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Physical & Chemical properties

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Additional information

Appearance/physical state/colour

On the basis of physical observation and using the sense of smell, 4,4'-dinitrostilbene-2,2'-disulphonic acid was found to be a yellow amorphous organic solid with characteristic odour at 37°C and 965 hPa.

Melting point/freezing point

The melting point of 4,4'-dinitrostilbene-2,2'-disulphonic acid was found to be 266 °C.

Boiling point

Boiling point of 4,4'-dinitrostilbene-2,2'-disulphonic acid was estimated to be 677.17 deg C by means of Adapted Stein and Brown Method.

Density

The bulk density of 4,4'-dinitrostilbene-2,2'-disulphonic acid by the mass by volume method was found to be 0.836 g/cm3 at room temperature of 37 °C .This value when converted at 20 degC is equivalent to 0.451.

Particle size distribution (Granulometry)

The particle size distribution (granulometry) of 4,4'-dinitrostilbene-2,2'-disulphonic acid by the sieve analysis method was found to be in the range of 75 micrometer to 500 micrometer. Majority of the particles were found to be in the size more than 150(47.834%) - 250(25.966%) micrometer in size.

Vapour pressure

The vapour Pressure of 4,4'-dinitrostilbene-2,2'-disulphonic acid was estimated to be 0.000000000000000013 Pa at 25 deg C by means of Modified Grain Method.

Partition coefficient

The experimental value of octanol water partition co-efficient (log Pow) of 4,4'-dinitrostilbene-2,2'-disulphonic acid is -0.248 at 37 degC and pH of 2.46.This value indicates that 4,4'-dinitrostilbene-2,2'-disulphonic acid is hydrophilic in nature.

Water solubility

The experimental value of the water solubility of 4,4'-dinitrostilbene-2,2'-disulphonic acid was found to be 105400 mg/L at 37 degC indicating that it is very soluble in water.

Solubility in organic solvents / fat solubility

Gravimetric method was used to determine the solubility of the substance in organic solvent. The experimental value of solubility of 4,4'-dinitrostilbene-2,2'-disulphonic acid in methanol at 37 degC was found to be 4864 mg/L indicating that this substance is soluble in methanol.Using the Soxhlet/Solvent extraction method the solubility of the substance in Petroleum ether is observed to be 180 mg/L at 37 °C indicating that this substance is moderately soluble in petroleum ether. The solubility value of4,4'-dinitrostilbene-2,2'-disulphonic acidin metthanol at 20 degC is equivalent to a value of 2629.189 mg/L.

Surface tension

In accordance with Column 2 adaptation statement of REACH Annex VII, information requirement 7.6, this end point was considered for waiver since surface activity was not a desired property of 4,4'-dinitrostilbene-2,2'-disulphonic acid.

Flash point

In accordance with Section 2 of REACH Annex XI, information requirement section 7.9, this study does not need to be conducted based on the physical state of the molecule. According to ECHA guidance, flash point is only relevant to liquids and low melting point solids.Therefore this study was considered for waiver.

Auto flammability

4,4'-Dinitrostilbene-2,2'-disulphonic acid did not catch fire on being exposed to air at room temperature of 37 degC and atmospheric pressure of 965 hPa. This indicates that 4,4'-dinitrostilbene-2,2'-disulphonic acid is not auto-flammable.

Flammability

From the experimental values of flammability, 4,4'-dinitrostilbene-2,2'-disulphonic acid ignited when the flame of bunsen burner having temperature of 950 degC was brought in contact with it. Thus it can be concluded that 4,4'-dinitrostilbene-2,2'-disulphonic acid is flammable only at high temperature of about 950 degC. However since such high temperatures are not found under normal circumstances of transportation and use, 4,4'-dinitrostilbene-2,2'-disulphonic acid was considered non-flammable for chemical safety assessment.

Explosiveness

In accordance with coulumn 2 of Annex VII, the testing was waived as there are no chemical groups associated with explosive properties in 4,4'-dinitrostilbene-2,2'-disulphonic acid.

Oxidising properties

4,4'-Dinitrostilbene-2,2'-disulphonic acid was found to have mild oxidising property since 154.90 ml of KMnO4 was required for getting the end point of the redox titration for 100 g of 4,4'-dinitrostilbene-2,2'-disulphonic acid. Thus, the chemical is considered as non-oxidising for the purpose of chemical safety report and classification.

Stability in organic solvents and identity of relevant degradation products

4,4'-Dinitrostilbene-2,2'-disulphonic acid was found to be stable in organic solvent dichloro methane and no degradation products were formed after 24 hours as evident from the GC-MS chromatogram obtained at 0 hours and that obtained after 24 hours.

pH

1% by volume solution of 4,4'-dinitrostilbene-2,2'-disulphonic acid was found to exhibit a pH of 1.89 at 27 degC. Thus 1% by volume solution of 4,4'-dinitrostilbene-2,2'-disulphonic acid is acidic in pH.

Dissociation constant

The experimental pKa value for 4,4'-dinitrostilbene-2,2'-disulphonic acid was found to be 0.000000721 at 37 degC indicating that it has dissociation properties. This pKa value when converted at 20 degC is equivalent to 0.000000389.

Viscosity

This end point was considered for waiver since viscosity is an inherent property of a liquid that offers resistance to its flow and 4,4'-dinitrostilbene-2,2'-disulphonic acid is a solid substance and hence this testing was considered scientifically unjustified for 4,4'-dinitrostilbene-2,2'-disulphonic acid.

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