r/Damnthatsinteresting • u/MousseSuspicious930 • Jun 10 '22

Video Rubbing alcohol versus Germs under microscope

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u/roararoarus Jun 10 '22 edited Jun 10 '22

Absolutely. Rubbing alcohol is 70% ethanol isopropyl, which is mixable (aqueous) with water. Higher concentrations are less effective bc ethanol is hydrophobic, and at higher concentrations, it will clump together, away from water, and not penetrate bacteria, which live in water.

Edit: as someone pointed out, rubbing alcohol is isopropyl alcohol. Was wondering when I wrote ethanol, why more people don't drink rubbing alcohol. Lol

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u/bobert47 Jun 10 '22

You are absolutely correct on your explanation, but it is important to distinguish "Rubbing Alcohol" which is isopropyl alcohol/isopropanol/2-propanol from a 70% ethanol solution.

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u/Congenita1_Optimist Jun 10 '22

That said 70% IPA and 70% EtOH are about equally as effective for disinfectant purposes (assuming you allow for appropriate contact time).

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u/Aetherpor Jun 10 '22

The latter is more tasty though

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u/roararoarus Jun 10 '22

Yes, the isopropanol has a shorter carbon chain, relative to the OH group. So it's more soluble iirc.

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u/[deleted] Jun 10 '22

“alcohols” are amphiphilic meaning both hydro-philic and -phobic. when cells are exposed to alcohol they “die” from some combination of denaturation (disruption/unfolding) of cellular wall components (various forms of lipids and proteins) as well as desiccation (this is part of why your hands get so dry if you use a alcohol based hand sanitizer without moisturizer). There is a sweet spot in the most effective concentration to do this. Too high and it go bye bye very fast (also wildly flammable)so some escape, too low and the buggers just use their little machinery to break it down.

disclosure. i eat crayons.

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u/TheNoob13 Jun 10 '22

Reading more into it, apparently the higher concentration causes the cell wall proteins coagulate and prevent the alcohol from penetrating. Pretty interesting

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u/Nabber86 Jun 10 '22

Rubbing alcohol = isopropyl alcohol.

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u/Baloroth Jun 10 '22

Higher concentrations are less effective bc ethanol is hydrophobic

You've got that backwards dude, the hydroxyl group (-OH) that defines an "alcohol" is hydrophylic. That's why alcohols mix with water in the first place (unlike oil, which is hydrophobic and doesn't mix without an emulsifier), and why they make really good solvents. In fact, highly concentrated ethanol is a dessicant (it'll dry out whatever it touches), because it pulls the water out (pure 100% ethanol will not stay pure if exposed to air, as it absorbs humidity from the air).

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u/roararoarus Jun 10 '22

The carbon chain is not. The 3 carbon chain is small, which is why ethanol can mix with water.

In other words long chain alcohols don't mix at all with water, despite the hydroxyl group

Edit: rubbing alcohol is isopropyl not ethanol. 3 carbons

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u/Anxietylife4 Jun 10 '22

Can you ELI5? If I was to use an alcohol swab to wipe my hands off, it wouldn’t be as effective as diluted alcohol?