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Article Dans Une Revue Inorganic Chemistry Frontiers Année : 2023

Tailoring accessibility and amphiphilicity in MWW zeolites for the two-phase glycerol ketalization

Diego Lima
Laura Silva
Iago Zapelini
Svetlana Mintova

Résumé

Two sets of MWW zeolite catalysts, the purely microporous MCM-22 (3D) and hierarchical ITQ-2 (2D), were synthesized and functionalized with an organosilane (?). These functionalized zeolites were employed in a two-phase glycerol ketalization reaction with acetone, eliminating the need for an additional solvent. There are two crucial factors to consider in this reaction: (i) the kinetic diameter of glycerol is comparable to the size of catalyst pores, limiting accessibility to the active sites, and (ii) glycerol exhibits poor solubility in acetone, causing the reaction to predominantly occur at the interfaces. Therefore, it is essential to focus on enhancing the accessibility of chemicals to the inner catalyst pores and adjusting the hydrophilic-hydrophobic balance of the functionalized catalysts to improve the reaction performance. The accessibility of the catalysts was indirectly evaluated by chemisorption of pyridine and 2,6-di-tert-butyl pyridine, which confirmed that ITQ-2 had a superior capacity to accommodate bulkier chemicals. Moreover, contact angle measurements of glycerol on ITQ-2 zeolites indicated that the functionalized materials exhibited reduced interaction with glycerol due to their increased hydrophobic nature. As a result, the functionalized materials tended to accumulate in the interfacial region, facilitating the dispersion of glycerol droplets within the reaction medium. However, the hydrophobic characteristics played a more significant role at the beginning of the reaction since, after reaching 25% conversion, the system transitioned into a single phase as the product itself acted as a solvent.

Domaines

Chimie
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Dates et versions

hal-04283462 , version 1 (13-11-2023)

Identifiants

Citer

Diego Lima, Laura Silva, Iago Zapelini, Svetlana Mintova, Leandro Martins. Tailoring accessibility and amphiphilicity in MWW zeolites for the two-phase glycerol ketalization. Inorganic Chemistry Frontiers, 2023, 10 (19), pp.5649-5661. ⟨10.1039/D3QI01067H⟩. ⟨hal-04283462⟩
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