Solvent Volatility

Run like hell...

Del is correct. You need oxygen for ignition, just like a candle wick burns by melting and vaporizing paraffin to burn.

Volatility has to do with the boiling point of the substance. The lower the boiling point the lower the flashpoint for ignition.

The problem with making a flat statement w/o qualifications.... Take for example carbon tetrachloride. It's BP is around 77 C. Butyl ether has a BP around 143 C. Which would you think would be the most flammable? Also, water will burn in Fluorine. Where's the oxygen? Then there are hypergolic mixtures, such as hydrazine and dinitrogen tetoxide that don't require an ignition source. Caution!! Don't play with these things unless you are thoroughly familiar with them!!

I think the argument circles around the definition of flash point, which I think is correctly used in my post.

From my link above, "The flash point of a volatile liquid is the lowest temperature at which it can vaporize to form an ignitable mixture in air."

Also, autoignition is a different phenomena than flash point. One requires no ignition source, the other does not preclude ignition, as defined above.

Agreed. I was extending the concept to include other avenues like ignition and the requirement for oxygen. In science, "oxidation" does not necessarily mean "reaction with oxygen", as you well know. We're on the same page.

There is flash point attached to every solvent. Flash point is auto sustainable ignition point. Based on ability of atmosphere to dilute a particular type of solvent and its easy to auto ignite under a flash ignition it will start burning.

All solvent will have flash point. High the molecular weight high carbon content and lower oxygen content will generally have higher flash point. Low carbon atom containing solvent will have lower flash point. Acetone will catch fire at lower vapor pressure than Isopropyl alcohol and examples are full in literature.

Masyood:

I dont quite understand about flash point. Do you mean it as "auto-ignition ability" of material (here is solvent). Does it have any connection with oxygen concentration?

Flash point is concentration of solvent vapor needed to produce flame but not have ability to have sustained burning of solvent. If you get above that concentration you will have sustainable burning of the solvent.

You can test out using equiopment which is available or develop your own test method if you are like me

Masywood:

Some corrections of your comments are needed. You wrote:

'Flash point is auto sustainable ignition point.'

Flash point and Auto ignition temperature are not the same. While, in rare cases, these might occur at the same temperature, they describe distinct qualities of a substance. Flash Point is the lowest temperature at which ignition can be initiated, while Auto Ignition Temperature is the lowest temperature at which ignition will occur without an obvious initiating event, (such as a spark).

'All solvent will have flash point.'

'Flash point' is a term used almost exclusively relating to flammable or combustible materials. The flashpoint of combustible materials generally does not exceed 200F. 100F is generally the limit for flammable.

Carbon tetrachloride is a solvent that has also been used to extinguish fires, describing a flashpoint of this non-flammable non-combustible material liquid seems a misuse of the concept.

My mistake and you are correct. This is typo. Flash point is nonsustained flame . Thanks you for correcting me

Chemical mistake could kill.