Registration Dossier
Registration Dossier
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.
The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 220-491-7 | CAS number: 2783-94-0
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, disodium 6-hydroxy-5-[(4-sulphonatophenyl)azo]naphthalene-2-sulphonate was found to be an organic dark maroon colour powder with characteristic odour at 26ºC and 966 hPa.
Melting point/freezing point:
Disodium 6-hydroxy-5-[(4-sulphonatophenyl)azo]naphthalene-2-sulphonate decomposes without melting when heated to 390 deg C.
Boiling point:
According to EPI (Estimation Programs Interface) Suitethe boiling point of disodium 6-hydroxy-5-[(4-sulphonatophenyl)azo]naphthalene-2-sulphonate by the Adapted Stein and Brown method is estimated to be 836.60 °C.
Density:
Mass by volume method was used to derive the bulk density of the substance and the bulk density of disodium 6-hydroxy-5-[(4-sulphonatophenyl)azo]naphthalene-2-sulphonate was found to be 0.617 g/cm3 at 26 °C. This density value at 20°C is equivalent to 0.474 g/cm3.
Particle size distribution (Granulometry):
The particle size distribution (Granulometry) of Disodium 6-hydroxy-5-[(4-sulphonatophenyl) azo] naphthalene-2-sulphonate by the sieve analysis method was found to be in the range of 150 micrometer to 500 micrometer. Majority of the particles were found to be in the size 250 (61.1%) and 500 (20.3%) micrometer in size.
Vapour pressure:
Vapour pressure of test substance disodium 6-hydroxy-5-[(4-sulphonatophenyl)azo]naphthalene-2-sulphonate was estimated to be 0.000000000133 Pa at 25 deg.C
Partition coefficient:
The experimental value of octanol water partition co-efficient (log Pow) of disodium 6-hydroxy-5-[(4-sulphonatophenyl)azo]naphthalene-2-sulphonate was found to be -0.244 at 26°C and pH of 6.32 by shake-flask method.This value indicates that disodium 6-hydroxy-5-[(4-sulphonatophenyl)azo]naphthalene-2-sulphonate is hydrophilic in nature.
The supporting study shows value different from the key study which could be due to the difference in the estimation conditions. However for the purpose of the dossier and chemical safety assessment, the key study values shall be used.
Water solubility:
The experimental value of the water solubility of Disodium 6-hydroxy-5-[(4-sulphonatophenyl)azo]naphthalene-2-sulphonate was found to be 4000 mg/L at temperature of 26deg C indicating that Disodium 6-hydroxy-5-[(4-sulphonatophenyl)azo]naphthalene-2-sulphonate is 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 Disodium 6-hydroxy-5-[(4-sulphonatophenyl)azo]naphthalene-2-sulphonate in ethanol at 26 degC was found to be 5000 mg/L indicating that the substance is soluble in ethanol. Using the Soxhlet/Solvent extraction method the solubility of the substance in Petroleum ether is observed to be 80 mg/L at 26 °C, indicating that the substance is slightly soluble in petroleum ether. The solubility value of Disodium 6-hydroxy-5-[(4-sulphonatophenyl)azo]naphthalene-2-sulphonate in ethanol at 20 degC is equivalent to a value of 3846.15 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 Disodium 6-hydroxy-5-[(4-sulphonatophenyl)azo]naphthalene-2-sulphonate.
Flash point:
The substance disodium 6-hydroxy-5-[(4-sulphonatophenyl)azo]naphthalene-2-sulphonate does not ignite even at 900°C and 966 hPa and hence the substance is considered as non flammable.
Auto flammability:
Disodium 6-hydroxy-5-[(4-sulphonatophenyl)azo]naphthalene-2-sulphonate did not catch fire on being exposed to air at room temperature of 26ºC and atmospheric pressure of 966 hPa. This indicates that Disodium 6-hydroxy-5-[(4-sulphonatophenyl)azo]naphthalene-2-sulphonate is not auto-flammable.
Flammability:
From the experimental values of flammability, Disodium 6-hydroxy-5-[(4-sulphonatophenyl) azo] naphthalene-2-sulphonate ignited when the flame of Bunsen burner having temperature of 950 deg C was brought in contact with it. Thus it can be concluded that Disodium 6-hydroxy-5-[(4-sulphonatophenyl) azo] naphthalene-2-sulphonate is flammable only at high temperature of about 950 deg C. However since such high temperatures are not found under normal circumstances of transportation and use, Disodium 6-hydroxy-5-[(4-sulphonatophenyl) azo] naphthalene-2-sulphonate was considered non-flammable for chemical safety assessment.
Explosiveness:
The substance disodium 6-hydroxy-5-[(4-sulphonatophenyl)azo]naphthalene-2-sulphonate though contains the chemical group (azo group) associated with explosive properties which include oxygen in the compound but the calculated oxygen balance is found to be less than - 200 (the value was obtained to be = -109.159). So, based on this calculation it can be inferred that the substance shall not be classified as explosive.
Oxidising properties:
Disodium 6-hydroxy-5-[(4-sulphonatophenyl) azo]naphthalene-2-sulphonate was found to have mild oxidising property since 361.1 ml of KMnO4 was required for getting the end point of the redox titration for 100 g of Disodium 6-hydroxy-5-[(4-sulphonatophenyl) azo]naphthalene-2-sulphonate.
Stability in organic solvents and identity of relevant degradation products:
Disodium 6-hydroxy-5-[(4-sulphonatophenyl)azo]naphthalene-2-sulphonate is found to be stable in organic solvent (dichloro methane) and no degradation products were formed as evident from the GC-MS chromatogram.
pH:
1% by volume solution of disodium 6-hydroxy-5-[(4-sulphonatophenyl)azo]naphthalene-2-sulphonate is found to exhibit a pH of 5.26 at 25°C.
Thus 1% by volume solution of disodium 6-hydroxy-5-[(4-sulphonatophenyl)azo]naphthalene-2-sulphonate is acidic in nature.
Dissociation constant:
The experimental pKa value for disodium 6-hydroxy-5-[(4-sulphonatophenyl)azo]naphthalene-2-sulphonate is found to be 0.000000001370 at
26 °C indicating that it has dissociating properties. The pKa value at 20 Deg C is equivalent to 0.000000001053.
Viscosity:
This end point was considered for waiver since viscosity is an inherent property of a liquid that offers resistance to its flow and Disodium 6-hydroxy-5-[(4-sulphonatophenyl) azo] naphthalene-2-sulphonate is a solid substance and hence this testing was considered scientifically unjustified for Disodium 6-hydroxy-5-[(4-sulphonatophenyl) azo]naphthalene-2-sulphonate.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
