George E. Cawthon wrote:

Doug Miller wrote:

In article , David Peters
wrote:

Does propanol's "three carbons and one hydroxyl" mean that it is more
likely than ethanol (with only two carbons and one hydroxyl) to
actually DISSOLVE some types of plastics which I am might be trying
to clean?



Don't know about your side of the pond, but over here (US) propanol is
normally sold in plastic bottles. I've used 2-propanol to clean a lot
of things, and never had it damage any plastic.

IMO your premise is wrong (that a longer-chain moleule is more likely
to dissolve plastic than a shorter one). I've also successfully used
paint thinner (mineral spirits) to clean various plastics without
damage. And I've not observed gasoline to be particularly harmful to
plastics either. OTOH, acetone (2-propanone) and MEK (2-butanone) are
terribly destructive to many common plastics. IOW, it ain't the length
of the chain, but what's attached to it, that does the damage.


Actually, what he stated is generally correct, but ethanol and propanol
are very close, so one would probably never see any significant difference.

Of course, what you said is correct also, what is on the end is
important, but when comparing two alcohols, the same thing is on the end.

As for plastics, oil has some fairly long chains and it is sold in
plastic bottles and oil/gas mixtures certainly don't bother the oil
bottle plastics. And then of course, there are plastic gas containers.
It would be a pretty lousy plastic that would be bothered by methanol,
ethanol, or propanol.

Surprisingy enough, methanol is quite agrresive. Dunno why.

I had a toy plastic plane once, with an engine that ran on
methonol/nitromethane/oil mix.

I tried to clean it with petrol...and it dissolved the surface!!!

There is no single simple amswer to which solvent dissolves which plastic.