Fatty acids, C14-18 and C18-unsatd., branched and linear, 2-ethylhexyl esters

Boiling point

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

boiling point

Type of information:

other: publication

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: publication

Principles of method if other than guideline:

Not applicable

GLP compliance:

no

Type of method:

other: not applicable

Key result

Remarks on result:

other: not applicable

In accordance with column 2 of EC 1907/2006 Annex VII the boiling point measurement does not need to be performed as the substance decomposes before boiling.  Boiling point is a property which shows a correlation between increase of molecular weight / chain length and increase of boiling point. Measured boiling points of fatty acids short chain methyl ester prove this correlation, so the highest measured boiling point  for C16 ME (MW = 270,4558) is 338°C, for C18 ME (MW = 298,5095) is 352 °C.  Blake et al. (J. Chem. Eng. Data, 1961, 6, 87-98) show for esters of long chain acids that all esters with β-hydrogen atoms in the alcohol (i.e. alcohols with C3, e.g. propanol) decompose in the range between 262 and 283 °C. Conclusion: Esters of fatty acids esterified with alcohols ≥ C3 and having a molecular weight exceeding 300 amu have a boiling point > 300 °C and decompose before boiling.

Conclusions:

> 300 °C, decomposition probable

Reference 2

Endpoint:

boiling point

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Read-across category

Key result

Atm. press.:

1 013 hPa

Decomposition:

yes

Decomp. temp.:

> 300 °C

Table 1: Results from studies on source chemicals for boiling point

ID#	CAS	Fatty acids chain length	MW	BP
Fatty acids, C8-16, 2-ethylhexyl esters	135800-37-2	C8-16	256.42 – 368.65	Trend analysis: >300 °C, decomposition probable
Fatty acids, coco, 2-ethylhexyl esters	92044-87-6	C12-14	312.53 – 340.60	Experimental result: >346 °C, decomposition
2-Ethylhexyl palmitate	29806-73-3	C16	368.65	<200°C at 2hPa Trend analysis: >300°C at 1013hPa
Fatty acids, C16-18 and C18-unsatd., 2-ethylhexyl esters	85049-37-2	C16-18, C18:1	368.65 – 396.7	384°C at 1013hPa with decomposition
Fatty acids, C16-18, 2-ethylhexyl esters	91031-48-0	C16-18	368.65 - 396.7	Trend analysis: >300 °C, decomposition probable
2-Ethylhexyloleate	26399-02-0	C18:1	394.67	Trend analysis: >300 °C, decomposition probable
2-Ethylhexylstearate	22047-49-0	C18	396.7	Trend analysis: >300 °C, decomposition probable

 

The physico-chemical properties of the category members are similar or follow a regular pattern over the category. The boiling point is a property which shows positive correlation with increasing molecular weight and chain length. Two of the category members tested fulfill this rule with a boiling point of 346°C and 384°C for the alkyl chains C12 -14 and C16 -18, C18 unsatd., respectively. Decomposition is also reported for these two substances at > 300°C. In contrast the third result is not consistent with the previous results and no information is reportedeither on the method used noron decomposition. Since the target substance is surrounded by the category members with the alkyl chains C12 -14 and C16 -18, C18unsatd.,it is considered that the target substance has a boiling point > 300°C and decomposes before boiling.

Conclusions:

According to the read across category approach, the boiling point of the target substance "Isostearate 2-ethylhexyl" is > 300°C and the substance decomposes before boiling.

Description of key information

The boiling point of the target substance, Isostearate 2-ethylhexyl, was considered > 300°C with a decomposition of the substance.

Additional information

Justification and rationale of the category approach for the isostearate 2-ethyl hexyl :

This category group covers 2-ethyl hexyl esters linked with fatty acid chains (C8 to C18) unsatured and satured. This category includes monoconstituent substances and UVCB substances varying fatty acid chain length. This category was made in order to provide sufficient information for physicochemical, ecotoxicological and toxicological caracterisation of the Fatty acids, C14-18 and C18-unsatd., branched and linear, 2-ethylhexyl esters (CAS No 85186-76-1).

The category group includes:

- Fatty acids, C8-16, 2-ethylhexyl esters (CAS No 135800-37-2)

- Fatty acids, coco, 2-ethylhexyl esters (CAS No 92044-87-6)

- 2-Ethyl hexyl palmitate (29806-73-3)

- Fatty acids, C16-18 and C18-unsatd., 2-ethylhexyl esters (CAS No 85049-37-2)

- Fatty acids, C16-18, 2-ethylhexyl esters (CAS No 91031-48-0)

- 2-Ethylhexyl oleate (CAS No 26399-02-0)

- 2-Ethyl hexyl stearate (CAS No 22047-49-0)

Target substance for Category Approach : Fatty acids, C14-18 and C18-unsatd., branched and linear, 2-ethylhexyl esters (CAS No 85186-76-1)

In accordance with article 13 (1) of Regulation (EC) No. 1907.2006, “information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI are met. In particular for human toxicity, environmental fate and ecotoxicity, information shall be generated whenever possible by means other than vertebrate animal tests which includes the use of information from structurally related substances (grouping or read across)”. Therefore, the available experimental data were collected and evaluated according to Annex XI requirements.

Summary of available information

Two of the category members, Fatty acids C12 -14, 2 -ethylhexyl and Fatty acids C16 -18, C18 unsatd. 2 -ethylhexyl, whose composition surrounds the target substance, have been tested for their boiling point using differential scanning calorimetry and they show values, 346° and 384°C, respectively, which are correlated to the length of the fatty acid chains. In both studies, decomposition > 300°C was also reported. Another tested substance, 2 -ethylhexyl palmitate, whose boiling point value (<200°C) was discarded since it was not consistent with the previous results and with the length of the carbon chain.

Additionally litterature data demonstrated that long chain fatty acids esters with a molecular weight > 300 amu and a β-hydrogen in the alcohol chain (≥ 3 C) have a boiling point > 300 °C and decompose before boiling.

Conclusion

According to the Regulation (EC) NO. 1907/2006, Annex XI, 1.5, A Read-Across Category for "Long Chain Fatty Acid, 2-ethylhexyl esters" was performed in order to provide information on Isostearate 2- Ethylhexyl .

This category was based on common and shared properties as:

- common functional group,

- common precursors and the likelihood of common impurities resulting from common process of

manufacturing,

- chemically structurally similar breakdown products obtained via the same biological processes into

the organisms, and

- constant pattern in the changing of the potency of the properties across the category.

On the basis of the results obtained for the category members, it can be deduced that the target substance has a boiling point > 300°C and that decomposition occurs before boiling. This estimated decomposition process was supported by litterature data.

So taking into account the similarity of structures between the tested substances and the target substance and using a weight of evidence approach based on available consistent results, the decomposition value > 300°C is considered to be relevant for the target substance "Isostearate 2 -ethylhexyl".