How can I lower the flash point of stearic acid (Palm Based Fatty Acids) [closed]








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I am trying to build a environmentally neutral firelighter that does not use petroleum based accelerant. I have found that the flash point is way to high to be viable in Stearic Acid (Hexadecanoic acid / Octadecanoic acid). Is it possible to have a "safe", "environmentally friendly" and biodegradable additive to lower the flash point? I am open to suggestions and alternatives. Any assistance in this is appreciated. 




could you have a small amount of a more volatile liquid with the hexadodecanoic acid - such as white spirit or kerosene? This would support a flame and raise the temperature to the point at which the hexadodecanoic acid acid will burn.


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What about a plant based terpene, maybe limonene? It has a flash point of 50 degree C and is very cheap (it's sometimes considered as a potential "green" solvent).


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Do you mean it is "too high"? ESL student? Setting aside your use of the word "safe", sure: use ethanol. It's conceivable that you do not know that "flash point" is a measure of a materials' safety with respect to fire. By definition, a material with a lower FP will be less safe than one with a higher FP (ceteris paribus). I'd suggest you study the history of the match, if you haven't already. You need to explain why a butane lighter isn't sufficiently "safe", "environmentally neutral" and "organic" (and dare we say "natural") for you. Same with safety and kitchen matches.  

In broad strokes, I can think of nothing which will be both exothermically reactive enough to work and be safe enough; adding a volatile to a non-volatile to make it more volatile seems to (obviously) fail the safety test. To initiate a flame, you need an (intense) energy source and a fuel. This reaction must (with 99.999% certainty) occur in the gas phase. Vapors are one possibility (the most efficient) the other is very, very finely divided powders. I can imagine a "firestarter" which uses a flint and a puff of powder to initiate the flame.
More specifically, it is only the rare azeotrope which will lower the minimum boiling point of the mixture below that of the lower boiling component. I doubt the difference will be enough to help you. Based on the chemical functional groups present, the slope of the vapor pressure vs temperature curves are indeed different. You want a steep curve, but you'd have to look into that correlation yourself. (You don't explain why you can't just enclose your "firestarter" to prevent evaporative losses...) One of the oldest "rules" in chemistry is "like dissolves like". In other words acetic or propionic acid might have significant solubility in stearic acid (but would be acid (corrosive to metals) and stinky, although mostly - imho - "non-toxic"). This type of mixture *might* be a way to lower FP. (or how about salts like ammonium acetate? (or other nitrogen bases) IDK...) Actually, flash point is a lousy way to quantify a compounds' fire properties. It is used because it is simple. Fire safety experts (which I am not) find measures of energy required to create a flame (*not* to sustain it) at a given temperature and (gas phase) composition much better. Because fuels provide the source of energy to sustain the flame reaction, it turns out that flame initiation it the process which requires the most energy input per molecule. Chemicals differ in the ease at which they start burning, at a given VP (of course, VP and Temperature are highly correlated in or near equilibrium, but that's not necessarily what you have when starting a fire). I'd look at it like this: 1. Find the most acceptable chemical with the lowest energy requirement at the temperatures the device "sparks" at. 2. find the most acceptable fuel to sustain that fire. (Note that here I mean sustaining for a second or two, long enough to start the "real" fire (or candle, etc.)). This implies that the first thing you need to do is locate a "environmentally neutral" source for your spark. (Do batteries meet your criteria? They wouldn't mine, how about ferrocerium or flint and steel? Or, what seems to be the "most" environmentally neutral energy source, a magnifying lens (only works when sun is shining, however.))


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