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Environmental fate & pathways

Hydrolysis

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Description of key information

From the available water solubility study it can be concluded that the calcium peroxide present in 100 mg/L of the test substance hydrolyses within 24 hours, giving rise to the formation of hydrogen peroxide, which itself further decomposes. The other components of the multi-constituent substance dissociate upon dissolving in the water phase.

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Additional information

The reaction mass of calcium carbonate and calcium dihydroxide and calcium peroxide will hydrolyze when it comes into contact with water. This property can be clearly demonstrated based on the results of the water solubility study. The water solubility was assessed via the flask method. Mixtures of water and the test substance in concentrations of 100, 1000 and 10000 mg/L were stirred for 24, 48 and 96h. Subsequently, quantitative analyses of calcium and hydrogen peroxide were performed.

 

The results of this experiment showed that:

 

1) The theoretical maximum concentration of calcium is obtained within 24 hours in the 100 mg/L test solution. As a consequence, the water solubility of the reaction mass of calcium carbonate and calcium dihydroxide and calcium peroxide is > 0.1 g/L but less than 1 g/L.

 

2) Hydrogen peroxide is being formed when the reaction mass of calcium carbonate and calcium dihydroxide and calcium peroxide is present in an aqueous environment.

 

3) The formed hydrogen peroxide itself is susceptible to decomposition in the aqueous environment, as can be deduced from the fact that the hydrogen peroxide concentration always is far below the theoretical concentration.

 

In conclusion, in a 100 mg/L solution of the reaction mass of calcium carbonate and calcium dihydroxide and calcium peroxide in water, the following reactions occur:

* The calcium peroxide hydrolyses within 24 hours.

* The hydrogen peroxide formed upon hydrolysis of calcium peroxide completely decomposes within 48 hours.

* The calcium hydroxide and calcium carbonate are completely dissolved within 48 hours.