Alcohol Based Instant Hand Sanitizers Separation

As a parent you see your kids use that instant hand sanitizer on a regular basis. They use it at school, or the petting zoo, anywhere where water is not readily available. It is convenient when you are out somewhere, especially since it is waterless, and does not require any rinsing. The base used for the sterilization process is alcohol. Sometimes it is Isopropyl Alcohol, and sometimes it is Ethanol. It generally contains 50-65% of whichever alcohol is used for sterilization. Recently, I was joking around at work that I am afraid if I get pulled over in my car (where I have a bottle of the ethanol based hand sanitizer) that a cop will mistake it, for me drinking and driving. This would make sense that since the alcohol in beer/wine/liquor is ethanol; the very same compound in the sanitizing gel. This conversation moved onto to someone claiming that you can add salt to the gel and fraction off the alcohol; they also claimed it is one of the many techniques prisoners use to get drinkable alcohol. This idea in my mind was worth entertaining, since I'm sure everyone has got that e-mail claiming somebody's child ate the hand sanitizer and ended up in the emergency room for alcohol poisoning.

I did an Internet search to see what I could find about its validity. Surprisingly (or not surprisingly depending on your skepticism), I did not see any verification of this process. Not wanting to drop the idea, when I got home I planned out an experiment, and included my kids in the project. I explained what I was doing and what should happen. They waited by anxious to see what was actually going to happen (because lets face it, things do not always work as planned).

I filled a test tube about half full with the sanitizer, and showed them how thick it was. I added about a teaspoon of table salt, capped the tube and shook it vigorously. We set it up and let it settle out. Just by looking at it, you could tell that it worked. The layer on the top was definitely thinner, and behaved more like alcohol than the gel. I showed the kids how the viscosity of the liquid changed, and how the top layer looked more water like. I opened the cap, and smell of ethanol was more than present. At that point they were done, because they did not like the smell of the alcohol. Now, let me state a very important fact, YOU CANNOT DRINK THIS! Amongst the alcohol, there is also Isopropyl Alcohol (Rubbing Alcohol), which will make you extremely ill if consumed. Not to mention anything else in the formulation that is soluble in ethanol.

So scientifically, what happened? These sanitizers are formulated with carbomer as the polymerizing agent (thickener). Carbomer is usually utilized when producing alcoholic gels, which of course these are. Carbomers swell at a specified pH, which causes the liquid (alcohol) to get thicker. When the salt is added, it reacts with the carbomer, and binds to it. Since the salt crystals are big and heavy they sink to the bottom, with the carbomer attached, releasing everything that was bound to it. So, with the carbomer on the bottom, the alcohol is free to float to the top, producing the two layers. It is a pretty cool reaction, but I am going to say this again, YOU CANNOT DRINK THIS. Just because somebody claims to do this in prison, does not mean it is acceptable in regular society. It will cause more harm than to you than just an alcohol buzz. The human body can not break down isopropyl alcohol, so it will make you very sick.

Anyways, just thought I would share the potential science project.