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Physical & Chemical properties

Water solubility

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Description of key information

No definitive experimental determination possible
Since the test item demonstrated significant surface active properties in water, EC Method A.6 and OECD 105 could not be followed. Instead, computer estimations of water solubility of simplified molecules using the software program WSKOWWIN were utilized. Computer estimation on simplified molecules indicated that the test item was essentially insoluble in water, the highest water solubility of simplified molecules (3.5 x 10-9 mg/l at 25°C) being estimated for the sodium salt of a mono-sulfonated myristoleic acid triglyceride.

Key value for chemical safety assessment

Additional information

The simplified molecules were selected in the following way:

As stated in the preamble, the raw material for the production of the test item is a triglyceride, i.e. an ester composed of a glycerol molecule bound to three molecules of fatty acids (RCOOH). The three fatty acids can be all different, all the same, or only two the same. The chain length of the fatty acids has an even number of C atoms and can vary between C12 and C24. Under the process conditions chosen, the degree of sulfonation of the triglyceride mixture is approximately one -SO3 group per three test item molecules. As a consequence, computer estimations were applied to:

1.    triglycerides with saturated fatty acids (three identical molecules bound to glycerol);

2.    triglycerides with unsaturated fatty acids (three identical molecules bound to glycerol); and

3.    triglycerides with unsaturated fatty acids (three identical molecules bound to glycerol) and one -SO3 group bound to one of the fatty acid chains.

The following fatty acids were used for the type 1 molecules: lauric acid (12:0), myristic acid (14:0), palmitic acid (16:0), stearic acid (18:0), arachidic acid (20:0), behenic acid (22:0).

The following fatty acids were used for the type 2 molecules: myristoleic acid (14:1), palmitoleic acid (16:1), oleic acid (18:1), gadoleic acid (20:1), erucic acid (22:1), linoleic acid (18:2), linolenic acid (18:3).

The same acids were used for the type 3 molecules, but an -SO3 group was added to one of the fatty acid chains.

 

Computer estimations gave the following results:

-      triglycerides with saturated fatty acids: water solubility equal to or lower than 1.1 x 10-11 mg/l

-      triglycerides with unsaturated fatty acids: water solubility equal to or lower than 3.7 x 10-14 mg/l

-      triglycerides with unsaturated fatty acids and one -SO3 group: water solubility equal to or lower than 3.5 x 10-9 mg/l.

A maximum water solubility value of 3.5 x 10-9 mg/l was therefore estimated for the sodium salt of a mono-sulfonated myristoleic acid triglyceride.