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I am doing a University project on Magnetically Assisted Combustion and am curious to know more about how magnetic fields may or may not affect gases such as butane and propane.

I think I am right in saying that due to the gas molecules being covalently bonded, there are no free electrons to be influenced in anyway by an induced magnetic field.

Someone briefly mentioned something about that depending on whether they are saturated or unsaturated but the conversation didn't go any further as he then promptly left.. so I am still unsure.

If anyone could shed any light on this or has any thoughts at all I'd be very grateful for your input.

The method of some experiments I have done was attach a neodynium magnetic arrangement around the fuel line of a gas burner and measuring heat transfer to water. So far the results have been fairly inconclusive as I am using a camping stove which has problems sustaining a constant gas flow as well as a number of inconsistonsies with heat loss and human error etc .. but that's another issue.

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  • $\begingroup$ You question is not precise, a bit of clarification could be useful. Flame test is not 'pure' as flames typically contain charged species, definitely interacting with magnetic field. Anyway, hydrocarbons DO interact with magnetic fields, exhibiting diamagnetic behavior (see wikipedia://diamagnetism). Also in most atoms the nucleus has non-zero magnetic moment, also (typically very weakly) interacting with magnetic field (used in NMR spectroscopy). $\endgroup$ – permeakra Nov 29 '15 at 10:20
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Just because there are no unpaired electrons doesn't mean magnetic fields can't influence something. Unpaired electrons tend to lead to strong interactions with magnetic fields (the dioxygen in air has two and is paramagnetic, an effect best seen in the liquid phase where a magnet will attract the cold liquid).

But compounds with paired electrons also interact with magnetic fields, though the effects are usually weak. But the repulsive effect is sometimes strong enough to levitate a diamagnetic substance (see this youtube video showing how strong magnets can levitate plates of graphite which is strongly paramagnetic).

It is unlikely that such effects would be easy to see in gases. But you are talking about combustion and the most likely effect will not be on the neutral gas but on the flame where the gas is not neutral but a plasma of charged particles. Charged particles or molecules will have a much stronger interaction with a magnetic field though it might still require sensitive apparatus to detect how the field makes a difference.

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Effects of magnetic fields on combustion and gas-flow were studied. Methane, propane and hydrogen gases were burned, and flames of these gases were exposed to gradient magnetic fields up to 1.6 T and 220 T/m. Flames bent so as to escape from magnetic fields of higher intensities. Apart from the combustion experiments, flows of gases such as carbon dioxide and oxygen were exposed to magnetic fields up to 2.2 T and 300 T/m. The flows of these gases with a flow velocity 20-140 ml/min were blocked or modified by the magnetic fields. The changes of flame-shape and gas-flow by magnetic fields are understood to be the result of the role of oxygen. Under the intensities of magnetic fields concerned, oxygen gases as paramagnetic molecules are not concentrated but are aligned so as to make a "wall of oxygen". The wall of oxygen presses back flames and other gases.

Published in: Magnetics, IEEE Transactions on (Volume:23 , Issue: 5 ) might be a double post and certainly very late

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