Kinetics for the sulfuric acid‐catalyzed reactions of ethylene oxide with water and ethylene glycols

Abstract

AbstractAdiabatic calorimeter experiments have quantified the sulfuric acid‐catalyzed reaction of ethylene oxide (EO) with water to form ethylene glycol (EG) and higher glycols. Conditions were selected relevant to industrial safety, such as a scenario of reverse flow of acid from a scrubber to an EO tank. Concentrations of 25–95 wt% EO with acidified water of pH 3.0 down to pH –0.7 were examined. In some experiments, EG was also added to the mix. The best fit apparent reaction rate expression exhibits a 1.5 order in EO concentration, third order in water concentration, nearly first order in acid concentration, and an activation energy of 76,500 kJ/kmol. The reaction model provides an adequate fit of adiabatic self‐heat rate versus temperature, pressure rate versus temperature, pressure versus time, and temperature versus time data for a large number of APTAC (Automatic Pressure Tracking Adiabatic Calorimeter) experiments. The model builds on one previously developed for the neutral reactions of EO with water and EGs. A case study involving a sulfuric acid‐contaminated EO railcar is presented. The reaction model can help quantify the behavior of EO contaminated with sulfuric acid solution below about 120°C. Above this temperature, other reaction pathways not characterized in this study become more prominent.