Trihexylamine

Water solubility

Administrative data

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 2017-11-14 to 2018-03-09

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Version / remarks:

adopted 24 January 2014

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Test material

Test material information

Constituent 1

Reference substance name:

Trihexylamine

EC Number:

203-062-9

EC Name:

Trihexylamine

Cas Number:

102-86-3

Molecular formula:

C18H39N

IUPAC Name:

trihexylamine

Results and discussion

Water solubility

Key result

Water solubility:

4.17 mg/L

Conc. based on:

test mat.

Loading of aqueous phase:

136 mg/L

Incubation duration:

96 h

Temp.:

20 °C

pH:

7.5

Remarks on result:

other: ± 0.24 mg/L

Details on results:

After a stirring time of 24 hours, 48 hours and 72 hours at 30 °C, the samples were equilibrated for another 24 hours at 20 °C. Afterwards, the samples were taken through a tap at the bottom of the flask, checked for Tyndall effect, diluted and analyzed by HPLC with MS/MS detection. The result found after an incubation time of 72 hours exceeded by more than 15 % (129 %) the result found after an incubation time of 48 hours. To verify whether the saturation was achieved,
the test was prolonged for another 48 hours at 30 °C followed by 24 hours equilibration time at 20 °C giving a total stirring time of 72 hours, 96 hours and 120 hours. There was no Tyndall effect observed in the test samples.
According to the test guideline, the result found after a defined incubation time should not differ by more than 15 % from the result found after a shorter incubation time. After 120 hours in comparison to 96 hours, 10 % increase of the test item concentration was observed. The acceptance criterium was therefore fulfilled, the saturation was achieved after 96 hours. The study is therefore valid. The first measurement of the 72 hours is unexpectedly high in comparison to the previous and following measurements and can be considered as an outlier, probably due to microdroplets even if no Tyndall effect was observed.

Any other information on results incl. tables

Table 1     Data of the Performance of the Water Solubility Test

Sample No.	1	4	2	5	3	6
Weighed amount of test item [mg]	111.88		114.03		105.72
Volume of water [mL]	840		840		840
Loading Rate [mg/L]	133		136		126
Agitation time at 30°C [hours]	24	72	48	96	72	120
Equilibration time at 20°C [hours]	24	24	24	24	24	24
pH value of test item solution	6.91	7.70	7.08	7.53	6.68	7.47

The tabulated values of the samples represent rounded results obtained by calculation using the exact data.

 

 

Table 2     Results of the Water Solubility of TRI-N-HEXYLAMINE

Sample No.	Stirring Time at 30°C [hours]	Measured Concentration x [µg/L]	Sample Preparation Factor F	Concentration of Test Item Determined c [µg/L]	pH	Water Solubility Mean Value [mg/L]	Difference with Sample Previously Measured [%]	Overall Mean ± Std. Dev. [mg/L]
6	120	43.4	101	4379	7.44	4.38	+10	4.17 ± 0.24
		43.3	101	4373	7.50
5	96	39.6	101	3998	7.59	3.97	+39
		38.9	101	3934	7.47
4*	72	28.2	101	2845	7.74	2.86	-0.1
		28.5	101	2880	7.65
3**	72	74.6	101	7530	6.78	6.96	+129
		63.4	101	6398	6.58
2*	48	30.0	101	3031	7.06	3.04	+64
		30.1	101	3041	7.11
1*	24	18.1	101	1832	6.87	1.85	-
		18.5	101	1864	6.95

The tabulated values of the samples represent rounded results obtained by calculation using the exact data.

* Was not used for the calculation of overall mean, as the saturation was achieved after 96 hours.

** Was not used for the calculation of overall mean, considered as an outlier, probably due to microdroplets

Applicant's summary and conclusion

Conclusions:

During this study, the water solubility of TRI-N-HEXYLAMINE was determined at 20 °C using OECD Guideline for the Testing of Chemicals, No. 105 adapted to a slow stirring design. The water solubility was found to be 4.17 mg/L ± 0.24 mg/L at a pH of 7.5.

Executive summary:

During this study the water solubility of TRI-N-HEXYLAMINE was determined based on the OECD Guideline for the Testing of Chemicals, No. 105: Water Solubility, modified to a slow-stirring test design, and following GLP.

For each time point, the test vessel was filled with 840 mL water. A defined amount of the test item (about 110 mg) was applied on the water surface of each of three glass vessels. The vessels were fitted with glass stoppers. The flasks were kept at about 30 °C via water surrounding circulation and stirred slowly (less than 100 rpm) to avoid formation of an emulsion.

The vessels were incubated for 24 hours, 48 hours and 72 hours, respectively. After that incubation period, the temperature was reduced to 20 °C and the samples were re-equilibrated for 24 hours without stirring. The concentration of the test item in the aqueous solution was determined by HPLC with MS/MS detection. Since the saturation of the water could not be demonstrated after 72 hours, the study was prolonged. The same vessels were further incubated at 30 °C for another 48 hours giving final stirring times at 30 °C of 72 hours, 96 hours and 120 hours. After that additional incubation period, the temperature was reduced to 20 °C and the samples were re-equilibrated for 24 hours without stirring. The concentration of the test item was determined in the aqueous solution by HPLC with MS/MS detection.

According to the test guideline, the result found after a defined incubation time should not differ by more than 15 % from the result found after a shorter incubation time. After 120 hours in comparison to 96 hours, 10 % increase of the test item concentration was observed. The acceptance criterium was therefore fulfilled, the saturation was achieved after 96 hours. The study is therefore valid.

The water solubility of TRI-N-HEXYLAMINE at 20 °C was found to be 4.17 ± 0.24 mg/L at a mean pH of 7.5.