Modeling and Safe Operation of Fatty Alcohol Ethoxylation in a Continuous Flow Calorimeter

A safe, continuous process for the base-catalyzed ethoxylation of fatty alcohols at the miniplant scale is developed in this work. A flow process model based on preexisting semibatch and literature data is used to design a Fluitec flow calorimeter miniplant. Validation experiments at 1.5 mol equiv (mequiv) of ethylene oxide (EO) agreed well with semibatch kinetics, while 3 mequiv experiments showed considerable discrepancies. Critically, observed temperature peaks increased at higher flow rates, while the model predicts the opposite behavior. Caloric measurements using 1.5 mequiv of EO resulted in an average reaction enthalpy of 88 ± 4 kJ/mol ethylene oxide, which is in good agreement with the literature. A conservative total-failure scenario model predicted maximum temperature rises of 60 K (1.5 mequiv) and 104 K (3 mequiv), whereas experimental values were significantly lower (22 and 38 K). This article shows how simulations and theoretical calculations should guide practical experimental work and vice versa. Moreover, it demonstrates the feasibility of transferring semibatch data to continuous flow systems and emphasizes the importance of model validation under flow conditions.