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Environmental fate & pathways

Phototransformation in air

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Description of key information

Model calculation using EpiSuite 4.0 (AOP program v1.92, US-EPA, 2013):
Half-life for reaction with hydroxyl radicals ( 1.5E6 OH/cm³) = 20.6 h
Half-life for reaction with ozone (at 7E11 mol/cm³) = 24.2 h

Key value for chemical safety assessment

Additional information

MAA does not possess UV-absorbing structures. Therefore, direct photolysis is not expected to occur to any significant degree.

While experimental data with model atmospheres exist for MMA which are broadly consistent with model data, no experimental photodegradation data exist for MAA. A model calculation using EpiWin v4.00 AOP v1.92 showed a rate constant for the reaction of MAA with hydroxyl radicals in the atmosphere of 18.6460 E-12 cm³/molecule*sec. From this rate constant the half-life for the reaction of OH radicals with the test substance is calculated as 20.6 h.

In conclusion, after evaporation or emission to air, methacrylic acid will be rapidly degraded by photochemical processes.