Phabulous phenol

I was thinking about phenol the other day. “Very interesting,” I hear you say, “now if you don’t mind I’ve got a fascinating patch of drying paint I need to keep an eye on.” But wait! Bear with me. Phenol is a very interesting molecule. It’s history has a little something for everyone, from lawyers to doctors to advertising copywriters. There are gruesome tales from history, legal wrangles, and even a warning about the dangers of believing everything you read on the internet. So drag yourself away from the eggshell white, find yourself a comfy seat and I’ll begin.


Phenol: a simple molecule with a complicated history.

Phenol is a simple molecule, consisting of a single -OH group attached to what chemists call a benzene ring (the structure of which was, so legend has it, finally determined after the German chemist August Kekulé dreamt of a snake eating its own tail).

You may think you’ve never heard of phenol, less still used it, but chances are you’ve come across the term ‘carbolic soap‘ somewhere. Phenol’s other name is carbolic acid, and it’s the main ingredient in carbolic soap, a mildly disinfectant cleaning agent that used to be a common household product in both Britain and America (in the form of Lifebuoy), was widely used in English state schools up until at least the 1970s, and is distributed to disaster victims for routine hygiene by the Red Cross to this day.

Carbolic soap isn’t so common these days since it has a tendency to irritate the skin and far gentler alternatives are available, although you can still find it in specialist outlets and apparently it’s quite popular in the Caribbean.

Friedlieb Ferdinand Runge

Friedlieb Ferdinand Runge

But back to phenol itself. It was discovered in 1834 when it was extracted from coal tar – a by-product of the coal industry – by the chemist Friedlieb Ferdinand Runge, also famous for identifying caffeine.


Joseph Lister

Despite his rather glorious name, Runge is not the best-remembered scientist associated with phenol. That honour almost certainly goes to Joseph Lister who, in the late 19th century, pioneered the technique of antiseptic surgery. It may seem difficult to believe today, but back then surgeons weren’t required to wash their hands before treating patients, and even took pride in the accumulated stains on their surgical gowns. Until Lister’s use of phenol (or carbolic acid), people were more likely to die from infection following the treatment than from the original injury itself. Lister started using phenol to sterilise surgical instruments and wounds and after seeing his results others soon followed, completely changing surgery as we know it today.

In case you’re wondering, Lister had nothing directly to do with the invention of the (phenol-free) mouthwash product that bears his name. It was, however, named after him in honour of his work. Interestingly, Listerine was first marketed as a surgical antiseptic, then a floor cleaner and a cure for gonorrhoea, before it eventually found success as a solution for bad breath.

carbolic smoke ballI mentioned lawyers earlier, and that’s because phenol was instrumental in one of the first examples of contract law: Carlill v Carbolic Smoke Ball Company [1892]. It was the main ingredient of the Carbolic Smoke Ball, an ineffective piece of medical quackery marketed in London in the 19th century as protecting the user against influenza and other ailments. The manufacturer advertised that buyers who found it did not work would be awarded £100.

The Carbolic Smoke Ball Company thought this was nothing more than an inspired piece of advertising, and tried to argue that it was “mere puff” that no reasonable person would take literally. The judge rejected their claims, ruled that the advert made an clear promise, and ordered the company to pay £100 to the unfortunate flu-suffering customer Louisa Carlill. To this day, this case is often cited as an example of the basic principles of contract and how they relate to every day life.


St. Maximilian Kolbe

Phenol also has a darker past, injections of it having been used as a means of execution. In particular, in World War II the Nazis used it in the euthanasia program, Action T4. Phenol was inexpensive, easy to make and fast-acting, and so quickly became the injectable toxin of choice. Famously, the Polish Catholic priest St. Maximilian Kolbe volunteered to undergo three weeks of starvation and dehydration in the place of another inmate and was ultimately executed by phenol injection. Kolbe was canonized on 10 October 1982 by Pope John Paul II; he is the patron saint of drug addicts.

Anyone who’s ever used phenol has probably experienced a phenol burn at some point. It doesn’t always hurt immediately but it slowly starts to burn after a little while, leaving white marks that ultimately turn red and slough off leaving brown-stained skin behind. It is, I should stress, not to be messed with – absorption of phenol through skin can result in phenol toxicity, and if left on the skin it can lead to cell death and gangrene. Even a tiny not-even-remotely-lethal spot is really quite painful. I can’t begin to imagine what death from phenol injection must have been like.

5012616170409Let’s end on a slightly lighter note. Have you got a bottle of TCP in your medicine cabinet? Many have fallen into the trap of believing that its initials relate directly to its ingredients, and specifically 2,4,6-trichlorophenol. In fact, a number of chemistry textbooks have stated this as hard, cold fact, as did a number of other online sources.

Not so, TCP originally contained trichlorophenylmethyliodosalicyl (not the same thing, and actually some have even wondered if this is truly a compound), but even that was replaced by other active ingredients in the 1950s. These days TCP contains a dilute solution of phenol (about 0.175% w/v) and halogenated phenols (0.68 w/v). So after all that, it does have phenol in it, but it’s not clear whether ‘halogenated phenols’ includes 2,4,6-trichlorophenol.

For a long time many, many websites stated that TCP contained trichlorophenylmethyliodosalicyl, probably traceable back to an earlier Wikipedia article (Wikipedia’s information has since been updated). As Jim Clark points out on his excellent Chemguide website, “The internet is a potentially dangerous tool. One single bit of misinformation can get multiplied over huge numbers of web sites”.

It’s true. Trust no one. (Except The Chronicle Flask of course*.)

(* If you spot an inaccuracy do let me know…)

Green hair and airborne wasabi: the Ig Nobel prizes

Next week on September 12th some extremely important prizes are about to be awarded that will undoubtedly rock the scientific community. Yes indeed, it’s that time again: the annual Ig Nobel prize award ceremony.

I first met the Igs about 15 years ago when I went to a conference in Seattle ig-nobel(yes I’m that old). The talk was a popular one, the Igs being a bit of light relief from all the serious science being discussed. That year there were awards for the development of a suit of armor impervious to grizzly bears, a study on the relationship between height, foot size and penile length (admit it, you’ve always wanted to know) and Jacques Benveniste of France, for his homeopathic ‘discovery’ that not only does water have memory, but that the information can be transmitted over telephone lines and the Internet (hmm).

So what are they, exactly? Some describe them as parodies of the official Nobel prizes. Home of the Igs AIR, the Annals of Improbable Research, describes them as awards for research that makes people laugh, and then think. Sometimes, as in the case of Benveniste, an Ig is awarded to someone for their, shall we say, excessively creative application of scientific ideas. More often these days they are awarded to scientists who’ve worked on something rather weird and wonderful, but which actually turns out to have some interesting applications.

So, since this is a chemistry blog, what have the last few Ig Nobel Chemistry prizes been awarded for?

2012Johan Pettersson, for solving the puzzle of why, in certain houses in the town of Anderslöv, Sweden, people’s hair turned green.
A great story, this: Several formerly blonde inhabitants of Anderslöv in southern Sweden suddenly acquired new green hairdos. Initially suspicion fell to the water supply, specifically copper contamination, since copper is known to dye hair green. But the problem was only affecting certain households. Testing revealed that copper levels were normal in the water supply itself, however when the water sat in the pipes in some recently-built houses overnight the copper levels rocketed. Why? Copper pipes in the new houses weren’t coated on the inside, so copper was leaching into the water. Residents who’d rather not have green hair have been told to wash their hair in cold water.

2011: Makoto Imai, Naoki Urushihata, Hideki Tanemura, Yukinobu Tajima, Hideaki Goto, Koichiro Mizoguchi and Junichi Murakami, for determining the ideal density of airborne wasabi to awaken sleeping people in case of a fire or other emergency, and for applying this knowledge to invent the wasabi alarm.
In this case the title says it all. As anyone that’s ever eaten a lump of that green stuff that comes with sushi knows, if wasabi gets into your nasal passages you know about it. The researchers worked out exactly how much wasabi would need to be in the air for it to be intolerable, and then developed and patented an alarm system that releases that concentration of wasabi in case of emergency. Well, at least it won’t wake up the neighbours.

2010: Eric AdamsScott SocolofskyStephen Masutani, and BPfor disproving the old belief that oil and water don’t mix.
A silly title with a serious motive, oil spills being something of a big deal. A team of scientists conducted controlled discharges of oil and water in the Norwegian sea at a depth of 844 meters and demonstrated that most oil from a spill in the deep ocean would in fact mix with water, rather than rise directly to the surface. The decision to award the prize jointly to BP, given the recent Deepwater Horizon incident, was particularly cutting.

2009: Javier MoralesMiguel Apátiga, and Victor M. Castañofor creating diamonds from liquid — specifically from tequila.
This might just be my favourite. It sounds ridiculous, and yet they published a serious paper. Scientists have long used various solvent mixtures to grow thin diamond films, and the researchers in this case were experimenting with mixtures of ethanol (‘drinking’ alcohol) and water. They noticed that the mixture that produced the best results had a similar composition to tequila, and so decided to experiment with the alcoholic beverage. It turned out that some types of tequila really did have exactly the right mixture of carbon, hydrogen and oxygen to promote growth of the films.

2008: Sharee A. Umpierre, Joseph A. Hill, Deborah J. Anderson and Harvard Medical School, for discovering that Coca-Cola is an effective spermicide, and to Chuang-Ye Hong, C.C. Shieh, P. Wu, and B.N. Chiang for discovering that it is not. 
The mind boggles, doesn’t it? There are many myths associated with pregnancy, and what does and doesn’t prevent it. No one would seriously recommend Coca-Cola as a contraceptive. However the first set of researchers decided to look into the question in a little more depth. They tested small samples of sperm with different types of Coca-Cola and found that they did, indeed, kill some sperm. However their results couldn’t be reproduced by the second set of scientists, who concluded that if Coke did have a spermicidal effect it was weak – little different to their control sample. A Coca-Cola spokesperson responded that “we do not promote any of our products for any medical use”. Glad they cleared that up.

You can see the full list of Ig Nobel prize winners here. The 2013 Ig Nobel prizes will be announced on Thursday September 12, 2013. You can join in on Twitter with the hashtag #IgNobel, and there’s also a webcast at 5:30pm EDT, which if my calculations are correct is 10:30am over here in the UK. I wonder what will be recognised this year…