The current COVID-19 situation has effectively shut down several countries, including Malaysia, South Korea and Italy. It has also caused a global shortage of surgical masks and hand sanitisers. Most of us have heard that hand sanitisers containing at least 70% alcohol can keep our hands clean. Because of this, many people started to make DIY alcohol-based hand sanitisers. Soon after, there was a shortage of industrial-grade alcohol too. Is alcohol really the solution to this whole pandemic situation?
Alcohol is found in many things – from alcoholic beverages, hand sanitisers to mouth wash. But what is alcohol exactly and is there a difference between the alcohol we drink versus that which we use to sanitise things?
In chemistry, alcohols are a group of organic compounds with –OH group, also known as the hydroxyl group. This hydroxyl group is attached to a carbon atom that usually belongs to a long chain of carbon atoms. How long the chain is, and whether it is straight or branched, will determine what type of alcohol it is. Ask any chemist, they will tell you that alcohol IS a solution. But is it THE solution?
Generally, alcohol that is used in alcoholic beverages such as beer or cider is produced by a process called fermentation. Alcohol that is used for medicinal or industrial purposes is produced using different methods.
Let’s take a look at the 3 most commonly found alcohols: methanol, ethanol and propanol.
Methanol is also known as “wood alcohol” since it was once produced by destructive distillation of wood. Just like ethanol and propanol, methanol is liquid at room temperature, transparent, highly volatile and highly soluble in water. It is also highly flammable. Methanol is used industrially as a precursor to synthesise other chemicals.
Unlike ethanol, methanol is highly toxic to the human body. This danger is amplified because methanol is often consumed unknowingly in large quantities alongside ethanol. Legitimate alcoholic beverage producers distil their product, often multiple times, to remove as much methanol from the beverage as possible. Bootleg alcohol producers, on the other hand, usually do not do this properly or may even skip this step altogether. This renders bootleg alcohol beverages (i.e. moonshine) highly unsafe for consumption.
In the human body, methanol is broken down into formaldehyde and formic acid. To put it in perspective, formaldehyde is used to preserve dead bodies and formic acid is found in bee stings. These two chemicals can also destroy your optic nerves. As little as 10 ml of pure methanol can cause permanent blindness. If you drink methanol, you will quite literally drink yourself blind.
Interestingly, the cure for accidental (or intentional) methanol poisoning is by competitive inhibition using ethanol. That is, drinking the good ol’ standard alcohol until your body is too busy dealing with ethanol that it forgets to metabolise the methanol and gets removed by the kidneys. Talk about fighting fire with fire.
In our everyday context, the word “alcohol” refers to ethanol. Ethanol is found mostly in alcoholic beverages. Different alcoholic beverages contain different percentages of alcohol by volume (ABV). Beer, for example, typically contains up to 10% ABV. Wine is usually around 15%. Hard liquors such as whisky (40% ABV) and absinthe (70% ABV) contain a lot more alcohol. Certain types of vodka can contain up to 95% ABV, making it the most potent commercially-available spirit in the world. Drinking it neat will absolutely get you smashed. After all, people always say that alcohol does not give you the solution, it just makes you forget the problem!
Ethanol-based mouthwash used to be very popular before the alcohol-free alternative came about. Ethanol is highly effective in killing germs in our mouths, but it also gives us a burning sensation within seconds of gargling it. In your mouth, there is a signal receptor called VR1. Hot food triggers the VR1 receptors, which relays the signal to our brain, resulting in a burning sensation. These receptors activate at around 42°C. However, when they are in contact with ethanol, the activation temperature is lowered to just 33°C. Given that our body’s average temperature is around 37°C, this produces a burning sensation.
In medical applications, ethanol is very commonly used as the main ingredient in hand sanitisers. Sanitisers containing at least 70% ethanol by volume is found to be effective in killing many different types of bacteria, including antibiotic-resistant bacteria and tuberculosis-causing bacteria. Sanitisers containing 90% ethanol can kill many kinds of viruses, including the flu virus, common cold virus and HIV. However, it is notably ineffective against the rabies virus. Due to its efficacy, the World Health Organization placed alcohol-based sanitisers in its list of essential medicines.
When it comes to curbing the spread of COVID-19, alcohol-based sanitisers definitely help, as long as the alcohol content is high enough. But you know what else helps? Washing your hands properly with soap and not touching your face with your grubby mittens!
In terms of getting you drunk, 1-propanol (also known as n-propanol) is around 4 times more potent than ethanol. The toxic dose of 1-propanol is also 4 times less than that of ethanol. But don’t go drinking 1-propanol just yet! Commercially available 1-propanol is made by synthesis using heavy metal catalysts. Drinking this stuff might not only get you drunk, it might also give you heavy metal poisoning!
Like ethanol and 1-propanol, 2-propanol (also known as isopropanol) is also a central nervous system depressant. Will it get you smashed? Absolutely. Is it safe to drink then? Well, here’s the kicker. We don’t exactly know how much 2-propanol is safe to drink. But we do know this: 2-propanol will be metabolised into acetone – the main ingredient of nail polish remover. So, within 20 minutes of drinking it, your breath will smell like nail polish remover! So, if that’s your thing, you do you! But don’t forget that it is detrimental to your liver and kidneys too, just like any other alcohol.
Commercially, 2-propanol is commonly used in medicine and cosmetics. Unlike ethanol, 2-propanol is less drying to the skin, which makes it the preferred choice for cosmetic ingredients. A solution of 75% 2-propanol can also be used as hand sanitiser.
So, is alcohol the solution? You should have the solution to that question now!
Written by Ferry Kurniawan
Illustrations by Toh Bee Suan