Kinetics, mechanism and thermodynamics of bisulfite-aldehyde adduct formation
The kinetics and mechanism of bisulfite addition to benzaldehyde were studied at low pH in order to assess the importance of this reaction in stabilizing S(IV) in fog-, cloud-, and rainwater. Previously, the authors established that appreciable concentrations of the formaldehyde-bisulfite adduct (HMSA) are often present in fogwater. Measured HMSA concentrations in fogwater often do not fully account for observed excess S(IV) concentrations, however, so that other S(IV)-aldehyde adducts may be present. Reaction rates were determined by monitoring the disappearance of benzaldehyde by U.V. spectrophotometry under pseudo-first order conditions, (S(IV))/sub T/ >>(phi-CHO)/sub T/, in the pH range 0 - 4.4 at 25/sup 0/C. The equilibrium constant was determined by dissolving the sodium salt of the addition compound in a solution adjusted to pH 3.9, and measuring the absorbance of the equilibrated solution at 250 nm. A literature value of the extinction coefficient for benzaldehyde was used to calculate the concentration of free benzaldehyde. All solutions were prepared under an N/sub 2/ atmosphere using deoxygenated, deionized water and ionic strength was maintained at 1.0 M with sodium chloride.
- Research Organization:
- California Institute of Technology, W.M. Keck Labs., 138-78, Pasadena, CA 91125
- OSTI ID:
- 5432304
- Report Number(s):
- CONF-860425-
- Journal Information:
- Am. Chem. Soc., Div. Pet. Chem., Prepr.; (United States), Vol. 31:2; Conference: 191. American Chemical Society national meeting, New York, NY, USA, 13 Apr 1986
- Country of Publication:
- United States
- Language:
- English
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ACID RAIN
ATMOSPHERIC CHEMISTRY
BENZALDEHYDE
RAIN WATER
SULFITES
ADDITIVES
CHEMICAL REACTION KINETICS
CHEMICAL REACTION YIELD
CLOUDS
DERIVATIZATION
FOG
PH VALUE
SPECTROPHOTOMETRY
SULFUR COMPLEXES
THERMODYNAMICS
ALDEHYDES
ATMOSPHERIC PRECIPITATIONS
CHEMICAL REACTIONS
CHEMISTRY
COMPLEXES
HYDROGEN COMPOUNDS
KINETICS
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
RAIN
REACTION KINETICS
SULFUR COMPOUNDS
WATER
YIELDS
500200* - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)