Glycerol acetylation catalyzed by an acidic styrene-co-dimethacrylate resin: experiments and kinetic modeling

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This work reports an experimental study and a kinetic model for glycerol acetylation. A sulfonated resin of styrene cross-linked with ethylene glycol dimethacrylate (EGDMA) was synthesized and applied as a catalyst in the referred reaction. Furthermore, the commercial sulfonated styrene–divinylbenzene resin Amberlyst 36® was also tested in the glycerol acetylation and the results were compared to those obtained with the synthesized resin. The reactions were carried out at two different temperatures: 80 and 90 °C. The experimental data were collected and compared to predictions of a homogeneous kinetic model of a second-order reaction using the Scilab software. The blank experiments had lower conversions than the catalyzed reaction. The difference found between the ion exchange capacities for PSEGDMA (3.45 mmol g−1) and Amberlyst 36 (5.45 mmol g−1) did not produce significant differences in the catalysis results. The average R2 obtained for the model fitting was 0.89733 and the rate constants of the catalyzed portion were found to be in the ranges: 0.01 × 10–5–1.30 × 10–5 L2 mol−2 min−1 for Amberlyst 36 and 0.01 × 10–5–2.74 × 10–5 L2 mol−2 min−1 for PSEGDMA. According to the rate constants obtained herein, it is concluded that PSEGDMA resins has a higher efficiency for application in the referred reaction. This conclusion can be verified by calculating the efficiency per catalytic sites, which were 51.78 and 104.24 for Amberlyst 36 and PSEGDMA, respectively. This calculation can be used because it is the same catalyst but supported in different structures, proven by calculating the swelling index of the resins, which are shown in the “Results” section.