Sciencemadness Discussion Board

Does denatured alcohol degrade over time?

Artemus Gordon - 3-1-2014 at 11:14

I've been using 91% isopropanol to fuel my alcohol lamp. I know that most refs. suggest hardware store denat. alco. I assume that it would have less water, so I expected it to burn better, but the flame is more orange, it makes little crackling noises, and when I compared both fuels' ability to heat 100 grams of water, the iso was 10 degrees hotter after 15 mins.
I bought 1 quart of Klean-Strip denat. alco. in a steel can and tried it within 2 days of purchase. However, the store I got it from is not a high volume store, so it probably sat on the shelf for several months.
MSDS says it is 45-50% EtOH, 45-50% MeOH and 1-4% Methyl Isobutyl Ketone. Is it possible it has degraded, or is this what I can always expect from this product?
P.S. I did try searching for this topic, but didn't find anything about possible degradation.

[Edited on 3-1-2014 by Artemus Gordon]

macckone - 3-1-2014 at 17:17

Quote: Originally posted by Artemus Gordon  

MSDS says it is 45-50% EtOH, 45-50% MeOH and 1-4% Methyl Isobutyl Ketone. Is it possible it has degraded, or is this what I can always expect from this product?


Ethanol contains less energy than isopropyl alcohol.
Methanol contains less energy than ethanol.

And it may also absorb water (which can cause problems).

I think that it is probably just the lower energy available though.

Artemus Gordon - 3-1-2014 at 17:54

Quote: Originally posted by macckone  


And it may also absorb water (which can cause problems).

I think that it is probably just the lower energy available though.


It does contain some water, i confirmed that with CoCl test strips, but I knew it would have some. The can seems airtight and in good condition, so I don't think it absorbed any extra beyond what it started with at the factory.
I guess I should just stick with my 91% Iso.
Thanks for the reply!