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Environmental fate & pathways

Phototransformation in air

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Description of key information

The estimated second-order rate constant for reaction with photochemically-generated hydroxyl radical is 17.5E-12 cm3/molecule*sec at 25 degrees C. 

Key value for chemical safety assessment

Half-life in air:
22 h

Additional information

The atmospheric fate of the 2,6-diemethylheptan-4-one substance was estimated using the U.S. EPA AOPWIN (v1.92a) software. An atmospheric half-life of 22 hrs (0.9 days) was estimated, based on predicted second-order reaction rate constant with photochemically-generated hydroxyl radical. This prediction was based on an ambient hydroxyl radical concentration of 500,000 molecules/cm3 and 24 hr photoday. Predictive accuracy of the software was evaluated by comparing measured and predicted rate constants for three analog substances: 2 -butanone; 3 -pentanone; and 3 -hexanone. Predicted values agreed within a factor of 1.3 of the experimental values, thereby validating the prediction for 2,6-diemethylheptan-4-one. Based on this estimation, the substance is not regarded as persistent in the atmosphere (i.e., half-life < 2 days).