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On the basis of physical observation the test chemical 4-amino-5-hydroxynaphthalene-1,7-disulphonic acid was found to be Off white color powder in appearance

Melting point:

The melting point determination of 4 -amino-5-hydroxynaphthalene-1,7-disulphonic acid (CAS No. 130-23-4 )was done following OECD Guideline 102 and according to the metal block capillary method. . The test item shows colour changes from grey to black but remains in powdered form in capillary .The test was conducted in replicates and mean decomposition point was found to be 258.8°C -263.8 °C at  966.8hPa.

Boiling point:

According to Column II of Annex VII, the boiling point study does not need to be conducted for solids which either melt above 300 °C or decompose before boiling. The substance 4-Amino-5-hydroxynaphthalene-1,7-disulphonic acid is a solid at room temperature and it is reported to decompose at a temperature of 258.8°C -263.8 °C without melting. Hence, it is not feasible to determine boiling point and the endpoint was considered for waiver.


The mean pourdensity and tappeddensity of test item 4-amino-5-hydroxynaphthalene-1,7-disulphonic acid (CAS No. 130-23-4) was determined following OECD Guideline 109 and according to the method recommended in the International Pharmacopoeia, fourth Edition, 2014 using bulk density apparatus .The mean pour density and tapped density of the test item was found to be 0.6458 g/cm3and 0.7417 g/cm3at 28.4oC and  966.9 hPa.

Particle Size Distribution:

The particle size distribution of test item 4-amino-5-hydroxynaphthalene-1,7-disulphonic acid(CAS No. 130-23-4)was determined by granulometric analysis with rotap sieve shaker. The particle size distribution was found to be in the range of 150 micron to 53 micron.

Partition coefficient:

From Danish QSAR modelling databse Partition coefficient of test substance 4-amino-5-hydroxynaphthalene-1,7-disulphonic acid was estimated to be log KoW -2.33.This value indicate that the test substance is hydrophilic in nature.

Vapour Pressure:

From Danish QSAR modelling database Vapour pressure of test substance 4-amino-5-hydroxynaphthalene-1,7-disulphonic acid was estimated to be 0.000000000000009879 Pa.

Water Solubility:

The water solubility determination of test the test item 4-amino-5-hydroxynaphthalene-1,7-disulphonic acid(CAS NO. 130-23-4) was done as per the shake flask method. The solubility was found to be 20 g/lt 26.4 °C .

Surface tension:

In accordance with column 2 of Annex VII of the REACH regulation, this testing needs to be carried out only if surface activity is a desired property of the chemical. The chemical 4-amino-5-hydroxynaphthalene-1,7-disulphonic acid is used as a an intermediate chemical for manufacture of another chemical. For this use, surface activity is not a desired property and hence this end point was considered for waiver.

Flash point:

The flash point determination of 4 -amino-5-hydroxynaphthalene-1,7-disulphonic acid (CAS No. 130-23-4 ) was done following closed cup method using Pensky-Martens flash point apparatus. The test was conducted in replicates and mean flash point was found to be Greater than 250 °C at 967.6hPa.

Auto Flammability :

4-amino-5-hydroxynaphthalene-1,7-disulfonic acid  did not catch fire on being exposed to air at room temperature of 27°C pressure of 966 hPa. This indicates that 4-amino-5-hydroxynaphthalene-1,7-disulfonic acid  is not auto-flammable.

Flammability :

4-amino-5-hydroxynaphthalene-1,7-disulfonic acid does not indicate any ignition when the flame of bunsen burner having temperature of approximately 950°C is brought in contact with it. Thus it can be concluded that 4-amino-5-hydroxynaphthalene-1,7-disulfonic acid is not flammable at high temperature. However since such high temperatures are not found under normal circumstances of transportation and use, thus 4-amino-5-hydroxynaphthalene-1,7-disulfonic acid was considered non-flammable.


The pH determination of test item 4-amino-5-hydroxynaphthalene-1,7-disulphonic acid(CAS No. 130-23-4)was done following OECD guideline 122. The mean pH of 1% w/vsolutionwas measured with the help of pH meter and it was observed to be 2.22 at 29 °C .