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Influence of temperature on the degradation of isothiazolone biocides in aqueous media and in a metalworking fluid concentrate

Journal Article · · Lubrication Engineering
OSTI ID:191837
 [1]
  1. Texaco Inc., Port Arthur, TX (United States)
The degradation of the active component of two isothiazolone biocides has been monitored at 24{degrees}, 40{degrees}, and 60{degrees} by reversed-phase liquid chromatography. The first-order rate constants are measured, and temperature-dependent kinetic data are used to show that the rate of degradation is doubled if the temperature is increased by 5{degrees}C and 6{degrees}C in aqueous media by pH 8.5 and 9.6, respectively. At pH 5.5, the active component is found to be stable at 24{degrees} and 40{degrees}C, and its depletion at60{degrees}C is about 10 percent over a period of three and one-half months. An estimated half-life of the active component in a metalworking fluid concentrate is six months at 24{degrees}C. However, at both 40{degrees} and 60{degrees}C, its degradation appears to be a two-step process. Initially, the concentration remains invariant or decreases slowly. This is followed by a rapid, first-order kinetic process. The overall times required for 50 percent loss of the active component are 12.2 and 1.6 days at 40{degrees} and 60{degrees}C, respectively.
OSTI ID:
191837
Journal Information:
Lubrication Engineering, Journal Name: Lubrication Engineering Journal Issue: 5 Vol. 50; ISSN 0024-7154; ISSN LUENAG
Country of Publication:
United States
Language:
English