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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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.

Diss Factsheets

Physical & Chemical properties

Endpoint summary

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Description of key information

Additional information

OB 4 -MSA is an organic green yellow powder at 20 °C and 1013 hPa; it is a member of the Stilbene Fluorescent Whitening Agents (SFWA) category, group 4, bis(2-hydroxypropyl)amino derivative, tetrasulphonated sodium salt.

The substance has no melting point in the temperature range of 25 - 400 °C at atmospheric pressure (1013 hPa) it changes the colour (decomposes) starting from approximately 340 °C (capillary method).

Particle size distribution showed that the substance is characterized by a MMD of 94 µm.

The partition-coefficient (n-octanol / water) has been determined by an appropriate in silico estimation method because Stilbene Fluorescent Whitening Agents are ionisable substances and therefore difficult to test. The partition coefficient value (experimentally measured) is expected to be outside the applicability range of the shake flask method, the HPLC method, and the slow-stirring method. Nevertheless, the estimated value can be considered an evidence of the much greater affinity of the substance towards the water phase, compared to the affinity towards the octanol phase (log kow: -6.73).

It is very soluble in water (1000 g/l at 20 °C and pH 9), and fat solubility is lower than 0.1 mg/100 g fat.

Under environmental conditions the substance dissociates completely in water.

Based on physicochemical properties above mentioned, vapour pressure, surface tension, flash point can be considered as negligible and disregarded, while viscosity determination is technically not feasible.

It does not ignite and propagate combustion; the screening evaluation failed to evidence any reason of concern, on the basis of the chemical structure analysis and the thermal behaviour investigation.

It does not meet the criteria to be considered as flammable/explosive/oxidising.