Ethanol (Alcohol) 75% and isopropyl alcohol (75%) - any difference?

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I was buying and studying the label on a bottle of alcohol spray and a bottle of liquid alcohol. Their ingredients were Ethanol(Alcohol) 75% and isopropyl alcohol(75%) respectively. Is there any difference?
 

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  • #2
BvU
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They are different chemical compounds !
 
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Isopropyl alcohol is a C3 carbon chain with an -OH placed on the 2nd carbon. Ethanol is a C2 carbon chain with an -OH placed on the 1st carbon.

Technically ethanol is less toxic than isopropyl alcohol, but unless you plan on drinking it (don't), it shouldn't make a difference.
 
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  • #4
jrmichler
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You can get good information on relative safety by comparing the safety data sheets. Search terms safety data sheet ethanol finds (among others) this for ethanol at 25% concentration: https://www-s.nist.gov/m-srmors/msds/2899A-MSDS.pdf. The toxicological information section is quite interesting. Be careful when searching SDS sheets for ethanol - many of the data sheets are for denatured ethanol, which has poison added. And search terms safety data sheet isopropyl alcohol 70 finds this (among others): https://fscimage.fishersci.com/msds/89530.htm.
 
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dextercioby
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I was buying and studying the label on a bottle of alcohol spray and a bottle of liquid alcohol. Their ingredients were Ethanol(Alcohol) 75% and isopropyl alcohol(75%) respectively. Is there any difference?
One uses isopropylic alcohol for disinfectant gels (like the ones we use now with the pesky virus around), in order to prevent idiots from drinking it. The „technical name” for it is „denaturated alcohol”.
 
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The rate of evaporation of isopropyl alcohol will be slower
 
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DaveE
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yes.
 
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f95toli
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One uses isopropylic alcohol for disinfectant gels (like the ones we use now with the pesky virus around), in order to prevent idiots from drinking it. The „technical name” for it is „denaturated alcohol”.
I don't believe that is correct.
As far as I know. "denaturated" just means that some extra chemicals have been added to prevent you from drinking the alcohol and -in some cases- induce vomiting. The actual "alcohol" can indeed be IPA but it can also be methanol or ethanol (or a mix of both).
Irrespective of the actual content, It is NOT something you can drink.
 
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  • #9
tech99
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Methanol is extremely toxic and I don't think it is added to these products.
 
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hutchphd
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Methanol is extremely toxic and I don't think it is added to these products.
It is denatured to avoid consumption by humans. Often methanol is used because it is cheap and the taxman didn't really care about your health.
Until the advent of federal income tax, the tax on beverage alcohol was a major source funds to the federal government in the US.
 
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marcusl
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Denatured alcohol, of the type used in wood finishing and alcohol stoves, is ethanol that is denatured with compounds to make it undrinkable. The denaturing agent is often methanol but also sometimes something really nasty—check out the sds for this brand, for instance
Jasco
Rubbing alcohol is just 70% isopropanol in water.
 
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Astronuc
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Ethanol(Alcohol) 75% and isopropyl alcohol(75%)
Ethanol, C2H5OH is a lighter molecule, than propanol C3H7OH. The lighter molecule is more volatile. Ethanol is less toxic to mammals than propanol. I presume both mixtures are 'denatured' as dextercioby mentioned.

I don't know what the other liquids would be, but perhaps some water. I have seen mixtures of ethanol and propanol. I have a first aid antiseptic (ethyl rubbing alcohol) that is 70% ethanol, and other 'inactive' ingredients: acetone, denatonium benzoate, methy isobutyl ketone, and water. It is NOT for human consumption, but topical use only. I've also used alcohol solutions that were 70% propanol (+30% water), and otherwise. Some denatured alcohols have used methanol, which is toxic, to 'denature' the alcohol. I don't believe that is the case anymore.

An example of 70% propanol solution
https://www.amazon.com/dp/B002M3JBH6/?tag=pfamazon01-20

I also have 99% propanol.

For antiseptic purposes, see
https://www.cdc.gov/infectioncontrol/guidelines/disinfection/disinfection-methods/chemical.html
 
  • #13
marcusl
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Ethanol denatured with methanol is commonly available at hardware stores from brands like Klean Strip and Sunnyside.
 
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Many compounds such as 'simple' sugars are much less soluble in ~70% IPA than in eg ~70% EtOH. I've used this to isolate the trace of antiseptic in sugary throat lozenges, the hard, coin-shaped variety. Adding 'neat' IPA to a lozenge dissolved in eg 10ml dilute acetic acid precipitates the sugar. Gotcha is it 'comes out' as milky as diluted anisette / ouzo / arak, but crystallises clean if stood in dark overnight...
 
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I used to manage a plant that made isopropyl alcohol (IPA) or isopropyl to give it its more up to date name. Then I moved on to market IPA along ewith other solvents. IPA has many uses in pharmaceuticals, cosmetics, paints and adhesives. It is also used as windscreen de-icer and in very large quantities as aircraft de-icer owing to it's freezing point depressant property when mixed with water. It is converted to it's ketone derivative, di methyl ketone (acetone) by dehydrogenation.
 
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  • #16
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Yes, all of these are toxic.
For reference:
Methanol is a single carbon with one -OH
Ethanol is two carbons with on -OH
n-Propanol is three carbons with one -OH at one end
Isopropanol is three carbons with one -OH in the middle
n-Butanol is 4 carbons with one -OH at one end
Isobutanol is 4 carbons with one -OH somewhere in the middle usually a second carbon from an end.
This can go on to many carbons with all sorts of branching.

Each has its own lethal dose for 50% of the population of test subjects (mice, dogs, ...). That is called the LD-50.
The non-lethal doses also have damaging effects. Methanol is blindness, butyl alcohol is deafness. Some countries allow alcoholic drinks to be fortified with method - living on the edge.

IPA can be found in drug stores as 50%, 70% and 91%. CDC recommend the final concentration of IPA for cleaning surfaces (skin on hands) be 70%. These means to make these disinfectants, you must start with something more concentrated than 70% so when it is diluted with other compounds, the final result is at least 70%.

The world is wonderous, fun and dangerous. Be aware. Live all you can so you can make the most...
 
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rayj said:
Some countries allow alcoholic drinks to be fortified with method - living on the edge.
What does "fortified with method" mean here? Isn't a fortified wine simply one that has had wine distillate added to it? Is that what you mean?
 
  • #18
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sysprog,

Thank you. Yes, you are correct. And I meant to spell methanol, not method.

Traditionally, wine is fortified with other distillates. The US only allows wines to be fortified with distillates of fruits. But other countries allow some amount of methanol to be added (it is cheaper) - but may have harsh side-effects.
 
  • #19
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sysprog,

Thank you. Yes, you are correct. And I meant to spell methanol, not method.

Traditionally, wine is fortified with other distillates. The US only allows wines to be fortified with distillates of fruits. But other countries allow some amount of methanol to be added (it is cheaper) - but may have harsh side-effects.
Are you sure? Methanol is far too toxic. Can you cite a source for this?
 
  • #20
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sysprog,

Thank you for holding fast. Methanol was not regulated in Italy until 1985 due to 20 deaths and dozens hospitalizations at that time. While methanol was a 'natural' product in making grappa, the levels were low. Methanol was added by some due to the masking affect of poorer quality production. After this intense occurrence, it was outlawed and the distillers were required to separate off the 'natural' methanol product before sale.
http://www.expo2015.org/magazine/en/economy/methanol-wine---we-learned-our-lesson-.html
 
  • #21
hutchphd
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It is my understanding that there are usually some organisms present that will convert pectin to methanol in any typical natural fermentation.
For spirits batch distilled from a such a mash it is common practice to discard the first few percent of the run because vapor pressure of methanol is high (its boiling point is lower). And I know this all only from books....

\
 
  • #22
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@rayj: It seems to me that the story to which you provided a link does not establish that "other countries allow some amount of methanol to be added", and explicitly states that Italy stopped allowing that in the '80s ##-## I think that we can agree that it should have been disallowed much earlier.
 
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IIRC, 'Moonshiners' who shun thermometers and barometers have problem that distillation temperatures vary with pressure. There's not a lot of difference with weather, unless fool enough to work through a hurricane's 'Deep Low', but relocating still up/down mountain to avoid detection could skew discard of early, methanol-rich distillate, the toxic fraction...
 

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