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Environmental fate & pathways

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Phototransformation in air

1,2-Cyclohexanedicarboxylic acid, 4-methyl- (4-MHHPAc)

Half-life for reaction with photochemically-produced hydroxyl radicals: 30.1 hours.

Overall degradation rate constant with OH radicals= 1.10E-6 cm3/(molecule-day)


Half life - at ph 4: 1.43 minutes at 20 deg C; 2.04 minutes at 30 deg C and 0.692 minutes at 50 deg C. at ph 7: 1.90 minutes at 20 deg C; 1.26 minutes at 30 deg C and 0.327 minutes at 50 deg C. at ph 9: 1.27 minutes at 20 deg C; 1.18 minutes at 30 deg C and 0.233 minutes at 50 deg C.



Ready biodegradability in water: 2% in 28 days



The potential for bioaccumulation of 4-MHHPAc (the hydrolysis produc of 4-MHHPA) is low, less than 2.4 L/Kg, as expected from low values of log Kow for both substances.


Henry's Law Constant

The Henry's Law constants of 1,2-Cyclohexanedicarboxylic acid, 4-methyl- (4-MHHPAc), as hydrolysis product of hexahydro-4-methylphthalic anhydride, was considered for the environmental assessment. The value of 2.75E-4 Pa m³/mol shows that 4-MHHPAc is essentially non volatile from surface water.