K10 montmorillonite catalysis

Soriente, Annunziata; Arienzo, Rosa; Rosa, Margherita De; Spinella, Aldo; Scettri, Arrigo; Palombi, Laura

doi:10.1039/a902102g

Cited by 32 publications

(14 citation statements)

References 15 publications

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“…Recently, clay based-materials such as K10-montmorillonite has attracted more attention since they are considered as environmentally friendly and recyclable catalysts [33], [34].The commercially available K10montmorillonite is a smectite clay activated by inorganic acid. The acid treatment increases BET surface area (change pore size distribution of montmorillonite) and results in an acidity strengthening hybrid catalysts.…”

Section: Introductionmentioning

confidence: 99%

Influence of Montmorillonite K10 Modification with Tungstophosphoric Acid on Hybrid Catalyst Activity in Direct Dimethyl Ether Synthesis from Syngas

et al. 2014

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Dimethyl ether synthesis was performed from syngas over hybrid catalysts comprising a Cu/Zn/Al as metallic function and K10-montorillonite (K10) as acidic function. The acidic properties of K10 were tuned by deposition of one monolayer of tungstophosphoric acid (H 3 PW 12 O 40 Á23.5 H 2 O, TPA). The changes in acidity were determined based on pyridine adsorption with FTIR detection. Due to the fact that TPA does not possess Lewis acid sites, deposition of TPA on the K10 surface (TPA-K10) resulted only in increase in Brønsted acid site concentrations and in increase in their strength in comparison with unmodified K10. Since both modified and unmodified K10 exhibited the same Lewis acid site concentrations and their strength, it was possible to investigate solely the impact of Brønsted acidity differences of acidic functions on the hybrid catalysts activity in syngas-to-DME process (STD). Additionally, the effect of TPA supported on K10 was investigated in methanol dehydration to DME under atmospheric pressure. In order to prepare metallic functions which differed in activity in CO hydrogenation to methanol (first step of STD), two synthesis methods were used: co-precipitation method (metallic function CZA) and decomposition of citrate complexes of metals (metallic function CZA citric). The hybrid catalysts (CZA/K10, CZA/ TPA-K10, CZA citric /K10, CZA citric /TPA-K10) for STD were prepared by physical mixing of metallic and acidic function in volume ratio equal to 2:1. The impact of K10 substitution with TPA-10 in hybrid catalysts depended on whether STD process was controlled by methanol synthesis step or dehydration methanol step. When K10 possessed adequate acidity to dehydrate methanol formed on metallic function (i.e. CZA citric), it substitution with TPA-K10 in hybrid catalyst did not improve DME yield. On the other hand, when metallic function (i.e. CZA) exhibited higher methanol activity and methanol dehydration rate was limited by insufficient acidity of K10 then usage of TPA-K10 of higher acidity in hybrid catalyst was found to increase significantly DME yield without light parrafins formation.

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Section: Introductionmentioning

confidence: 99%

Influence of Montmorillonite K10 Modification with Tungstophosphoric Acid on Hybrid Catalyst Activity in Direct Dimethyl Ether Synthesis from Syngas

et al. 2014

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“…( S )‐3‐(3‐Oxocyclohexyl)pentane‐2,4‐dione: See Table 5, Entry 2 43. Following the general procedure, acetylacetone (103 μL, 1.0 mmol) and 2‐cyclohexen‐1‐one (106 μL, 1.1 mmol) were reacted at 90 °C for 21 h. Flash column chromatography on silica gel ( n ‐heptane/ethyl acetate, 2:1 + 2 % triethylamine) afforded the product (184 mg, 94 %, 79 % ee ).…”

Section: Methodsmentioning

confidence: 99%

Asymmetric Lewis Acid Catalysis in Water: α‐Amino Acids as Effective Ligands in Aqueous Biphasic Catalytic Michael Additions

et al. 2009

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This article explores the potential of native α-amino acids as chiral ligands in aqueous asymmetric Lewis acid catalysis, employing the C-C bond forming Michael addition as a model reaction. Some insights are provided regarding the details of Yb(OTf) 3 /α-amino acid-catalyzed Michael additions in water through new kinetic data as well as studies on how both yield and selectivity are influenced by variations in metal/ligand ratio, pH, temperature, and structure of the α-amino acid. Through this investigation it was found that reaction conditions that require only 5 mol-% of the Lewis acid, provides enantiomeric excesses of up to 79 % and is

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“…Generally,t he installationo fah eteroaromatic group on ah eterocyclic ring may change its biological activity dramatically.Acommonly used approach for the preparation of heteroaryl-substituted heterocycles such as 4-heteroaryl-substitutedp yrazoles and isoxazoles,5 -heteroaryl-substituted pyrimidines and 3-heteroaryl-substituted-3H-benzo [b] [1,4]diazepines is the condensation of a-heteroaryl-substitituted 1,3-diketones with additional reagents like hydrazine,h ydroxylamine, guanidine and o-diaminobenzene( Scheme 1, above). The a-furyl-substituted 1,3-diketone is relatively easy to obtain from a1 ,3-diketone and 2,5-dihydro-2,5-dimethoxyfuran (DHDMF), [2] however no convenient method is available for the preparation of a-thienyl, a-benzofuryl and a-pyrrolyl-substituted 1,3-diketones (Scheme 1, middle). Fore xample,o ne method for the synthesis of these compounds is the cross-coupling of heteroaryl-lead triacetate compounds with 1,3-diketones.…”

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confidence: 99%

One‐Pot Synthesis of 4‐Heteroaryl‐Substituted Pyrazoles: A Gold‐Catalyzed Oxidation/1,2‐Heteroaryl Migration Cascade Constitutes the Key Step

et al. 2016

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An efficient gold-catalyzed oxidation/1,2-heteroarylm igration cascade leading to 2-heteroaryl-substituted 1,3-diketones andi ts further application in the one-pot synthesis of 4-heteroaryl-substituted pyrazoles andt he preparation of 4-heteroarylsubstituted isoxazoles are reported. Aw ide variety of 4-heteroaryl-substituted pyrazoles were obtained, indicating the broad substrate scope and functional group tolerance of this method.

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K10 montmorillonite catalysis

Cited by 32 publications

References 15 publications

Influence of Montmorillonite K10 Modification with Tungstophosphoric Acid on Hybrid Catalyst Activity in Direct Dimethyl Ether Synthesis from Syngas

Influence of Montmorillonite K10 Modification with Tungstophosphoric Acid on Hybrid Catalyst Activity in Direct Dimethyl Ether Synthesis from Syngas

Asymmetric Lewis Acid Catalysis in Water: α‐Amino Acids as Effective Ligands in Aqueous Biphasic Catalytic Michael Additions

One‐Pot Synthesis of 4‐Heteroaryl‐Substituted Pyrazoles: A Gold‐Catalyzed Oxidation/1,2‐Heteroaryl Migration Cascade Constitutes the Key Step

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