Optimization and kinetic study of N‐methyldiethanolamine‐based esterquats production

Abstract A sustainable alternative process for the production of bio‐based esterquats via heterogeneous transesterification of palm methyl ester and N‐methyldiethanolamine was developed. The transesterification process conditions over CaO/γ‐Al 2 O 3 catalyst were optimized using Response Surface Methodology (RSM). At 146°C, 83.2% di‐ester yield was obtained after 6 h when 4.1 wt% of the synthesized catalyst was used with 1.8:1 methyl ester/N‐methyldiethanolamine molar ratio. CaO/γ‐Al 2 O 3 was able to be reused for 3 cycles without a significant deactivation. A kinetic model was proposed based on irreversible second‐order kinetics and it was the best‐fitted experimental data with an overall reaction rate constants ranging between 0.0892 and 0.695 L/mol.min and an activation energy of 48 kJ/mol. The first experimental investigation on kinetic can be applied to provide insights on large scale reactor design for bio‐based esterquats production. The synthesized esterquats was found to be readily biodegradable, as it reached the pass level of 60% of biodegradation within the period of incubation (28 days). It exhibits similar chemical and physical properties to the commercially available tallow‐based esterquats, thus offering a potential substitute for the animal fat‐based feedstock with the most abundantly available and renewable palm‐based oleochemicals.