Disodium 3,3'-[[6-[bis(2-hydroxyethyl)amino]-1,3,5-triazine-2,4-diyl]bis[imino(3-methoxy-4,1-phenylene)azo]]bis[benzenesulphonate]

Endpoint summary

Description of key information

Orange organic powder at 20 °C and 1013 hPa. The substance decomposes before melting/boiling; it is very water soluble and has a negative log Kow.

Based on the available information, it is not characterized by physical hazard(s).

Additional information

APPEARANCE AND STATE

Direct Yellow 142 is a orange organic powder at 20 °C and 1013 hPa; it is characterized by a D50 of 220 μm.

Thermal behaviour was investigated by the Differential Scanning Calorimetry (DSC) and capillary method: no melting/boiling points were recorded up to the decomposition temperature.

In the DSC-measurements the test item showed a first exothermic effect from 220 °C with an average energy release of -20 J/g. An endothermic effect is detected from 240 °C. This effect leads into an exothermic effect, starting from 260 °C with an average energy release of -350 J/g. Thus, the substance decomposed before melt/boil. Because of the physicochemical properties, vapour pressure and surface tension can be considered as negligible.

SOLUBILITY and PARTITION COEFFICIENT

Water solubility test was performed using the flask method. The concentration of the test substance in the aqueous solution was determined by a validated HPLC-UV analytical method. In the main test, to verify the accuracy of the analytical method, a fresh prepared standard solution (prepared with the test item) was measured in between the samples of the flask method. The recovery rate of the measured standard solutions was in the range from 96.3 % to 101.1 %, which shows a good accuracy of the analytical method. The water solubility was determined to be 21.03 g/l at 20 °C and pH 8.5.

The partition coefficient of test item was determined by shake-flask method following the procedures outlined into the OECD guideline 107 and OECD guideline 105. On the basis of the values of the water solubility determined specific test (i.e. average 21.03 g/l at 20 °C) and the estimated solubility in octanol from this preliminary test, the partition coefficient was estimated to be below -2.3. Therefore, the log Pow was carried out by determining the solubility in 1-octanol by means of the flask method, which is also used for the determination of the water solubility and the partition coefficient was calculated from the solubilities in water and 1-octanol. The water solubility of the test item was determined in the specific study abovementioned. The partition coefficient (Pow) of the test item was calculated to be 4.88 x10^-04 (log Pow = -3.31).

To verify the accuracy of the analytical method a fresh prepared standard solution (prepared with the test item) was measured in between the samples of the flask method. The recovery rate of the measured standard solutions was in the range from 99.9 % to 102.3 %, which shows a good accuracy of the analytical method.

PHYSICAL HAZARDS

Direct Yellow 142 does not ignite and propagate combustion.

The flammability test was carried out according to the Recommendations on the Transport of dangerous goods: Manual of Tests and Criteria, 6th edition 2015, Test N.1 and VDI  2263, sheet 1 (1990). In the preliminary test, the test item did not ignite at room temperature using a flame as ignition source being applied for at least 2 minute. Thus, the performance of the main test was not necessary.

On the basis of the results obtained in the preliminary investigation, a complete explosiveness test was not necessary. The thermal behaviour of test item was assessed using the DSC analysis, according to the OECD guideline 113; the determination of the thermal stability of a substance was performed via Differential Scanning Calorimetry (DSC). The test item showed a first exothermic effect from 220 °C with an average energy release of -20 J/g. An endothermic effect was detected from 240 °C. This effect caused an exothermic effect, starting from 260 °C with an average energy release of -350 J/g. Due to the decomposition energy being below the threshold of -500 J/g, further tests for explosive properties did not have to be performed.

Based on the chemical structure, the substance is expected to be incapable of reacting exothermically with combustible materials: it contains oxygen atoms, which are not chemically bonded to nitrogen or oxygen.