Advice requested - alcohol combustion chemistry

[Dave H]

Today I visited a friend in his shop. He uses direct heat for wood bending, with a nifty little alcohol burner. But he thinks there is some unhealthy chemistry to alcohol combustion. I love my unpressurized alcohol stove aboard "Sandpiper" for cooking. Can anyone please advise about the chemistry of alcohol combustion? I have always tried to ventilate as much as possible while cooking, as a general practice. I purchase my alcohol in the Home Depot paint section. The product label indicates "for use with Marine Stoves."
Thanks.
Dave

[Tom Keevil]

2 C2H6O + 7 O2 ---> 4 CO2 + 6 H2O

As long as there is enough oxygen available, all you get is carbon dioxide and water. Propane produces the same products.

2 C3H8 + 10 O2 ---> 6 CO2 + 8 H2O

Alcohol (ethanol) produces less heat, since it already has an oxygen atom in it's molecular structure. Depending upon how you operate your stove, you may cause some of the alcohol to evaporate before it burns, and that causes the odor you may associate with the stove. The alcohol you buy for stove use (as opposed to drinking) has been denatured by the addition of toxic materials, so breathing these vapors in a high concentration for a long time is probably not good for your health. The denaturing agents also burn to form carbon dioxide and water.

If I were exposed to high concentrations of denatured alcohol vapors as a routine part of my job, I might be a bit concerned. The occasional exposure from my Origo stove is no big deal.

[Dave H]

Thanks Tom.
Dave

[tartansailor]

The denaturants in ethanol vary from cinnamon oil to gasoline.
Although not the same BTU's as ethanol, my choice would be
5 gallons of methanol from a chemical supply store.
Same oxidation products as above but cleaner.
Dick

[Dave H]

Thanks Dick.
Dave

[Tom Keevil]

Methanol, sometimes called wood alcohol, is definitely a toxic substance. Drinking it causes blindness. Ethanol is metabolized to acetate, which can be used as an energy source by cells. Methanol is metabolized to formate, which causes all kinds of cellular problems.

Your body can deal with occasional exposure to small quantities of methanol, and it does burn cleanly to carbon dioxide and water, but it is clearly a toxic addition to ethanol. It is also more volatile than ethanol.

In British Columbia, you cannot buy denatured ethanol, and people use methanol (known as methyl hydrate) for stove fuel. I much prefer to bring ethanol with us from the states to avoid the methanol exposure.