Is 99% Glycerine the same as glycerol? Cheap source: Glycerol/99%alcohol
March 15, 2020 7:13 AM   Subscribe

The WHO recipe for hand sanitizer calls for glycerol 98%. I am having trouble finding glycerol, but I found 99% glycerine. After researching a bit, some sites say the only difference is purity. If the glycerine is 99%, is it actually glycerol? If not, does anyone have a good, fair priced source for glycerol? Also, does anyone have a cheap, reliable source for 99% gallons of alcohol? I am giving this away to my friends and neighbors so I don't want it to be too expensive to make.
posted by Studiogeek to Health & Fitness (12 answers total) 2 users marked this as a favorite
This chemistry forum may answer your question.

It sounds like, maybe - which doesn't help. Does the bottle of glycerol have more details on it?
posted by Toddles at 7:22 AM on March 15 [1 favorite]

I did not buy it yet but I'll see if the eBay add has a clear picture. That is a good idea. I also emailed the seller but did not receive an answer yet.
I will check that stack exchange site for sure.

Thanks Toddles!
posted by Studiogeek at 7:26 AM on March 15

It’s the same, for most purposes.

The word “glycerine” is often used for cosmetics and/or for less-than-100%-pure glycerol.

For a topical hand-rub, “glycerine” or “glycerol” is fine.
posted by chemicalsyntheticist at 9:05 AM on March 15 [2 favorites]

Gallons of alcohol are available at hardware stores.
posted by Kirth Gerson at 10:12 AM on March 15 [2 favorites]

But where to buy glycerine/glycerol?
posted by Rash at 10:16 AM on March 15 [1 favorite]

The glycerine/glycerol is really about the health of your hands (not drying them out) and not the effectiveness of the sanitizer.

As long as your overall percentage alcohol ends up in the sweet spot and you have some kind of bacterial inhibitor (eg hydrogen peroxide) the exact makeup and source of the glycerine/glycerol is the least critical part.

It can be bought from cooking suppliers, pharmacies, loads of places really. You may already have some in the house without knowing it. Many cosmetic products have it as a primary ingredient, many common in sexual lubricants for example are just water, glycerine, antibacterial agent and a fragrance. Lots of "gel" cosmetic products like tea tree gels have it as a base too. As its the minority ingredient (you really don't need or want much) a 24oz bottle of lube is probably the cheapest source in an average supermarket. But there will be a lot of water in there too, so be careful not to dilute you alcohol more than the recipe calls for.
posted by samworm at 11:33 AM on March 15 [1 favorite]

Denatured alcohol - the solvent alcohol in the paint section of the hardware store - is not safe / not as safe as isopropyl for skin contact. For your doorknobs or steering wheel, probably fine.

SDS for a popular brand of denatured alcohol
posted by Glomar response at 5:27 PM on March 15 [1 favorite]

Glomar response - YIKES! that SDS.

Ethyl alcohol 30.0 - 60.0 %
Methanol 30.0 - 60.0 %
Methyl isobutyl ketone 0.1%

Yeahsure the methanol should probably inactivate coronavirus (even more effectively than ethanol) but the ranges in composition: 30 - 60 percent!

This is typically done for "trade secrets" purposes, but also speaks to horrific inter-batch QC.

The methanol concentration here is pretty damn high. Enough that toxicity through skin-absorption is a serious problem, not to mention the inhalation of vapours.

Please don't make paint stripper into hand sanitizer.
posted by porpoise at 5:52 PM on March 15 [2 favorites]

Sorry, I misunderstood.

There are very many different types of denatured alcohol, with paint stripper being only one type.

Technically, isopropanol is "denatured" by law and statute (as in, non-potable).
posted by porpoise at 5:57 PM on March 15

Wikipedia just puts glycerol and glycerin in the same article. I think it's more of a common-use name vs technical-name sort of thing. The percentage purity in my understanding is more like alcohol's percentage. Glycerine (like alcohol) is hygroscopic and will suck moisture out of the air. So you can have 100% but as soon as you open it it goes down to 98% because it's now glycerol and a little bit of water. You just want food grade if you're going to use it in cooking or *ahem* personal lubrication.

It's also heavily used in the vaping community (it's the part that makes the clouds all cloudy) and in soap-making, and bubble-solution for giant bubbles.

You can get 5 gallons for ~$50 (USP,Food Grade,Kosher) from places like Vegetable Glycerin - Cheap USP Vegetable Glycerin | LNW or other vape/soap suppliers.

Really for hand sanitizer use, get whatever. It wouldn't need to be Food Grade or Kosher (made from vegetable vs animal source). You can also search Vegetable Glycerine (VG) which is what most of the vape/soap people call it.
posted by zengargoyle at 6:52 PM on March 15

Glycerin and glycerol are the same exact thing. They are two names for the same chemical compound, which consists of a 3 carbon chain with each carbon of the chain bearing one hydroxyl group. In your formulation for sanitizer it serves multiple purposes:

a) it will make it thicker
b) it will slow the evaporation of the alcohol (the effective ingredient)
c) it will slow the damaging and drying effects of the alcohol

I've been specifically vague about which alcohol you would have, namely because it doesn't matter much. Drinking alcohol (ethanol) will work as will rubbing alcohol (isopropanol) or even wood alcohol (methanol). Deatured alcohol (alcohol that would be toxic if consumed) would be cheapest to obtain in bulk,and as discussed above will result in a mix of alcohols, some of which might be toxic. I personally wouldn't worry about using hand sanitizer made from methanol as the absorption rate through skin is 8.1 +/- 3.7 mg cm-2 h-1 source. This means that for each square centimeter of skin you would absorb approximately 8.1 mg of methanol in an hour. Since the use of sanitizer is meant to be a very short term exposure (think seconds) then even though you have significant surface area on your hands this will still result in minimal exposure. The reference dose (safe dose) of methanol is 0.5 mg /kg /day. So a 100 kilo person can safely drink 50 milligrams of methanol. Unfortunately that is an oral dose and not a transdermal dose, so some ADME issues could remain unseen, but I'll go with the data at hand. Assuming 1000 square centimeters of surface area on the hand (probable overestimate) and 5 seconds of exposure (again an overestimate) you would get a "dose" of approximately 11 mg per use. This dose value also essentially assumes that you are somehow soaking in the sanitizer for 5 seconds rather than spreading a thin layer around over your skin. Compared to the reference acceptable long term dose of 50mg per day means that if you use the sanitizer 4 times a day you would be well under the limit. The 50 mg per day limit is also established using a safety margin, coupled with the notion that the antidote to methanol is ethanol I would happily use the "bad" denatured ethanol to wash my hands with no qualms about methanol toxicity.
posted by koolkat at 5:17 AM on March 16 [2 favorites]

Hardware stores also sell Isopropyl alcohol. It smells better than the other kind they sell. I found a largish bottle of 99% Aloe Vera gel at the local Family Dollar.
posted by Kirth Gerson at 8:54 AM on March 16

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