Alcohols, C9-11-branched and linear

Viscosity

Link to relevant study record(s)

Reference

Endpoint:

viscosity

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

1. HYPOTHESIS FOR THE CATEGORY APPROACH
The hypothesis is that the category members have similar structures, and viscosity properties, which vary in strength across the category, forming a regular pattern (Scenario 4 in the RAAF). The interpretation of the observed trends of variation of this property across the category is discussed in the endpoint summary.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Please refer to the test material identity information within each endpoint study record.

The long chain linear aliphatic alcohol Category has at its centre an homologous series of increasing carbon chain length alcohols. The category members are structurally very similar. They are all primary aliphatic alcohols with no other functional groups. The category members are linear or contain a single short-chain side-branch at the 2-position in the alkyl chain, which does not significantly affect the properties (‘essentially linear’). The category members have saturated alkyl chains or contain a small proportion of naturally-occurring unsaturation(s) which does not significantly affect the properties. The branched and unsaturated structures are considered to have such similar properties that their inclusion in the category is well justified.
Impurities: Linear and/or ‘essentially linear’ long chain aliphatic alcohols of other chain lengths may be present. These are not expected to contribute significantly to the properties in respect of this endpoint due to predictable trends (see point 3).
There are no impurities present at above 1% which are not category members or which would affect the properties of the substance.

3. CATEGORY JUSTIFICATION
The category members are structurally very similar (see point 2) and are biochemically very similar. The metabolic synthesis and degradation pathways are well established. This Category is associated with a consistency and predictability in the physicochemical, environmental, and toxicological property data across its members.

The context of trends observed in this property across the range of chain lengths covered by this Category is described in the Endpoint Summary and in the Category Report attached in Section 13.

In this registration, the information requirement is interpolated based on read-across from reliable data measured with nonan-1-ol, decan-1-ol and undecan-1-ol, members of the category with the same carbon number in the alkyl chains, providing evidence of the range of values expected for the constituents of the registration substance.

4. DATA MATRIX
A data matrix for the C6-24 alcohols Category is attached in Section 13.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

other: ASTM D446/07

Deviations:

no

Type of method:

capillary viscometer (static)

Temp.:

40°C

Parameter:

kinematic viscosity (in mm²/s)

Value:

ca. 8 - ca. 10

Conclusions:

 

Description of key information

The kinematic viscosity of Alcohols, C9-11-linear and branched is expected to be ca. 8-10 cSt (8-10 mm²/s) at 40°C on the basis of read across, expert judgement and weight of evidence. Values of 8, 9, 9 and 10 mm²/s at 40°C are reported in reliable secondary literature.

Key value for chemical safety assessment

Viscosity:

9 mm²/s (static)

at the temperature of:

40 °C

Additional information

The available results form a weight of evidence.

The kinematic viscosity of 9 cSt (9 mm²/s) at 40°C is reported in reliable company product literature for the UVCB. Values of 8 - 10 cSt (8-10 mm²/s) at 40°C are based upon read across from recent reliable measurements for commercial samples of analogous mono-constituent substances nonan-1-ol, decan-1-ol and undecan-1-ol).

Discussion of trends in the Category of C6-24 linear and essentially-linear aliphatic alcohols:

As chain length increases, kinematic viscosity increases. This is because molecular weight is higher and intermolecular forces in the substance are all higher.