Disodium 4,4'-bis(2-hydroxynaphthalen-1-ylazo)biphenyl-2,6'-disulphonate

Endpoint summary

Additional information

The substance to be registered is an odourless red powder.

In a DSC analysis (SPO STR 028 method, similar to OECD 102) has been noted that from 25 -120 °C water/solvent is released from the substance, followed by a decomposition of the product between 127- 174 °C (onset at 137.7 °C; enthalpy – 4.2 J/g). Furthermore it was estimated a melting point value of 349.84 °C with MPBPVP 1.43 (EPISUITE).

Relative density was determined by means of a pycnometer (OECD 109) and the result value was D at 20 °C 1.579.

Granulometry of the sample (SPO STR 071 method) was performed with and without 2 minutes of sonication. The substance presented a granulometry (D50 after 2 minutes of ultrasonic of 16.891 µm) that can be considered as inhalable fractions.

According to Annex VII of the REACH Regulation 1907/2006/EEC, Column 2, the study of vapour pressure does not need to be conducted for this substance but the lowest value accepted by EUSES has been reported for a complete Risk assessment (0.0000001 Pa).

Partition coefficient was determined by a Shake Flask Method (OECD 107); the average log Kow measured was – 1.1192 at 20°C. Estimated data of Log Kow using calculation software EpiSuite 4.1 (KOWWIN v1.68 estimate) was 1.19.

The tested substance is considered very soluble by OECD 105 (water solubility = 8.85 g/L, mean).

According to Annex VII of REACH Regulation 1907/2006/EEC, Column 2 no surface activity is expected or can be predicted; therefore the testing can be waived. As solid, the substance has no a flash point and the test can also be waived.

There is no a potential for spontaneous ignition is not expected for the following reasons:

-Is a non-pyrophoric solid because it does not react with air in small amounts in a more or less instantaneous manner;

-Can be considered as a non-self-heating solid because it does not react with air in large amounts and after an extended period of time;

Furthermore the substance is produced and used regularly since many years in Europe according to the above qualifications, transported by ship from outside Europe under various conditions and in various amounts. Evidence connected to the long experience in handling and use of the molecule confirms the not spontaneous ignition property. In addition, it is soluble in water at room temperature and forms a stable solution with water. No reactions with water or emission of flammable gases have ever been noted. For soluble dyes a reaction with water is not a desirable property from the use point of view.

Therefore it is not to be classified as a substance which in contact with water may react to emit flammable gases and an experimental determination according to the EC test guideline A.12 needs to be performed according to the REACH Regulation.

Flammability of the substance was assessed by EU Method A.10, described in Regulation n. 440/2008: it is not flammable.

Furthermore evidences connected to the long experience in handling of the substance confirms that no flammable properties have never been observed and reported up to now in the usual conditions of production, stock, transport and use.

No explosive or oxidizing properties could be associated to the substance because an according to Annex VII of the REACH Regulation 1907/2006/EEC, Column 2, both test can be waived. In addition, after the calculation of the oxygen balance an the evaluation of the exothermic energy (DSC performed) the substance could be considered with no explosive or oxidising properties.