Fluoromethane

Auto flammability

Administrative data

Endpoint:

auto-ignition temperature (gases)

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Justification for type of information:

1. HYPOTHESIS FOR THE CATEGORY APPROACH
The hypothesis is proposed that the autoignition temperature of fluoromethane (target substance) lies between the autoignition temperature of methane and difluoromethane (source substances).
Target and source substances have in common that they are none-, mono- and disubstituted fluoro-methanes.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
a. Target substance
The target substance fluoromethane is a mono-constituent substance (EC No 209-796-6/CAS No 593-53-3/fluoromethane). The typical concentration of the constituent is <99 % (w/w). The substance does not contain any impurities that affect the classification.

b. Source substance
The source substances are

-methane, a mono-constituent substance (EC No 200-812-7/CAS No 74-82-8/methane). The typical concentration of the constituent is <99 % (w/w). The substance does not contain any impurities that affect the classification.

and

-difluoromethane, a mono-constituent substance (EC No 200-839-4/CAS No 75-10-5/difluoromethane). The typical concentration of the constituent is <99 % (w/w). The substance does not contain any impurities that affect the classification.

c. Purity and impurities
The source and target substances are characterized by similar purities (>99 % (w/w)). Target and source substances do not contain any known impurities that are classified for any hazard and are not considered as hazardous for the chemical safety assessment of the target and source substances.

3. CATEGORY APPROACH JUSTIFICATION
The basic structures of the target and source substances follows this pattern:
(unsubstituted) methan, mono fluoro-substituted methan, difluoro-substituted methan (CH4, CH3F, CH2F2).
Experimental data shows that the auto-ignition temperatures of fluorosubstituted methanes and ethanes follow a clear pattern as outlined in the two data matrices and as summarized below:

Experimental autoignition temperatures:

Ethane > Fluoroethane >=1,1-Difluoroethane
472 °C > 455 °C >=455 °C


Methane > Difluoromethane
537 °C > 530 °C

The autoignition temperature of the fluoro-hydrocarbon decreases with increasing substitution with fluorine. The autoignition temperature of fluoroethane and 1,1-difluoroethane is identical.

4. DATA MATRIX

The data matrices contain the auto-ignition temperatures of fluorosubstituted hydrocarbons as described in section 3.

5. CONCLUSION
From the experimental pattern of fluorosubstituted hydrocarbons is can be concluded that the autoignition temperature of the target substance (Fluoromethane) lies between the autoignition temperatures of the two source substances, methane and difluoromethane:

Methane > Fluoromethane >=Difluoromethane
537 °C > Autoignition temp. of target substance >=530 °C

Materials and methods

Test material

Test material information

Constituent 1

Reference substance name:

Fluoromethane

EC Number:

209-796-6

EC Name:

Fluoromethane

Cas Number:

593-53-3

Molecular formula:

CH3F

IUPAC Name:

fluoromethane

Test material form:

gas

Results and discussion

Auto-ignition temperature (liquids / gases)

Auto-ignition temperature:

>= 530 - <= 537 °C

Atm. press.:

ca. 1 atm