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Henry's Law Constants for Paint Solvents and Their Implications on Volatile Organic Compound Emissions from Automotive Painting
Author(s) -
Kim Byung R.,
Kalis Edward M.,
Dewulf Thomas,
Andrews Kari M.
Publication year - 2000
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.2175/106143000x137121
Subject(s) - chemistry , toluene , ketone , henry's law , formaldehyde , solvent , equilibrium constant , ethyl acetate , methyl isobutyl ketone , organic chemistry , inorganic chemistry , solubility
This paper describes experimental results of equilibrium partitioning of several significant paint solvents and formaldehyde between air and water to quantify the potential for capturing and retaining the constituents in spraybooth scrubber water during automotive painting. The compounds studied are toluene, n ‐butanol, methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone, methyl amyl ketone, butyl cellosolve, butyl cellosolve acetate, butyl carbitol, and n ‐methyl‐2‐pyrrolidinone. A set of field data collected at a Ford Motor Company assembly plant was also analyzed to determine whether data were consistent with the equilibrium phenomenon. The primary findings include: (a) There were more than six orders of magnitude difference in the Henry's law constants among the solvents studied. A solvent with a smaller constant is less easily stripped from water. The Henry's law constants decrease in the following order: toluene and xylenes methyl ethyl ketone n ‐butanol butyl cellosolve acetate butyl cellosolve formaldehyde butyl carbitol n ‐methyl‐2‐pyrrolidinone. (b) Field data showed accumulation of n ‐methyl‐2‐pyrrolidinone and stable concentrations of butyl carbitol, butyl cellosolve, and n ‐butanol in the paint‐sludge pit water during a 2‐month period. Stable concentrations indicate a continuous, balanced capture and stripping of the solvents. Data were consistent with measured Henry's law constants. (c) The low Henry's law constant for formaldehyde is the result of the fact that it is hydrated when dissolved in water.