1,1,2,3,4,4-hexafluorobuta-1,3-diene

Additional physico-chemical information

Administrative data

Endpoint:

other: decomposition

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Reference

Endpoint:

auto-ignition temperature (gases)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Reason / purpose for cross-reference:

reference to same study

Principles of method if other than guideline:

The determination of autoignition temperature at 6 bar have been performed.

GLP compliance:

not specified

Key result

Remarks on result:

other: No autoignition tempererature have been measured at 6 bar up to 500°C

The criterion for autoignition was sudden temperature and pressure increase.

During the screening test up to 500°C a sudden decomposition was not observed. At temperatures of more than 450°C a moderate pressure decrease was found. Maybe, this is caused by a slow decomposition or cracking reaction.

Additionnal test were performed at a maximum temperature of 500°C, no autoignition reaction was observed. So the autoignition at 6 bar is above 500°C.

Conclusions:

The autoignition temperature of the test substance is higher than 500°C at 6 bar.

Executive summary:

The autoignition of the test substance was performed according to a method which meets generally accepted scientific principles and was well documented.

The test substance was put into a heated flask (100°C), then the temperature of the flask is increased. Pressure and temperature of the flask were measured. A sudden increase of these two parameters is the criterion for autoignition of the test substance.

The autoignition temperature of the test substance is higher than 500°C at 6 bar.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

In order to determine the explosion behaviour of the test item without any oxidizer (like oxygen and air), the following test were performed:
- determination of the limiting pressure for decomposition in gasesous phase at 50°C
- determination of explosion parameters in gaseous phase at 50°C

Test material

Test material information

1

Reference substance name:

1,1,2,3,4,4-hexafluorobuta-1,3-diene

EC Number:

211-681-0

EC Name:

1,1,2,3,4,4-hexafluorobuta-1,3-diene

Cas Number:

685-63-2

Molecular formula:

C4F6

IUPAC Name:

hexafluorobuta-1,3-diene

Test material form:

gas

Results and discussion

Results:

The limiting pressure at 50°C is 1.8 bar. The calculated limited pressure at 22°C is 2 bar.

The explosion pressure and maximum pressure are respectively: 32.65 bar, 104.9 bar/s at 50°C and 48.68 bar, 196.1 bar/s at 60°C.

At 70 bar, the maximum temperature of liquid was 118°C. The liquid phase did not decompose.
At 250 bar, the maximum temperature of liquid is higher than 1 000°C. The complete mass of the test item decomposed.

Any other information on results incl. tables

Results for limiting pressure for decomposition (pl):

The test was carried out with an ignition energy of 60 - 80 Ws. The criterion for a dangerous decomposition reaction was a pressure rise after ignition of more than 20%.

The limiting pressure (pl) at which at 50°C no run-away decomposition reaction in gaseous phase occurs is 1.8 bar (abs). At this initial pressure 2 check tests were carried out. The limiting decomposition pressure corresponds to an equilibrium temperature of 22°C have been calculated. The value obtained in: 2 bar (abs)

Results of explosion parameters in gaseous phase:

The explosion pressure and the maximum pressure rise were measured in each 3 ignition trials at 3.0 bars and 4.5 bar. The 3 tests at 4.5 bar had to carry out at a temperature of 60°C.

The ignition energy was 75 - 95 Ws.

Test	Temperature (°C)	Initial pressure (bar)	Explosion pressure (bar)	maximum pressure rise (bar/s)
1	50	2.98	31.93	64.5
2	50	3.00	32.65	104.9
3	50	3.00	31.80	53.8
4	60	4.46	48.68	196.1
5	60	4.49	49.32	127.2
6	60	4.52	48.74	100.4

For safety aspects the worst case results (bold numbers) should be used to design explosion protectop, devices.

Results for explosion parameters with 20 vol% of additional liquid phase

3 tests were carried out in a heated autoclave at 50°C. The ignition energy was 75 - 80Ws. The measured equilibrium pressure was 4.8 bar (abs).

At 70 and 250 bar, the pressure increased moderate during the first two seconds. Then it accelerated strongly. In case of 70 bar, the maximum temperature of liquid phase was 118°C and then decreased. The liquid phase did not decompose.

At 250 bar, the temperature increased rapidly and the two thermocouples (used to determine the temperature inside the test vessel) were destroyed. At this time, the pressure and temperature inside the vessel were in an supercritical state and the complete mass of the test item decomposed. A fast decomposition reaction of liquid phase at lower temperature, similar to an explosive, was not observed.