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Description of key information

non explosive

Key value for chemical safety assessment

non explosive

Additional information

The test was performed on the structural analogue Similar Substance 01, according to the GLP principles and conducted according to internationally accepted testing method A.14. Similar substance 01 is not sensitive with respect to heating, shock and hiction; it was concluded that it has no explosive properties.

Similar Substance 01 is a chromate-pyrazol dye, as Acid Violet 090. They are characterized by aromatic rings, which are substituted in different manners. Acid Violet 090 has a simmetric structure, characterized by two dihydro-methyl-oxo-phenyl-pyrazolylazo hydroxynaphthalene-sulphonato groups. Similar Substance 01 has a sodium hydroxynitronaphthalene-sulfonate group instead of sodium hydroxynaphthalene-sulfonate, a hydroxynaphthalene instead of hydroxymethyl-phenyl pyrazole one and it has a hydroxy-nitrophenyl group instead of a sodium hydroxynaphthalene-sulfonate. Nitronaphtalen sulphoned group and naphtalen sulphoned group are both electron poor rings, due to the presence of electron acceptators substituents. The unsubstituted naphtalen of Similar Substance 01 and the phenyl group on pyrazol ring in the Acid Violet 090 structure have a similar reactivity in terms of electrophylic substitution aromatic. Furthermore, the similar Substance 01 is a disodium salt, while Acid Violet 090 is a trisodium salt.

The different functionalisation of the complex ligands and their sulfonation degree do not significantly impact the potential for explosiveness of the dyes.

The tested lot has Similar Substance 01 content of approximately 55 % and the impurity profile is comparable to that of AV090. Assuming that the remaining components have no impact on the test results the read across can be considered suitable.

Acid Violet 090 and Similar substance 01 have a comparable thermal behaviour. The Differential Scanning Calorimetry analyses performed on both the analogous, reported a first endothermic rection between 25 - 110/130 °C, involving moderate amounts of energy, probably attributable to the imbibition water/solvent release. Around the temperature of 250 - 300 °C dyes are expected to undergo to decomposition: in the case of Similar Substance 01 the DSC graph describes a peak associated with decomposition of the substance (297 - 434 °C; details in attachment). Unfortunately, the DSC analysis of Acid Violet 09 has been stopped around 300 °C, temperature at which the substance seems to start the decomposition process.

Furthermore, in general, chromate-pyrazol derivatives share the same thermal behaviour, with exothermic decomposition energy less than 500 J/g. Chromato-pyrazole dye complexes are substances characterized by several aromatic rings, in resonance, which determine the coloured aspect of the dye (its primary function). The actual energy of the molecule in resonance is lower than might be expected for any of the contributing structures and it can be expect that the resonance could improve the substance stability. The azo double bond seems not impact the stability of these substances. Experimental results on assays performed on chromate-pyrazole complexes do not deny this deduction.

Based on the structural assessment and thermal behaviour comparison with structural analogues, it is expected that Acid Violet 090 it is expected to have no explosive properties. Furthermore evidences connected to the long experience in handling of the substance confirms that no explosive properties have never been observed and reported up to now in the usual conditions of production, stock, transport and use.

Justification for classification or non-classification

According to the CLP Regulation (EC 1272/2008), 2.1 section, an explosive substance or mixture is a solid or liquid substance or mixture of substances which is in itself capable by chemical reaction of producing gas at such a temperature and pressure and at such a speed as to cause damage to the surroundings. Pyrotechnic substances are included even when they do not evolve gases.

Substances, mixtures and articles of this class are classified as explosive on the basis of the results obtained from the test performed according to the methods described in Part I of the UN Recommendations on the Transport of Dangerous Goods, Manual of Tests and Criteria.

The explosiveness assessment was based on the read across approach; test item is not sensitive with respect to heating, shock and hiction, therefore even the Acid Violet 090 is expected to be non explosive.

In conclusion, according to the CLP Regulation (EC 1272/2008) Acid Violet 090 is not classified for explosiveness.