-desorption tests, ammonia temperature-programmed desorption (TPD), and 27 Al magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

“…Despite its porous nature and potential as a catalyst via ion exchange or acid treatment, [2,12,14,33] its application in catalysis is limited due to insufficient activity or stability. Reports on its use in catalytic reactions such as cracking, isomerization, alkylation, and methanol to olefin conversion remain restricted despite its low cost and wide availability [12,14,22,34–39] …”

Section: Introductionmentioning

confidence: 99%

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Temperature‐Induced Modifications in Natural Zeolite Clinoptilolite: Effects on Acidity and Catalytic Acetalization

Muhammad,

Al‐Muqati,

Schulz

et al. 2024

ChemNanoMat

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This study delves into the acid modification of natural zeolite clinoptilolite, focusing on the identification of acid site types and their catalytic activity in the Brønsted acid‐catalyzed acetalization of benzaldehyde with 1,3‐butanediol. Following calcination, the samples underwent acidification via ammonium‐ion exchange, resulting in approximately 45% of the clinoptilolite cations being exchanged with ammonium ions. The investigation evaluates the structural, morphological, and textural alterations induced by this modification using XRD, FTIR, and nitrogen adsorption‐desorption measurements. Ammonia‐temperature‐programmed desorption (NH3‐TPD) analysis confirms the presence of medium to strong acidic protons, highlighting the acidity of the modified samples. Employing 27Al and 29Si magic‐angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy elucidated changes in the state and coordination of aluminum post‐sample activation. Specifically, the 27Al MAS NMR spectra indicate a partial dealumination, evidenced by the emergence of 5 and 6‐fold coordinated aluminum. Moreover, 29Si MAS NMR measurements tracked variations in the Si/Al ratio. The study probes the nature of these sites, their influence on catalytic activity, and the synergistic interplay between Brønsted acid sites and 5‐fold coordinated aluminum. The results showcase that the prepared acidic natural clinoptilolite catalysts augment acidity and porosity, fostering promising implications for catalytic applications.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Temperature‐Induced Modifications in Natural Zeolite Clinoptilolite: Effects on Acidity and Catalytic Acetalization

Muhammad,

Al‐Muqati,

Schulz

et al. 2024

ChemNanoMat

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“…It was shown that this process was most favorably performed at 210 • C, with the catalyst content of 15 wt% and for 3 h. Under these conditions, the yield of carvacrol amounted to 90 mol%. The therapeutic properties of carvacrol, such as, its analgesic, antioxidant, antibacterial, antiparasitic, and antifungal properties, make it suitable for use in medicine [27].…”

Section: Introductionmentioning

confidence: 99%

The Application of Clinoptilolite as the Green Catalyst in the Solvent-Free Oxidation of α-Pinene with Oxygen

et al. 2023

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In this work, we present the catalytic application of the naturally occurring zeolite, clinoptilolite, in the oxidation of α-pinene, a natural terpene compound. Clinoptilolites with different average particle sizes, designated as (in μm) clin_1 (20), clin_2 (50), clin_3 (200), and clin_4 (500–1000), were used as the green catalysts in the solvent-free oxidation of α-pinene with oxygen. Prior to their application in catalytic tests, the catalysts were characterized by the following methods: nitrogen sorption at 77 K, EDXRF, XRD, SEM, UV-Vis, and FTIR. The effects of the temperature, amount of the catalyst, and reaction time on the product’s selectivity and α-pinene conversion were determined. At the optimal conditions (a temperature of 100 °C, catalyst content (clin_4) in the reaction mixture of 0.05 wt%, and 210 min reaction time), the following compounds were obtained as the main products: α-pinene oxide (selectivity 29 mol%), verbenol (selectivity 17 mol%), and verbenone (selectivity 13 mol%). The conversion of α-pinene under these conditions amounted to 35 mol%. Additionally, the kinetic modeling of α-pinene oxidation over the most active catalyst (clin_4) was performed. The proposed method of oxidation is environmentally safe because it does not require the separation of products from the solvent. In addition, this method allows for managing the biomass in the form of turpentine, which is the main source of α-pinene. The catalytic application of clinoptilolite in the oxidation of α-pinene has not yet been reported in the literature.

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“…Carvacrol is contained in essential oil of oregano, thyme or savory. A large scale of carvacrol biologic effects (antibacterial, insecticidal, antifungal, analgetic, antioxidant or antiparazitic) was reported [1,2]. Moreover, carvacrol can be oxidized to obtain thymoquinone-a substance with possible anticancer, antioxidant and cholesterol lowering effects.…”

Section: Introductionmentioning

confidence: 99%

“…Yield of carvacrol > 96% was obtained (160 • C, toluene, 3 h [15]) in the case of montmorillonite. A natural zeolite-clinoptilolite was also catalytically active in carvone isomerization-yield of carvacrol > 90% was obtained in solvent-free synthesis (210 • C, 3 h [1]). Rare mentions of specific catalysts, e.g., complex of NHC ligand and palladium or Pt(IV) complex, can be also found [11,16].…”

Section: Introductionmentioning

confidence: 99%

Acid Treated Montmorillonite—Eco-Friendly Clay as Catalyst in Carvone Isomerization to Carvacrol

et al. 2021

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Acid-treated montmorillonites (MMT) were used as catalysts of carvone isomerization to carvacrol. Mineral acids—sulfuric, hydrochloric, nitric acids and organic acids (acetic and chloroacetic)—were used for the acid treatment. Prepared materials were characterized by available characterization methods, namely XRD, EA, TPD, TPO, UV-Vis, laser light scattering and nitrogen physisorption. The structure of montmorillonite remained intact after treatment. However, TPD proved the increase of acidity of acid-treated materials comparing pure montmorillonite. All materials were tested in the isomerization of carvone, producing carvacrol as the desired product. The initial reaction rate increased using the materials in the row MMT-COOH < MMT-HNO3 < MMT-ClCOOH < MMT-H2SO4 < MMT-HCl, which is in accordance with the pKa of acids used for the treatment. The number of weak acid sites strongly influenced the selectivity to carvacrol. The optimal solvent for the reaction was toluene. Total conversion of carvone and the selectivity to carvacrol 95.5% was achieved within 24 h under 80 °C, with toluene as solvent and montmorillonite treated by chloroacetic acid as catalyst. The catalyst may be reused after calcination with only a low loss of activity.

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The isomerization of S-carvone over the natural clinoptilolite as the catalyst: the influence of reaction time, temperature and catalyst content

Cited by 3 publications

References 29 publications

Temperature‐Induced Modifications in Natural Zeolite Clinoptilolite: Effects on Acidity and Catalytic Acetalization

Temperature‐Induced Modifications in Natural Zeolite Clinoptilolite: Effects on Acidity and Catalytic Acetalization

The Application of Clinoptilolite as the Green Catalyst in the Solvent-Free Oxidation of α-Pinene with Oxygen

Acid Treated Montmorillonite—Eco-Friendly Clay as Catalyst in Carvone Isomerization to Carvacrol

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