Dipotassium tetraborate

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

04/06/2010 to 02/07/2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

not specified

GLP compliance:

yes

Type of method:

flask method

Water solubility:

163.2 g/L

Conc. based on:

test mat.

Loading of aqueous phase:

118.5 g/L

Incubation duration:

24 h

Temp.:

20 °C

pH:

9.9

Remarks on result:

other: calculated based on the measured weight% assuming a density of 1g/mL

Water solubility:

16.32 other: w/w

Conc. based on:

test mat.

Loading of aqueous phase:

118.5 g/L

Incubation duration:

24 h

Temp.:

20 °C

pH:

9.9

Remarks on result:

other: calculated from the titration of boric oxide.

Preliminary Test:

Weight of test item used = 0.1009 g

Temperature of test = 20°C

Total Volume of distilled water added (mL)	0.1	0.5	1	2	10	100	>100
Was test item totally dissolved? (y/n)	No	No	Yes	N/A	N/A	N/A	N/A
Approximate solubility (g/L)	> 1000	1000 - 200	200 - 100	100 - 50	50 - 10	10 - 1	< 1

Based on the preliminary test the water solubility of the test item is from 100 – 200 g/L. The MSDS for the test item stated that the water solubility was 158 g/L which is within this range. The amount of test item required for 1 L of water would be 5 x 158 = 790 g and as this test is done in triplicate the total amount of test item is 790 x 3 = 2370 g. However based on the approximate amount of test item available the maximum weight of test item available for each replicate was11.85 g. Based on the MSDS solubility of 158 g/L then the amount of water required for 11.85 g of test item would be:

(11.85/5)/158 x1000 = 15 mL 

Approximately 11.85 g of test item was then accurately weighed into each of three flasks, 15 mL of distilled water was added to each and the flasks were then placed in a temperature controlled shaker at 30°C. Testing was then carried out.

Shake Flask Details:

Replicate Number	Weight of test item used (g)	Volume of distilled water added (mL)	Number of days shaking	pH of aqueous solution after shaking, 24 hours in 20°C water bath and centrifugation and filtration
Replicate 1	11.8486	15	1	9.92
Replicate 2	11.8503	15	2	9.90
Replicate 3	11.8371	15	3	9.92

After removal from the shaker the test item solutions were placed in a water bath, set at 20°C, for 24 hours prior to centrifugation, filtration and analysis. However due to a delay in the analysis the centrifuged and filtered aqueous test item solutions were placed back in the 20°C water bath and kept at temperature until analysed.

Water Solubility Solution Analysis Results:

Replicate Number	Volume of aqueous test item solution taken (mL)	Weight of aqueous test item solution taken (g)	Volume of 0.5N hydrochloric acid added (mL)	Volume of 0.5N sodium hydroxide added at first titration end point (mL)	Potassium oxide content (% w/w)	Potassium pentaborate content (% w/w)	Volume of 0.5N sodium hydroxide added at second end point (after addition of mannitol) (mL)	Boric oxide content (% w/w)	Potassium pentaborate content (% w/w)
Replicate 1	4	4.4120	25	14.85	5.28	17.12	19.25	7.61	16.70
Replicate 2	4	4.4062	25	15.30	5.04	16.36	18.75	7.43	16.29
Replicate 3	4	4.3986	25	15.55	4.92	15.95	18.40	7.30	16.01
				Mean =	5.08	16.48	Mean =	7.45	16.32
				SD =	0.18	0.59	SD =	0.16	0.35
				%RSD =	3.59	3.59	%RSD =	2.12	2.12

Conclusions:

Interpretation of results : soluble (1000-10000 mg/L)
The dipotassium tetraborate test item was analysed for water solubility, following EU Method A.6. The results show that the mean water solubility for the dipotassium tetraborate test item is 16.32 % w/w (calculated from the titration for boric oxide).

Executive summary:

The dipotassium tetraborate test item was analysed for water solubility, following EU Method A.6 under GLP compliance. Flask method was used. The results show that the mean water solubility for the dipotassium tetraborate test item is 16.32 % w/w (163.2 g/L assuming a density of 1 g/mL) at 20 °C (calculated from the titration for boric oxide).

Description of key information

The dipotassium tetraborate test item was analysed for water solubility, following EU Method A.6 under GLP compliance. Flask method was used. The results show that the mean water solubility for the dipotassium tetraborate test item is 16.32 % w/w (163.2 g/L assuming a density of 1 g/mL) at 20 °C (calculated from the titration for boric oxide).

Key value for chemical safety assessment

Water solubility:

163.2 g/L

at the temperature of:

20 °C