Registration Dossier

Physical & Chemical properties

Endpoint summary

Administrative data

Description of key information

Additional information

Data on physical properties were obtained from a number of proprietary and secondary sources. The data in the secondary sources are based on a critical evaluation of peer-reviewed data and the selected values are considered to be reliable and representative of the property under investigation. Information on the review process was documented in the introduction of the source. The use of Klimisch codes (Klimisch et al. 1997) was extended to these secondary sources and a reliability code of (2) valid with restrictions was assigned when using the authoritative secondary source. The data in the proprietary sources are taken from non-GLP, company specific datasheets, either with or without test guidelines. Although there is limited data available, as the results have been taken from company pro-forma, they have been assigned a reliability code of (2) reliable with restrictions and are considered suitable for use as supporting studies for the physico-chemical endpoints.

High purity DCPD is a crystalline solid at ambient temperature, whilst commercial DCPD is a liquid. The melting point of DCPD varies with the purity of the sample, with melting points of <0°C at <85% purity, rising to 10°C at >90% purity and >30°C at 100% purity. Therefore, physico-chemical data are presented, where available for both the pure (solid) and impure (liquid) forms of DCPD.

High purity DCPD is a solid at ambient temperature and commercial DCPD is a liquid. Physico-chemical properties are presented in the dossier, where available, for both the solid and liquid forms of the substance. For (eco)toxicity, since DCPD is dissolved in aqueous media or vehicles, there is not expected to be any difference in the test results between the two forms of the substance. For toxicity, it is expected that the hazards associated with DCPD would not change for the different forms of the substance. There may be some potential theoretical change in DCPD active entity (i.e. nominal versus actual dose and small changes in dimers amount (see SIP) etc.) but, generally testing has been conducted with high purity DCPD dissolved in a proper vehicle so there should be no difference between the exposure to the solid and liquid physical state anyway.

DCPD is a liquid or low melting point solid, depending on the purity of the substance, and therefore the flammability classification has been based on the flash point of the substance in combination with its boiling point. DCPD has a harmonised classification as Flammable Liquid Category 2 under CLP. High purity DCPD has coincident melting and flash points at 32°C and a boiling point of 172°C. Commercial DCPD has a melting point of <0°C to >30°C depending on the purity, a flash point of >23°C and a boiling point of 80 -190°C. Therefore, as both high purity and commercial DCPD have flash points of between 23°C and 60°C, a self-classification of Flammable Liquid Category 3 would be indicated by the CLP criteria.