Amines, C12-14 (even numbered)-alkyldimethyl, N-oxides

Water solubility

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

A saturated aqueous solution, based on visual observation, was prepared by mixing 10 g of lyophilised test substance with 15 mL of deionised water. This mixture was stirred for 24 hours at room temperature followed by centrifugation at 2500 rpm to separate undissolved solids from the aqueous phase. The concentration of the substance dissolved in the aqueous phase was analysed using a simplified DBAS method (Disulfine Blue Active Substances, Ref. Q.W. Osburn, Analytical method for Cationic Fabric Softener in Water and Wastes, JAOCS vol 59, No 10 (October 1982) p 453-457.

GLP compliance:

no

Type of method:

flask method

Remarks:

Refer to principles of method above.

Water solubility:

409.5 g/L

Remarks on result:

other: No information on temperature or pH.

Conclusions:

The water solubility was determined to be 409.5 g/L in this study.

Reference 2

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

disregarded due to major methodological deficiencies

Study period:

28/06/2010 - 20/07/2010

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The substance is manufactured and supplied as an aqueous solution. For the purposes of REACH compliance, attempts were made to freeze dry a sample of the substance so that some of the applicable physico-chemical testing could be completed. NMR and IR was used to confirm that the freeze drying process had not degraded the substance immediately after drying. However, some of the phys-chem tests, such as water solubility, gave unexpected results. Further analytical work subsequently confirmed that the dry substance had degraded to some extent, forming the free amine. Thus the reliability of this study cannot be assessed as the purity of the substance at the time of testing is unknown.

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

GLP compliance:

yes

Type of method:

flask method

Water solubility:

12.46 g/L

Temp.:

20 °C

pH:

10.13 - 10.49

Remarks on result:

other: The commercial amine oxide is manufactured typically as a 30 %w/w solution in water, with a pH of around 8.5

Description of key information

The water solubility was measured as 409.5 g/L.

Key value for chemical safety assessment

Water solubility:

409.5 g/L

at the temperature of:

20 °C

Additional information

Two studies are available. In the key study [Lammens M & Rottiers A (2002)] a saturated aqueous solution, based on visual observation, was prepared by mixing 10 g of lyophilised test substance with 15 mL of deionised water. This mixture was stirred for 24 hours at room temperature followed by centrifugation at 2500 rpm to separate undissolved solids from the aqueous phase. The concentration of the substance dissolved in the aqueous phase was analysed using a simplified DBAS method. The water solubility of the substance was 409.5 g/L. No information is given in the report on stability of the lyophilised substance, but the result is in line with actual concentrations of amine oxide achieved during routine manufacturing and is considered to be reliable.

In the second study, the water solubility of a sample of freeze-dried substance was measured [Younis S (2010)]. The water solubility was reported as 12.46 g/L, far below the expected concentration. In addition, it was noted that the pH of the solution was > 10, whereas standard solutions have a pH around 8.5. Subsequent analysis of a sample of the freeze-dried material showed that it had degraded in part to the free amine.