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Physical & Chemical properties

Dissociation constant

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Reference
Endpoint:
dissociation constant
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
other:

Description of key information

Dissociation constant: 10.14 to 10.15 (calculation)

Key value for chemical safety assessment

pKa at 20°C:
10.14

Additional information

In accordance REACH Annex XI, this study is considered to be scientifically unjustified for the following reasons:

Amyl Salicylate is a mixture of two salicylic acid alkyl esters. Therefore, to assess whether the phenol group in these molecules does ionize in the environmentally relevant pH range, the pKa was estimated using the SPARC software (v4.5), recommended for this purpose by the Technical Guidance Document to Industry on the Information Requirements for REACH, to be 10.14 and 10.15 at 25°C for the two isomers respectively. This suggests that the pKa of Amy Salicylate is outside the environmentally relevant pH range (4 to 9 for surface waters, about 8 for marine environments and between 5.5 and 7.5 for agricultural soil and STP tanks - ECHA Guidance Ch R.7a ), and that Amyl Salicylate therefore is undissociated under normal conditions.