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Partition coefficient

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Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
1984-08-03 to 1985-01-10
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
For this substance the shake flask method utilized tends to underestimate the Kow due to formation of emulsions and micelles in the water phase. A slow stir method (OECD Guideline 123) is more appropriate but this method was not in place at the time of this study.
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)
Deviations:
not specified
GLP compliance:
yes
Type of method:
shake-flask method to: flask method
Partition coefficient type:
octanol-water
Analytical method:
gas chromatography
Type:
Pow
Partition coefficient:
520 000
Temp.:
25 °C
Remarks on result:
other: pH was not reported
Details on results:
All calculations were made using the observed peak area to interpolate the µg found from a normalized standard curve. The calculations were performed using a TI Model 66 progammable calculator utilizing linear regression analysis. The minimum detectable amount for the samples was 0.0012 ppm of DOTP. The ppm concentrations of DOTP were used to calculate the octanol/water partition coefficient as P= Co/Cw. Triplicate GLC analysis of duplicate 0.1% and 1.0% DOTP-in-octanol samples yielded a mean P value of 5.2x10E5 in well water, with a relative standard deviation of 60%.
Conclusions:
The octanol/water partition coefficient for DOTP in well water was determined to be 5.2x10E5.
Executive summary:

The octanol/water partition coefficient (P) of DOTP was determined through shake-flask batch extraction and gas-liquid chromatography. The octanol/water partition coefficient for DOTP in well water was determined to be 5.2x10E5.

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
1984-08-03 to 1985-01-10
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
For this substance the shake flask method utilized tends to underestimate the Kow due to formation of emulsions and micelles in the water phase. A slow stir method (OECD Guideline 123) is more appropriate but this method was not in place at the time of this study.
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)
Deviations:
not specified
GLP compliance:
yes
Type of method:
shake-flask method to: flask method
Partition coefficient type:
octanol-water
Analytical method:
gas chromatography
Type:
Pow
Partition coefficient:
180 000
Temp.:
25 °C
Remarks on result:
other: pH was not reported
Details on results:
All calculations were made using the observed peak area to interpolate the µg found from a normalized standard curve. The calculations were performed using a TI Model 66 progammable calculator utilizing linear regression analysis. The minimum detectable amount for the samples was 0.0012 ppm of DOTP. The ppm concentrations of DOTP were used to calculate the octanol/water partition coefficient as P= Co/Cw. Triplicate GLC analysis of duplicate 0.1% and 1.0% DOTP-in-octanol samples yielded a mean P value of 1.8x10E5 in sea water, with a relative standard deviation of 19%.
Conclusions:
The octanol/water partition coefficient for DOTP in sea water was determined to be 1.8x10E5.
Executive summary:

The octanol/water partition coefficient (P) of DOTP was determined through shake-flask batch extraction and gas-liquid chromatography. The octanol/water partition coefficient for DOTP in sea water was determined to be 1.8x10E5.

Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Study period:
2009
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: QSAR (ACDLabs) used and acceptable in accordance with REACH Annex XI.
Justification for type of information:
QSAR prediction: migrated from IUCLID 5.6
Guideline:
other: QSAR (ACDLabs) used and acceptable in accordance with REACH Annex XI.
Principles of method if other than guideline:
QSAR (ACDLabs)
GLP compliance:
not specified
Type of method:
other:
Partition coefficient type:
octanol-water
Type:
log Pow
Partition coefficient:
9.54
Temp.:
25 °C
pH:
7
Details on results:
No pH data entry for QSAR. pH assumed to be neutral.
Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Study period:
2009
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification
Justification for type of information:
QSAR prediction
Guideline:
other: QSAR (EPISUITE-KOWIN) used and accepatble in accordance with REACH Annex XI.
Principles of method if other than guideline:
QSAR (EPISUITE)
GLP compliance:
not specified
Type of method:
other: QSAR (EIPSUITE-KOWIN)
Partition coefficient type:
octanol-water
Analytical method:
other: QSAR modelling
Type:
log Pow
Partition coefficient:
8.39
Temp.:
25 °C
pH:
7
Details on results:
No pH entry for QSAR. Assumed to be neutral.

CAS Number: 6422-86-2 
SMILES : O=C(OCC(CCCC)CC)c(ccc(c1)C(=O)OCC(CCCC)CC)c1 
CHEM   : 1,4-Benzenedicarboxylic acid, bis(2-ethylhexyl) ester 
MOL FOR: C24 H38 O4  MOL WT : 390.57 
------------------------------ EPI SUMMARY (v4.00) --------------------------
  Physical Property Inputs: 
Log Kow (octanol-water):   7.81
 Boiling Point (deg C)  :   375.00
 Melting Point (deg C)  :   -67.20
 Vapor Pressure (mm Hg) :   8.6E-006
 Water Solubility (mg/L):   0.004 
Henry LC (atm-m3/mole) :   
------  KOWWIN Program (v1.67) Results: ===============================  
Log Kow(version 1.67 estimate): 8.39 
    
SMILES : O=C(OCC(CCCC)CC)c(ccc(c1)C(=O)OCC(CCCC)CC)c1 
CHEM   : 1,4-Benzenedicarboxylic acid, bis(2-ethylhexyl) ester 
MOL FOR: C24 H38 O4  MOL WT : 390.57
 -------+-----+--------------------------------------------+---------+-------- 
TYPE  | NUM |        LOGKOW FRAGMENT DESCRIPTION         |  COEFF  |  VALUE  
-------+-----+--------------------------------------------+---------+-------- 
Frag  |  4  |  -CH3    [aliphatic carbon]                | 0.5473  |  2.1892 
Frag  | 10  |  -CH2-   [aliphatic carbon]                | 0.4911  |  4.9110
 Frag  |  2  |  -CH     [aliphatic carbon]                | 0.3614  |  0.7228
 Frag  |  6  |  Aromatic Carbon                           | 0.2940  |  1.7640
 Frag  |  2  |  -C(=O)O  [ester, aromatic attach]         |-0.7121  | -1.4242
 Const |     |  Equation Constant                         |         |  0.2290
 -------+-----+--------------------------------------------+---------+--------
 Log Kow   =   8.3918
Conclusions:
Estiamted Log KoW value is 8.39 at 25 C.
Executive summary:

Estiamted Log KoW value is 8.39 at 25 C.

Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Study period:
June 2009
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Estimated Using QSAR (SPARC software), in accordance with REACH Annex XI.
Justification for type of information:
QSAR prediction
Guideline:
other: QSAR (SPARC) used and acceptable in accordance with REACH Annex XI
Principles of method if other than guideline:
Partition Coefficient estimated using SPARC software.
GLP compliance:
not specified
Type of method:
other: QSAR (SPARC)
Partition coefficient type:
octanol-water
Type:
log Pow
Partition coefficient:
7.81
Temp.:
25 °C
pH:
7
Details on results:
SPARC software used to estimate. No SPARC entry for pH. Assumed to be neutral.

Description of key information

Key value for chemical safety assessment

Log Kow (Log Pow):
8.34
at the temperature of:
20 °C

Additional information

The octanol/water partition coefficient (P) of the test compound, di(2-ethylhexyl)terephthalate also known as DOTP, was determined through shake-flask batch extraction and gas-liquid chromatography (GLC) using procedures equivalent to OECD 107 guidelines. Triplicate GLC analyses of duplicate 0.1% and 1% DOTP-in-octanol samples yielded a mean P value of 5.2 X 105 for well water (log Pow = 5.72), with a relative standard deviation (RSD) of 60%. The mean P value in sea water was found to be 1.8 X 105 (log Pow = 5.26), with an RSD of 19%. However, for this substance it is recognized that the shake-flask method does not adequately distinguish between test substance that is truly in water solution and that which may be suspended in micelles and trace particulate matter in water, which would lead to an erroneously high measured concentration in the water phase and an underestimation of the actual Kow.

The studies were performed before the development of the slow-stir methodology (OECD 123) which eliminates this problem. Therefore these studies are believed to be unreliable. Estimations of the log Kow were performed using 3 different well recognized models, SPARC, KOWIN, and ACD Labs. These models provided log Kow values for this substance of 7.81, 8.39, and 9.54 respectively. This endpoint is provided as a range of these values using a weight of evidence approach. Of these values the value generated by KOWIN, log Kow = 8.34, provides a estimated water solubility value from the WSKOW model that is consistent with the experimentally derived water solubility value determined by a slow-stir technique similar to the methods used in OECD 123. Therefore, greater confidence is placed on that value being the best estimate of Kow for this substance.