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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information


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.