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Physical & Chemical properties

Water solubility

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Reference
Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
key study
Study period:
21 November 2016 - 01 December 2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
The determination of water solubility was performed using the slow stirring method adapted from OECD Guideline No 123. This study was considered as reliable without restrictions because it was conducted under GLP.
Reason / purpose:
reference to same study
Reason / purpose:
reference to other study
Qualifier:
according to
Guideline:
other: adapted from OECD Guideline 123
Deviations:
no
Principles of method if other than guideline:
In a stirring vessel maintained at 20 +/- 0.5°C, ultra-pure water containing the test item was slow stirred. The stirring rate was adjusted in order to form a minimal vortex. The aim of this method was to prevent the formation of emulsions when saturating water. That can occur with the shake flask method and lead to a solubility overestimation. The water solubility was given by the mass concentration of the substance in water when this had reached a plateau as a function of time. A second experiment is performed in the same conditions
GLP compliance:
yes
Type of method:
other: slow-stirring method
Water solubility:
34.76 mg/L
Temp.:
20 °C
pH:
>= 4.26 - <= 6.35
Remarks on result:
other: First determination (vessel 1)
Water solubility:
ca. 34.26 mg/L
Temp.:
20 °C
pH:
>= 4.55 - <= 6.35
Remarks on result:
other: Second determination (vessel 2)
Key result
Water solubility:
ca. 34.51 mg/L
Temp.:
20 °C
pH:
>= 4.26 - <= 6.35
Remarks on result:
other: Mean of two solubility values obtained in two different experiments.

Preliminary test

10.3 mg of the test item were introduced into a 100 mL flask. The test item was not dissolved by 100 mL of water after 24h.

The approximate solubility determined by the preliminary test was lower then 100 mg/L.

Main test:

The following table presents the concentrations (in mg/L) obtained during the study (the sampling in vessel 2 only started when the concentrations observed in vessel 1 approached an equilibrium state):

 Sampling date Vessel 1   Vessel 2
 21/11/2016 08:30  7.06 No sampling
 21/11/2016 13:00  32.15  No sampling
 22/11/2016 08:30  40.14  No sampling
 22/11/2016 13:00  39.07  No sampling
 22/11/2016 18:00  36.49  No sampling
 23/11/2016 08:00  44.86  No sampling
 23/11/2016 13:00  52.67  No sampling
 23/11/2016 18:00  35.15  No sampling
 24/11/2016 08:00  34.73  No sampling
 24/11/2016 13:00  35.81  No sampling
 24/11/2016 18:00  34.79  36.07
 25/11/2016 08:00  33.38  35.45
 25/11/2016 13:00  35.49  33.37
 28/11/2016 08:00  34.66  34.43
 28/11/2016 13:00  33.83  31.68
 29/11/2016 08:00  36.64  35.54
 29/11/2016 13:00  n.a.*  n.a.*
 29/11/2016 18:00  n.a.*  n.a.*
 30/11/2016 08:00  34.79  33.97
 30/11/2016 13:00  34.79  34.29
 30/11/2016 18:00  34.88  34.94
 01/12/2016 08:00  34.35  34.46
 01/12/2016 13:00  35.00  33.63
 01/12/2016 18:00  36.34  35.04

* n.a.: non available due to an analytical instrument problem.

These concentrations are presented as a function of time in the figure.

The pH values in both systems were measured at the beginning and at the end of the experiments. The pH values were:

-       beginning of the experiment : 6.35 in both systems

-       end of the experiment : 4.26 in vessel 1 and 4.55 in vessel 2.

The acidification observed probably can be due to a minor test item degradation product with acidic properties and/or a dissolution of carbon dioxide from the air. Since the test water was not buffered, a low concentration of an acidic compound can cause a high decrease of pH.

 

Equilibrium demonstration:

The equilibrium is declared as reached on 01/12/2016 at 13h. The following table demonstrates that the equilibrium criteria are valid for each vessel at that moment.

 Criteria Vessel 1  Vessel 2 

 Maximum difference observed

in the 5 last samples

(must be < 30%)

 Min: 34.35 mg/L

Max: 35.00 mg/L

Difference: 1.9%

Min: 33.63 mg/L

Max: 34.94 mg/L

Difference: 3.8% 

 Conclusion  Equilibrium reached  Equilibrium reached
Conclusions:
The means of the five samples before the equilibrium state declaration (01/12/2016 13h) for each vessel are:
- Vessel 1: 34.76 mg/L
- Vessel 2: 34.26 mg/L
The difference observed among the two determinations is 1.5%, which proves that an acceptable repeatability is obtained (the OECD 105 acceptability criterion for the maximum difference between two tests by the column elution method is < 30%, and < 15% for the flask method).

The NERYL ACETATE solubility in water is thus given by the mean of the values obtained for the two ultrapure vessels:
NERYL ACETATE water solubility = 34.51 mg/L at 20 +/- 0.5°C

These solubility values were calculated considering the test item major constituent representing 90.9% of the test item.

The NERYL ACETATE solubility in water, corresponding to the mean of two determinations, was 34.51 mg/L at 20 +/- 0.5°C.
Executive summary:

A study was performed to assess the water solubility of the test item NERYL ACETATE by the slow stirring method.

Two determinations in ultrapure water were carried out. 5 mL of the test item were carefully poured at the top of 250 mL of water thermostated at 20 + 0.5°C. The systems were allowed to equilibrate until the test item concentration reached a plateau. The test item concentrations were monitored by HPLC-DAD.

The NERYL ACETATE solubility in water based on the mean of the two determinations was 34.51 mg/L at 20 +/- 0.5°C.

Description of key information

The water solubility of neryl acetate is 34.51 mg/L at 20 °C.

Key value for chemical safety assessment

Water solubility:
34.51 mg/L
at the temperature of:
20 °C

Additional information

A study was performed to measure the water solubility of neryl acetate with the slow-stirring method and according to OECD guideline 105 and 123. The result was considered with a reliability of 1 (reliable without restrictions) because it is scientifically acceptable and obtained under GLP.