Registration Dossier

Administrative data

Endpoint:
melting point/freezing point
Data waiving:
study technically not feasible
Justification for data waiving:
other:

Data source

Materials and methods

Results and discussion

Applicant's summary and conclusion

Conclusions:
In accordance with REACH Annex XI, the Melting/freezing point study (required in section 7.2) does not need to be conducted as this test is technically not feasible. The melting point of Activated Carbon - Low Density Skeleton is estimated to be well above 1,000 degrees Celsius. Attached is a phase diagram for graphite, which is expected to be comparable to activated carbon with regard to melting point, indicating a melting point of approximately 4,500 K. A recent study (Harris, P.J.F., Liu, Z. and Suenaga, K., 2008. Imaging the atomic structure of activated carbon. J. Phys: Condens. Matter 20 (2008) 362201 (5pp)) indicates a melting point for activated carbon of over 2,000 K under an inert (Ar) atmosphere. Current OECD guidelines provide no methodology for determining melting points above 1,000 degrees Celsius.

Furthermore, at higher temperature Activated Carbon - Low Density Skeleton will lose it's "activated" properties due to ignition and reaction with oxygen. Any testing should thus take place under an inert atmosphere.

Due to the extreme requirements for testing the melting point of activated carbon and the fact that no guidelines for testing at these temperatures is available, we suggest that a test for this endpoint should be waived.
Executive summary:

In accordance with REACH Annex XI, the Melting/freezing point study (required in section 7.2) does not need to be conducted as this test is technically not feasible. The melting point of Activated Carbon - Low Density Skeleton is estimated to be well above 1,000 degrees Celsius. Attached is a phase diagram for graphite, which is expected to be comparable to activated carbon with regard to melting point, indicating a melting point of approximately 4,500 K. A recent study (Harris, P.J.F., Liu, Z. and Suenaga, K., 2008. Imaging the atomic structure of activated carbon. J. Phys: Condens. Matter 20 (2008) 362201 (5pp)) indicates a melting point for activated carbon of over 2,000 K under an inert (Ar) atmosphere. Current OECD guidelines provide no methodology for determining melting points above 1,000 degrees Celsius.

Furthermore, at higher temperature Activated Carbon - Low Density Skeleton will lose it's "activated" properties due to ignition and reaction with oxygen. Any testing should thus take place under an inert atmosphere.

Due to the extreme requirements for testing the melting point of activated carbon and the fact that no guidelines for testing at these temperatures is available, we suggest that a test for this endpoint should be waived.