Sciencemadness Discussion Board

Turpentine + iodine - any ideas?

eidolonicaurum - 2-1-2014 at 05:00

I came across this reaction many years ago in a James Herriot book, and decided to try it out. You get a violent reaction and some interesting smells and smoke, not to mention iodine vapour. Problem is, I have no idea what goes on chemically, and would love to find out.
The other thing is cleaning the wretched glassware! :mad: You get a thick, black, not unpleasant smelling goo/tar/substance which clings like glue to pretty much anything and everything. :mad: Its unaffected by concentrated NaOH, hot too, and has iodine in it too, though that can be washed off. Any ideas what the heck this stuff is, and how to get rid of it?!?!?!?!

Maximus - 2-1-2014 at 06:32

Turpentine contains unsaturated compounds like pinene, I'd gess one can espect the addition compounds beetween double bonds and the halogen (in this case Iodine) witch most of the times is exothermic due to the diference of energy beetween the pi and sigma bonds. Regards.

eidolonicaurum - 7-1-2014 at 03:33

I have managed to clean it off!! I used a concentrated solution of sodium percarbonate, which oxidised it to a sufficient extent that I could remove it.

ScienceSquirrel - 7-1-2014 at 04:10

The end product is mainly p - cymene
You do get quite a bit of goo as well though.
The very high heat of reaction is from the formation of the aromatic ring

http://en.wikipedia.org/wiki/Alpha-Pinene

blogfast25 - 7-1-2014 at 05:49

Quote: Originally posted by eidolonicaurum  
I came across this reaction many years ago in a James Herriot book, and decided to try it out. You get a violent reaction and some interesting smells and smoke, not to mention iodine vapour.


Can you describe a little better what exactly you did? 'How do I clean my glassware' threads aren't very interesting.

Derivatives of alpha-pinene run like a red thread through many aromatic components of plants. Evolution in action, I guess.

ScienceSquirrel - 7-1-2014 at 06:40

I am not sure which Herriot book it is in but it is one of the ones describing his early career as a veterinary surgeon.
I read it as a teenager and tried the experiment at university when I had some spare time.
I identified the main product as p-cymene by NMR.
In the book, Siegfried Farnon, his new employer, demonstrates it to James as an impressive way to treat an infected animal's foot with iodine.
A small amount of solid iodine is placed in an open container and a few drops of turpentine is then added.
A vigorous exothermic reaction ensues with clouds of iodine vapour coming off, the container is held close to the foot so the vapour condenses on to the wounded foot.

Chapter 3, a few pages in has the description;

http://www.amazon.co.uk/All-Creatures-Great-Small-Yorkshire/...


[Edited on 7-1-2014 by ScienceSquirrel]

eidolonicaurum - 9-1-2014 at 00:59

That is the exact book, and exactly what I did!