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Partition coefficient

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Reference
Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
01 July 2020 to 02 October 2020
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Reason / purpose for cross-reference:
reference to other study
Qualifier:
according to guideline
Guideline:
OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)
Version / remarks:
2004
Deviations:
no
Qualifier:
according to guideline
Guideline:
other: EU Method A.24 (Partition coefficient (n-octanol/water), High Performance Liquid Chromatography (HPLC) Method)
Version / remarks:
2016
Deviations:
no
Qualifier:
according to guideline
Guideline:
other: OPPTS 830.7570
Version / remarks:
1996
Deviations:
no
GLP compliance:
yes
Remarks:
Date of inspection: 10-17 December 2019 Date on certificate: 24 February 2020
Type of method:
HPLC method
Partition coefficient type:
octanol-water
Analytical method:
high-performance liquid chromatography
Key result
Type:
log Pow
Partition coefficient:
1.5
Temp.:
35 °C
pH:
7
Remarks on result:
other: For the reaction product of N-Phenyl-diethanolamine with a single molecule of formaldehyde constituent
Key result
Type:
log Pow
Partition coefficient:
1.3
Temp.:
35
pH:
7
Remarks on result:
other: For n-phenyl-diethanolamine constituent
Details on results:
The Pow of N-Phenyl-diethanolamine was calculated to be 1.1 (log Pow 1.0) using the Rekker calculation method. No pKa values for acidic groups in the molecular structure of the test item in the logarithm range of 1 - 14 were calculated.
The pKa value in the logarithm range of 1 - 14 for the basic group in the molecular structure of the test item (ARNH(R1R2)+) was calculated to be 1.9 using the Perrin calculation method.

The results of the HPLC method are given in the table below. The equation of the regression line was log k' = 0.540 x log Pow - 0.532 (r = 0.99, N = 12)

Substance

Retention time (min)

log Pow

Pow

Peak area
(%)

tr,1

tr,2

mean

Formamide (t0)

0.592

0.593

0.593

 

 

 

Benzylalcohol

1.308

1.306

 

1.1

 

 

Nitrobenzene

2.300

2.292

 

1.9

 

 

Bromobenzene

7.807

7.755

 

3.0

 

 

1,4-Dichlorobenzene

13.291

13.187

 

3.4

 

 

Biphenyl

28.480

28.196

 

4.0

 

 

1,2,4-Trichlorobenzene

29.881

29.615

 

4.2

 

 

Test item – N-Phenyl-diethanolamine

1.462

1.461

1.462

1.3

2.0 ´ 101

79

Test item – the reaction product of N-Phenyl-diethanolamine with a single molecule of formaldehyde*

1.774

1.772

1.773

1.5

3.5 ´ 101

2.4

Test item – the reaction product of N-Phenyl-diethanolamine with two molecules of formaldehyde*

4.148

4.140

4.144

2.4

2.7 ´ 102

18

*Identity of the test item components is based on work performed in Test Facility Study No. 20194899 (cross-referenced in this record). Previously performed work confirmed that N-Phenyl-diethanolamine component of the test item elutes first from C18 reverse phase column, while the reaction product of N-Phenyl-diethanolamine with two molecules of formaldehyde elutes the last from the column. A verified copy of the identification work performed in Test Facility Study No. 20194899 is documented in this study.   

Conclusions:
Log Pow for n-phenyl-diethanolamine was determined to be 1.3 and log Pow for the reaction product of N-Phenyl-diethanolamine with a single molecule of formaldehyde was determined be 1.5.
Executive summary:

The partition coefficient of the test item was determined using the HPLC method (OECD 117, EC A.24). The log Pow for n-phenyl-diethanolamine was determined to be 1.3 and log Pow for the reaction product of N-Phenyl-diethanolamine with a single molecule of formaldehyde was determined be 1.5. This aligns well with the calculated log Pow of 1.1.

Description of key information

log Pow 1.3 - 1.5; OECD 117; Petrovic, D. (2020)

Key value for chemical safety assessment

Log Kow (Log Pow):
1.3
at the temperature of:
35 °C

Additional information

The Log Pow value of 1.3 is is used as the key value for this endpoint. It is the most appropriate value to use for the chemical safety assessment, due to rapid abiotic transformation in aqueous environments where the reaction product of N-phenyl-diethanolamine with a single molecule of formaldehyde constituent is transformed to the n-phenyl-diethanolamine constituent, with a half-life of 9 minutes at 25 °C (OECD 111).

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