Pyrocatechol

Partition coefficient

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The publication of Leo et al. (1971) is a reference review article listing more than 5800 Log P values for numerous chemicals in different solvent systems, including octanol. The log Pow values cited are either issued from measurement, or calculated. In the case of catechol, measured values are provided, without further details on experimental conditions. However, these data are highly consistent with those reported in the other endpoint study records.

Qualifier:

no guideline available

Principles of method if other than guideline:

Review article listing measured and calculated log P values without reference to the method used.

GLP compliance:

not specified

Partition coefficient type:

octanol-water

Type:

log Pow

Partition coefficient:

0.88

Remarks on result:

other: Measured value issued from C. Church & C. Hansch, unpublished results

Type:

log Pow

Partition coefficient:

1.01

Remarks on result:

other: Measured value issued from Tichy & Bocek (private communication)

Conclusions:

Based on the log Pow values, catechol is not potentially bioaccumulable.

Reference 2

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Both studies of Garst & Wilson (1984) and Garst (1984) were parts of a same experimental work. Experiments were well described, and were performed following a method close to OECD Guideline 117. However, as the publications synthetised a high number of chemicals, each substance was not identified in details (with respect to purity for example). Similarly, the experimental procedure was not detailed substance per substance, but presented in a global way.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)

Deviations:

not specified

GLP compliance:

not specified

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Type:

log Pow

Partition coefficient:

0.88

Temp.:

25 °C

Remarks on result:

other: Measured value reported in Garst & Wilson (1984)

Type:

log Pow

Partition coefficient:

0.9

Temp.:

25 °C

Remarks on result:

other: Measured value #1 reported in Garst (1984)

Type:

log Pow

Partition coefficient:

0.95

Temp.:

25 °C

Remarks on result:

other: Measured value #2 reported in Garst (1984)

Type:

log Pow

Partition coefficient:

0.84 - 1.01

Temp.:

25 °C

Remarks on result:

other: Literature values cited in Garst & Wilson (1984) and Garst (1984) for comparison with the measured values

Conclusions:

Based on the log Pow values, catechol is considered as not potentially bioaccumulable.

Executive summary:

In two studies (Garst & Wilson 1984, Garst 1984), the partition coefficient of catechol was determined by HPLC, following a method close to OECD 117 guideline. Three logPow values were reported at 25 °C: 0.88, 0.9 and 0.95. They were very close to the literature data cited in the publications: 0.84 - 1.01 at 25°C.

Reference 3

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: This publication describe a new method to determine the partition coefficient. However, the study did not follow a recognized guideline, but was well described. Furthermore, the results were in the same range than those obtained with other methods.

Qualifier:

no guideline followed

Principles of method if other than guideline:

The compound of interest is dissolved in water with sonication and a hollow fiber containing octanol inside is placed in the sample solution to perform microextraction. After microextraction the concentrations in both the aqueous and n-octanol phases are analyzed by HPLC with UV detection.

GLP compliance:

not specified

Type of method:

other: Hollow-fiber membrane solvent microextraction coupled with HPLC.

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Type:

log Pow

Partition coefficient:

0.89

Details on results:

There were 3 measures. Results obtained were 0.9, 0.89 and 0.88.
In this study, experimental logPow values obtained by use of this new direct method were in good agreement with experimental data in the literature.
The new experimental apparatus and procedure were therefore reliable.
The study showed that repeatability was good.

Conclusions:

Based on the log Pow value, catechol is considered as not potentially bioaccumulable.

Reference 4

Endpoint:

partition coefficient

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The value is not an experimental result. However, the QSAR model is recommended by the ECHA guidance on information requirements and chemical safety assessment, and is well documented with regard to validation parameters according to OECD principles. Moreover, the substance is fully characterised towards the applicability domain.

Justification for type of information:

QSAR prediction

Qualifier:

no guideline followed

Principles of method if other than guideline:

QSAR estimation

GLP compliance:

no

Partition coefficient type:

octanol-water

Type:

log Pow

Partition coefficient:

1.03

Below are the detailed results provided by KOWWIN :

TYPE	NUM	LOGKOW FRAGMENT DESCRIPTION	COEFF	VALUE
Frag	6	Aromatic Carbon	0.2940	1.7640
Frag	2	—OH [hydroxy, aromatic attach]	-0.4802	-0.9604
Const		Equation constant		0.2290
			Log Kow = 1.0326

The molecular weight of catechol is 110.111 g/mol, hence within the estimation domain of the validation set (27.03 - 991.15 g/mol). All the functional groups are included in the list of descriptors, and the occurrence of each fragment is below the maximum number in the training/validation sets:

Fragment Description	Coef	Training Set		Validation Set
		Max	Number	Max	Number
Aromatic Carbon	0.2940	24	1790	30	8792
—OH [hydroxy, aromatic attach]	-1.4086	6	187	9	1525

Conclusions:

Based on the log Pow value of 1.03, catechol is considered as not potentially bioaccumulable.

Executive summary:

The partition coefficient of catechol was estimated using the recommended QSAR model KOWWIN. The substance is within the applicability domain (i.e. molecular weight and descriptors). The calculated result is: Log Kow = 1.03.

Description of key information

Partition coefficient range: 0.84 to 1.03.

Key value for chemical safety assessment

Log Kow (Log Pow):

0.93

Additional information

Several experimental and estimated results give consistent values. One of the experimental study, divided in two publications (Garst & Wilson 1984, Garst 1984), was selected as a key study, while the others (experimental and calculated results) were selected as supporting studies. An average of all the Klimisch 2 data was calculated to obtain the key value for chemical safety assessment.