Synthesis of acetate from α-pinene catalyzed by carbon-based solid acid derived from sulfonated glucose/p-toluenesulfonic acid composite

With the rise of green chemistry and cleaner production, the carbon-based solid acids as environment-friendly catalysts have received increasing attention worldwide. In this paper, A composite catalyst was obtained by a combination of sulfonated glucose (SG) and p-toluenesulfonic acid (PT), and identified as a catalyst for the esterification reaction between alpha-pinene and acetic acid (AC). It is demonstrated that the composite catalyst, possessing a high density of active sites (1.59 mmol/g of sulfonic acid and 5.05 mmol/g of total acid, respectively) and mesoporous structure (5.7 nm), demonstrates outstanding catalytic activity with a conversion of alpha-pinene reaching 100 % and a selectivity of 51.2 % for total ester under optimum reaction conditions. Kinetic analysis shows that the esterification reaction behaves according to pseudo-first-order kinetics, featuring an activation energy of 135.86 kJ/mol. Moreover, the thermodynamic enthalpy (Delta H) and Gibbs free energy (Delta G) associated with the esterification reaction are 133.05 kJ/mol and 85.86 kJ/mol, respectively, implying that this reaction is endothermic and not spontaneous. Moreover, the catalyst has been shown to be reusable up to 4 times while retaining high catalytic activity. Overall, the catalyst has demonstrated significant potential as a heterogeneous catalyst for transforming alpha-pinene into valuable acetates.