3-methyl-1-phenyl-5-pyrazolone

Oxidising properties

Description of key information

The purpose of the study was to determine the oxidizing properties of the test item following A17 method and GLP.

In a preliminary test the dried test item / cellulose mixture (2/1) was formed into a small cone-shaped pile and was ignited. The mixture burned evenly. As the result was open to doubt a full test was performed.

In the framework of the full study (main test), the test item – cellulose mixtures in steps of 10 % increments were tested by the main test.

According to main test, the mixture consisting of 10 % to 90 % test item did burn evenly.

As the next step, the test was repeated six times for each of the three mixtures giving the fastest burning rates. Test item cellulose mixtures consisting of 40 %, 50 % and 60 % test item were tested. While each mixture burned evenly the highest value of the burning rate of 5.13 mm/sec was found for the mixture consisting of 50 % test item and 50 % cellulose. For the comparing of the results, the test was done with the mixtures barium nitrate and cellulose. The highest value of the burning rate in this case was 4.44 mm/sec.

To ensure that no false positive results were observed the test was repeated using kieselguhr as inert substance in place of cellulose.

The test was repeated six times for each of the three mixtures giving the fastest burning rates (40 %, 50 % and 60 % test item). All three mixtures burned and the highest value of the burning rate was 3.23 mm/sec.

The material may be considered not to possess oxidizing properties and thus the results from the A.17. test may be considered as a “false posi-tive” if the mixtures of the test substance with both cellulose and kieselguhr showed similar propagation rates and the two series of tests showed an approximately similar pattern of change in the rate of propagation as the composition of the mixtures is altered (for example: the mixture 40 % test item has a maximum of the burning rate with cellulose 4.55 mm/sec and with kieselguhr 3.13 mm/sec). In conclusion, the test item is considered to be inert in terms of oxidizing properties, according to the criteria as described in the guideline.

Key value for chemical safety assessment

Oxidising properties:

non oxidising

Justification for classification or non-classification

The material may be considered not to possess oxidizing properties and thus the results from the A.17. test may be considered as a “false positive” if the mixtures of the test substance with both cellulose and kieselguhr showed similar propagation rates and the two series of tests showed an approximately similar pattern of change in the rate of propagation as the composition of the mixtures is altered (for example: the mix-ture 40 % test item has a maximum of the burning rate with cellulose 4.55 mm/sec and with kieselguhr 3.13 mm/sec).