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Coumarin is an important chemical in agricultural and pharmaceutical industries. This work studied the synthesis of 7hydroxy-4-methylcoumarin via the Pechmann condensation reaction catalyzed by H-Beta zeolite catalyst using a combination of experimental and theoretical means. Adsorptions and reactions taking place inside the 34T cluster (T = Si or Al atoms) of H-Beta zeolite were examined by using density functional theory with the M06-2X functional. The coumarin synthesis reaction was proposed to be a three-step mechanism: the transesterification, the intramolecular hydroxyalkylation and the dehydration. The total activation energies for each step were calculated to be 17.8, 3.5 and 13.5 kcal⋅mol À 1 , respectively.The zeolite framework stabilized the adsorption complexes and decreased the activation barriers for the Pechmann condensation reaction. The synthesis of 7-hydroxy-4-methylcoumarin from resorcinol and ethyl acetoacetate on H-Beta zeolite was experimentally examined without solvent at various conditions. The adsorption of 7-hydroxy-4-methylcoumarin on H-Beta zeolite was detected by the FT-IR spectroscopy technique. The experimental activation energy of 6.7 kcal⋅mol À 1 agreed very well with the calculated apparent value of 10.6 kcal⋅mol À 1 . The H-Beta zeolite can be reused at least four times with persistently high percent yield.

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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.