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Environmental fate & pathways


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Description of key information

In aqueous solutions Sodium perborate reacts rapidly forming hydrogen peroxide and sodium metaborate as hydrolysis products.

Key value for chemical safety assessment

Half-life for hydrolysis:
0.01 d
at the temperature of:
298 K

Additional information

Hydrolysis is a key issue for the Environmental Risk Assessment of Sodium perborate.

In aqueous solutions, sodium perborate hydrolyses to hydrogen peroxide and sodium metaborate, the equilibrium is instantly established. At low concentrations (below 2 g/l, i.e. also in the environmentally relevant concentration range) the equilibrium is largely on the side of the hydrolysis products (Koberstein 1970). Via degradation to active oxygen and water the hydrogen peroxide can be removed from the equilibrium leading to an irreversible shift of the equilibrium to the degradation products sodium metaborate and water.

In several degradation tests with sodium perborate as initial test substance, the decomposition was determined by measuring the decrease of active oxygen. In sterile batches of the Closed Bottle Test no elimination of the substance was found (Solvay 1993, cf. 5.2.1). In the reconstituted water of a daphnia test only low amounts of the applied test substance were decomposed (Solvay 1993, cf. 6.1.4). Even at increased temperatures the degradation rate of the perborate in pure water appears to be rather slow: Gericke (1976) reported a degradation rate of 50% of a solution of 30 g/L sodium perborate tetrahydrate which was heated to 95°C in a 25-minute time period, the high temperature being held for about 5 minutes and then cooled down to the room temperature.

There are risk assessment reports for the hydrolysis products of sodium perborate available:

ECB (2003) EU Risk Assessment Report on Hydrogen Peroxide. European Chemicals Bureau. Final report. Rapporteur Finland.

ECB (2009) Assessment Report Boric acid. Product-type 8 (Wood preservative). 20 February 2009