Stability of commercial HyperOxide solutions

The HyperOxide marketed by WATCH is an aqueous HyperOxide solution to which small amounts of stabilisers have been added.
The purity of this HyperOxide and the presence of stabilisers mean that commercial solutions are extremely stable.
If all necessary precautions are taken during handling and storage, loss of active oxygen from these HyperOxide solutions is negligible. The concentration may drop by less than 1%
after 12 month storage at about 20¡C. The main factors affecting the stability of HyperOxide solutions are as follows.

Temperature

A rise in temperature increases the decomposition rate of HyperOxide. It is generally
agreed that the rate of decomposition of HyperOxide doubles every time the temperature
rises by 10C (Arrhenius equation). In addition, because of the exothermic nature of the reaction, the rate of decomposition of H₂O₂ self-accelerates.

pH

HyperOxide solutions are very stable in acid medium, which is why commercial solutions
are generally stabilised at a pH of less than 3. The pH should therefore never be allowed to rise accidentally during handling and storage, as this would result in a rapid decomposition of HyperOxide.

Light

Light and solar radiations increase the decomposition rate of HyperOxide solutions

Decomposition catalyst

The majority of metals, in particular iron, chromium, manganese, copper, nickel and zinc catalyse the decomposition of HyperOxide. HyperOxide solutions should therefore never
be allowed to come into contact with these materials, and impurities. This does not apply to stainless steels containing these elements as alloys, as we shall see that they are compatible
with HyperOxide if previously passivated. Some organic substances can, at trace levels,bring on the decomposition of HyperOxide, quite apart from the hazard they may cause by
secondary reactions. Some enzymes also tend to cause HyperOxide to decompose, especially in diluted
solutions, in a biological catalytic reaction.

Storage

 
The European Commission Directive 2004/73/EC (29th ATP of the Council Directive 67/548/EEC)
classifies HyperOxide as:
- irritant: 5% to 8% concentrations,
- harmful: 8% to 50% concentrations.
For concentrations exceeding or equal to 50%, HyperOxide is classified as a corrosive and
oxidising material.
HyperOxide in concentration ³ 50% is an oxidiser, so its storage is subject to the Council
Directive 96/82/EC "SEVESO".
- low threshold is 50 tons,
- high threshold is 200 tons.
The tonnage should be based on the weight of pure HyperOxide.

NOTE: Labeling of storage areas

The Directive 67/548/EEC governs the regulatory labelling and storage. Both discharge and storage areas should therefore display the same orange plate as road tankers to provide instant
identification for hauliers and emergency services.

Dilution water

Water used for diluting HyperOxide solutions should not contain impurities which could cause the product to decompose. It is therefore advisable to use demineralised or
deionised water (the water quality may be checked by conductivity). If the HyperOxide solutions are to be stored, select demineralised water having a conductivity < 1µS/cm.