Bis-sec-butyl peroxydicarbonate

Vapour pressure

Administrative data

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Date: 28 July 2009

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2000

Report date:

2000

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Method 1:
In the first method, the DSC (differential scanning calorimeter) is applied. The pressure is measured accurately with an electronic micro membrane manometer. The vacuum DSC experiments were carried out at various controlled pressure levels.
Approximately 15 mg is weighed into a 70 micro litre aluminium cup with a pierced lid.
After reaching a constant pressure, the DSC temperature scan is started. The heating rate is 5°C/min. During this scan, the product will evaporate. A sudden increase in the endothermic heat flow is then obtained. This represents the initial boiling point of the mixture at the pre-set pressure. A condenser, cooled by CO2ice extrudates, captures the gases. After at least 4 DSC scans at different pressures, a plot is constructed with10log p (p: mbara) versus T(K), the Antoine plot of the product.
 
Method 2:
In the second method, a closed system is created. The headspace temperature of the system is set at the same value as the sample temperature. The system is equipped with a turbo molecular vacuum pump. This pump is additional to the 2-stage oil vacuum pump and is applied to give extra low initial pressure values. This pump is positioned in the line between the first pump and the flask.
Approximately 5 ml product is put into a clean, dry 500-ml flask. The flask is closed and the valve to the vacuum pumps is opened. The 2-stage vacuum pump is started. The dissolved gases are removed. When the substance gasses intensively, the boiling point is already reached. The temperature here, is lower then in the bath. The valve has to be closed and wait for constant temperature.
Again, the valve has to be opened. When the boiling point is reached again, immediately close the valve. If below 0.5 mbara still no boiling point is reached, the turbo molecular vacuum pump is started.
After reaching a constant value (boiling), the valve to the pumps is closed. The initial value p(initial), during the first few seconds, is close to the vapour pressure of the product. After closing the valve, the pressure rises slowly. This is partly the result of a small leakage. The leak-value determined is before, in an empty system and will be used later on for correction.
The decomposition products formed during the experiment will also contribute to the total pressure.

GLP compliance:

not specified

Type of method:

other: DSC method

Test material

Test material information

Constituent 1

Reference substance name:

Bis-sec-butyl peroxydicarbonate

EC Number:

243-424-3

EC Name:

Bis-sec-butyl peroxydicarbonate

Cas Number:

19910-65-7

Molecular formula:

C10H18O6

IUPAC Name:

2-[({[(butan-2-yloxy)carbonyl]peroxy}carbonyl)oxy]butane

Test material form:

liquid

Results and discussion

Vapour pressure

Vapour pressure 1

Key result

Test no.:

#1

Temp.:

10 °C

Vapour pressure:

< 0.051 mBar

Vapour pressure 2

Key result

Test no.:

#2

Temp.:

40 °C

Vapour pressure:

< 0.1 mBar

Any other information on results incl. tables

The test results of the closed system with a high sensitive pressure sensor (0.001-1.000 mbar range) are given in table 5.3. A turbo molecular vacuum pump was attached to the system.

 

Table 5.3          Vapour pressure experiments in 0.5 L-flask (~700 ml total)

product	temperature(°C)	p(mbara)
Tx SBP	10	<0.051

The maximum pressure values in table 5.3, column 3, are calculated as follows: p(max) = p(initial) * 1½

Where the real vapour pressure p ≤ p(max).

p(initial) is the pressure at which the vacuum system is closed. The vacuum pump is disconnected from the system.

The system is validated with dodecane. A relatively small difference between measurement and literature values for n-dodecane is found using method 2. Therefore, the factor 1½ is sufficient to set the upper vapour pressure limit.

 

After the introduction of the turbo molecular vacuum pump in the DSC method, lower pressures could be reached.

The system was not able to control the pressure accurately. While the pressure rises during the temperature scan, the pressure increased a little. However lower pressures were achieved, again, no boiling effect of the peroxides was observed. Only maximum values at certain temperatures can be given.

 Vapour pressure experiments with extended DSC method

product	temperature(°C)	p(mbara)
Tx SBP	40	<0.1

Applicant's summary and conclusion

Conclusions:

Vapour pressure data could be determined for most of the requested organic peroxides. As already known, the measurement of the vapour pressure of thermally very unstable peroxides is difficult to perform. This includes Trigonox SBP. Only the conclusion “ below 0.1 mbar ”or something like that, at a certain temperature can be given for these unstable organic peroxides.

Executive summary:

Vapour pressure data could be determined for most of the requested organic peroxides. As already known, the measurement of the vapour pressure of thermally very unstable peroxides is difficult to perform. This includes Trigonox SBP. Only the conclusion “ below 0.1 mbar ”or something like that, at a certain temperature can be given for these unstable organic peroxides. The vapour pressure data of the organic peroxides are given in the Table 5.4.

Table 5.4

product	temperature(°C)	p(mbara)
Tx SBP	40	<0.1