charley1957
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Yellow methanol
Several years ago I was given a gallon of methanol. It was used as a natural gas pipeline antifreeze and is supposedly 100% methanol. Lately I’ve
been thinking about an alkaloid extraction from a desert plant, and methanol seems to be the choice. My methanol is pale yellow. An internet search
told me that most impurities from the manufacture of methanol are ketones, aldehydes and ethanol. So I’ve started distilling my methanol and it
distills over at 63-64 degrees C. Its bp is 64.7 C. It is beautifully clear while the still pot gets more yellow as the process proceeds. I can’t
rule out the yellow color coming from the tank it was stored in, a basic steel tank. I’m leaning toward the yellow coming from the tank, but wanted
the input from those who are smarter than me. Do these other compounds cause a color change in methanol?
You can’t claim you drank all day if you didn’t start early in the morning.
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fx-991ex
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ive had a 5 gallon of methanol for cleaning pain gun and it was slighly yellow too.
Lower grade/cheap with impurity.
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bnull
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It may be a yellow azo dye, possibly a "Solvent Yellow" kind of dye. The 2015 revision of the MSDS for "Yellow Heet" (attachment) mentions methanol
and two "proprietary" components--traces of them, in fact--and I suppose that at least one is a yellow dye and the other is something to avoid human
consumption.
The 2019 revision removed the proprietary substances from the list, perhaps because one could use the LD50 values to identify the substances.
Attachment: Heet-Gasline-Antifreeze.pdf (459kB)
This file has been downloaded 137 times
Edit: I forgot to include the file. What an ass.
[Edited on 9-5-2024 by bnull]
Quod scripsi, scripsi.
B. N. Ull
P.S.: Did you know that we have a Library?
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charley1957
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When the distillation was all done, I took the remains from the still pot and vacuum filtered it. Nothing stayed on the filter, the remains were
still cloudy. Swirling the pot you could see some sort of yellow settlement on the bottom, maybe rust/dirt. Those amounts of proprietary substances
were really small percentages. Might very well have been a dye of some kind.
You can’t claim you drank all day if you didn’t start early in the morning.
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fx-991ex
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I dont think it was a dye, that methanol had a unusual odor/stink. it was definitely dirty.
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paulll
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Mood: It's fine. Really.
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Quote: Originally posted by charley1957  | | When the distillation was all done, I took the remains from the still pot and vacuum filtered it. Nothing stayed on the filter, the remains were
still cloudy. Swirling the pot you could see some sort of yellow settlement on the bottom, maybe rust/dirt. |
Maybe worth treating the crud with a bit of toluene or xylenes and see what it does?
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