(64a) Biphasic Aldol Condensation of n-Butyraldehyde: Kinetic Study Using Stirred Cell

Biphasic aldol condensation of n-butyraldehyde (nBAL), catalyzed by sodium hydroxide (NaOH), is a part of 2-ethyl hexanol process. To model this biphasic reaction in a stirred-tank reactor, intrinsic kinetics and interfacial area are required. In this study, the intrinsic reaction rate is obtained in the range of 110~150°C and 0.76~1.9 M NaOH, which is in the mass transfer regime dominated by the reaction rate in the film. A stirred cell is used to obtain stable interface between the organic and aqueous phases. The reaction dominant mass transfer controlled regime was confirmed by plateau region experiment and calculations of mass transfer. As a result, considering solubility and diffusivity, the rate was found to be 1^st order for both nBAL and NaOH concentrations, along with 13.5±0.4 kcal/mol activation energy. The parameter sensitivity using several models for solubility, diffusivity and salt effect was also studied. This work demonstrates that it is possible to determine intrinsic reaction kinetics in the mass transfer controlled regime, dominated by reaction rate in the film. The results of the present work will be useful to model the biphasic reaction of nBAL in a stirred-tank reactor.