Benzenesulfonic acid, 4-C20-24 (even numbered) sec-alkyl derivs., sodium salts

Water solubility

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

water solubility

Type of information:

(Q)SAR

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE
EPI Suite WSKOW

2. MODEL (incl. version number)
v1.42

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
Where applicable, the following conditions were entered into the methods.
Molecular formula: C30 H53 O3 S1 Na1
SMILES Notation: CCCCCCCCCCCCCCCCCCCCCC(CC)C1=CC=C(C=C1)S(=O)(=O)[O-].[Na+]

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
It was not possible to determine the water solubility experimentally. The water solubility was estimated by using quantitative structure-activity relationship (QSAR) methods from Log Kow (WSKOW v1.42).
Full details of the model can be find in the WSKOWWIN User's Guide, US Environmental Protection Agency. Office of Chemical Safety and Pollution Prevention, 1200 Pennsylvania Ave, N.W. Washington DC, 20460-0001, USA.
http://epa.gov/oppt/exposure/pubs/episuite.htm

5. APPLICABILITY DOMAIN
The water solubility was estimated using the EPI Suite v4.11 QSAR method.

6. ADEQUACY OF THE RESULT
Substance falls within the boundaries of the model

Principles of method if other than guideline:

The water solubility of the test substance was estimated using EPI Suite WSKOWWIN v1.42

Key result

Water solubility:

0 mg/L

Conc. based on:

test mat.

Temp.:

25 °C

Remarks on result:

other: pH not indicated

Water Sol: 1.649e-005 mg/L

SMILES : CCCCCCCCCCCCCCCCCCCCCC(CC)c1ccc(cc1)S(=O)(=O)O([Na])

CHEM   :

MOL FOR: C30 H53 O3 S1 Na1

MOL WT : 516.81

---------------------------------- WSKOW v1.42 Results ------------------------

Log Kow  (estimated)  :  8.82

Log Kow (experimental):  not available from database

Log Kow used by Water solubility estimates:  8.82

Equation Used to Make Water Sol estimate:

  Log S (mol/L) = 0.796 - 0.854 log Kow - 0.00728 MW + Correction

      (used when Melting Point NOT available)

     Correction(s):         Value

     --------------------   -----

      No Applicable Correction Factors

  Log Water Solubility  (in moles/L) :  -10.496

  Water Solubility at 25 deg C (mg/L):  1.649e-005

Conclusions:

The water solubility was estimated by using quantitative structure-activity relationship (QSAR) methods. The water solubility estimate from the EPI Suite v4.11 QSAR method conducted was 1.65E-05 mg/L.

Reference 2

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

14 – 15 June 2018; 17 July 2018; 02 – 09 October 2018

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

The water solubility is determined by visual observation and limited to the available test method

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:

yes

Type of method:

flask method

Specific details on test material used for the study:

- Batch n°: 2712-106
- Analytical purity: 100%
- Expiration date: not indicated
- Storage condition: at room temperature

Key result

Water solubility:

< 10 mg/L

Loading of aqueous phase:

10 mg/L

Remarks on result:

other: No temperature or pH is reported

Details on results:

Testing indicates that the test material is forming a stable micro-emulsion. Filtration and centrifugation does not separate the solutions into their dissolved and undissolved phases so sampling for formal testing would not be possible. From the results obtained from the visual estimation, the solubility of the test material is observed as <10 mg/L. It is possible that water solubility is lower than 10 mg/L but cannot be confirmed visually and it is not possible to determine this value using the test methods available.

Preliminary results

Table: Preliminary estimation

Mass of sample (mg)	Volume of water in which sample dissolves (ml)	Estimated solubility (g.L-1)
1	1000	< 0.01

Estimated water solubility: <1 g/L

After initial solubility estimation a further investigation was performed to establish the cut-off point of the solubility indicating solubility was less than 3.7 mg/L.

Using 1 mg of the test sample water was added in 100 ml increments. The cut off of the solubility was found to be 300 ml (3.33 mg/L).

Table: Preliminary estimation

Mass of sample (mg)	Volume of water in which sample dissolves (ml)	Estimated solubility (g/L)
0.78	600	< 0.01

Estimated water solubility: <1.3 mg/L

After review of the data from the previous estimation, there were concerns about the results based on known information about the test item.

The estimation was repeated with 600 mL of water added to 0.78 mg of the test material and shaken. However there were traces of sample in suspension. It was deemed that the water solubility of the test material is less than 1.3 mg.L-1. This is below the limit of detection of the test apparatus available.

Due to the disparity in results from the two estimations performed further investigation was made on the test item.

Further estimations

HPLC analysis was performed (see description above, in the methods section).

After standing over the weekend (over 60 hours) the saturated and filtered solutions remained as yellowish opaque solutions i.e. no separation or settling out of any solid material was observed.

500 μL of the previously filtered saturated solution was filtered through a 0.2 μm syringe filter for a second time. No change in the clarity of the solution was observed. The sample remained as an opaque solution.

Visual water solubility estimation

This result implies that the solubility of the test material is between 10 and 100 mg.L-1. However it should be noted that the sample had undergone a filtration step during the preparation.

Visual evaluation of particles present

The observation possibly implies that the test material is forming an emulsion or micelles and that this material is passing through a 0.2 micron filter.

Dilute solutions

All three solutions (1, 2 and 3 mg/L) appeared as clear solutions with no observable particulate matter present.

Additional solutions were prepared in a similar manner at concentrations of 10, 23 and 40 mg.L-1. The 23 and 40 mg.L-1 solutions were cloudy in comparison to the 1, 2 and 3 mg.L-1 solutions. Although the 10 mg.L-1 was cloudy in comparison to the 1, 2 and 3 mg.L-1 solutions, it was not as easy to distinguish the difference.

The 10 mg/L solution of the test material was diluted by a factor of two to give a 5mg/mL solution of the test material. It was not possible to see any difference between the 1, 2 and 3 mg/L and 5 mg/L solutions.

No separation was observed after centrifugation.

Conclusion

Testing indicates that the test material is forming a stable micro-emulsion. Filtration and centrifugation does not separate the solutions into their dissolved and undissolved phases so sampling for formal testing would not be possible.

From the results obtained from the visual estimation, the solubility of the test material is observed as <10 mg.L-1. It is possible that water solubility is lower than 10 mg.L-1 but cannot be confirmed visually and it is not possible to determine this value using the test methods available.

Conclusions:

From the results obtained from the visual estimation, the solubility of the test material is observed as <10 mg/L. It is possible that water solubility is lower than 10 mg/L but cannot be confirmed visually and it is not possible to determine this value using the test methods available.

Description of key information

The water solubility was estimated by using quantitative structure-activity relationship (QSAR) methods. The water solubility estimate from the EPI Suite v4.11 QSAR method conducted was 1.65E-05 mg/L. This value is considered reliable with restrictions (K2) in a key approach.

From the results obtained from the visual estimation, the solubility of the test material is reported to be <10 mg/L (Dekra, 2018). It is possible that water solubility is lower than 10 mg/L but this cannot be confirmed visually and it is not possible to determine this value using the test methods available. Therefore, the result is reported in this supporting study as an unbound value and is considered to be reliable with restrictions (K2).

In conclusion, the substance is considered to exhibit a low to very water solubility.

Key value for chemical safety assessment

Water solubility:

0 mg/L