Reaction Kinetics and Thermodynamic Equilibrium for Butyl Acrylate Synthesis from <i>n</i>‑Butanol and Acrylic Acid

Abstract

The esterification reaction of <i>n</i>-butanol with acrylic acid in the presence of a commercial ion-exchange resin, Amberlyst 15-wet, was carried out in a batch reactor. The reactions were performed at different temperatures (50 to 90 °C), different <i>n</i>-butanol/acrylic acid molar ratios (2 and 3), and different catalyst amounts (1 wt % to 3.5 wt %). Different reaction rate expressions were evaluated. A simplified Langmuir–Hinshelwood–Hougen–Watson kinetic model was found to be the best model to describe the experimental results. This model is given by the following expression: <i>r</i> = <i>K</i>_c·((<i>a</i>₁·<i>a</i>₂ – (<i>a</i>₃·<i>a</i>₄)/<i>K</i>_eq)/(1 + <i>K</i>₄·<i>a</i>₄)²), with <i>k</i>_c (mol·<i>g</i>_cat^–1·min^–1) = 1.52 × 10⁷ – 66 988/(<i>RT</i>) and <i>K</i>₄ = 1.589. Also equilibrium experiments were carried out. The proposed equilibrium equation was <i>K</i>_eq = exp((−(1490 ± 577)/<i>T</i> + (7.21 ± 1.67)). From this equation, it was possible to determine the reaction standard enthalpy and entropy values: Δ<i>H</i>° = 12.39 ± 4.80 [kJ/mol] and Δ<i>S</i>° = 59.98 ± 13.87 [J/mol·K]