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Environmental fate & pathways

Phototransformation in water

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Description of key information

For phthalic acid in sea water a half-life of 0.93 hours was determined at 50°C (Armstrong 1968).

Key value for chemical safety assessment

Half-life in water:
0.93 h

Additional information

A photochemical reactor, using a medium power mercury arc lamp for oxidation of organic matter in sea water is used to measure the influence of light on degradation of phthalic acid. The decomposition of the substance in distilled water and in sea water at 50°C, using a 380 W lamp, was followed via titration. A first order rate constant for photooxidation of phthalic acid of about 0.75 h-1 that is equivalent to a half-life of 0.93 hours was obtained (Armstrong, 1968).