N,N'-(10,15,16,17-tetrahydro-5,10,15,17-tetraoxo-5H-dinaphtho[2,3-a:2',3'-i]carbazole-4,9-diyl)bis(benzamide)

Water solubility

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

water solubility

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

weight of evidence

Study period:

2018

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Justification for type of information:

1. SOFTWARE
EpiSuite / WSKOW v1.42

2. MODEL (incl. version number)
EpiSuite 4.1
WSKOW v1.42

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
CAS : 131-92-0

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attachment

5. APPLICABILITY DOMAIN
See attachment

6. ADEQUACY OF THE RESULT
See attachment

Principles of method if other than guideline:

WSKOW v1.42 in EpiSuite 4.1: The estimation methodology used by WSKOWWIN (Meylan and Howard, 1994a,b) is described in the document prepared for the U.S. Environmental Protection Agency (OPPT): Upgrade of PCGEMS Water Solubility Estimation Method (May 1994).  A companion document (Validation of Water Solubility Estimation Methods Using Log Kow for Application in PCGEMS & EPI) also discusses the methodology.  WSKOWWIN uses equations 19 and 20 from these documents because they are the best available equations for estimating Wsol.

Equation 19 is:  log S (mol/L) = 0.796 - 0.854 log Kow - 0.00728 MW + Corrections
Equation 20 is:  log S (mol/L) = 0.693 - 0.96 log Kow - 0.0092(Tm-25) - 0.00314 MW + Corrections

(where MW is molecular weight, Tm is melting point (MP) in deg C [used only for solids])
Corrections are applied to 15 structure types (eg. alcohols, acids, selected phenols, nitros, amines, alkyl pyridines, amino acids, PAHS, multi-nitrogen types, etc); application and magnitude depends on available MP.  

Equation 20 is used when a measured MP is available; otherwise, equation 19 is used. These equations were derived from a dataset consisting of 1450 compounds with measured log Kow, water sol, and MP. Eq 20 has the following statistical accuracy: correlation coefficient (r2) = 0.97, standard deviation = 0.409 log units, and absolute mean error = 0.313 log units.  Application to a validation dataset of 817 compounds gave the following statistical accuracy: correlation coefficient (r2) = 0.902, standard deviation = 0.615 log units, and absolute mean error = 0.480 log units.

GLP compliance:

no

Type of method:

other: calculation

Key result

Water solubility:

0.001 mg/L

Conc. based on:

act. ingr.

Remarks on result:

other: calculated

Conclusions:

The water solubility of Vat Brown 3 is calculated to be 0.001368 mg/L.

Reference 2

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

March 13, 2017 - March 17, 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline 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:

no

Type of method:

flask method

Key result

Water solubility:

1.5 mg/L

Conc. based on:

test mat.

Loading of aqueous phase:

50 mg/L

Temp.:

20 °C

pH:

ca. 6

Individual results

 Preliminary visual estimation of the water solubility

Three preliminary tests were carried out with specified amounts of the test item and 100 mL and 500 mL demineralized water, respectively. After each addition of an amount of water, the mixture was stirred for at least 24 hours, and visually checked for any undissolved particles

Table3: Results of the preliminary visual estimation of the water solubility

Amount of test item / mg	Total volume of dist. water / mL	Appearance of mixture
9.9	100	not dissolved
11.0	500	not dissolved
4.3	500	not dissolved

The preliminary visual experiments showed that the water solubility of the test item is < 10 mg/L.As the item is insoluble in organic solvents, it is impossible to coat the sea sand of the columns with the test item. For this reason, the column elution method is not applicable and the water solubility had to be determined by the flask method.

Flask method

The flask method was performed. The data for the evaluation are given in Table4. After the equilibration time precipitate was observed in the flasks of the experiments excluding in the blank experiment.The water solubility was calculated from the measured and unrounded concentration values and not from the rounded values given in Table4.

Table4: Water solubility experiments of the test item

Experiment	24 h experiment	48 h experiment	72 h experiment	Blank experiment (72 h)
Amount of test item / mg	2.5	2.6	2.5	--
Amount of demineralized water / mL	50	50	50	5
Stirring time at 30 °C / h	24	48	72	72
pH at 23 °C	5.8	6.0	6.0	5.4
Aliquot of the flasks / mL	1	1	1	1
1^stDilution to volume / mL	1	1	1	1
Dilution factor	1	1	1	1
Measured concentration / mg C/L	1.11 / < 1.04	1.25 / 1.21	< 1.04 / < 1.04	< 1.04 / < 1.04
Mean concentration / mg C/L	1.08	1.23	< 1.04	--
Water solubility / mg/L	1.48	1.70	< 1.43	--

The test item contained 72.7 % (w/w) organic carbon according to the certificate of analysis. The water solubility of the test item at 20 °C was determined to be 1.5 mg/L (± 0.1 mg/L).

Executive summary:

The water solubility c_S of the test item Vat Brown 3 at a temperature of 20 °C was determined according to the flask method. It was found to be:

                                                                 c_S = 1.5 mg/L (± 0.1 g/L)

Description of key information

The water solubility of the test item at a temperature of 20 °C was determined according to the flask method. As the test item is insoluble in water and organic solvents, no feasible quantification method for the dye itself is available. Therefore, the dissolved total organic carbon was measured.

It was found to be c_S = 1.5 mg/L

As this results contains not only the test item, but all impurities containing carbon, the water solubility of the test item was calculated with WSKOW v1.42 included in EpiSuite 4.1.

It was calculated to be 0.001 mg/L

Key value for chemical safety assessment

Water solubility:

0.008 g/L

at the temperature of:

20 °C