boron nitride (cubic)

Water solubility

Administrative data

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

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

Type of method:

flask method

Test material

Test material information

Constituent 1

Reference substance name:

boron nitride (cubic)

EC Number:

701-307-9

Cas Number:

10043-11-5

Molecular formula:

BN

IUPAC Name:

boron nitride (cubic)

Test material form:

solid: crystalline

Results and discussion

Water solubility

Water solubility:

< 0.01 mg/L

Temp.:

21 °C

pH:

7.2

Details on results:

Preliminary Visual Estimation of the Water SolubilityThe preliminary visual experiments showed that the water solubility of the test item is < 13 mg/L. According to the guidelines the water solubility should be determined with the column elution method in that case. For the column elution method an inert support material (sea sand) is coated with an excess of the test item by dissolving the test item in a volatile solvent. As the test item is an inorganic material insoluble in volatile solvents, it is not possible to dissolve it in such a solvent. Therefore, the column elution method is not applicable for this test item and the water solubility was determined by the "flask method".

Any other information on results incl. tables

Preliminary Visual Estimation of the Water Solubility

Table 1. Appearance of the test mixtures

Amount of the test item (mg)	Total volume (ml)	Appearance of mixture
97.96	0.1	undissolved
	0.5	undissolved
	1	undissolved^1)
	2	undissolved^1)
	10	undissolved^1)
	100	undissolved^1)
11.66	100	undissolved^2)
13.30	500	undissolved^2)
12.50	1000	undissolved^2)

¹⁾: After adding the amount of water, the solution was treated with ultrasound for 3 min.

²⁾: After adding the amount of water, the solution was first treated with ultrasound for 5 min and afterwards stirred at room temp. for about 24 h.

Flask-Method

Table: substance concentration in the water extracts - experiments A to D

Experiment	A	B	C	D (blank)
Mean concentration of boron (g/l) (rounded value)^1)	0.010	0.013	0.008	<5*10^-5
Mean concentration of calcium (g/l) (rounded value)^2)	1.3*10^-4	0.6*10^-4	1.1*10^-4
Mean concentration of Mn and Li (g/l) (rounded value)^3)	<2.0*10^-5	<2.0*10^-5	<2.0*10^-5	<2.0*10^-5

¹⁾:

Average experiments A to C: 0.010 g/l

Standard deviation (mean concentration of boron): 0.002 g/l

Relative standard deviation (mean concentration of boron): 22 %

²⁾:

Average experiments A to C (corrected for the blank value): 1.0*10^-4 g/l

Standard deviation (mean concentration of calcium, corrected for the blank value): 0.4*10^-4 g/l

Relative standard deviation (mean concentration of calcium, without correction for the blank value): 15 %

Relative standard deviation (mean concentration of calcium, corrected for the blank value): 35 %

³⁾: As the measured concentrations of manganese and lithium in the water extracts in the experiments A to C are below the reporting level, the concentration of these analytes in the water extracts is: < 2.0*10^-5 g/1.

Applicant's summary and conclusion

Conclusions:

The concentration of boron, calcium, lithium and manganese, dissolved in water extracts of the test item at a temperature of 20 °C, was determined to: Boron: 0.008 to 0.013 g/L, Calcium: < 1.3 *10E-4 g/L, Manganese : < 2.0 *10E-5 g/L, Lithium: < 2.0 *10E-5 g/L. Therefore, boron nitride can be considered to be practically insoluble in water.

Executive summary:

The objective of the present study was to analyse, if water extracts of the test item Synthetic cubic Boron Nitride Grade 2 (2 micron) Powder contain measurable amounts of boron, calcium, lithium and manganese. The method to determine the water solubility according to the OECD test guideline No. 105 and the European Commission Regulation (EC) No.440/2008, 4.6. has been applied. For the determination of water solubility the flask method was applied. As the test item is an inorganic substance, which is not soluble in water, it is not possible to determine the water solubility of the complete test item. Therefore, the concentrations of boron, calcium, lithium and manganese in water extracts of the test item were determined using ICP-OES method to demonstrate that cubic boron nitride is practically insoluble in water.

The concentration of boron, calcium, lithium and manganese, dissolved in water extracts of the test item at a temperature of 20 °C, was determined to:

Boron: 0.008 to 0.013 g/L

Calcium: < 1.3 *10^-4 g/L

Manganese : < 2.0 *10^-5 g/L

Lithium: < 2.0 *10^-5 g/L

The small amount of boron which has been found in the sample extracts most probably results from boron containing impurities of boron nitride. The concentration of boron in the water extracts and thus, the concentration of soluble impurities in boron nitride is very low. Against this background, boron nitride can be regarded as being practically insoluble in water.