reaction mass of cerium(IV)oxide, praseodymium(III,IV)oxide and zirconium (IV)oxide

Oxidising properties

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

oxidising solids

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

10 June 2005 - 13 October 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

EU Method A.17 (Oxidising Properties (Solids))

Version / remarks:

Cited as Directive 92/69/EEC, A.17

Deviations:

yes

Remarks:

Ignition source: use of a platinum wire heated by electrical power instead a direct flame. This modification has no effect on the conclusion.

GLP compliance:

yes

Contact with:

powdered cellulose

Sample tested:

1:1 sample-to-cellulose ratio

Parameter:

mean burning time

Remarks on result:

mixture does not ignite and burn

Preliminary test:

Reference mixture (barium nitrate / cellulose - ratio 2/1) took 89 seconds to burn.

The combustion of the substance mixture (test item / cellulose - ratio 2/1) stopped immediately.

Main study:

Nominal proportion of test item (%)	Weight of cellulose (g)	Weight of Test item (g)	Burning time (s)	Remarks
10	13.547	1.511	Ignition by the hot wire, but no flame propagation
20	11.975	2.953	"
30	10.524	4.465	"
40	9.016	5.974	"
50	7.479	7.558	"
60	5.999	9.033	"
70	4.485	10.487	"
80	2.955	11.972	"
90	1.488	13.509	"

The test item did not burn.

CERIUM DIOXIDE has no oxidising properties under the conditions of the test.

Interpretation of results:

GHS criteria not met

Conclusions:

Cerium dioxide has no oxidising properties under the conditions of the test.

Executive summary:

The determination of the oxidising properties of cerium dioxide was performed according to EU Method A17 using a powder train about 250 mm long. The test item was mixed with a combustible substance, being powdered cellulose. The test item / cellulose mixtures contained 10-90% test item in 10% increment by weight. As a reference, a barium nitrate / cellulose mixture was prepared. A pile of each mixture was ignited with the hot wire, and the burning time was recorded. No flame propagation was observed with each mixture of test item and cellulose. In conclusion, cerium dioxide has no oxidising properties.

Reference 2

Endpoint:

oxidising solids

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

17 July 2012 - 21 January 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

UN Manual of Tests and Criteria: Test O.1 (Test for oxidizing solids)

Deviations:

yes

Remarks:

see below

Principles of method if other than guideline:

The electrical resistance of the ignition wire used was 3.9 Ω/m, which is a deviation from the electrical resistance of 6.0 ± 0.5 Ω/m specified in the Method O.1. However, the material (Nickel/Chromium), length (30 cm) and diameter (0.6 mm) of the wire met the method specifications. In addition, the appropriate combination of current and voltage was used to ensure that the electrical power dissipation in the wire (150 ± 7 W) also met the method specifications. Therefore, as the physical parameters of the wire and the power dissipation (i.e. the heat applied to the test) met the method specifications, the deviation from the electrical resistance of the wire had no effect on the test.

GLP compliance:

yes (incl. QA statement)

Contact with:

powdered cellulose

Sample tested:

reference: 3:7 mixture potassium bromate + cellulose

Parameter:

mean burning time

Result:

98 s

Remarks on result:

other: The cone burned with a yellow flame producing sparks and grey smoke, leaving a grey/black residue.

Sample tested:

4:1 sample-to-cellulose ratio

Parameter:

mean burning time

Result:

374 s

Remarks on result:

other: The cone ignited with a yellow flame, grey smoke and some sparks. The flame extinguished but the cone continued to glow red. Some grey charred remains were observed.

Sample tested:

1:1 sample-to-cellulose ratio

Parameter:

mean burning time

Result:

676 s

Remarks on result:

other: The cone ignited with a large yellow flame and grey smoke. The flame extinguished but the cone continued to glow red. Some grey charred residues remained.

Table 1 Potassium Bromate and Cellulose Mixture (3:7 by Mass)

Test Number	Burning Time (seconds)	Observations
1	94	The cone burned with a yellow flame producing sparks and grey smoke, leaving a grey/black residue.
2	91	The cone burned with a yellow flame producing sparks and grey smoke, leaving a grey/black residue.
3	110	The cone burned with a yellow flame producing sparks and grey smoke, leaving a grey/black residue.
4	102	The cone burned with a yellow flame producing sparks and grey smoke, leaving a grey/black residue.
5	95	The cone burned with a yellow flame producing sparks and grey smoke, leaving a grey/black residue.

Mean burning time = 98 seconds

Room temperature: 20 - 21 °C

 

Table 2 Test Material and Cellulose Mixture (4:1 by Mass)

Test Number	Burning Time (seconds)	Observations
1	466	The cone ignited with a yellow flame, grey smoke and some sparks. The flame extinguished after 145 seconds but the cone continued to glow red. Some grey charred remains were observed.
2	361	The cone ignited with a yellow flame, grey smoke and some sparks. The flame extinguished after 134 seconds but the cone continued to glow red. Some grey charred remains were observed.
3	340	The cone ignited with a yellow flame, grey smoke and some sparks. The flame extinguished after 134 seconds but the cone continued to glow red. Some grey charred remains were observed.
4	383	The cone ignited with a yellow flame, grey smoke and some sparks. The flame extinguished after 155 seconds but the cone continued to glow red. Some grey charred remains were observed.
5	320	The cone ignited with a yellow flame, grey smoke and some sparks. The flame extinguished after 110 seconds but the cone continued to glow red. Some grey charred remains were observed.

Mean burning time = 374 seconds

Room temperature: 19 °C

 

Table 3 Test Material and Cellulose Mixture (1:1 by Mass)

Test Number	Burning Time (seconds)	Observations
1	565	The cone ignited with a large yellow flame and grey smoke. The flame extinguished after 278 seconds but the cone continued to glow red. Some grey charred residues remained.
2	619	The cone ignited with a large yellow flame and grey smoke. The flame extinguished after 266 seconds but the cone continued to glow red. Some grey charred residues remained.
3	622	The cone ignited with a large yellow flame and grey smoke. The flame extinguished after 246 seconds but the cone continued to glow red. Some grey charred residues remained.
4	637	The cone ignited with a large yellow flame and grey smoke. The flame extinguished after 287 seconds but the cone continued to glow red. Some grey charred residues remained.
5	936	The cone ignited with a large yellow flame and grey smoke. The flame extinguished after 257 seconds but the cone continued to glow red. Some grey charred residues remained.

Mean burning time = 676 seconds

Room temperature: 19 °C

 

Discussion

The ignition wire broke during each of the tests for the mixtures of test material and cellulose. Breaking of the ignition wire often occurs with test material and cellulose mixtures but this is not the case for the reference mixtures. Test O.1 states that if the wire breaks during the test, then the test should be repeated unless the wire breaking clearly does not affect the result. In each case that the wire broke, it was judged not to have affected the test.

 

As the mean burning times for the mixtures of test material and cellulose were greater than the mean burning time for the 3:7 (by mass) mixture of potassium bromate and cellulose, it was not necessary to determine the mean burning times for the faster burning reference mixtures.

Interpretation of results:

GHS criteria not met

Conclusions:

Under the conditions of this study, the test material has been determined not to be an oxidising solid and requires no classification in accordance with EU criteria.

Reference 3

Endpoint:

oxidising solids

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

Since no reliable studies on this endpoint are available for the reaction mass of cerium dioxide, praseodymium(III,IV) oxide and zirconium dioxide, read across was performed using studies performed with praseodymium(III,IV) oxide and cerium dioxide. No such study is available for zirconium dioxide, however, as explained below, zirconium dioxide can be concluded not to exhibit oxidising properties based on non-testing information. The read across justification document is attached to IUCLID Section 13.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Parameter:

other: read across conclusion

Remarks on result:

other: The reaction mass of cerium dioxide, praseodymium(III,IV) oxide and zirconium dioxide is not expected to exhibit oxidising properties.

Remarks:

This conclusion is based on testing information for cerium dioxide and praseodymium(III,IV) oxide and non-testing information for zirconium dioxide.

Interpretation of results:

GHS criteria not met

Conclusions:

Cerium dioxide and praseodymium(III,IV) oxide have been demonstrated not to exhibit oxidising properties. No testing information is available for zirconium dioxide, however, zirconium in zirconium dioxide is in its highest possible oxidation state (4+) and is therefore not considered to be sensitive to oxygen release. Based on this information on its main constituents, the reaction mass of cerium dioxide, praseodymium(III,IV) oxide and zirconium dioxide can be considered not to be oxidising either.

Description of key information

No key information is available on the oxidising properties of the reaction mass of cerium dioxide, praseodymium(III,IV) oxide and zirconium dioxide. Given the studies and data available on these properties for the individual constituents forming the reaction mass, namely cerium dioxide, praseodymium(III,IV) oxide and zirconium dioxide, it can be concluded that the reaction mass will not exhibit this property either.

Key value for chemical safety assessment

Oxidising properties:

non oxidising

Additional information

1. Information on cerium dioxide

In a guideline study (Cerutti, 2005; Klimisch 1), it was concluded that cerium dioxide does not exhibit oxidising properties.

2. Information on praseodymium(III,IV) oxide

In a guideline study (White, 2013; Klimisch 1) it was concluded that praseodymium(III,IV) oxide does not exhibit oxidising properties.

3. Information on zirconium dioxide

Zirconium in zirconium dioxide is in its highest possible oxidation state (4+). Therefore, the substance is not expected to be sensitive to oxygen release and it can be concluded not to exhibit oxidising properties.

4. Conclusion on the reaction mass of cerium dioxide, praseodymium(III,IV) oxide and zirconium dioxide

Based on the experimental evidence and data available on its individual constituents, the reaction mass can be concluded not to exhibit oxidising properties.

Justification for classification or non-classification

The reaction mass of cerium dioxide, praseodymium(III,IV) oxide and zirconium dioxide does not need to be classified for oxidising properties, based on experimental evidence and non-testing data available for its individual constituents.