Diboron calcium tetraoxide

Water solubility

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2003

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:

49.2 g/L

Temp.:

20 °C

pH:

3.7

Details on results:

Preliminary solubility test
The estimated water solubility is approximately 8.29 g/L. This value means that the shake-flask method had to be applied. Because of the theoretical water solubility (47 g/L) the water solubility test was performed using the theoretical value.
The mean value of the water solubility of Test 1, 2 and 3 is 49.20 ± 0.35 g/L.

Solubility (shake flask method): Test number, stirring time, Tyndall value and the water solubility of the test substance at 20 ºC:

Test number	Stirring time (h)	pH	Tyndall	Water solubility (g/L)
1	24	3.75	0.0020 (0.0018)	48.86
2	48	3.54	0.0031 (0.0020)	49.57
3	72	3.98	0.0022 (0.0021)	49.16

The value between parentheses is Tyndall value of the blank.

Conclusions:

The water solubility of the test substance was 49.20 ± 0.35 g/L at 20.0 ± 0.5 ºC.

Executive summary:

Water solubility of the test item was assessed in a GLP-conform guideline study according to EU method A.6. The water solubility of the test substance was 49.20 ± 0.35 g/L at 20.0 ± 0.5 ºC.

Reference 2

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2005-02-23 - 2006-06-02

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline 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:

48.37 g/L

Temp.:

20 °C

pH:

3.6

Water solubility:

36.24 g/L

Temp.:

10 °C

pH:

3.9

Water solubility:

62.54 g/L

Temp.:

30 °C

pH:

4.4

Details on results:

The mean value of the water solubility of all test was: 48.37 ± 0.62 g/L at 20 ºC
The mean value of the water solubility of all test was: 36.24 ± 1.03 g/L at 10 ºC
The mean value of the water solubility of all test was: 62.54 ± 0.81 g/L at 30 ºC
The mean value of the water solubility at pH 7 of all tests was: 54.13 ± 0.75 g/L at 20 ºC
The mean value of the water solubility at pH 9 (tris buffer) of all tests was: 62.95 ± 1.47 g/L at 20 ºC
The mean value of the water solubility at pH 9 (ammonium carbonate buffer) of all tests was: 66.38 ± 0.13 g/L at 20 ºC

The test medium, stirring time, re-equilibration temperature, pH, Tyndall value and the water solubility of the test substances:

Test	Test medium	Stirring time (h)	Re-equilibration temperature (ºC)	pH test solution	Tyndall value*	Solubility (g/L)
A.1.	Water	24	20	3.61	-	47.8
A.2.	Water	48	20	3.62	-	49.2
A.3.	Water	72	20	3.61	-	48.1
B.1.	Water	24	10	3.95	-	35.6
B.2.	Water	48	10	3.91	-	37.6
B.3.	Water	72	10	3.95	-	35.6
C1.	Water	24	30	4.46	-	61.7
C.2.	Water	48	30	4.36	-	62.3
C.3.	Water	72	30	4.38	-	63.5
D.1.	KH2PO4-Buffer	24	20	5.69	0.0032 (0.0016)	54.98
D.2.	KH2PO4-Buffer	48	20	5.60	0.0024 (0.0015)	53.86
D.3.	KH2PO4-Buffer	72	20	5.68	0.0026 (0.0015)	53.55
E.1.	Tris-buffer	24	20	5.65	0.0027 (0.0015)	63.71
E.2.	Tris-buffer	48	20	5.64	0.0024 (0.0015)	63.87
E.3.	Tris-buffer	72	20	5.69	0.0029 (0.0016)	61.25
F.1.	Ammonium bicarbonate-buffer	24	20	5.96	0.0018 (0.0022)	66.35
F.2.	Ammonium bicarbonate-buffer	48	20	6.01	0.0035 (0.0042)	66.52
F.3.	Ammonium bicarbonate-buffer	72	20	5.97	0.0018 (0.0038)	66.27

* Tyndall value between parentheses is the Tyndall value of the blank. Calculations were performed using the values prior to rounding, calculations with rounded values presented in the table may differ slightly.

Conclusions:

The mean value of the water solubility of all test was: 48.37 ± 0.62 g/L at 20 ºC
The mean value of the water solubility of all test was: 36.24 ± 1.03 g/L at 10 ºC
The mean value of the water solubility of all test was: 62.54 ± 0.81 g/L at 30 ºC
The mean value of the water solubility at pH 7 of all tests was: 54.13 ± 0.75 g/L at 20 ºC
The mean value of the water solubility at pH 9 (tris buffer) of all tests was: 62.95 ± 1.47 g/L at 20 ºC
The mean value of the water solubility at pH 9 (ammonium carbonate buffer) of all tests was: 66.38 ± 0.13 g/L at 20 ºC

Executive summary:

Water solubility of the test item was assessed in a GLP-conform guideline study according to EU method A.6. The water solubility of the test substance was 48.4 g/L at 20 °C.

Description of key information

In the environment the transformation/hydrolysis of boron compounds is complex and is dependent on environmental factors; however, under typical aquatic environmental conditions it is expected that boric acid will be the most common and dominant species and it is also not expected to degrade further due to the high energy required to break the B – O bond (523 kJ/mol). Therefore, a read-across approach is considered appropriate to use the source substance, boric acid in the aquatic environment, rather than the target compound (calcium metaborate), refer to Section 13. 

 

In two GLP EU Method A.6 (Water Solubility) flask method studies water solubility values of 48.4 and 49.2 g/L at 20 °C were determined on the source substance, boric acid at pH 3.6 and 3.7, respectively.

 

An arithmetic mean was calculated from the water solubility source substance values.

Key value for chemical safety assessment

Water solubility:

48.8 g/L

at the temperature of:

20 °C