Phthalylsulfathiazole

Endpoint summary

Additional information

Appearance/physical state/colour:

On the basis of physical observation and using the sense of smell, phthalylsulfathiazole was found to be an amorphous colourless substance with characteristics odour

Melting point/freezing point:

The melting point of phthalylsulfathiazole by the capillary method was found to be 350.4 degC at an atmospheric pressure of 975 hPa. There was no decomposition & sublimation observed of phthalylsulfathiazole at the melting point. This melting point value at 101325 Pa is equivalent to 364.14 deg C.

 Boiling point:

The boiling point of phthalylsulfathiazole by the distillation method was found to be 357.3 degC at the atmospheric pressure of 975 hPa. No decomposition of phthalylsulfathiazole was observed at the boiling point. This boiling point value at 101325 Pa is equivalent to 371.31 deg C

 Density:

The bulk density of phthalylsulfathiazole by the mass by volume method was found to be 0.700 g/cm3 at room temperature of 28 °C . This value when converted into 20 degC is equivalent to 0.5 g/cm3. The supporting study shows value different from key studies which could be due to difference in the estimation conditions.

 Particle size distribution (Granulometry) :

The particle size distribution (granulometry) of phthalylsulfathiazole 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 (67.15%) - 75 (17.25%) micrometer in size.

Vapour pressure:

Vapour pressure of phthalylsulfathiazole was estimated to be 0.00000000000000283 mm Hg at 25 deg C by using Modified Grain Method. This value when converted to Pascal is equivalent to 0.000000000000377 Pa. The supporting study shows value different from key studies which could be due to difference in the estimation conditions. However for the purpose of chemical safety report, key study values shall be considered

Partition coefficient:

The experimental value of octanol water partition co-efficient (log Pow) of phthalylsulfathiazole by Shake flask method was found to be -2 at temperature 28 degC and pH of 4.87.This value indicates that phthalylsulfathiazole is relatively hydrophobic in nature.

 Water solubility :

The experimental value of the water solubility of phthalylsulfathiazole was found to be 400 mg/L at 28 degC indicating that it is moderately soluble in water.The supporting study shows value different from key studies which could be due to difference in the estimation conditions However for the purpose of chemical safety report, key study values shall be considered

 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 phthalyl sulfathiazole in methanol at temperature of 28 degC was observed to be 2300 mg/L indicating that phthalyl sulfathiazole is soluble in methanol but more soluble than water. This value at 20 degC is equivalent to 1642.85 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 phthalylsulfathiazole.

 Flash point:

The substance phthalylsulfathiazole was found to be non flammable at 975 hPa atmospheric pressure. Substance does not have the activity of flash even at 390⁰C

Auto flammability:

Phthalylsulfathiazole did not catch fire on being exposed to air at room temperature of 28 degC and atmospheric pressure of 975 hPa. This indicates that phthalylsulfathiazole is not auto-flammable.

Flammability:

From the experimental values of flammability, phthalylsulfathiazole ignited when the flame of bunsen burner having temperature of 950 degC was brought in contact with it. Thus it can be concluded that phthalylsulfathiazole 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, phthalyl sulfathiazole was considered non-flammable for chemical safety assessment.

 Explosiveness:

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

Oxidising properties:

The substance, phthalylsulfathiazole was found to have oxidising property since 30.09 mg of KMnO4 was required for getting the end point of the redox titration for 100 g of phthalylsulfathiazole. But this property is not sufficient to classify the substance as oxidising in nature and so will not be considered for the same.

Stability in organic solvents and identity of relevant degradation products:

Phthalylsulfathiazole 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.

Dissociation constant:

The average experimental pKa value for phthalylsulfathiazole was found to be 0.00000333666667 at 28 degC indicating that it has dissociating properties. This value when converted to 20 deg C is equivalent to 0.000002383.

Viscosity:

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