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Melting point / freezing point

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melting point/freezing point
Data waiving:
study technically not feasible
Justification for data waiving:

Description of key information

OO-tert-butyl monoperoxymaleate in its marketed form is a suspension at 20 °C. OO-tert-butyl monoperoxymaleate is a solid, but due to the substance's thermal instability (SADT +55 °C) it is only available together with a liquid phlegmatizer. According to Guidance on Information Requirements and Chemical Safety Assessment Chapter R.7a: Endpoint specific guidance, Chapter R.7.1.2, the “melting point / freezing point” is defined as "the temperature at which the phase transition from the solid to the liquid state occurs at atmospheric pressure and this temperature ideally corresponds to the freezing temperature”.

This definition is not applicable to the test item, which is a suspension at 20 °C. The study is disregarded because for the determination of the actual melting point of the active ingredient OO-tert-butyl monoperoxymaleate, which is the solid component of the suspension, the test item needs to be heated. During heating, solving effects of the liquid phlegmatizer may occur and the differentiation between a real phase transition (melting) and solving is not possible. Additionally, the test item is only stable up to a temperature of +55 °C and afterwards decomposes thermally.

Key value for chemical safety assessment

Additional information