Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Administrative data

Description of key information

Additional information

OB 3c-MSA is an organic yellow green powder at 20 °C and 1013 hPa; it is a member of the Stilbene Fluorescent Whitening Agents (SFWA) category, subgroup 3c, diethylamino derivative, tetrasulphonated sodium salt.

The substance has no melting point in the temperature range of 25 – 400 °C at atmospheric pressure (1013 hPa).

Particle size distribution showed that the substance is characterized by a MMAD of 225 µm.

The partition-coefficient (n-octanol / water) was 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 ranges of the shake flask, the HPLC, and the slow-stirring methods. 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.


It is very soluble in water (140 g/l at 20 °C and pH 9).

Under environmental conditions the substance dissociates completely in water.

Since it is a solid, properties like vapour pressure, surface tension, and flash point can be disregarded, while viscosity determination is technically not feasible.

It does not ignite and propagate combustion; no chemical groups associated with oxidising properties are present in the molecule and there is no evidence 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.