Registration Dossier
Registration Dossier
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EC number: 233-139-2 | CAS number: 10043-35-3
Vapour pressure
Administrative data
Link to relevant study record(s)
- Endpoint:
- vapour pressure
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 1998
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- EU Method A.4 (Vapour Pressure)
- Deviations:
- no
- GLP compliance:
- yes
- Type of method:
- effusion method: vapour pressure balance
- Temp.:
- 25 °C
- Vapour pressure:
- 0 Pa
- Transition / decomposition:
- no
- Conclusions:
- Boric acid was determined to have a vapour pressure of less than 0.000099 hPa at 25 °C, using a vapour pressure balance.
- Executive summary:
In a GLP-study the vapour pressure of the test item was determined according to EU method A.4 (effusion method: vapour pressure balance). The test item was determined to have a vapour pressure of less than 0.000099 hPa at 25 °C.
Reference
Essentially the vapour pressure of boric acid is negligible at ambient temperatures and water vapour starts to be evolved at above 100 °C because of partial decomposition.
No statistical analyses were performed because the balance readings were too low and variable for a line of best fit to have any meaning. Instead it was considered more appropriate to impose a regression slope on a chosen data point to provide an estimate of the maximum value for the vapour pressure at 25 ºC. Run 4 was chosen as the sample had been under vacuum for the longest period prior to this run and so degassing would have been the most complete. The reading at 148 ºC (421.15 K) was chosen because this is the datapoint which gives the highest estimated vapour pressure at any given temperature when a slope of -1500 K is imposed upon it.
The value of -1500 K is an in-house value and is the shallowest slope observed whilst determining the vapour pressure on a wide range of samples using the vapour pressure balance method. Extrapolation to 25 ºC gave a vapour pressure of 9.893 x 10-6 Pa which has been taken as a maximum value for this material.
The test material did not change in appearance under the conditions used in the determination.
The vapour pressure of boric acid was determined to be less than 9.9 x 10-6 Pa at 25 ºC.
Description of key information
In a GLP-study the vapour pressure of the test item was determined according to EU method A.4 (effusion method: vapour pressure balance). The test item was determined to have a vapour pressure of less than 0.000099 hPa at 25 °C.
Key value for chemical safety assessment
- Vapour pressure:
- 0 Pa
- at the temperature of:
- 25 °C
Additional information
Vapour pressure for CSA is below the stated value. 0.000099 hPa at 25 °C can be seen as worst-case value.
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