Fatty acids, coco, iso-Bu esters

Water solubility

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

water solubility

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The target substance FATTY ACIDS, COCO, ISO-BU ESTERS (CAS 91697-43-7) and the source substance FATTY ACIDS, C16-18, ISOBUTYL ESTERS (CAS 85865-69-6) are both Short Chain Alcohol Esters (SCAE C2-C8) composed by a fatty acid (C16-C18) and a C4 alcohol (isobutanol).
The source and the target substance show therefore the same reactive groups and a similar composition. A read-across to the source is therefore justified.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Both target and source substances are fatty acid esters produced by chemical reaction of an alcohol (isobutanol) with organic acids (e. g. stearic acid) in the presence of an acid catalyst. The esterification reaction is started by a transfer of a proton from the acid catalyst to the acid to form an alkyloxonium ion. The carboxylic acid is protonated on its carbonyl oxygen followed by a nucleophilic addition of a molecule of the alcohol to a carbonyl carbon of acid. An intermediate product is formed. This intermediate product loses a water molecule and proton to give an ester. Monoesters are the final product of esterification.

3. ANALOGUE APPROACH JUSTIFICATION
Since both target and source substances are fatty acid esters produced by chemical reaction of an alcohol (isobutanol) with an organic acid and therefore share similar/overlapping structural features and functional groups, it is justified to use a read across approach. The source substance has been registered already and its water solubility has been investigated. The water solubility of the source substance was found being < 0,05 mg/L at 20 °C. The same value is predicted for the target substance.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Water solubility:

< 0.05 mg/L

Temp.:

20 °C

pH:

>= 5.2 - <= 7.5

Conclusions:

The water solubility of the source susbtance Fatty acids, C16-18, isobutyl esters (source substance) was found being < 0,05 mg/L at 20 °C.
Since both target and source substances are fatty acid esters produced by chemical reaction of an alcohol (isobutanol) with an organic acid and therefore share similar/overlapping structural features and functional groups, it is justified to use a read across approach. The results of the study conducted on the source is applicable to the target substance Fatty acids, coco, iso-Bu esters.

Executive summary:

The target substance FATTY ACIDS, COCO, ISO-BU ESTERS (CAS 91697-43-7) and the source substance FATTY ACIDS, C16-18, ISOBUTYL ESTERS (CAS 85865-69-6) are both Short Chain Alcohol Esters (SCAE C2-C8) composed by a fatty acid (C16-C18) and a C4 alcohol (isobutanol).

The source and the target substance show therefore the same reactive groups and a similar composition. A read-across to the source is therefore justified.

Since both target and source substances are fatty acid esters produced by chemical reaction of an alcohol (isobutanol) with an organic acid and therefore share similar/overlapping structural features and functional groups, it is justified to use a read across approach. The source substance has been registered already and its water solubility has been investigated. The water solubility of the source substance was found being < 0,05 mg/L at 20 °C. The same value is predicted for the target substance.

Reference 2

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

07 - 12 Dec 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

GLP compliance:

no

Type of method:

column elution method

Water solubility:

< 0.05 mg/L

Temp.:

20 °C

pH:

5.2 - 7.5

Remarks on result:

other: pH of millipore water: 7.0

	Sample	Sampling time [mL]	pH	Concentration [mg/L]
Run 1: Flow rate 25 mL/h	1	25	7.5	n.d. < 0.05
	2	50	7.4	n.d. < 0.05
	3	75	7.1	n.d. < 0.05
	4	100	6.7	n.d. < 0.05
	5	125	6.8	n.d. < 0.05
	6	150	6.8	n.d. < 0.05
	7	175	6.8	n.d. < 0.05
	8	200	6.7	n.d. < 0.05
Run 2: Flow rate 12.5 mL/h	1	25	5.9	n.d. < 0.05
	2	50	5.8	n.d. < 0.05
	3	75	5.7	n.d. < 0.05
	4	100	5.7	n.d. < 0.05
	5	125	5.6	n.d. < 0.05
	6	150	5.6	n.d. < 0.05
	7	175	5.3	n.d. < 0.05
	8	200	5.2	n.d. < 0.05
Mean of all concentration values:				n.d. < 0.05

 

The calibration curve fits over the whole working range from 0.05 – 5.1 mg/L with r²=0.999 (linear fit).

In course of the recovery experiment, an average recovery rate of 97.6% was determined.

Key value for chemical safety assessment

Water solubility:

0.05 mg/L

at the temperature of:

20 °C