If you want to quantity how an atomized liquid fuel resists self-ignition then a scale with one pure liquid fuel on the one end and a different pure liquid fuel on the other seems a reasonable way to go. The choice of those standard fuels is more or less arbitrary, though you do want the range between to cover the fuels and fuel mixtures that you are interested in classifying.dRic2 said:I'm sorry, may fault. Let me rephrase my question: Why is a mixture of n-heptane and iso-octane chosen to be the reference to establish the tendency of a fuel to resist self-ignition? Why n-heptane and not other substances ?
High purity n-heptane was readily available when the heptane/octane rating system was conceived.dRic2 said:Why n-heptane and not other substances ?
[joke]And resublimated thiotimoline is finicky when dissolved in iso-octane.[/joke]Asymptotic said:High purity n-heptane was readily available when the heptane/octane rating system was conceived.
You can Google for "The Endochronic Properties of Resublimated Thiotimoline". It is an article written by some guy named Azimuth or @asymptotic or something in the 40's.dRic2 said:I don't understand
n-heptane (C7) and iso-octane (C8) are both in the mix of what constitutes gasoline (C4 through C9). A major difference between the two is n-heptane has a straight chain structure while iso-octane is branched, and it turns out that straight chain HCs are more prone to causing detonation. You'd have to research this further, but my suspicion is these things in combination make n-heptane and iso-octane good proxies for how much 'knock' to expect from a particular gasoline formulation.dRic2 said:Ok so I guess it's just an arbitrary decision based upon historical circumstances, there is not a scientific explanation for this.
Asymptotic said:You'd have to research this further
Asymptotic said:it turns out that straight chain HCs are more prone to causing detonation.
N-heptane is a colorless, flammable liquid hydrocarbon compound that is commonly used as a reference fuel for octane ratings. It is important to understand its explosive properties because it is a common ingredient in fuels and solvents, and knowledge of its behavior can help prevent accidents and ensure safety in handling and storage.
N-heptane is inherently flammable and has a relatively low flash point, meaning it can ignite easily at certain temperatures. However, for it to be considered truly explosive, it must be mixed with air in specific concentrations and exposed to a source of ignition, such as a spark or flame.
N-heptane has a similar explosive potential to other hydrocarbon fuels, such as gasoline and diesel. However, its flash point is slightly lower, making it slightly more volatile and potentially more dangerous in certain circumstances.
Yes, n-heptane can be made less explosive by blending it with other compounds, such as ethanol or isooctane, which can increase its flash point and reduce its volatility. It can also be made more stable by adding stabilizers or inhibitors to prevent chemical reactions that could lead to explosions.
When handling n-heptane, it is important to wear protective gear, such as gloves and goggles, to prevent contact with skin and eyes. It should also be stored in a cool, well-ventilated area away from sources of ignition. Proper labeling and handling procedures should also be followed to avoid accidents. In case of a spill or fire, appropriate measures should be taken, such as using absorbent materials and fire extinguishers, and seeking medical attention if necessary.