Preparation of Tunisian Acid Activated Clay and the Green Acetalization of Acetophenone Derivatives: A Mechanistic Study

Tunisian acid-activated clay catalysts have been extensively studied and shown to be effective in various catalytic processes. The acid activated clay AH2 was characterized using X-ray diffraction, Fourier-transform infrared spectroscopy, cation exchange capacity, and atomic absorption spectroscopy. We investigated in our work, the acetalization of acetophenone derivatives 1a-d with ethylene glycol 2 using the AH2 catalyst under autoclave pressure and under mild solvent-free conditions. The reactions were analyzed to determine the optimal contact time by evaluating the catalyst's activity, stability, and chemical properties. The catalytic activity of the AH2 clay demonstrated high performance, achieving a yield of 78% for 2-(4-bromophenyl)-2-methyl-1,3-dioxolane 3d in the acetalization reaction of reagent 1d, with only 10 wt% of the catalyst at 100 °C for three hours.