Reaction mass of 2-amino-2-methyl-1-propanol hydrochlorid (3207-12-3) and 2-amino-2-methyl-1-propanol (124-68-5)

Partition coefficient

Administrative data

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018-10-16

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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:

other: OECD 105

Version / remarks:

1995

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other:

Version / remarks:

This study follows the indications given in the guidance on information requirements and chemical safety assessment, chapter R.7a, pp77 and 107

Deviations:

no

Principles of method if other than guideline:

This study follows the indications given in the guidance on information requirements and chemical safety assessment, chapter R.7a, pp77 and 107 and in the OECD Guideline for the Testing of Chemicals n°105, adopted on July 27,1995.

GLP compliance:

no

Type of method:

estimation method (solubility ratio)

Partition coefficient type:

octanol-water

Test material

Test material information

1

Reference substance name:

(2-hydroxy-1,1-dimethylethyl)ammonium chloride

EC Number:

221-713-5

EC Name:

(2-hydroxy-1,1-dimethylethyl)ammonium chloride

Cas Number:

3207-12-3

Molecular formula:

C4H11NO.ClH

IUPAC Name:

1-hydroxy-2-methylpropan-2-aminium chloride

Test material form:

liquid

Study design

Analytical method:

high-performance liquid chromatography

other: The water solubility was calculated by determination of the nitrogen content of a saturated water solution.

Results and discussion

Partition coefficient

Key result

Type:

log Pow

Partition coefficient:

-1.95

Temp.:

20 °C

Remarks on result:

other: pH was not determined

Details on results:

With the previous results for water solubility (687.0 g/L) and 1-Octanol solubility (7.73 g/L), the estimation of the partition coefficient of the test substance is -1.95

Any other information on results incl. tables

1-OCTANOL SOLUBILITY

A chromatogram of a typical solution of the test substance in 1-octanol solutions was available. Under our conditions, the retention time of the interesting peak is about 8.46 minutes.

The calibration curve is attached in appendix 2. Its equation and correlation coefficient are:

Y = - 1.382498* 10000 x2 + 1.251259*1000000x

R²= 0.999990

Where y means the peak area and x the concentration in g/L of the corresponding sample aliquot.

Table 1 shows the weighted samples (x g/20 mL 1-Octanol), the peak areas of the signals, the resulting 1-Octanol solubility of the test substance as well as the average and the standard deviation.

Table 1: 1 -octanol solubility of the test substance

Flask	Shaking Duration in (h)	Weighted sample in g/20 mL	Peak areas of the signals	1-Octanol solubility of the test substance mg/L	Average g/L	Average g/L	Standard deviation g/L
OCT-1	24	0.4489	3417934	7341.1	7.680	7.73 g/L	0.10
OCT-2	24	0.5524	4891693	7831.2
OCT-3	24	0.6783	4914095	7866.9
OCT-4	48	0.5427	4772631	7641.1	7.667
OCT-5	48	0.5583	4545913	7279.1
OCT-6	48	0.6666	5047143	8079.3
OCT-7	72	0.6596	4914095	7834.3	7.853
OCT-8	72	0.7697	5179710	8290.9
OCT-9	72	0.5274	4642938	7434.1

 

After determining of the concentration of the test substance, the evaluation is carried out analogously to OECD 105 (water solubility): If the concentrations measured in at least the two last days do not differ by more than 15 %, the test is satisfactory.

 

The individual results differ by 1.29 % for 1 -octanol solubility, which makes tests correct. Global results are:

Solubility of the test substance in 1 Octanol (20 °C): 7.73 ± 0.10 g

 

WATER-SOLUBILITY

The water-solubility was calculated by determination the nitrogen content of a saturated water solution. The crystal slurry of the test substance is cooled to 20 °C and then centrifuged for 6 min. at 3500 rpm. The liquid supernatant is used to analyze the nitrogen content.

 

 

Table 2: Nitrogen determination by Kjeldahl digestion

Sample	weighted sample	mg nitrogen found	% nitrogen found	Average	Standard deviation
1	0.1590	76447	7.64	7.66 %	0.016
2	0.2336	76767	7.68
3	0.1089	76626	7.66

 

Relative standard deviation: 0.016 %

Result: Nitrogen content 7.66 %

 

Calculation of water solubility:

Amount of Nitrogen: 7.66 % = 0.547 mol

Amount of the test substance as hydrochloride (MW 125.6 g/mol) = 0.547 * 125.6 =68.70 %

Solubility of the test substance in Water (20 °C): 687.0 ± 0.1 g/L

 

ESTIMATION OF THE PARTITION COEFFICIENT

 

The partition coefficient of the solute can be estimated with the following formula:

logPow = log ([solute]1-octanol/[solute] water)

 

With the previous results for water solubility (687.0 g/L) and 1-Octanol solubility (7.73 g/L), the estimation of the partition coefficient of the test substance is:

 

log Pow = log (7.73 g/L/687.0 g/L) = -1.95 ± 0.01

Applicant's summary and conclusion

Conclusions:

The estimated partition coefficient of the test substance is -1.95.

Executive summary:

The log Pow was estimated based on the solubility of the test item in water (687.0 g/L) and n-octanol (7.73 g/L). The resulting log Pow is -1.95.