What’s the methanol/ethanol azeotrope? I can’t find it listed anywhere. Is it 50:50? Also, what's the boiling temperature?

Hard to say the ration.

Azeotropic mixture is supposed to be non-distillable. That is, if one tries to distill azeotropic mixture of methanol:ethanol at 64 C (methanol BP) the vapors will contain equal amounts of methanol and ethanol. Ethanol should boil at 78C, but even at 64C a good amount will evaporate, so it's not easy to separate them

There has to be a formula to calculate ratios, however in an methanol:ethanol azeotropic mixture I would assume much more ethanol than methanol. One could even go about and call it denatured ethanol or methylated spirit. Which makes sense, if a country is to allow methylated spirits on the market (= non-drinkable therefore non-taxable, cheap alcohol) they may as well make it more difficult for people to take the methanol out and make pure spirit.

I have tons of info on various azeotropes of ethanol and of methanol with other solvents, but none of them list the methanol/ethanol azeotrope.

SWIM has some denatured alcohol (Klean Strip brand). It’s 45-50% ethanol and 45-50% methanol, with the rest being methyl isobutyl ketone. SWIM didn’t know it was so high in methanol, he was assuming 95% ethanol and 5% other. He’s quite disappointed to find it’s nearly half methanol.

He was going to use this for a cactus extraction based on Poisson’s high yielding tech for San Pedro which uses ethanol in a Soxhlet for the initial extraction, but the methanol content is way too high and so it can’t be used. Nothing less than 90% ethanol should be used.

If SWIM distilled it, how much of the distillate would be ethanol? He’s hoping more than 50%, but can’t seem to find that information anywhere. He has a Vigreux distilling column that’s 400mm which should give better separation. He was hoping maybe in the ballpark of 90% ethanol?