Registration Dossier

Physical & Chemical properties

Endpoint summary

Administrative data

Description of key information

Additional information

As no data was available for the density, vapour pressure, partition coefficient, surface tension, auto-ignition temperature and flammability of (benzoato-O,O')hydroxy(octadecanoato-O,O')aluminium these endpoints were read across from the substance aluminum, benzoate C16-18-fatty acids complexes.

Aluminum, benzoate C16-18-fatty acids complexes (CAS No. 94166-87-7, EC No. 303-385-6) is considered suitable for read across to (benzoato-O,O')hydroxy(octadecanoato-O,O')aluminium as it is structurally similar being an approximate 2:1 mixture of (benzoato-O,O')hydroxy(octadecanoato-O,O')aluminium and (benzoato-O,O')hydroxy(hexadecanoato-O,O')aluminium. The only significant difference is the presence of about 30% of the aluminium complex containing the saturated C16-fatty acid, hexadecanoate, in place of the saturated C18-fatty acid, octadecanoate. This small difference would not be expected to have a significant influence on physico-chemical properties.

 

Appearance/physical state/colour

(Benzoato-O,O')hydroxy(octadecanoato-O,O')aluminium is in the form of off-white crystals at ambient temperature. The data are taken from substance identification information in a GLP-compliant, guideline study available as an unpublished report (Lammers 2016).

Melting point/freezing point

A melting point of 234°C (507K) was determined for (benzoato-O,O')hydroxy(octadecanoate-O,O')aluminium using DSC. The melting point of the substance was determined in a GLP-compliant study following OECD guideline 102 (WIL 2015).

Boiling point

No experimental determination of the boiling temperature was possible for (benzoato-O,O')hydroxy(octadecanoato-O,O')aluminium as detailed in Method A2 Boiling Temperature of Commission Regulation (EC) No 440/2008 of 30 May 2008, and Method 103 of the OECD Guidelines for Testing of Chemicals, 27 July 1995, because the test item had been demonstrated to decompose prior to melting.

Density

The density of (benzoato-O,O')hydroxy(octadecanoato-O,O')aluminium was estimated to be 1080 kg/m3 at 20.0 ± 1.0°C (relative density value 1.08) based on read-across from aluminum, benzoate C16-18-fatty acids complexes. The density of the read-across substance was determined in a GLP-compliant air comparison pycnometer (for solids) test following OECD guideline 109 (Harlan 2013).

Vapour pressure

The vapour pressure of (benzoato-O,O')hydroxy(octadecanoato-O,O')aluminium was determined to be 0.000044 Pa at 25°C based on read-across from aluminum, benzoate C16-18-fatty acids complexes. The vapour pressure of the read-across substance was determined in a GLP-compliant study (Harlan 2013) following OECD guideline 104.

Water solubility

(Benzoato-O,O')hydroxy(octadecanoato-O,O')aluminium is considered insoluble, as the water solubility at 20°C was determined to be < 0.025 mg/L. The study is reliable without restrictions as it was GLP-compliant study conducted according to OECD guideline 105.

Partition Coefficient

No determination of the partition coefficient was possible by the shake-flask method as detailed in Method A8 Partition Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 107 of the OECD Guidelines for Testing of Chemicals, 27 July 1995. This was due to the insolubility of the substance in water, as determined to be less than 0.000025 g/L (WIL 2016) and the expected insolubility in n-octanol based on read-across of data from the structural analogue substance, aluminum, benzoate C16-18-fatty acids complexes. Further to this, determination of the partition coefficient by the HPLC estimation method as detailed in Method A8 Partition Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 117 of the OECD Guidelines for Testing of Chemicals, 13 April 2004, was also not possible. This was due to the expected insolubility of the substance in suitable reverse phase HPLC solvents based on read-across from the structural analogue substance, aluminum, benzoate C16-18-fatty acids complexes.

The partition coefficient was estimated by QSAR but the result is considered not to be relevant to the substance itself. As (benzoato-O,O')hydroxy(octadecanoato-O,O')aluminium is an ionisable salt, the partition coefficient can vary greatly depending on pH and the pKa of the substance. In order to compare partition coefficient values of different, ionisable compounds on a relative basis, partition coefficient values are sometimes reported as "corrected for ionisation", indicating that the value represents the partition coefficient at a pH where a compound exists primarily in the non-ionised form. However, KOWWIN (KOWWIN v1.68 in EPISuite v4.00, US EPA 2009) considers (benzoato-O,O')hydroxy(octadecanoato-O,O')aluminium to be “ion pairs” and as such only provides estimates for the ionised fatty acids and benzoic acid rather than the salt. The partition coefficient value for the salt itself therefore could not be determined.

(Benzoato-O,O')hydroxy(octadecanoato-O,O')aluminium is typically not synthesized as the “pure” compound and seldom exists except in the presence of the oil matrix. High temperature stability indicates that the grease thickener structure is robust and resistant to diffusion out of the oil. Dissolution of the grease thickener from grease into water is very unlikely as the thickener is poorly water soluble and the thickener is embedded in the hydrophobic grease matrix and is designed not to leach out. Thus the partition coefficient of the substance is not expected to be relevant.

Surface tension

The surface tension of a 90% saturated aqueous solutions of (benzoato-O,O')hydroxy(octadecanoato-O,O')aluminium was estimated to be 72.6 mN/m at 20.0 ± 0.5°C based on read-across from aluminum, benzoate C16-18-fatty acids complexes. Since the read-across substance showed a surface tension greater than 60 mN/m it was considered not to be surface active. The surface tension of the read-across substance was determined in a GLP-compliant ring balance test following OECD guideline 115 (Harlan 2013).

Auto-flammability

The relative self-ignition temperature of (benzoato-O,O')hydroxy(octadecanoato-O,O')aluminium was estimated to be 383°C based on read-across from aluminum, benzoate C16-18-fatty acids complexes. The relative self-ignition temperature of the read-across substance was determined in a GLP-compliant study following EC 440/2008 A16 method (Harlan 2013).

Flammability

Based on read across from aluminum, benzoate C16-18-fatty acids complexes, (benzoato-O,O')hydroxy(octadecanoato-O,O')aluminium was determined to be not highly flammable as it would fail to propagate combustion along 200 mm within 4 minutes. The flammability of the read-across substance was determined in a GLP-compliant test following the method EC440/2008 A10 (Harlan 2013).

Experience in manufacture and handling shows that (benzoate-O,O')hydroxy(octadecanoato-O,O')aluminium does not ignite spontaneously on coming into contact with air at normal temperatures and is stable at room temperature for prolonged periods of time (days). Experience has also shown that the substance does not react with water. It therefore does not meet the criteria for classification as a pyrophoric substance or a substance which in contact with water emits flammable gases.

Other physico-chemical endpoints

As (benzoato-O,O')hydroxy(octadecanoato-O,O')aluminium is a solid, the flash point endpoint is not required. Based on the structure of the substance, the explosiveness and oxidising properties studies have not been conducted as there are no structural alerts that would indicate explosive or oxidising properties. As the substance is manufactured and used in situ in a base oil and not marketed or used in isolated forms, the particle size distribution test has been waived.

Classification and labelling

The substance is not classified for physico-chemical hazards. Based on the structure of the substance, it does not meet the criteria for oxidising or explosive properties and based on experimental data, read across from a structural analogue, the substance does not meet the criteria for flammable solids. Experience in manufacture and handling shows that the substance is not a self-heating solid.