N-butyl phenyl ether

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Type of method:

HPLC method

Partition coefficient type:

octanol-water

Specific details on test material used for the study:

Test Material Name: Butyl phenyl ether
Chemical Name: Butoxybenzene
Synonyms: None
Lot/Reference/Batch Number: 06027KH
Purity/Characterization (Method of Analysis and Reference): The non-GLP certificate of analysis lists the purity as 99.5% by gas liquid chromatography with structure confirmation by infrared spectroscopy (Rajzer, 2007).

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

4.26

Temp.:

30 °C

Remarks on result:

other: pH not recorded for this methodology

Details on results:

Retention times of the reference materials ranged from approximately 1.0 to 9.5 minutes, while that for the test material averaged 2.87 minutes. Table 1 summarizes retention times for reference materials, while Table 2 summarizes retention time, calculated k’, and log Pow values associated with elution of the test material. The estimated log Pow value was 4.26, which is in fair agreement with the value of log Pow = 3.55 estimated from the structure-fragment calculation method of US EPA KOWWIN program (US EPA, 2012).

TABLE 1: Measured Log P_ow and HPLC Retention Times for the Reference Materials

Sample ID	Retention Time (min).
	Acetanilide (log Pow= 0.733)	Methyl Benzoate (log Pow= 2.27)	Chlorobenzene (log Pow= 3.11)	Phenanthrene (log Pow= 4.40)	DDT (log Pow= 6.39)
std mix 1	1.06	1.39	1.78	3.07	9.42
std mix 2	1.06	1.39	1.78	3.07	9.43
std mix 3	1.07	1.40	1.79	3.09	9.49
std mix 4	1.07	1.40	1.79	3.09	9.49

TABLE 2: Retention Time and Estimated Log P_owValue

Sample ID	Retention Time (min)	k'	log k'	Log Pow
Butyl Phenyl Ether - 1	2.87	2.21	0.345	4.26
Butyl Phenyl Ether - 2	2.87	2.22	0.346	4.26
Average	2.87	2.21	0.345	4.26

The t₀ retention time from the Urea injection was 0.89 minutes.

The OECD Guideline gives recommendations for validating the results of this log P_ow prediction by HPLC. For example, the value of log P_ow derived from repeated measurements made under identical HPLC conditions and using the same set of reference substances should fall within a range of + 0.1 log units. Typically, the correlation coefficient R for the relationship between log k’ and log P_ow for a set of test substances is around 0.9, corresponding to a variation in estimated octanol/water partition coefficient of log P_ow ± 0.5 log units. The results of the present study meet or exceed these recommended validation criteria, where replicate log P_ow determinations were identical, and the correlation coefficient (R) was 0.994.

Conclusions:

The estimated log Pow value was 4.26, which is in fair agreement with the value of log Pow = 3.55 estimated from the structure-fragment calculation method of US EPA KOWWIN program (US EPA, 2012).

Executive summary:

The octanol/water partition coefficient (log P_ow) for butyl phenyl ether was estimated following the OECD Guideline 117: HPLC method. A standard solution was prepared for calibration of log P_ow versus HPLC retention time (capacity factor, log k’) relationship, which contained five reference compounds (25 mg/L each) having measured log P_ow values ranging from 1.0 – 6.5. Analysis of this standard solution,

along with a similarly prepared solution of the test material produced HPLC retention times (t_R) for each of the reference compounds and test material based on detection of chromatographic peaks by the UV-absorbance/diode array detector. The dead time (t_o) for the HPLC assay was determined from duplicate analyses of a solution containing an unretained substance (urea). A linear regression of the HPLC capacity factor (k’) versus log P_ow was made from the resulting data, giving a line with slope = 3.34, intercept = 3.10, and coefficient of determination (R²) = 0.988. From this resulting regression equation, a log P_ow value of 4.26 was estimated from the HPLC retention time of butyl phenyl ether.

Description of key information

The octanol/water partition coefficient (logP_ow) for butyl phenyl ether was estimated following the OECD Guideline 117: HPLC method.

Key value for chemical safety assessment

Log Kow (Log Pow):

4.26

at the temperature of:

30 °C

Additional information

The octanol/water partition coefficient (logP_ow) for butyl phenyl ether was estimated following the OECD Guideline 117: HPLC method. The log P_ow was determined to be 4.26 at 30 degrees C.