GreenD - 16-11-2012 at 15:46
I have some thionyl chloride in lab that is about 1-2 years old. Not sure the purity, and the previous chemist was a scatter brain, so I don't know
what its been through.
I would like to purify it, and have been told to simply distill it.
However, this source talks about distilling with a diterpene. This can be further purified with distillation from linseed oil (1-2%).
my question is, will just a simple distillation with only my unknown purity SOCl2 degrade the product significantly? What is going on with the
diterpene? Are these acting as reducing agents?
What would YOU do?
Another source simply states a distillation was done to purify SOCl2 via simple distillation - product was obtained at 74.8°C
[Edited on 16-11-2012 by GreenD]
Dr.Bob - 16-11-2012 at 18:17
I would just simply distill it if I don't have a specific reason to do otherwise. Most chemicals do OK with a simple distillation.
However, I can understand that the diterpene or linseed oil, which appear to be a source of double bonds, which might help absorb the HCl likely to be
in the SOCl2 after sitting for years. However, that would mostly go away during a distillation as HCl if you simple blow a little N2 through the
distillation, as the HCl won't condense much in a water cooled condenser anyway.
A lot depends on the next step. If I am reacting this with a simple aliphatic acid, that HCl won't bother, I would just use the SOCl2 as is, and
just evaporate the excess. But if your carboxylic acid is sensitive to HCl, has a double bond (that HCl will add across) or has a -OH that can be
chlorinated or dehydrated by acid, then I would try to make it as pure as possible. I use a bottle of SOCl2 that looks older than I am, and it works
great for my chemistry, but my acids are stable as a rock.
GreenD - 16-11-2012 at 20:03
Thanks much Doctor.
Made it all crystal clear.