| dc.description.abstract | This study is divided into two parts. In the first part, taking advantage of mesoporous silica materials with high specific surface area, tunable pore size, and pore volume, sulfonic acid functional groups were directly synthesized on the surface of a series of three-dimensional mesoporous silica materials. Through SAXRD, BET, TEM, and XPS characterization, the structure and stability of the S16SX (X = 10, 15, 20, 25, 30) series catalysts were confirmed. This series of catalysts possesses high specific surface area, pore uniformity, and abundant acidic sites, and is expected to be applied in the catalytic Fischer esterification reaction of di(trimethylolpropane) (Di-TMP). By exploring the effects of different mesoporous silica structures, the ratio of sulfonic acid functional groups, different catalyst loading, and different ratios of acrylic acid to Di-TMP on the selective production of Di-TMPDA, it was found that the optimal reaction conditions were using 1.8 g of S16S20 as the catalyst with a starting material molar ratio of AA to Di-TMP of 2:1. Under the conditions of maintaining the temperature at 95°C and continuous water removal, after 24 hours of reaction, the proportion of Di-TMPDA in the total product was about 65%, and the production of Di-TMPTriA and Di-TMPTetraA was reduced. Therefore, the catalyst S16S20 exhibits high catalytic activity and can selectively produce the product Di-TMPDA.
In the second part, wasted coffee grounds were transformed into porous biochar materials through hydrothermal acidic hydrolysis and KOH chemical activation methods under high-temperature calcination. The activated biochar was functionalized with sulfonic acid groups by reacting with 4-benzene-diazoniumsulfonate and hypophosphorous acid. Elemental analysis, XPS, TEM, and other characterizations confirmed the successful preparation of acidic biochar (S-WCG). This catalyst was applied in the Pechmann condensation reaction of resorcinol with ethyl acetoacetate to synthesize 7-hydroxy-4-methylcoumarin. The study explored the effects of calcination temperature, KOH ratio, catalyst loading, and reaction temperature on the catalytic activity. Finally, under the conditions of a calcination temperature of 800°C and a KOH-to-carbon source ratio of 2:1, the acidic wasted coffee ground-derived biochar (S-WCG-800-21) achieved the highest coumarin yield of 88% at 130°C in 20 minutes. | en_US |