Registration Dossier

Physical & Chemical properties

Density

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

Density (HEBMP-H): The weight of evidence from company data is for specific gravity values in the range 1.26 - 1.39 g/cm³ at ambient conditions for various commercial solutions.

Key value for chemical safety assessment

Additional information

In solution, HEBMP-H (CAS 5995-42-6) undergoes a reversible internal condensation reaction to form a pH-dependent equilibrium mixture with the cyclised structure 4-(Phosphonomethyl)-2-hydroxy-2-oxo-1,4,2-oxaza-phosphorinane (CAS 32422-02-9, c-HEBMP) and water. The precise proportion of the two forms is dependent on pH, temperature and time, and under acidic or neutral conditions, the proportion of c-HEBMP in the multi-constituent substance may reach proportions as high as ≥ 50% w/w. Spectroscopic evidence from 31P-NMR analysis suggests that in the pH range ca. 1 – 7 a high proportion (50-75% w/w) is present as the cyclised form. The two forms exist in equilibrium therefore it is extremely difficult to separate and purify both forms. The properties of the whole substance, in which both forms are present at representative levels, are used in the chemical safety assessment.

No values are available for relative density of a solid, but this does not constitute a data gap since no solid HEBMP-H products are known. A number of specific gravity values of the commercial sample are available. While many of the individual sources are secondary literature, meaning that in most cases the reliabilities are not assignable, overall the weight of evidence is taken to be adequately reliable for the purpose of registration.

The following company data of non-assignable reliability are available:

1) A specific gravity of 1.36 g/cm3 at 20 °C was reported for the acid (personalc ommunication) of major supplier in the EU. The original reference was not available for review and no further information is available.

2) A specific gravity of 1.26 - 1.32 g/cm3 at 20°C was reported for the acid in a company product data sheet. The original reference was not available for review and no further information is available.

3) A density of 1.26 - 1.39 at 20 °C was reported for the substance in a company safety data sheet. The original reference was not available for review and no further information is available.