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Partition coefficient

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partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 08 January 1996 to 07 February 1996
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
The study was conducted according to an internationally recognised method. No deviation affected the quality of the study. Substance ID is adequately specified with isomers composition. Therefore full validation applies.
according to
OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)
Version / remarks:
according to
EU Method A.8 (Partition Coefficient)
Version / remarks:
(Directive 92/69/EEC)
GLP compliance:
Type of method:
HPLC method
Partition coefficient type:
Analytical method:
high-performance liquid chromatography
Key result
log Pow
Partition coefficient:
25 °C
ca. 0 - ca. 14
 Reference substances  Log Kow  tR1 tR2 tRm  k  log k
 Thiourea  --- 1.38 1.37  1.37    
 Aniline  0.9 2.12 2.10 2.11  0.539  -0.269
 Acetophenone  1.7 2.56 2.53 2.54  0.853 -0.069
 Benzophenone  3.2 4.67 4.66  4.67  2.401 0.380
 Naphtalene  3.6 5.62 5.62  5.62  3.092 0.490
 1,2,4 -trichlorobenzene  4.2 9.01 9.01  9.01  5.565 0.745
 n-butylbenzene  4.6 10.68 10.66  10.67  6.884 0.838
 Triphenylamine  5.7 20.08 20.14  20.11  13.651 1.135

tR1, tR2, tRm: retention times (1st and 2nd calibration, average)

k = (tR/t0) -1: capacity factor

t0: dead time = retention time of thiourea

Linear regression parameters: log Kow = a x log k + b

a = 3.296

b = 1.869

r² = 0.996

Test substance:

A chromatogram of Butyl Cyclohexyl Acetate obtained in the same conditions but with simultaneous UV and RI detections confirmed that both isomers correspond to one single peak at Rt ca 11.64 - 11.72 min.

tR1 = 11.722

tR2 = 11.641

tRm = 11.6815

k = 7.511

log k = 0.876

log Kow = 4.8

The substance has potential to bioaccumulate in the environment, according to CLP classification criteria for aquatic chronic toxicity (log Kow >4).
Executive summary:

The partition coefficient of the test substance Butyl Cyclohexyl Acetate was measured, under GLP, according to the OECD 117/EU A8 guideline, HPLC method.

The system was calibrated with 7 reference substances, between logK 0.9 and 5.7, and the result for the sample was interpolated from the linear regression.

The partition coefficient (log Kow) of the test substance has been determined to be 4.8 (at 25°C, pH not specified).

Description of key information

The substance (both isomers having the same value) has potential for bioaccumulation, according to CLP classification criteria for aquatic chronic toxicity (log Kow >4).

Key value for chemical safety assessment

Log Kow (Log Pow):
at the temperature of:
25 °C

Additional information

A fully reliable experimental study, conducted according to a recognized OECD/EC method and under GLP, is available. It is considered as a key study, and the result is retained as key data for purpose of CSA.