2,2'-isopropylidenebis(p-phenyleneoxy)diethanol

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

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 105 (Water Solubility)

Deviations:

yes

Remarks:

Adaptation with the slow-stirring method described in the OECD 123 guideline

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Key result

Water solubility:

111.8 mg/L

Conc. based on:

act. ingr.

Loading of aqueous phase:

3 g/L

Incubation duration:

4 d

Temp.:

20.4 °C

pH:

5

Details on results:

Sample filtration or centrifugation followed or not by fitration did not yield different results in term of measured concentrations. Therefore, the three sample preparation methods were considered equivalent. The data obtained from filtered samples were used to determine the water solubility of the test item.

The test concentrations reached a plateau at around 112 mg/L in filtered samples after 72-hour stirring. Based on OECD test guideline 105 specification, the saturation equilibrium was considered to be reached from 48 hours. Indeed, the concentrations measured in at least the four last sampling points (24, 48, 72 and 96 h) did not differ by more than 15% during this period. The water solubility of the test item was therefore calculated as the mean of the concentrations determined during this period. The solubility of the test item in water is 111.8 mg/L.

Table 1: concentration of test item in the successive samples in the control flask and the two replicate flasks. Three sample processing were used. They did not yield different results and were thus considered equivalent. Measures were done in triplicate for each sample.

Sampling time	Flask	Sample treatment	Test item concentration(mg/L)
			Measure 1	Measure 2	Measure 3	Mean	RSD (%)
24h	Control	Raw sample	<DL	<DL	ND	NA	NA
	Replicate 1	Raw sample	98.5	107.0	101.4	102.3	4.2
		Filtered	96.9	113.0	116.6	108.8	9.7
		Centrifuged	103.0	102.1	104.7	103.3	1.3
	Replicate 2	Raw sample	99.2	99.9	102.1	100.4	1.5
		Filtered	109.2	114.9	105.2	109.7	4.4
		Centrifuged	90.4	86.6	90.8	89.3	2.6
48h	Control	Raw sample	<DL	<DL	ND	NA	NA
	Replicate 1	Raw sample	112.0	114.1	113.1	113.1	0.9
		Filtered	114.7	116.6	115.7	115.7	0.8
		Centrifuged	107.0	106.9	113.7	109.2	3.6
	Replicate 2	Raw sample	110.5	117.2	113.8	113.8	2.9
		Filtered	109.1	116.9	118.2	114.8	4.3
		Centrifuged	106.7	107.0	101.5	105.1	2.9
72h	Control	Raw sample	<DL	<DL	ND	NA	NA
	Replicate 1	Raw sample	115.6	123.3	120.5	119.8	3.3
		Filtered	118.1	120.0	115.3	117.8	2.0
		Centrifuged	114.4	109.1	107.1	110.2	3.4
	Replicate 2	Raw sample	114.5	112.6	113.6	113.6	0.9
		Filtered	115.8	118.5	112.0	115.4	2.8
		Centrifuged	107.2	110.4	113.6	110.4	2.9
96h	Control	Raw sample	<DL	<DL	ND	NA	NA
	Replicate 1	Filtered	118.5	119.1	117.2	118.3	0.8
	Replicate 2	Filtered	112.8	113.9	112.2	113.0	0.8

Conclusions:

Water solubility of 2,2'-isopropylidenebis(p-phenyleneoxy)diethanol is 111.8 mg/L.

Executive summary:

The OECD test guideline 105 for the Testing of Chemicals (Water solubility) served as a basis for the procedure. According to the first results obtained and as the test item was a viscous liquid, the definitive test protocol was adapted from the flask method under slow stirring conditions as described in the OECD test guideline 123. Special temperature controlled glass-jacketed test vessels described in the OECD test guideline 123 with a sampling tap at the lower end and a magnetic stir bar at their bottom were used. Three flasks were used for the test (1 control flask and 2 replicate flasks). The preparation was made at 3 g/L. The solution were continuously stirred throughout the test period with the magnetic stir bar so as to create a vortex depth of around 0.5 cm. Over the test period, test samples were taken from the flasks after a 10 min cooling period at 24, 48, 72 and 96 hours. Samples were repeatedly sampled from the same flasks over time. Each sample was divided into 3 aliquots: one was not processed, one was filtered (through 0.8 µm then 0.2 µm filters) and one was centrifuged (2000 g, 10 min). These protocols were applied to avoid undissolved particles or droplets in the samples taken for analysis. However, for the last sampling time (96 hour), only filtered aliquot was analysed as no significant difference between processing methods was observed at the three previous sampling times (i.e., the slow-stirring very probably allowed avoiding the presence of particles or droplets in the samples). Based on OECD test guideline 105 specification, the saturation equilibrium was considered to be reached from 48 hours. Indeed, the concentrations measured in at least the four last sampling points (24, 48, 72 and 96 h) did not differ by more than 15% during this period. The water solubility of the test item was therefore calculated as the mean of the concentrations determined during this period. The solubility of the test item in water is 111.8 mg/L.

Description of key information

The OECD test guideline 105 for the Testing of Chemicals (Water solubility) served as a basis for the procedure. According to the first results obtained and as the test item was a viscous liquid, the definitive test protocol was adapted from the flask method under slow stirring conditions as described in the OECD test guideline 123. Special temperature controlled glass-jacketed test vessels described in the OECD test guideline 123 with a sampling tap at the lower end and a magnetic stir bar at their bottom were used. Three flasks were used for the test (1 control flask and 2 replicate flasks). The preparation was made at 3 g/L. The solution were continuously stirred throughout the test period with the magnetic stir bar so as to create a vortex depth of around 0.5 cm. Over the test period, test samples were taken from the flasks after a 10 min cooling period at 24, 48, 72 and 96 hours. Samples were repeatedly sampled from the same flasks over time. Each sample was divided into 3 aliquots: one was not processed, one was filtered (through 0.8 µm then 0.2 µm filters) and one was centrifuged (2000 g, 10 min). These protocols were applied to avoid undissolved particles or droplets in the samples taken for analysis. However, for the last sampling time (96 hour), only filtered aliquot was analysed as no significant difference between processing methods was observed at the three previous sampling times (i.e., the slow-stirring very probably allowed avoiding the presence of particles or droplets in the samples). Based on OECD test guideline 105 specification, the saturation equilibrium was considered to be reached from 48 hours. Indeed, the concentrations measured in at least the four last sampling points (24, 48, 72 and 96 h) did not differ by more than 15% during this period. The water solubility of the test item was therefore calculated as the mean of the concentrations determined during this period. The solubility of the test item in water is 111.8 mg/L.

Key value for chemical safety assessment

Water solubility:

111.8 mg/L