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Environmental fate & pathways

Hydrolysis

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Description of key information

At 12°C:
pH 7: t1/2= 15.75 years
pH 7.5: t1/2 = 5 years
pH 8: t1/2= 1.57 years
pH 9: t1/2= 58 days

Key value for chemical safety assessment

Half-life for hydrolysis:
5 yr
at the temperature of:
12 °C

Additional information

In a reliable scientific publication (RL 2) hydrolysis of several substituted methyl benzoates (including methyl-p-toluate) was investigated. Using Hammet Linear Free Energy Relationships a general equation was deduced allowing calculation of hydrolysis half-lives for a given temperature and pH using Hammet substituent constants determined in the study. As a result, using the given equation derived in this work for calculation at 12°C, the following hydrolysis half-lives for methyl-p-toluate are resulting:

pH 7: t1/2= 15.75 years

pH 7.5: t1/2 = 5 years

pH 8: t1/2= 1.57 years

pH 9: t1/2= 58 days

QSAR estimations (not reliable) of half-lives for hydrolysis are between 8.5 to 11 years at pH 7 and 1.1 years at pH 8 (no clear temperature declared).