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Description of key information

DT50 pH 4 (25 °C) = 26 hours
DT50 pH 7 (25 °C) = 219 hours
DT50 (25 °C) = 1147 hours

Key value for chemical safety assessment

Additional information

The abiotic degradation of ethyl 3,5 -dichloro-4 -hexadecyloxybenzoate (AF-366) via hydrolysis was investigated by Rhemrev-Boom (1989) and Rhemrev-Boom and Houtzager (1992). The first study was a preliminary test conducted according to OECD 111 under GLP conditions. The test substance was incubated for 5 days at 50 °C in three different buffered solutions, at pH 4, pH 7 and pH 9. The results of the test showed that > 10% hydrolysis took place in all three solutions (30% at pH 4, 39% at pH 7 and 49% at pH 9) and therefore, further testing was needed in order to determine the precise abiotic degradation of the substance.


The second (main) test was performed according to the Council Directive 67/548/EEC method “Hydrolysis as a function of pH”. A preliminary study was carried out for 44 hours, after which it was deemed necessary to continue with the full test. The test substance was incubated at pH 4, 7 and 9 at two different temperatures (25 °C and 50 °C). The entire test was conducted under sterile conditions and the temperature controlled within 0.5 °C of the nominal temperatures. Under environmentally relevant conditions (25 °C) the half-lives of the substance were 26 hours, 219 hours and 1147 hours at pH 4, pH 7 and pH 9, respectively.


These values indicate that ethyl 3,5 -dichloro-4 -hexadecyloxycarbonyloxybenzoate (AF-366)

can be expected to be rapidly degraded abiotically in water at pH 4 and pH 7, but is considered to be hydrolytically stable at pH 9.