Reaction mass of N,N,N',N'-tetrabutylmethylenediamine and dibutylamine

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

May 2022 to Feb 2023

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study was conducted in accordance OECD 203 (Jul-1992) guideline without deviation, under GLP. The study was appropriately modified using the principles outlined by Letinski et al., 2002 due to the possibility of critical micelles/emulsions forming.

Reason / purpose for cross-reference:

other: to support approach to CSA and study design of water solubility study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Version / remarks:

27 July 1995

Deviations:

yes

Remarks:

An adaptation of the standard method was performed taking into account the findings of Letinski, D.J., et al. (2002) “Slow-stir water solubility measurements of selected alcohols and diesters”, Chemosphere 48, 257-265 (7)

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

yes

Remarks:

An adaptation of the standard method was performed taking into account the findings of Letinski, D.J., et al. (2002) “Slow-stir water solubility measurements of selected alcohols and diesters”, Chemosphere 48, 257-265 (7)

Principles of method if other than guideline:

In a stirring vessel maintained at 20 ± 0.5 °C, ultrapure 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. Emulsions can be formed 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 a plateau was reached as a function of time and the experiment was replicate a total of three times.

GLP compliance:

yes (incl. QA statement)

Type of method:

other: Slow stirring method

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: confidential
- Expiration date of the lot/batch: 01 July 2022
- Purity test date: N/D

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: 2-8 °C, protected from light
- Stability under test conditions: Presumed stable
- Solubility and stability of the test substance in the solvent/vehicle: not relevant

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing (e.g. warming, grinding): None
- Preliminary purification step (if any): None
- Final concentration of a dissolved solid, stock liquid or gel: N/A

Key result

Water solubility:

156 mg/L

Conc. based on:

act. ingr.

Remarks:

Dibutylamine

Loading of aqueous phase:

100 g/L

Incubation duration:

9 d

Temp.:

20 °C

Remarks on result:

other: Measured value for dibutylamine

Key result

Water solubility:

2 917 mg/L

Conc. based on:

act. ingr.

Remarks:

N,N,N,N-Tetrabutylmethylenediamine

Loading of aqueous phase:

100 g/L

Incubation duration:

9 d

Temp.:

20 °C

Remarks on result:

other: Measured value for N,N,N’,N’-Tetrabutylmethylenediamine

Details on results:

Incubation of vessel one was performed for 9 days. The samples collected on day 4, 7, 8 and 9 indicated that the concentrations of TBMDA and DBA had reached equilibrium. This was verified based on the two following criteria; 1. The slope of concentrations vs time for these samples was not significantly different from 0. 2. The maximum difference between the four samples was below 15%.

The solubility of the test item main constituents (TBMDA and DBA) in water is given by the mean of the equilibrium concentrations determined for each vessel:
- 2917 ± 101 mg/L for N,N,N’,N’-TETRABUTYLMETHYLENEDIAMINE;
- 156 ± 5 mg/L for DIBUTYLAMINE.

The maximum differences observed between the determinations from the three vessels was 8% for TBMDA and 7% for DBA, which proves that an acceptable repeatability is obtained (the OECD 105 acceptability criterion for the maximum difference is 15% for the shake flask method).

Measured Concentrations in Vessel 1

		TBMDA			DBA
Sampling date (y/m/d h:min)	Stirring duration (day)	Rep. 1	Rep. 2	Mean	Rep. 1	Rep. 2	Mean
2022/5/9 10:40 (Preparation T0)	0	-	-	-	-	-	-
2022/5/10 9:55	1	4955	4328	4642	397	376	387
2022/5/11 9:50	2	3151	3521	3336	269	280	275
2022/5/12 8:50	3	3073	3353	3213	194	176	185
2022/5/13 8:30	4	3014	3434	3224	172	156	164
2022/5/16 8:30	7	3309	3038	3174	170	175	173
2022/5/17 10:50	8	2927	2865	2896	157	147	152
2022/5/18 8:30	9	2795	2909	2852	163	162	163

Measured Concentrations in Vessels 2 and 3

	TBMDA			DBA
	Rep. 1	Rep. 2	Rep. 1	Rep. 2	Rep. 1	Rep. 2
Vessel 2	3240	2610	2925	153	150	152
Vessel 3	2914	2666	2790	156	152	154

Average Equilibrium Concentrations

	TBMDA	DBA
Vessel 1	3037	163
Vessel 2	2925	152
Vessel 3	2790	154

 

 

Conclusions:

The water solubility of TBMDA and DBA was determined to be
- 2917 ± 101 mg/L for N,N,N’,N’-TETRABUTYLMETHYLENEDIAMINE;
- 156 ± 5 mg/L for DIBUTYLAMINE.

Executive summary:

The water solubility of N,N,N',N'-tetrabutylmethylenediamine and dibutylamine was determined in an OECD 105 study using a slow stirring method. Test vessels were spiked with the test item at a loading rate of 100 g/L and stirred for a total of 9 days. The concentration of N,N,N',N'-tetrabutylmethylenediamine and dibutylamine were determined and the water solubility of each substance was determined as the average measured concentration at equilibrium. 

The water solubility of TBMDA and DBA was 2917 mg/L and 156 mg/L, respectively.  

Description of key information

Water solubility = 156 mg/L; OECD 105 (using Letinski et al. (2002) modification); Mata, 2023

Key value for chemical safety assessment

Water solubility:

156 mg/L

at the temperature of:

20 °C

Additional information

A surface tension study in water was also performed on dibutylamine alone. The test supports the methods employed for water solubility.  Dibutylamine is known to be surface active and therefore critical micelles below the water solubility may impact water solubility interpretation. However, as no critical micelles were formed below the water solubility of dibutyamine, this effect would not affect interpretation of the results for water solubility.  Moreover, in this mixture, dibutylamine's water solublity was < 1000 mg/L, thus no critical micelles would have formed. The test was also conducted to ensure that water solubility was the most relevant parameter to use during exposure assessment. It also meant that, if any micelles formed below 3.8 g/L that this could be attributed to N,N,N',N' tetrabutylmethylenediamine.