An Experimental and Theoretical Study on the Aldol Condensation on Zirconium-Based Metal-Organic Framework

Abstract

The aldol condensation of acetone in zirconium-based metal-organic framework functionalized by a sulfonic acid group (UiO-66-SO3H) has been theoretically investigated using the density functional theory. Acetone adsorbed on the UiO-66-SO3H with the adsorption energy of -17.4 kcal/mol. The catalyzed reaction has been proposed to be a two-step mechanism: the tautomerization of keto form to produce enol form of acetone, and the aldol condensation to produce diacetone alcohol. The activation energies were calculated to be 27.2 and 6.4 kcal/mol, respectively. For the experimental part, UiO-66-SO3H catalyst was synthesized and characterized by X-ray diffraction and IR spectroscopy. The catalytic reaction was carried out in a stirred batch reactor at different temperatures to optimize the reaction conditions. The obtained products were analyzed by 1H-NMR spectroscopy and chromatography techniques. This study demonstrated that UiO-66-SO3H can be used as a solid catalyst for the aldol condensation reaction.

Combined Experimental and Theoretical Study of the Synthesis of 5,7-Dihydroxy-4-methylcoumarin via a Pechmann Condensation in the Presence of UiO-66-SO3H Catalysts

“…Among these, an isoreticular Zr-MOF, namely UiO-66 synthesized with different linker ligands has been used as catalysts for various reactions with high thermal and chemical stabilities. , UiO-66 and defective UiO-66 have been applied for the glucose conversion . Both UiO-66 and UiO-66-SO 3 H have been successfully used to catalyze organic reactions such as isomerization, green synthesis, and condensation. ,− Recently, UiO-66 has been employed for hydroxylation and used for luminescent properties. , …”

“… 7 Both UiO-66 and UiO-66-SO 3 H have been successfully used to catalyze organic reactions such as isomerization, green synthesis, and condensation. 6 , 8 − 10 Recently, UiO-66 has been employed for hydroxylation and used for luminescent properties. 11 , 12 …”

Functionalized UiO‐66 as an efficient catalyst for the synthesis of bio‐based poly(1,3‐propylene sebacate)

“…18 The thermal sparing stabilization of the partially sulfonated UiO-66 derivative UiO-66-SO 3 H(x) to the guest molecule has been used for various catalytic processes. [19][20][21][22] The amino functionalized UiO-66 is the result of the coexistence of base sites and Lewis acid sites, which have a stronger catalytic activity than UiO-66. 23 Functionalization strategies using a synergistic combination of functional groups offer an opportunity to tailor and balance all targeted characteristics without altering the underlying framework and physicochemical properties.…”

“…UiO‐66 lacks the chemical robustness to work under highly acidic or caustic conditions, but the nitro functionalized UiO‐66‐NO 2 can tolerate such situations 18 . The thermal sparing stabilization of the partially sulfonated UiO‐66 derivative UiO‐66‐SO 3 H(x) to the guest molecule has been used for various catalytic processes 19–22 . The amino functionalized UiO‐66 is the result of the coexistence of base sites and Lewis acid sites, which have a stronger catalytic activity than UiO‐66 23 …”