Kinetic study of Pt/Al 2 O 3 -catalyzed stearamide synthesis at atmospheric pressure

Stearamide is a widely used fatty acid amide serving as a slip agent, lubricant, and anti-blocking additive in polymer processing. In this study, the kinetics of stearamide synthesis from stearic acid and urea over a Pt/Al2O3 catalyst were systematically investigated under atmospheric pressure conditions. Reaction progress was monitored via acid value measurements as an indicator of residual stearic acid concentration. A transition in apparent kinetic behavior was observed based on the comparative fitting of integrated kinetic models at different stearic acid/urea molar ratios. Temperature significantly affected the reaction rate, with the apparent rate constant increasing from 7.0 × 10−5 L.mol−1.min−1 at 160 °C to 1.0 × 10−4 L.mol−1.min−1 at 200 °C. Similarly, increasing catalyst concentration from 0.5 to 2 wt% improved the reaction rate. An apparent kinetic model was developed to describe the observed reaction behavior. The results identify a stearic acid/urea molar ratio of 1:2, temperature of approximately 177 °C, and catalyst concentration of 1.5 wt% as favorable conditions for efficient stearamide synthesis under atmospheric pressure.