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Physical & Chemical properties

Dissociation constant

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Description of key information

Study has been waived as scientifically not possible to perform. 

Key value for chemical safety assessment

Additional information

According to 7.16 column 2 of Annex IX of the European Union (EU) Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) 1907/2006 regulation, the study does not need to be conducted if it is scientifically not possible to perform the test, for instance if the analytical method is not sensitive enough. Experimental evaluation of the water solubility resulted only in a limit value (actual value <1.25 mg/L, slightly soluble) due to the necessity to employ a visual method. Subsequent computer modeling of individual components, performed to provide definitive solubility data, resulted in a majority of the estimated values being within the “insoluble” classification range (actual values 0.005 to 0.21 mg/L). The titration method was, therefore, considered to be not applicable. The substance is a complex reaction mixture containing ionisable and non-ionisable forms; the non-ionisable forms degrade in water to yield the ionisable forms (DT50 is 10.3 days). It is not possible to accurately quantitate the respective forms using a spectrometric method. Due to the limited water solubility, the conductometric method is not appropriate as it is not possible to accurately measure the conductivity at different dilutions due to the potential formation of emulsions and microemulsions. This endpoint is waived, therefore, on the basis that it is not scientifically feasible to perform the test.