Kinetics and chemical equilibrium of the hydration of formaldehyde

Abstract The reaction rate of the hydration of formaldehyde is obtained from the measured, chemically enhanced absorption rate of formaldehyde gas into water in a stirred cell with a plane gas–liquid interface, and mathematically modelling of the transfer processes. Experiments were performed at the conditions prevailing in industrial formaldehyde absorbers, i.e. at temperatures of 293– 333 K and at pH values between 5 and 7. The observed rate constants could be correlated as k h =2.04×10 5 × e −2936/T s −1 . Using the results, and the dehydration reaction rate constant, obtained previously at similar conditions, the chemical equilibrium constant for the hydration is obtained as K h =e 3769/ T −5.494 .