Registration Dossier

Physical & Chemical properties

Endpoint summary

Administrative data

Description of key information

Additional information

Appearance/physical state/colour

On the basis of physical observation and using the sense of smell, 2-aminobenzenesulphonic acid was found to be a light brown organic amorphous solid with characteristic odour at 23°C and 955 hPa.

Melting point/freezing point

Melting point of 2-aminobenzenesulphonic acid was found to be 315°C .

Boiling point

Boiling point of 2-aminobenzenesulphonic acid estimated as 363.26 deg.C by using Stein and Brown method.

Density

The bulk density of 2-aminobenzenesulphonic acid by the mass by volume method was found to be 3.05 g/cm3 at room temperature of 23 °C .This value when converted at 20 degC is equivalent to 2.65.

Particle size distribution (Granulometry)

The particle size distribution (granulometry) of 2-aminobenzenesulphonic acid by the sieve analysis method was found to be in the range of 53 micrometer to 500 micrometer. Majority of the particles were found to be in the size more than 150 (62.80%) - 300 (17.83%) micrometer in size.

Vapour pressure

Vapour pressure of 2-aminobenzenesulphonic acid was estimated to be 0.000027 Pa at 25 degC by means of modified Grain method.

Partition coefficient

The experimental value of octanol water partition co-efficient (Pow) of 2-aminobenzenesulphonic acid is 1 at 23 degC and pH of 2.29.This value indicates that 2-aminobenzenesulphonic acid is hydrophilic in nature.

Water solubility

The experimental value of the water solubility of 2-aminobenzenesulphonic acid was found to be 3100 mg/L at 23 degC indicating that it is soluble in water. The supporting studies also indicate that the substance 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 of2-aminobenzenesulphonic acidin methanol at 23 degC was found to be 4100 mg/L indicating that the substance is soluble in methanol.Using the Soxhlet/Solvent extraction method the solubility of the substance in Petroleum ether is observed to be 800 mg/L at 23 °C, indicating that the substance is moderately soluble in petroleum ether.The solubility value of 2-aminobenzenesulphonic acid in methanol at 20 degC is equivalent to a value of 3565.21 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 2-aminobenzenesulphonic acid.

Flash point

The experimental result of flash point for 2-aminobenzenesulphonic acid by the closed cup method was infers to be non flamable at 955 hPa atmospheric pressure.

Auto flammability

2-aminobenzenesulphonic acid did not catch fire on being exposed to air at room temperature of 23 degC and atmospheric pressure of 955 hPa. This indicates that 2-aminobenzenesulphonic acid is not auto-flammable.

Flammability

From the experimental values of flammability, 2-aminobenzenesulphonic 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 2-aminobenzenesulphonic 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, 2-aminobenzenesulphonic acid was considered non-flammable for chemical safety assessment.

Explosiveness

According to theoretical considerations based on chemical structure, 2-aminobenzenesulphonic acid does not possess explosive properties. The reason for this is there are no chemical groups associated with explosive properties in 2-aminobenzenesulphonic acid. Thus, as per column 2 of Annex VII this end point was considered for waiver.

Oxidising properties

2-aminobenzenesulphonic acid was found to have mild oxidising property since 169.2 ml of KMnO4 was required for getting the end point of the redox titration for 100 g of 2-aminobenzenesulphonic acid.

Stability in organic solvents and identity of relevant degradation products

2-aminobenzenesulphonic 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 2-aminobenzenesulphonic acid was found to exhibit a pH of 1.94 at 24 degC. Thus 1% by volume solution of 2-aminobenzenesulphonic acid is acidic in nature.

Dissociation constant

The average experimental pKa value for 2-aminobenzenesulphonic acid was found to be 0.0021033 at 23 degC indicating that it has dissociation properties.This pka value when converted at 20 degC is equivalent to 0.0018289.

Viscosity

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