Tall oil, maleated

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Initiation: September 24, 2013 Completion May 20, 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Specific details on test material used for the study:

The test item was dark, viscous liquid

Key result

Water solubility:

0.376 g/L

Conc. based on:

test mat.

Incubation duration:

30 d

Temp.:

20 °C

pH:

>= 5 - <= 6

Samples were taken from the three flasks at seven time points, corresponding to 47, 71, 144, 216, 384, 552 and 719 hours. The final four samples were taken 7 days apart as it was obvious from the initial samples that the concentration steadily increased over the first 3 weeks of incubation.

After about 400 hours of incubation, the solubility greatly increases, corresponding with an observed clouding of the solution, and the adoption of the characteristic blue hue of Tyndall scattering.

The agreement between replicate samples is generally good until the final stages of the test. As mentioned earlier, the samples took on a cloudy appearance in the last two time periods, displaying the characteristic blue hue of Tyndall scattering. This could be caused by the formation of an aggregate, like a micelle, in solution. The variability in the measurements of the three flasks at the final time point corresponds to the depth of their cloudiness. Thus, it can be concluded that the variability is not simply due to analytical variability but a true difference in the amount solubilized.

The difference between samples collected in the first 23 days was not less than 15%, therefore additional samplings were necessary. Based on the average of the day 23 and 30 samples, which agreed within 4.5%, the water solubility of tall oil, maleated was determined to be 375.9 mg/L.

It was observed that the UV spectrum changed over time, with the appearance of an absorbance at about 280 nm (a shoulder on the main absorption at 240 nm). The change in UV spectrum may be due to chemical instability occurring after 3 weeks of incubation in water, but could also correspond with the formation of a more water soluble aggregate. Oxidation or polymerization are possible chemical conversions.

Conclusions:

Tall oil, maleated had a water solubility of 0.376 g/L at 20.0 °C as determined by OECD Test No. 105.

Executive summary:

The water solubility of tall oil, maleated was determined according to OECD Guideline 105.

A preliminary test was conducted in order to approximate the amount of test item that would dissolve in water and the time required to reach saturation. The preliminary test, conducted as described in OECD 105, indicated a water solubility of less than 1000 mg/L.

The flask method was used for determination of solubility. Samples were taken from three flasks at seven time points, corresponding to 47, 71, 144, 216, 384, 552 and 719 hours. The final four samples were taken 7 days apart as it was obvious from the initial samples that the concentration steadily increased over the first 3 weeks of incubation. The absorbance of the extracts was measured at 240 nm.

The difference between samples collected in the first 23 days was not less than 15%; therefore, additional samplings were necessary. Based on the average of the day 23 and 30 samples, which agreed within 4.5%, the water solubility of tall oil, maleated was determined to be 375.9 mg/L.

Conclusion: It was observed that the UV spectrum changed over time, with the appearance of an absorbance at about 280 nm (a shoulder on the main absorption at 240 nm). The change in UV spectrum may be due to chemical instability occurring after 3 weeks of incubation in water, but could also correspond with the formation of a more water soluble aggregate. Oxidation or polymerization are possible chemical conversions.

Tall oil, maleated had a water solubility of 0.376 g/L at 20.0 °C as determined by OECD Test No. 105.

Description of key information

Tall oil, maleated had a water solubility of 0.376 g/L at 20.0 °C as determined by OECD Test No. 105.

Key value for chemical safety assessment

Water solubility:

0.376 g/L

at the temperature of:

20 °C