Reaction mass of 1,4-bis(methoxymethyl)benzene, 1,6-dihydroxynaphtalene and Epichlorohydrin

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

24 March 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

During the method validation (Test Facility Study code: 19/117-316AN), the test item was thoroughly examined. The individual characteristic of the test item from view of the water solubility was justified experimentally. The procedure and results are presented from the method validation.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

GLP compliance:

not specified

Other quality assurance:

other: Not Specified

Type of method:

column elution method

Specific details on test material used for the study:

No further details specified in the study report

Key result

Water solubility:

< 1 mg/L

Conc. based on:

test mat.

Temp.:

25 °C

Remarks on result:

not determinable because of methodological limitations

Remarks:

Substance is a UVCB, technically not feasilbe to determine a water solubility value

Details on results:

Due to the polymer nature of this substance, it is not technically feasible to make a definitive concentration, a single water-solubility value cannot be given.

It was concluded that this test item contains a few detectable water-soluble components, which can be used as a marker of test item in water. But some components are so insoluble, that those will not dissolve in water under ambient conditions.

Saturation of the test item in ultrapure water to justify the water solubility study

The test item is a multicomponent polymer with several detectable components with a wide range of physicochemical characteristics (high and low LogP), which means, that those components have different solubilities in water.Therefore, the water solubility of the test item is not fully quantifiable as a well-defined saturated concentration in water; it can be said that approximately 4% of the test item was water soluble, depending on the test item : water ratio.

This mentioned phenomenon is common in case of the multicomponent substances. Therefore, to demonstrate the solubility or quasi-solubility of the substance, the measured area (mAU×s) of some selected components is reported and evaluated. The basis of the concentration analysis, that the measured area of the peak is in correlation of its concentration. This correlation is described with the calibration equation within the calibration series.

However, the criterion of the concentration determination for each detected component is that each component has to be a separate calibration series. In case of this polymer, this is not possible, without individual standards of the detected components. Furthermore, approximately 96% of the test item does not dissolve or is not detectable in water.

Therefore, to justify and interpret the water solubility of the test item, the measured areas of the detected components are reported. Each quasi-saturated solution was diluted in duplicate to 2-fold with ACN in order to reach the proper sample matrix for the measurement. Each dilution was injected twice.

To justify the solubility of the test item, several components were chosen and those measured area values were compared to the similarly identified components from the highest calibration standard (5 µg/mL). A minimal shift of the evaluated components was observed, therefore those components were consider as identical, which had shift of the retention time within 0.1 minutes. In the absence of any structural analysis of the individual components in the aqueous samples and the calibration sample (dissolved in organic solvents), it cannot be concluded, that those components are the same. But, for the theoretical calculations, it was considered to equal. The measured mean values are presented in the table below.

Comparison of the measured mean area values of the quasi-saturated solutions in water to the calibration standard

Chosen component (detected peak)			Measured mean area (mAU×s)
			≥75% of organic solvent	ultrapure water
Retention time range (min)			Calibration standard (solution: concentration in µg/mL)	Oversaturated or quasi-saturated (maximal nominal concentration in µg/mL)
Number	from	to	5	Control: 0	106	1006	10000	25492	52002
1	2.78	2.80	15.7	nd	628.1	3189.9	5827.4	6425.4	7073.0
2	3.14	3.20	8.6	nd	10.2	227.0	936.9	1060.1	1150.4
3	3.93	3.96	758.8	28.5	34.1	2613.1	3278.7	3931.9	3581.6
4	4.69	4.78	20.2	nd	nd	29.2	37.1	45.7	41.1
5	4.88	4.95	17.9	nd	nd	23.7	30.8	41.2	35.6
6	8.20	8.29	517.0	nd	nd	nd	2.7	2.5	5.1
7	18.76	18.83	136.5	nd	nd	nd	nd	nd	nd
8	20.78	20.86	115.5	nd	nd	nd	nd	nd	nd
Sum area:			1590.2	28.5	672.3	6082.8	10113.6	11506.7	11886.8

nd: not detected

Based on the results of the above table, it can be seen, that some components are enriched significantly (the components with lower retention times, which means that those components are more water-soluble than the others). This means that the components with higher retention times are fully insoluble in water. In the absence of any structural information, no water solubility or concentration information can be concluded about the supposed main polymer component(s).

In the below table, according to the former data from the above table, it is shown, that the individual components and how many times enriched they are compared to the highest calibration standard on the day of measurement. For the calculation, the measured area of the calibration standard was used as a relative value of 1 and the measured components from water was compared to it, after the calculation with the 2-fold dilution ratio.

The standard was used as a relative value of 1 and the measured components from water were compared to it, after the calculation with the 2-fold dilution ratio.

Enrichment of the chosen components in water

Chosen component			Mean area (mAU×s)	Enrichment ratio compared to the calibration standard (5 µg/mL)
			≥75% of organic solvent	ultrapure water
Retention time range (min)			Calibration standard (solution: concentration in µg/mL)	Oversaturated or quasi-saturated (maximal nominal concentration in µg/mL)
Number	from	to	5	Control: 0	106	1006	10000	25492	52002
1	2.78	2.80	15.7	0	80	407	743	819	902
2	3.14	3.20	8.6	0	2.4	53	219	247	268
3	3.93	3.96	758.8	0.04	0.09	6.9	8.6	10.4	9.4
4	4.69	4.78	20.2	0	0	2.9	3.7	4.5	4.1
5	4.88	4.95	17.9	0	0	2.6	3.4	4.6	4.0
6	8.20	8.29	517.0	0	0	0	0.01	0.01	0.02
7	18.76	18.83	136.5	0	0	0	0	0	0
8	20.78	20.86	115.5	0	0	0	0	0	0
Sum area:			1590.2	28.5	672.3	6082.8	10113.6	11506.7	11886.8
Theoretical saturation (%):			100		3.99	3.80	0.64	0.28	0.14

 

Based on Table 3., it can be concluded clearly, that some components can be enriched from 80 times to even 900 times relative to the 5 µg/mL calibration standard, this depends on the amount of test item

Based on this result, it can be supposed, that the test item contains several components in different amounts, furthermore, those components have very different water-solubilities, which is consequent to the retention times (and LogP values).

Therefore, only a theoretical saturation value can be given, which depends on the amount of the test item in water before the saturation. If we recognize that the calibration standards are clear solutions, due to the acetone and acetonitrile content, then we can suppose that the ratio of the different detected peaks are in correlation with the dispersion% in the pure test item. At this point, it has to be supposed that the individual components have similar or the same molar absorption coefficients (this fact is not known in the absence of the molecular structure of each component). After the acceptance of these criterion, we can assume, that the measured sum areas would be in correlation of the whole test item.

According to this theoretical criterion, it can be supposed based on the measured sum areas of the chosen components, that in the lowest saturation level (106 mg/L as nominal WAF concentration) had reached the highest saturation level compared to the initial amount of test item in water. This value is less than 4% of the amount of the test item.

In absolute terms, when the initial amount of the test item is increased significantly, the well-soluble components can dissolve in water, based on their individual solubility behaviours and initial amount of the pure test item. Therefore, the amount of the well-soluble components in water can be increased to almost infinity, depending on the test item amount. However, the insoluble components will not appear with any amount of the test item, therefore, the saturation% will decreased with the increasing initial test item amount.

Conclusions:

It was concluded, that based on the measurements, the test item contained a maximum of 4% water soluble components, in the case of the lowest saturation level tested.

Executive summary:

In the above mentioned guidelines for the determination of water solubility (OECD 105 and A.6) two test methods are described, from which both apply to essentially pure substances. The water solubility of the test item can be considerably affected by the presence of impurities.

The test item (CAS 577978-76-8)is a multicomponent polymer with several detectable components with a wide range of physicochemical characteristics (high and low Log P; log P_owvalues of the detectable components from the test item was found to be in range of <1.6 to >6.5, but it is plausible some large-molecule components were not seen due to column retention etc, Test Facility Study code: 19/117-346AN). The components have different solubilities in the water, a single test item concentration value was not fully quantifiable but was provided as evidence that the test item was present in the water.

A High-Pressure Liquid Chromatography method with UV Detector (HPLC-UV) for the analysis of CAS 577978-76-8 in ultrapure water to support OECD 105 Study type was validated (Test Facility Study code: 19/117-316AN). During the validation, the multicomponent nature with different individual solubility characteristic of the test item was justified.

Regarding the water solubility of the test item, it was clearly shown that a definitive water-solubility value cannot be given, but it was concluded, that this test item contains a few well-soluble components in water, which can dissolve depending on the amount of test item in the media. However, some components are insoluble, they will not dissolve in water under ambient conditions.

It was concluded that based on the measurements, that it is not technically feasible to produce a single concentration value for water-solubility due to the multicomponent nature of the test item; the test item contained a maximum of 4% water soluble components, in case of the lowest saturation level tested.

Description of key information

It was concluded that based on the measurements, that it is not technically feasible to produce a single concentration value for water-solubility due to the multicomponent nature of the test item; the test item contained a maximum of 4% water soluble components, in case of the lowest saturation level tested.

 

Additional information

The guidelines for the water solubility determinations can apply to essentially pure substances.

Due to the polymer nature of this substance, it is not technically feasible to make a definitive concentration, a single water-solubility value cannot be given.