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Isopropyl?

Discussion in 'off topic' started by moffer, Mar 22, 2020.

  1. stevec67

    stevec67 pfm Member

    If you sanitize your hands you use maybe 5ml, the vast majority of which evaporates. Meths is about 90% ethanol, 5% methanol, 5% residual water. They codistil at that level. A pint of beer has 20ml of ethanol, you absorb it all. So we're comparing 0.25 ml methanol, minimally absorbed, with 20ml of ethanol alcohol that's actually ingested. As you say, make your choice. Choose your poison. And dose.
     
  2. guydarryl

    guydarryl pfm Member

    I think Methylated spirits is actually more like 10% Methanol.
    The way that ethanol is oxidised by the body results in the formation of acetic acid (found in vinegar), Methanol ultimately is converted to Formic acid (ant bites etc) which is not so easily tolerated by the body. Neither are "healthy' but never mind it is personal choice.
     
  3. sean99

    sean99 pfm Member

    On balance it’s probably healthier than a dose of covid19
     
    guydarryl likes this.
  4. guydarryl

    guydarryl pfm Member

    Choice is important, lets hope for immunity (although I think the body would have enough to deal with without continual doses of methanol ;))
     
  5. tqineil

    tqineil pfm Member

    Methylated spirt (meths) and methanol arevery different materials. Typically meths is 90+% ethanol and can't permeate the skin (methanol can and is sometimes an impurity added at low percentages to stop people drinking it)
     
  6. Alex S

    Alex S carbon based lifeform

    I know that perfectly well. I have a license to buy IMS and have a responsibility to know what it is. That is why I have consistently advised the use of bio ethanol for any diy sanitiser and not once advised meths. Any ingestion of methylated spirit would be more dangerous than ethanol.

    Sorry if the post was confusing. To be clear, I attempted to say ‘methylated’ - the addition of substance(s), usually methanol, to ‘spirit’ - ethanol = methylated spirit.

    I come into contact with IMS regularly and make it VERY clear to students that just because it is colourless (since it does not contain the dye of what is readily available) it is NOT for making homemade vodka.
     
  7. PaulMB

    PaulMB pfm Member

    If my memory is not playing tricks, around 1963 my model aeroplane's Diesel engine ran on a mixture of methanol, ether and castor oil. The smell was wonderful! And American dragsters ran on methanol, much more potent than petrol.
     
  8. stevec67

    stevec67 pfm Member

    Your memory is correct, I think. I had diesel and glowplug engines, they were methanol based with a LOT of castor oil for cooling and lubrication. Great things.
    Methanol isn't more potent than petrol, it actually contains less energy per gram or ml. You can find this in chemi stry data tables. The reason it is used in dragsters is that it will run a greater ignition advance before detonation occurs so the engine is less likely to explode at maximum power.
     
  9. PaulMB

    PaulMB pfm Member

    Yes, you are right! The quantity of castor oil was about 20%! The stink my poor parents had to put up with!
     
  10. stevec67

    stevec67 pfm Member

    At risk of this turning into a chemistry fest, I think that the reason meths contains methanol isn't that it is added but that it is a natural contaminant when it is manufactured by chemical means. This does make it unfit for consumption, the additives are there to stop people drinking it. Otherwise it would be relatively palatable and some people would consume it. Once you have a mixture of ethanol, methanol, and or water no amount of distillation will separate them, they form an azeotrope where the components co distill because their boiling points are similar, being 100, 78 and methanol I don't know, probably about 65C. This is why moonshine is dangerous, get the process wrong and it poisons you.
     
  11. stevec67

    stevec67 pfm Member

    It did stink! I was allowed to use mine in the garage, so no harm done. The neighbours used to love the noise of a 0.75c.f. 2 stroke engine running at 10,000 rpm without an exhaust, I'm sure.
     
  12. tqineil

    tqineil pfm Member

    Appreciate that, it’s separates when distilled over potassium carbonate - hence absolute alcohol at 99+% ethanol
     
  13. Joe

    Joe pfm Member

    I have a still.

    When distilling the vapours start to come over at around 50C, thats when I start the condenser. Between 50c and 79 c methanol distills out...it is easily detectable by taste (! ) and smell...it smells like nail polish remover..acetone .Distilling a run where I expect to get 5l of pure spirit from the wash I discard the first 250ml. Above 79c you're good to go and ethanol comes over in abundance .As the temperature of the vapour gets up to 93/94 c I look to finish the run even though what is coming over is still around 30 proof because the quality takes a dive after that. I imagine that with methylated spirit they just don't bother discarding the first part of the run. I suspect that you could re-distill meths to obtain just the ethanol from it .
     
    Alex S likes this.
  14. stevec67

    stevec67 pfm Member

    That's interesting, hence the discarding of toppings and tailings in spirit manufacture. In fact you can't redistil meths to remove the ethanol alone, that's the meaning of an azeotrope, or is it azeotropic mixture. The methanol co-distills with water and ethanol, hence why as someone else said you use chemical means to manufacture absolute alcohol.
     

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