The kinetics of the dehydration of methylene glycol were measured under con
ditions relevant in industrial formaldehyde absorbers (293 K less than or e
qual to T less than or equal to 333 K; 6.0 less than or equal to pH less th
an or equal to 7.8). The rapid reaction between formaldehyde and SO32- to h
ydroxymethane sulphonate (HMS-) was used as a formaldehyde scavenger:
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Under the experimental conditions the rate determining step in the formatio
n of HMS- appeared to be the dehydration of methylene glycol. The observed
reaction rate constant for the dehydration of methylene glycol could be cor
related as k(d) = 4.96 x 10(7) x e(-6705/T) s(-1). The dehydration rate is
shown to be independent of the concentrations of both sulphite and hydroxid
e ions. (C) 2000 Elsevier Science Ltd. All rights reserved.