Production of isopropyl palmitate in a catalytic distillation column: Experimental studies

The fatty acid esters produced using monohydric alcohols have a wide range of applications in the cosmetic and personal care products. The conventional method for the production of esters has several drawbacks such as product quality degradation due to relatively long exposure to heat, necessity of catalyst neutralization and relative high alcohol demand. The reactive distillation (RD) process for the production of fatty acid esters overcomes these drawbacks. The production of isopropyl palmitate (IPP) in the RD column is reported in the present study. The reaction was catalyzed by the zinc acetate supported on silica gel. A pilot plant RD column of 102 mm diameter with a packing height of 3 m was designed, fabricated and used for the experimental studies. The process parameters total feed flow rate (30–100 mol/h), reboiler duty (0.5–2.0 kW), palmitic acid (PA) feed composition (40–100 mol%), PA feed temperature (80–120∘C), molar ratio of isopropanol feed to PA feed (1–2) and reflux ratio (0.5–2.5) were varied during the experimental study. The experimental optimum values of these parameters obtained were 50 mol/h, 0.64 kW, 100 mol%, 120∘C120∘C, 2 and 0.5, respectively within the range of study. The average IPP purity of 86 mol% and PA conversion of 94% were obtained at the optimum operating conditions. The experimental data were used to validate the theoretical predictions obtained from steady-state model and rate-based model. The predictions from the rate-based model matched with the experimental results qualitatively and quantitatively.