Cyclohexylidenebis[tert-butyl] peroxide

Vapour pressure

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

disregarded due to major methodological deficiencies

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Remarks:

The measurement was conducted above the SADT.

Qualifier:

equivalent or similar to guideline

Guideline:

other: ASTM E1782

Deviations:

not specified

Principles of method if other than guideline:

Measurement of vapour pressure with DSC ( Differential Scanning Calorimetry)

GLP compliance:

not specified

Type of method:

other: differential scanning calorimetry (DSC)

Key result

Temp.:

58.7 °C

Vapour pressure:

0.92 mBar

Remarks on result:

other: measured result, not calculated by Antoine fit or Clausius Clapeyron

Temp.:

65.6 °C

Vapour pressure:

1.33 mBar

Remarks on result:

other: measured result, not calculated by Antoine fit or Clausius Clapeyron

Temp.:

71.3 °C

Vapour pressure:

2.01 mBar

Remarks on result:

other: measured result, not calculated by Antoine fit or Clausius Clapeyron

Temp.:

78.5 °C

Vapour pressure:

2.98 mBar

Remarks on result:

other: measured result, not calculated by Antoine fit or Clausius Clapeyron

Temp.:

100.1 °C

Vapour pressure:

11.4 mBar

Remarks on result:

other: measured result, not calculated by Antoine fit or Clausius Clapeyron

Temp.:

25 °C

Vapour pressure:

12.3 Pa

Remarks on result:

other: Estimation of the vapour pressure using EUSES.

- The test substance vapour pressure was measured in the temperature range of 58 °C up to 100 °C. Extrapolation was carried out, showing that error increases drastically with too far extrapolation

- The measurements were performed at tempertaures that are far above the SADT of the test substance. Handeling the test substance at these temperatures while doing the DSC test was possible because very low amounts were used and the measurements were very fast.

Conclusions:

At temperatures between 58 °C to 100 °C vapour pressure between 0.92 to 11.4 mBar were measured for 1,1-bis(tert-butylperoxy)cyclohexane.

Executive summary:

The vapour pressure of 1,1-bis(tert-butylperoxy)cyclohexane, 82 % in isododecane, was measured at various temperatures with vaccum DSC. The temperature range of the method is limited. The lower pressure limit depends on the capacity of the vacuumpump (about 0.5 mbar), the lower temperature limit of the DSC-apparatus (25 °C) or by the melting point of the product. The upper limit depends on the thermal stability of the product.In the case 1,1-bis(tert-butylperoxy)cyclohexane the lower pressure is limited by the pumpcapacity.The vapour pressure of 1,1-bis(tert-butylperoxy)cyclohexane in the temperature range of 58 °C to 100 °C was measured although the temperatures were above the SADT. That was feasible in this DSC test as the amounts used were low and the measurements were very fast. At temperatures between 58 °C to 100 °C vapour pressure between 0.92 to 11.4 mBar was measured for 1,1-bis(tert-butylperoxy)cyclohexane. Extrapolation of the obtained results showed that the error in the pressure will increase at extrapolation.

Reference 2

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2020-03-12

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 104 (Vapour Pressure Curve)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.4 (Vapour Pressure)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

static method

Key result

Temp.:

20 °C

Vapour pressure:

399 Pa

Temp.:

25 °C

Vapour pressure:

488 Pa

n	Temperature T	Pressure p	Temperature T	1/T	log p
	°C	hPa	K	1/K	log Pa
1	20.0	4.1	293.15	0.00341122	2.6128
2	28.0	5.5	301.15	0.00332060	2.7404
3	36.1	7.3	309.25	0.00323363	2.8633
4	44.0	9.5	317.15	0.00315308	2.9777
5	51.9	12.8	325.05	0.00307645	3.1072
6	45.0	10.5	318.15	0.00314317	3.0212
7	37.0	8.1	310.15	0.00322425	2.9085
8	28.9	6.1	302.05	0.00331071	2.7853
9	21.0	3.9	294.15	0.00339963	2.5911
10	16.0	3.3	289.15	0.00345841	2.5198

 

Parameter	Value
Slope	-1536.607121
Intercept	7.842222637
Correlation coefficient r	-0.995809771
Coefficient of determination r^2	0.991637099

 

Parameter	Value	Unit
Vapour Pressure (20.0 °C)	399	Pa
Vapour Pressure (25.0 °C)	488	Pa

Conclusions:

The estimated vapour pressure of the test item at 25 °C is 488 Pa.

Executive summary:

The vapour pressure of test item was measured using the static method according to OECD 104 resp. EU A.4. Ten pairs temperature/vapour pressure were used to calculate a regression from which vapour pressure at ambient temperature could be estimated. The vapour pressure at 20 and 25 °C was determined to be 399 and 488 Pa, respectively.

Description of key information

The estimated vapour pressure of the test item at 25 °C is 488 Pa.

Key value for chemical safety assessment

Vapour pressure:

488 Pa

at the temperature of:

25 °C

Additional information

The vapour pressure of test item was measured using the static method according to OECD 104 resp. EU A.4. Ten pairs temperature/vapour pressure were used to calculate a regression from which vapour pressure at ambient temperature could be estimated. The vapour pressure at 20 and 25 °C was determined to be 399 and 488 Pa, respectively.

The study from 1996 was disregarded because the measurement was performed above the SADT of the sample. Therefore, the measured value is not representative for the test item. In comparison, the study from 2020 was performed with an improved method and according to relevant guidelines. Thus, the study from 2020 is seen as more reliable and used as key study.