Benzene and Perfumes

[ERICK84]

Benzene in its nature is poisonous and according to my research most of Perfumes containing Benzene are harmful.How can we extract the aromatic nature of Benzene without its harmful nature?

[gen2]

My understanding is that benzene is only present in perfumes in trace amounts. The distinctive aroma of scents comes from a mixture of many more complex compounds, some of which are derivatives of benzene. Derivatives of benzene do not necessarily have the same toxic properties as benzene.

For instance, phenol is a simple derivative and is considered to be safe to use in TCP.
Another derivative is Methyl salicylate (Oil of Wintergreen)

[theprof]

gen2 is correct in all that he says.

Benzene is indeed a very toxic, carcininogenic chemical and in my laboratories, severe safeguards have to be in place before the top of the container is opened. When we need it from the stores, it's transported on special trolleys that make spillage virtually impossible.

Nevertheless, benzene is detectable in perfumes in minute amounts. When it is there, it's usually as a result of degradation or impurities in the substance in the perfume that makes it smell nice.

As an example, there's a chemical called 4-hydroxy-3-methoxybenzaldehyde which is derived from benzene. This substance is more commonly known as Vanillin and it adds a vanilla like odour to perfumes. Now you may think that such a complex chemical would have to manufactured in the laboratory, but nothing's further from the truth. Vanillin occurs in nature in vanilla pods as well.

Now if you look up the structural formula of vanillin on Wikipedia etc, you'll see it's basically a hexagon with a number of "arms" leading off it. The hexagon is known as a benzene ring and is a simple way for chemists to represent C6H6, also known as benzene.

So what's so special about this benzene ring? Well, it's the fundamental basis for something called aromatic organic chemistry and it's found in all aromatic organic compounds. But here's the important part. The benzene ring is not "free" to impart its toxic properties within vanillin, but locked safely away.

In general, all organic compounds including the synthetic chemicals used in perfumes are manufactured by adding, removing or relocating the functional groups shown at the end of those arms shown in the Wikipedia article. Benzene based odours must not be thought of as extracted but as derived from the repositioning, adding or subtracting of the functional groups. Some of the changes that occur as a result may be very subtle and hardly

[theprof]

noticeable, but at the end of the day many of the most famous perfumes in the world have been derived by trial and error.

Rest assured, perfumery chemists are very good and clever at what they do and are amongst the brightest chemists in the world.

[JPChenet]

dont drink perfume

brake fluids dangerous but people still manage to use it without killing themselves

[chakka35]

gen2 isn't quite right about phenol being used in TCP.
Phenol is benzene with one hydrogen atom replaced by a hydroxyl radical, OH. Its other name is carbolic acid, a disinfectant used in, among other things, coal-tar soap.

If you replace another three hydrogen atoms in phenol with chlorine atoms you get tri-chloro-phenol -TCP. So phenol is not a constituent of TCP - TCP is derived from it.

[gen2]

I accept that chakka35. I had to hurredly complete my post when the phone rang. The point I was trying to make was that derivatives of benzene do not necessarily inherit the dangerous qualities of benzene. By the time I came back to it, theprof had given a much fuller explanation and so I didn't see any point in re-posting.


And JPChenet, I don't see the point of your post as you obviously have no idea about the dangers posed by benzene. Drinking it is the least of your worries.

[theprof]

chakka35, I'm sorry to say that you are incorrect.

You assert that TCP is tri-chloro-phenol. I'm afraid that tri-chloro-phenol does not exist and therefore cannot have the acronym TCP. Let's look at this again. The compound C6H3Cl3O has a molecular weight of 197.45. However, you don't seem to have picked up on the fact that there are six isomers of this compound. They are:

2,3,4 - Trichlorophenol
2,3,5 - Trichlorophenol
2,3,6 - Trichlorophenol
2,4,5 - Trichlorophenol
2,4,6 - Trichlorophenol
3,4,5 - Trichlorophenol

If you'd like to look at the individual properties of these isomers, the following link provides a good summary:

http://chemicalland21.com/lifescience/agro/2,4 ,6-TRICHLOROPHENOL.htm

Now although these isomers possess the same molecular weight, I'm sure you appreciate that they are all individual organic compounds with their own specific physical and chemical properties. This is why each of them has it's own assigned CAS number and you'll note that they vary in such things as solubility in water. Because these are individual compounds, under no circumstances should any of them be referred to as "tri-chloro-phenol" which at best could be thought of as meaningless blanket term

(continued)

[theprof]

I'd now like to point you in the direction of one of these isomers, namely the 2,4,6 isomer. When we refer to TCP in laboratories, this is the usual isomer that's referred to. It comes in the form of white/yellow needles or flakes, which are almost insoluble in water. Now obviously as the 2,4,6 isomer is insoluble in water, it would not be feasible to consider it as the main constituent of TCP Liquid Antiseptic unless it was dissolved in some polar solvent. Well it's not. TCP Liquid Antiseptic is a mixture of the isomers listed above, which when combined show a greater solubility in water. Without intending to complicate matters too much, sometimes TCP is wrongly as an acronym for one or more of the other isomers too.

In support of my statement, I'd point you to the back of a TCP bottle which says "TCP is a clear yellow solution of halogenated phenols 0.68% w/v". It does not state it is a solution of one particular isomer nor a solution of "tri-chloro-phenol"

Furthermore the bottle also states that it contains 0.175% w/v phenol. The phenol is added as a synergist to increase the efficacy of the halogenated phenol mix. Therefore, phenol is a constituent of TCP Liquid Antiseptic which is what gen2 said originally.

It might interest you to know that you're not the only person who thinks that TCP stands for the chimerical �tri-chloro-phenol�. It's a bit of an urban legend amongst chemists and I still see the odd student who swears it's true. Still it's better than the other title "Tom Cat's (Urine)". I'll leave you find a substitute for the word in brackets.

[chakka35]

Thank you,the prof. I stand corrected.