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Title: Temperature dependence of the equilibrium CH/sub 2/(OH)/sub 2/ + HSO/sub 3//sup -/ = CH/sub 2/(OH)SO/sub 3//sup -/ + H/sub 2/O in aqueous solution

Journal Article · · J. Phys. Chem.; (United States)
DOI:https://doi.org/10.1021/j100405a033· OSTI ID:5532914

Ultraviolet absorption spectrometry was used to measure concentrations of bisulfite in thermal equilibrium with formaldehyde and hydroxymethanesulfonate in deaerated, argon-saturated aqueous solutions. The equilibrium constant of the title reaction was determined as a function of temperature in the range 288-318 K for pH values of 5-6, and at 298 K as a function of pH in the range 4.1-9.7. The temperature dependence (at pH 5-6) is represented by log 1/K/sub 1a/ = (2854 +/- 59)/T - (3.0 +/- 0.2) which leads to values for the reaction enthalpy and entropy of (-54.60 +/- 1.10) kJ/mol and (57.6 +/- 3.7) J/(mol K), respectively. The pH dependence of the equilibrium is shown to result from the equilibrium between sulfite and bisulfite. Finally, the decomposition of hydroxymethanesulfonate was studied at 25/sup 0/C. The effective rate coefficient is 1.1 x 10/sup -5/ s/sup -1/ at pH 5.6. The value is compared with other recent data.

Research Organization:
Johannes-Gutenberg-Universitaet, Mainz, West Germany
OSTI ID:
5532914
Journal Information:
J. Phys. Chem.; (United States), Vol. 90:14
Country of Publication:
United States
Language:
English