7-methyl-3-methyleneocta-1,6-diene

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

9 December 2013 - 13 December 2013

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

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 with restrictions because not enough details on quantification of the substance were reported in the report.

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

other: adapted from OECD Guideline 123

Deviations:

no

Principles of method if other than guideline:

In a stirring vessel maintained at 20°C +/- 0.5°C, ultra-pure water covered by a thin layer of the test item is slow stirred. The speed was adjusted so that a minimal vortex is formed. The aim of this method is 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 is given by the mass concentration in water when a plateau as a function of time is reached. A second experiment is performed in the same conditions.

GLP compliance:

no

Type of method:

other: slow-stirring method

Key result

Water solubility:

ca. 5.06 mg/L

Temp.:

20 °C

pH:

5

Remarks on result:

other: Mean of two solubility values obtained in two different experiments.

Details on results:

Solubility value in the first experiment (mean of the five last samples) = 5.09 mg/L (The relative difference = 5.13% : less than 15% as required by the OECD 105 - flask method).
Solubility value in the second experiment (mean of the five last samples) = 5.03 mg/L (The relative difference = 4.15% : less than 15% as required by the OECD 105 - flask method).

Preliminary test

The 10 mg sample was not fully dissolved in 10 mL of water. Therefore the experiment was extended with 100 mL of water.

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

First experiment

The concentrations obtained as a function of time during this first experiment are presented in graph 1 : "Concentrations observed- first experiment"

Measured pH :

-       at the beginning of the experiment : 7

-       at the end of the experiment : 5

The mean ± standard deviation of the five last samples is 5.09 ± 0.10 mg/L.

 

The maximum difference observed in the five last samples is

           5.20 - 4.94 = 0.26 mg/L

 

The mean of these two maximum values is

           (5.20 + 4.94) / 2 = 5.07 mg/L

 

The relative difference, corresponding to the ratio of the maximum difference and the mean of the two maximum values is

           0.26 / 5.07 = 5.13 %

 

Second experiment

The concentrations obtained as a function of time during this second experiment are presented in graph 2 : "Concentrations observed- second experiment".

Measured pH :

-       at the beginning of the experiment : 7

-       at the end of the experiment : 5

 

The mean ± standard deviation of the five last samples is 5.03 ± 0.08 mg/L

 The maximum difference observed in the five last samples is

           5.16 – 4.95 = 0.21 mg/L

 

The mean of these two maximum values is

           (5.16 + 4.95) / 2 = 5.06 mg/L

 

The relative difference, corresponding to the ratio of the maximum difference and the mean of the two maximum values is

0.21 / 5.06 = 4.15%

 

Conclusions:

Two determinations were conducted according to the slow stirring method (adapted form OECD Guideline No 123).
The mean of the water solubility values obtained in the two different experiments is: (5.03 + 5.09) / 2 = 5.06 mg/L
The relative difference between the results of the two experiments is: (5.09 – 5.03) / 5.06 = 1.19 %

Executive summary:

The determination of the water solubility of MYRCENE was performed using the slow stirring method adapted from OECD Guideline No 123. Due to the physicochemical properties of the test item (stability, volatility, adsorption on glass), the samples were analyzed as soon as possible after sampling. This precaution is crucial in order to avoid underestimation and variations of the measured concentrations.

It should be noted that an acidification of the test water has been observed during these experiments. However, since test item MYRCENE does not possess acido-basic properties, these pH variations did not affect the solubility of the test item.

Two independent experiments were carried out. The concentration of the substance was regularly measured by HPLC-UV (High Performance Liquid Chromatography with UV detector). The water solubility was recorded when the concentration reached a plateau.

The water solubility of MYRCENE is 5.06 mg/L. This value is the mean of two independent measurements.

Description of key information

A study was conducted to determine the water solubility of myrcene according to OECD Guideline 123 using the slow stirring method.
The water solubility obtained for myrcene is the mean of two independent determinations at 20°C: 5.06 mg/L.

Key value for chemical safety assessment

Water solubility:

5.06 mg/L

at the temperature of:

20 °C

Additional information

This experimental value was measured in a study performed according to OECD Guideline 123 with minor deviations.

The value was considered with a reliability of 2 (reliable with restrictions) because the result is scientifically acceptable but not obtained under GLP and some details were lacking in the report.

However, the obtained water solubility value is considered as key value for this endpoint.