Reaction mass of calcium dihydroxide and calcium peroxide

Hydrolysis

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

hydrolysis

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
Calcium peroxide decomposes into hydrogen peroxide and calcium hydroxide. The hydrogen peroxide will subsequently further decompose into water and oxygen. Furthermore, the calcium hydroxide dissociates when brought into aqueous medium. The different chemical reactions are:
CaO2 + 2 H2O -> Ca2 + + 2 (OH)- + H2O2
H2O2 + H2O -> 2 H2O + O2
Ca(OH)2 -> Ca2 + + 2 OH-

The water solubility test performed on calcium peroxide also demonstrates the formation of hydrogen peroxide upon reaction of the substance with water, and the subsequent decomposition of the formed hydrogen peroxide.

Reason / purpose for cross-reference:

data waiving: supporting information

Reference 2

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Principle of test: hydrolytic loss of calcium peroxide by measurement of active oxygen loss in a water solution.
- Short description of test conditions: Deionized water solution of test item at 25ºC.
- Parameters analysed / observed: Loss of calcium peroxide as a loss of the active oxygen concentration. Measurement of PH evolution.

GLP compliance:

not specified

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

- Sampling intervals: <30 days

Details on test conditions:

Deionized water solution of test item at 25ºC.

Duration:

1 yr

pH:

12

Temp.:

25 °C

Initial conc. measured:

76.8 other: % CaO2

Positive controls:

no

Negative controls:

no

Transformation products:

not measured

% Recovery:

ca. 20.5

pH:

12

Temp.:

25 °C

Duration:

ca. 1 yr

Details on results:

TEST CONDITIONS
-The final pH stabilized near 12.0, which is dictated by the hydroxyl anion concentration.

Validity criteria fulfilled:

not applicable

Conclusions:

The test item based on 76.8% CaO2 was found to hydrolyze in water at 25ºC. At the end of one year, ca. 20.5% CaO2 was measured.

Executive summary:

Hydrolysis of the test item was studied in deionized water at 25ºC. The test item had a content of calcium peroxide of 76.8% at the beginning of the study. The loss of calcium peroxide was determined by measurement of the active oxygen concentration. The pH remained aroud 12 throughout the study. The test item was found to hydrolyze with a remaining content of CaO2 of ca. 20.5% at the end of one year.

Reference 3

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Principle of test: hydrolytic loss of calcium peroxide by measurement of active oxygen loss in a water solution.
- Short description of test conditions: Deionized water solution of test item at 25ºC.
- Parameters analysed / observed: Loss of calcium peroxide as a loss of the active oxygen concentration. Measurement of PH evolution.

GLP compliance:

not specified

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

- Sampling intervals: <30 days

Details on test conditions:

Deionized water solution of test item at 25ºC.

Duration:

5 mo

pH:

12

Temp.:

25 °C

Initial conc. measured:

68.7 other: % CaO2

Positive controls:

no

Negative controls:

no

Transformation products:

not measured

% Recovery:

ca. 0.3

pH:

12

Temp.:

25 °C

Duration:

ca. 5 mo

Details on results:

TEST CONDITIONS
-The final pH stabilized near 12.0, which is dictated by the hydroxyl anion concentration.

Validity criteria fulfilled:

not applicable

Conclusions:

The test item based on 68.7% CaO2 was found to hydrolyze in water at 25ºC. After 5 months, ca. 0.3% CaO2 was measured.

Executive summary:

Hydrolysis of the test item was studied in deionized water at 25ºC. The test item had a content of calcium peroxide of 68.7% at the beginning of the study. The loss of calcium peroxide was determined by measurement of the active oxygen concentration. The pH remained aroud 12 throughout the study. The test item was found to hydrolyze with a remaining content of CaO2 of ca. 0.3% after 5 months.

Description of key information

Data waiving (study scientifically not necessary): Calcium peroxide decomposes into hydrogen peroxide and calcium hydroxide. The hydrogen peroxide will subsequently further decompose into water and oxygen. Furthermore, the calcium hydroxide dissociates when brought into aqueous medium. The different chemical reactions are:
CaO2 + 2 H2O -> Ca2 + + 2 (OH)- + H2O2
H2O2 + H2O -> 2 H2O + O2
Ca(OH)2 -> Ca2 + + 2 OH-

The water solubility test performed on calcium peroxide also demonstrates the formation of hydrogen peroxide upon reaction of the substance with water, and the subsequent decomposition of the formed hydrogen peroxide.

 

Supporting study (calcium peroxide): The Hydrolysis of calcium peroxide was demonstrated in two commercial calcium peroxide based products by measurement of the loss of active oxygen concentration in deionized water solutions of the respective products at 25ºC.