p-benzoquinone

Water solubility

Administrative data

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

17.07.2018 - 27.07.2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

GLP compliance:

no

Type of method:

flask method

Test material

Test material information

Constituent 1

Reference substance name:

p-benzoquinone

EC Number:

203-405-2

EC Name:

p-benzoquinone

Cas Number:

106-51-4

Molecular formula:

C6H4O2

IUPAC Name:

1,4-benzoquinone

Test material form:

solid: particulate/powder

Results and discussion

Water solubility

Key result

Water solubility:

14.7 g/L

Conc. based on:

test mat. (dissolved fraction)

Incubation duration:

>= 24 - <= 72 h

Temp.:

20 °C

pH:

>= 3.4 - <= 3.7

Any other information on results incl. tables

Preliminary Test

The preliminary test of study CSL-18-0141.06 at room temperature showed, that the water solubility of the test item was between 1.0 and 7.5 g/L.

Table: Preliminary test for the water solubility

Amount of test item [mg]	Total volume of added water [mL]	Time in ultrasonic bath [min]	Remark
101.32	0.1	--	not dissolved
	0.6	--	not dissolved
	1.6	3	not dissolved
	3.6	3	not dissolved
	13.6	3	not dissolved
	100.0	6	dissolved

The solubility of the test item in water at room temperature was estimated to be between 1.0 and 7.5 g/L. Due to this result, the flask method was performed.

Main Test (flask method)

For the main test three flasks were prepared with an amount of test item and water, and one flask only with water. After stirring and centrifugation the aqueous phases were diluted with double distilled water and measured by means of HPLC. The solution of each flask has been measured twice. The values represented in the table are rounded values. The calculation was carried out with the original not rounded values.

Table: Results of the flask method

Flask	1a	2a	3a	4a
measured value [mg/L]	46.99 / 46.51	47.77 / 48.48	47.43 / 45.21	0 / 0
aliquot of the flask [mL]	0.08	0.08	0.08	1
total volume after dilution [mL]	25	25	25	1
water solubility [g/L]	14.7 / 14.5	14.9 / 15.2	14.8 / 14.1	0 / 0
average water solubility [g/L]	14.6	15.0	14.5	0
mean value of the water solubility [g/L]	14.7			0
standard deviation [g/L]	0.3			--
relative standard deviation [%]	2.0			--

To verify the accuracy of the analytical method freshly prepared standard solutions (prepared with the test item) were measured in between the samples of the flask method.

Table: Measurements of standard solutions

Standard solution (nominal value [mg/L])	Measured value [mg/L]	Repeatability [%]
Ü1 (24.02)	23.91	99.5
	23.70	98.7
Ü2 (32.40)	34.22	105.6
	34.13	105.3

The recovery rate of the measured standard solutions was in the range from 98.7 % to 105.6 %, which shows a sufficient accuracy of the analytical method.

Applicant's summary and conclusion

Conclusions:

The water-solubility of p-benzoquinone using the flask-method was determined to be 14.7 g/L.

Executive summary:

According to OECD Test Guideline 105 (1995) and Regulation EC No. 440/2008 Method A.6. the water solubility at 20 °C of the test item p-Benzoquinone was determined to be: c_S = 14.7 g/L, RSD = 2.0 %.