Now I'm quite certain you have mixed up trichloroethylene with 1,1,1-trichloroethane.
What I was confusing was my spelling (which always happens with me with alkanes, alkenes,
et. al.). You are right, I did mean trichloroeth
ane. In my defence, I was just copying the existing misspelling perpetrated by another because the Servisol referred to before was most definitely 1,1,1-trichloroethane. I was thinking about the right thing but writing about the wrong one. As I say, not the first time I've done that with the whole alkane/alkene/alkyne thing.
Carbon Tet. was all over the place back in the day. Used to be used by dry cleaners until somebody finally got the memo that it was rather more than just a suspected carcinogen. Replaced in dry cleaning with Trichlorethylene. I always associate the smell of Trichlorethylene and with libraries, there was a dry cleaners smack next to the main library where I grew up and there was always a lingering smell of it in the area.
Dry cleaning solvent is almost entirely perchloroethylene (tetrachloroethylene).
I was thinking back to the 60s when Carbon Tet. was replaced with thichlorethane in the UK (under the tradename Trilene
(my spelling of that may be off)) and was then subsequently replaced with perchorethylene.
I saw some 60% carbon tetrachloride in an old fire extinguisher. Looked like it was still full. Great stuff I'm sure.
We had one of those - a brass 'syringe' affair that my Father dug up from somewhere. He was rapidly dissuaded from putting it on the wall in the kitchen by both my mother (a chemist) and me.
As far as methylated spirits/denatured alcohol goes;
I believe the ratio of ethanol:methanol is 10:1 or more, which makes it less dangerous to contact the skin. The reason for this is that ethanol and methanol compete for the same enzyme, alcohol dehydogenase. Ethanol gets metabolized by this enzyme to acetaldehyde (the cause of hangovers), whle methanol gets metabolized to formaldehyde (a neurotoxin and cell destroyer). If the active site of the enzyme always bumps into an ethanol molecule, it can't metabolize methanol, which is why the treatment for methanol poisoning is high doses of ethanol.
It is still not a good idea to intentionally put it on the skin.
Really it's not much of an issue putting any of these on your skin as long as you don't bathe in them. The whole point of all these skin sanitisers using alcohols of one sort or another is that the alcohol used
is toxic, if it wasn't it wouldn't kill off the things it's supposed to kill off.
LD
50 (skin) for Methanol is 15.8g/kg (rabbit), Isopropanol > 10g/kg (rabbit) and Ethanol 15.8g/kg (rabbit); so methanol is no worse a toxin
for skin contact than good old ethanol. This shouldn't be a surprise because the mechanism of transfer
across the skin to where it can exercise any toxicity is going to be similar, if not probably identical, for all three alcohols. The skin is evolved to be a barrier and does a very good job of that, you have to get through quite a layer of no longer living material before you can get to the living stuff to do it any harm.
On a side note, ADH actually preferentially binds to ethanol over methanol.
The formulae used around the world for denatured alcohol vary quite a lot. Only some contain methanol, many contain other denaturants either alone or in combination with methanol. I'd have more concern about some of the other denaturants used
in terms of through-skin toxicity than I would have about methanol
per se. A common addition is methyl ethyl ketone, which has an LD
50 (skin) of 5g/kg (rabbit) and because of its affinity for and high solubility in lipids it can do a much better job of crossing the skin's barrier.
The official formulation for "completely denatured alcohol" in the UK is
Per hectolitre of absolute ethanol:
1 litre of isopropyl alcohol
1 litre of methyl ethyl ketone
1 gram of denatonium benzoate
(There are other formulae in common use in the EU at that URL)
So "methylated spirits" may actually not contain any methanol nowadays.