Cobalt(2+) propionate

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

JUSTIFICATION FOR READING ACROSS INFORMATION FOR VAPOUR PRESSURE
The vapour pressure of a substance is defined as the saturation pressure above a solid or liquid substance. In EU method A.4, seven different measuring methods are listed for the measurement of the vapour pressure of solids and liquids. However, the vapour pressure does not need to be measured due to technical reasons if calculations indicate that the value is significantly less than 10^-5 Pa. Cobalt propionate is a solid substance (salts of an organic acid and an inorganic cation) with a decomposition temperature approx. 201 °C. In view of this, the volatility of this substance can therefore be safely assumed to be negligible, i.e. below the level of significance (10^-5 Pa). For purposes of comparison, the reference (Lide DR, Ed. (2008) CRC handbook of chemistry and physics, 88th edition) stated following vapour pressures for propionic acid (please refer to the respective study record): 1 kPa at 35.1 °C, 10 kPa at 79.9 °C, 100 kPa at 140.8 °C.

Since cobalt propionate is an inorganic salt in which propionic acid is present as anion in a salt, one may safely assume that the vapour pressure of that compound will be magnitudes lower than the vapour pressure of the uncharged free acid. The binding affinity in an ionic structure is characterised by Coulomb attraction, which has a higher dissociation energy than intra-molecular forces (van-der Waals binding). Ionic substances are usually characterised by higher intra-molecular forces and thus a higher vapour pressure. Based on the above reasons, experimental testing is not required.

In conclusion, the conduct of further experimental verification is considered to be neither technically nor scientifically feasible, and for the reasons stated above derogation from testing is hereby applied for.

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
Based on the above, the vapour pressure of cobalt propionate is considered to be negligible based on the fact that
(i) the vapour pressure of the corresponding acid is already very low (see above) and
(ii) the vapour pressure of the corresponding ionic species is considered to be magnitudes lower since the ionic bond strength is higher compared to the Van-der-Waals interactions of the uncharged molecule. In consideration of the ionic nature of this compound, it can therefore be anticipated that the vapour pressure of cobalt propionate is well below the value for the organic acid, and thus negligible.


2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Source: Propionic acid (see source study records; purity is not of relevance for this endpoint)
Target: Cobalt propionate (purity is not of relevance for this endpoint)

3. ANALOGUE APPROACH JUSTIFICATION
see justification given above

4. DATA MATRIX
not required

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

no guideline followed

GLP compliance:

not specified

Type of method:

other: not specified

Remarks on result:

other: please refer to the field `Justification for type of information´

Conclusions:

The vapour pressure of a substance is defined as the saturation pressure above a solid or liquid substance. In EU method A.4, seven different measuring methods are listed for the measurement of the vapour pressure of solids and liquids. However, the vapour pressure does not need to be measured due to technical reasons if calculations indicate that the value is significantly less than 10^-5 Pa. Cobalt propionate is a solid substance (salts of an organic acid and an inorganic cation) with a decomposition temperature approx. 201 °C. In view of this, the volatility of this substance can therefore be safely assumed to be negligible, i.e. below the level of significance (10^-5 Pa). For purposes of comparison, the reference (Lide DR, Ed. (2008) CRC handbook of chemistry and physics, 88th edition) stated following vapour pressures for propionic acid (please refer to the respective study record): 1 kPa at 35.1 °C, 10 kPa at 79.9 °C, 100 kPa at 140.8 °C.

Since cobalt propionate is an inorganic salt in which propionic acid is present as anion in a salt, one may safely assume that the vapour pressure of that compound will be magnitudes lower than the vapour pressure of the uncharged free acid. The binding affinity in an ionic structure is characterised by Coulomb attraction, which has a higher dissociation energy than intra-molecular forces (van-der Waals binding). Ionic substances are usually characterised by higher intra-molecular forces and thus a higher vapour pressure. Based on the above reasons, experimental testing is not required.

Based on the above, the vapour pressure of cobalt propionate is considered to be negligible based on the fact that
(i) the vapour pressure of the corresponding acid is already very low (see above) and
(ii) the vapour pressure of the corresponding ionic species is considered to be magnitudes lower since the ionic bond strength is higher compared to the Van-der-Waals interactions of the uncharged molecule. In consideration of the ionic nature of this compound, it can therefore be anticipated that the vapour pressure of cobalt propionate is well below the value for the organic acid, and thus negligible.

In conclusion, the conduct of further experimental verification is considered to be neither technically nor scientifically feasible, and for the reasons stated above derogation from testing is hereby applied for.

Key value for chemical safety assessment

Vapour pressure:

0 Pa

at the temperature of:

20 °C

Additional information

This `key value for chemical safty assessment´ stated above is only used for CHESAR calculations.

The vapour pressure of a substance is defined as the saturation pressure above a solid or liquid substance. In EU method A.4, seven different measuring methods are listed for the measurement of the vapour pressure of solids and liquids. However, the vapour pressure does not need to be measured due to technical reasons if calculations indicate that the value is significantly less than 10^-5 Pa. Cobalt propionate is a solid substance (salts of an organic acid and an inorganic cation) with a decomposition temperature approx. 201 °C. In view of this, the volatility of this substance can therefore be safely assumed to be negligible, i.e. below the level of significance (10^-5 Pa). For purposes of comparison, the reference (Lide DR, Ed. (2008) CRC handbook of chemistry and physics, 88th edition) stated following vapour pressures for propionic acid (please refer to the respective study record): 1 kPa at 35.1 °C, 10 kPa at 79.9 °C, 100 kPa at 140.8 °C.

Since cobalt propionate is an inorganic salt in which propionic acid is present as anion in a salt, one may safely assume that the vapour pressure of that compound will be magnitudes lower than the vapour pressure of the uncharged free acid. The binding affinity in an ionic structure is characterised by Coulomb attraction, which has a higher dissociation energy than intra-molecular forces (van-der Waals binding). Ionic substances are usually characterised by higher intra-molecular forces and thus a higher vapour pressure. Based on the above reasons, experimental testing is not required.

Based on the above, the vapour pressure of cobalt propionate is considered to be negligible based on the fact that

(i) the vapour pressure of the corresponding acid is already very low (see above) and

(ii) the vapour pressure of the corresponding ionic species is considered to be magnitudes lower since the ionic bond strength is higher compared to the Van-der-Waals interactions of the uncharged molecule. In consideration of the ionic nature of this compound, it can therefore be anticipated that the vapour pressure of cobalt propionate is well below the value for the organic acid, and thus negligible.  

In conclusion, the conduct of further experimental verification is considered to be neither technically nor scientifically feasible, and for the reasons stated above derogation from testing is hereby applied for.