Effect of acid modification of kaolin and metakaolin on Brønsted acidity and catalytic properties in the synthesis of octahydro-2H-chromen-4-ol from vanillin and isopulegol

Timofeeva, Maria N.; Panchenko, Valentina N.; Волчо, К. П.; Закусин, С. В.; Krupskaya, V. V.; Gil, Antonio; Mikhalchenko, Oksana S.; Vicente, M.A.

doi:10.1016/j.molcata.2016.01.010

Cited by 36 publications

(21 citation statements)

References 28 publications

(37 reference statements)

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“…Recently, it has been shown, that in catalytic condensation of a natural allyl alcohol (−)‐isopulegol (I) with aldehydes, substituted octahydro‐2 H ‐chromen‐4‐ol (III) as 4 R ‐ and 4 S ‐diastereomers was formed along with a dehydration product IV (Scheme ). Different catalysts such as I 2 , p ‐toluenesulfonic acid, BF 3 ⋅Et 2 O, zeolites, clays were used in this reaction . A relatively high 4 R /4 S ratio (9.0) with overall yields of 70–88 % were observed in condensation of isopulegol (obtained by cyclization of R ‐citronellal) with aromatic aldehydes at −78 °C using scandium triflate .…”

Section: Methodssupporting

confidence: 92%

Acid‐modified Halloysite Nanotubes as a Stereoselective Catalyst for Synthesis of 2H‐Chromene Derivatives by the Reaction of Isopulegol with Aldehydes

et al. 2018

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Acid-modified halloysite nanotubes were used for the first time as a stereoselective catalyst for synthesis of oxygen-containing heterocycles applying of allyl alcohol (À)-isopulegol condensation with aldehydes to the octahydro-2H-chromenol (4R-and 4S-diastereomers) as an example. The catalysts were characterized by XRF, XRD, N 2 -adsorption, FTIR with pyridine and MAS NMR methods. A high ratio of 4R/4S diastereomers (7.6-14.5) under mild conditions in cyclohexane was considerably exceeding previously reported results. Unprecedented selectivity (79-83 %) to 4R isomer of thiophenyl-substituted chromenol exhibiting high analgesic activity was achieved. An increase in stereoselectivity with a decrease in the halloysite drying temperature and catalyst acidity clearly indicates formation of 4R diastereomer on the weak Brønsted sites. This work is an example that control of the stereoselectivity of acid-catalyzed organic reactions can be effectively carried out by varying water content on the aluminosilicate surface. Modified halloysite nanotubes can be considered as extremely promising catalysts for stereoselective synthesis of heterocyclic compounds.

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Section: Methodssupporting

confidence: 92%

Acid‐modified Halloysite Nanotubes as a Stereoselective Catalyst for Synthesis of 2H‐Chromene Derivatives by the Reaction of Isopulegol with Aldehydes

et al. 2018

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“…Using ultrasound and microwaves in addition to an acid treatment intensifies smectite mineral transformation [27]. In industry, acid-modified bentonites are most commonly used as catalysts [28][29][30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of Montmorillonite Structure and Transformation of Its Properties under Treatment with Inorganic Acid Solutions

et al. 2017

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This paper discusses the mechanism of montmorillonite structural alteration and modification of bentonites' properties (based on samples from clay deposits Taganskoye, Kazakhstan and Mukhortala, Buriatia) under thermochemical treatment (treatment with inorganic acid solutions at different temperatures, concentrations and reaction times). Treatment conditions were chosen according to those accepted in chemical industry for obtaining acid modified clays as catalysts or sorbents. Also, more intense treatment was carried out to simulate possible influence at the liquid radioactive site repositories. A series of methods was used: XRD, FTIR, ICP-AES, TEM, nitrogen adsorption, and particle size analysis. It allowed revealing certain processes: transformation of montmorillonite structure which appears in the leaching of interlayer and octahedral cations and protonation of the interlayer and -OH groups at octahedral sheets. In turn, changes in the structure of the 2:1 layer of montmorillonite and its interlayer result in significant alterations in the properties: reduction of cation exchange capacity and an increase of specific surface area. Acid treatment also leads to a redistribution of particle sizes and changes the pore system. The results of the work showed that bentonite clays retain a significant portion of their adsorption properties even after a prolonged and intense thermochemical treatment (1 M HNO 3 , 60 • C, 108 h).

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“…Использование в дополнение ультразвука и микроволн повышает скорость преобразования смектитовых минералов (Thommes et al, 2015). Наиболее широко кислотно-модифицированные бентониты используются в промышленности в качестве катализаторов (Adams, 1987;Brown, 1994;Bovey, Jones, 1995;Timofeeva et al, 2016).…”

Section: преобразование структуры и адсорбционных свойств монтмориллоunclassified

“…Как было показано ранее многочисленными исследованиями, метод инфракрасной спектроскопии является одним из наиболее чувствительных при изучении структурных преобразований слоистых силикатов, происходящих под воздействием растворов неорганических кислот (Komadel et al, 1990(Komadel et al, , 1996(Komadel et al, , 2006. В первую очередь на инфракрасных спектрах после обработки растворами кислот проявляется снижение интенсивности полос, отвечающих присутствию Fe, Mg в октаэдрических сетках за счет их вымывания при обработке неорганическими кислотами (Timofeeva et al, 2015(Timofeeva et al, , 2016. Вследствие вымывания октаэдрических катионов увеличивается число позиций ОН-групп, над которыми не располагаются межслоевые катионы, что приводит к усилению связи ОН (Besson, Drits, 1997;Zviagina et al, 2004) и, соответственно, к повышению интенсивности полосы поглощения AlOHAl при 3654 см -1 (рис.…”

Section: преобразование структуры монтмориллонита при воздействии азоunclassified

Transformation of the montmorillonite structure and its adsorption properties due to the thermochemical treatment

et al. 2019

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Complex studies revealed changes in the composition, structure, and properties of bentonite clays from the Taganskoye (Kazakhstan) and Dashkovskoe (Moscow region) deposits due to the thermochemical treatment. The leaching of cations from the interlayer and octahedral positions, protonation of the interlayer and OH-groups, leads to modification of the interlayer and 2:1 layer composition, which in turn contributes to significant changes in properties:-a decrease in the cation exchange capacity due to a decrease in the layer charge and increase in the specific surface due to destruction and partial amorphization. Bentonites from the Dashkovskoye deposit demonstrated higher resistance to thermochemical treatment than the bentonites from the Taganskoye deposit due to the protecting effect of the organic matter. Results of the work showed that even after quite intensive thermochemical treatment (13M HNO3, 90 °C, 5 hours), bentonite clays retain a significant part of the adsorption capacity.

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Effect of acid modification of kaolin and metakaolin on Brønsted acidity and catalytic properties in the synthesis of octahydro-2H-chromen-4-ol from vanillin and isopulegol

Cited by 36 publications

References 28 publications

Acid‐modified Halloysite Nanotubes as a Stereoselective Catalyst for Synthesis of 2H‐Chromene Derivatives by the Reaction of Isopulegol with Aldehydes

Acid‐modified Halloysite Nanotubes as a Stereoselective Catalyst for Synthesis of 2H‐Chromene Derivatives by the Reaction of Isopulegol with Aldehydes

Experimental Study of Montmorillonite Structure and Transformation of Its Properties under Treatment with Inorganic Acid Solutions

Transformation of the montmorillonite structure and its adsorption properties due to the thermochemical treatment

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