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Physical & Chemical properties

Vapour pressure

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Endpoint:
vapour pressure
Type of information:
not specified
Adequacy of study:
weight of evidence
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
secondary literature
Remarks:
Data comes from a secondary source, accepted as a reliable data source; however does not refer directly to the property of concern under the present point, therefore reliability cannot be granted.
Reason / purpose for cross-reference:
reference to other study
Principles of method if other than guideline:
unspecified
Remarks on result:
other: Essentially zero. (ref.5)

HSDB database provide data on melting point from several sources:

mp = 770°C, decomposes (ref.1) supposed anhydrous form

mp = 250°C, decomposes   (ref.2) Melts when gradually heated; at 250 deg C loses its water

mp = 770°C, decomposes (ref.3)

mp = 86.5°C, decomposes (ref.4) Aluminum Sulphate Octadecahydrate

Conclusions:
Very low volatility expected.
Executive summary:

A reference database provides different melting point values for aluminium sulphate, showing that the hydrated form looses the crystallisation water, before the anhydrous form decomposes at 770°C. This confirms that the vapour pressure is expected to be very low, essentially zero as stated in the same database, and likely below the measurable range (10E-10 Pa).

Endpoint:
vapour pressure
Type of information:
not specified
Adequacy of study:
weight of evidence
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
secondary literature
Remarks:
Data does not refer to the parent substance nor directly to the property of concern under the present point, therefore reliability cannot be granted.
Principles of method if other than guideline:
unspecified
Remarks on result:
not determinable because of methodological limitations
Remarks:
VP expected negligible as decomposition before mp at 300°C

m.p. = 300°C (loses water)

Conclusions:
Very low volatility expected.
Executive summary:

Litterature provides melting point data for aluminium hydroxide, with a decomposition value (water loss) of 300°C. Based on this property, the vapour pressure is expected to be very low, and likely below the measurable range (10E-10 Pa).

Endpoint:
vapour pressure
Type of information:
not specified
Adequacy of study:
weight of evidence
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
secondary literature
Remarks:
Data comes from a secondary source, containing only basic data without references therefore reliability cannot be granted.
Principles of method if other than guideline:
unspecified
Temp.:
20 °C
Vapour pressure:
< 10 Pa
Conclusions:
Low volatility.
Executive summary:

Litterature provides data for aluminium hydroxide, with a limit vapour pressure value of less than 10 Pa at ambient temperature.

Endpoint:
vapour pressure
Type of information:
not specified
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Remarks:
Data from a secondary source, accepted as a reliable data source according to Chapter R.7a of REACH Guidance on information requirements and chemical safety assessment, adequate for assessment. Restrictions apply as no experimental details and purity is not specified.
Reason / purpose for cross-reference:
reference to other study
Principles of method if other than guideline:
unspecified
Temp.:
58.4 °C
Vapour pressure:
1 Pa
Temp.:
76.5 °C
Vapour pressure:
10 Pa
Temp.:
97.1 °C
Vapour pressure:
100 Pa
Temp.:
120.7 °C
Vapour pressure:
1 kPa
Temp.:
148.2 °C
Vapour pressure:
10 kPa
Temp.:
180.5 °C
Vapour pressure:
100 kPa
Solid at each temp. Deriving a regression from the above data, the Vapour Pressure is extrapolated to be ca 4 mPa at 20°C (9 mPa at 25°C).
Conclusions:
Low volatility.
Executive summary:

Litterature provides data for aluminium chloride between 58 and 180°C, showing a vapour pressure of less than 1 Pa at ambient temperature.

Endpoint:
vapour pressure
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Temp.:
25 °C
Vapour pressure:
< 1 Pa
Remarks on result:
other: literature value on aluminium chloride
Temp.:
20 °C
Vapour pressure:
< 10 Pa
Remarks on result:
other: literature value on aluminium hydroxide
Vapour pressure:
ca. 0 Pa
Remarks on result:
other: literature value on aluminium sulphate
Transition / decomposition:
yes
Transition temp.:
ca. 300 °C
Remarks on result:
other: literature value on aluminium hydroxide; decomposes (water loss) without melting from 300°C. VP of the pure salt expected below the measuring range (<10E-10 Pa)
Transition / decomposition:
yes
Transition temp.:
ca. 770 °C
Remarks on result:
other: literature value on aluminium sulphate
Conclusions:
Very low volatility expected from analogues.
Executive summary:

Based on the varying Cl/OH/SO4 ratio (UVCB), it was considered suitable to estimate the vapour pressure of the parent substance from pure aluminium chloride, pure aluminium hydroxide and pure aluminium sulphate.

Description of key information

From analogues, aluminium chloride hydroxide sulphate is anticipated to have negligible vapour pressure at ambient temperature.

Key value for chemical safety assessment

Vapour pressure:
0.001 Pa
at the temperature of:
20 °C

Additional information

No experimental value can be measured on aluminium chloride hydroxide sulphate, as the substance is only manufactured as aqueous solutions, which stabilises the composition. Based on the varying Cl/OH/SO4 ratio (UVCB), it was considered suitable to estimate the vapour pressure of the parent substance from pure aluminium chloride, aluminium hydroxide and aluminium sulphate. For the three analogue salts, literature provided indications of low vapour pressure, respectively <10 mPa at ambient temperature for chloride, mp ca 300°C with decomposition (meaning no measureable VP) for hydroxide, and mp ca 770°C with decomposition for sulphate. Therefore aluminium chloride hydroxide sulphate is also considered to have a very low vapour pressure.

However, a key value is required for purpose of CSA. As no realistic value can be provided, an arbitrary value of 0.001 Pa is proposed, in order to lie below the lower threshold of 0.01 Pa used by the risk assessment model.