David Peters wrote:
Why is isopropyl alcohol (propanol) reckoned by many people to be a
better general cleaner around the house than the ethyl alcohol
(ethanol) which is found in methylated spirits?


Hmm dunno if it is, is it? It may depend on the relative concentrations
of each when compared to each other.

For example 0.02M propan-2-ol (isopropyl alcohol) will be stronger than
0.002M ethanol. Assuming the same concentrations (water to pure chemical
ratio), then the only two reasons I can see are that:

1. Propan-2-ol has a longer hydrocarbon chain than ethanol (dunno how
much difference this can make apart from making the chemical more
viscous)...

H H H H H
| | | | |
H-C-C-C-H H-C-C-H
| | | | |
H O H O H
| |
H H
(propan-2-ol) (ethanol)

2. The functional alcohol (O-H) group is on the second chain in
propan-2-ol and therefore is joined to a carbon with only one
hydrogen atom connected to it... Therefore propan-2-ol is a secondary
alcohol. As to why this would make too much of a difference I am not
sure, look up the chemistry of primary and secondary alcohols. Since
I don't think you are fully oxidising them I can't see how this would
make too much difference.

Another thing apart from concentrations, is that you mention meths...
It is only valid really comparison if the two chemicals are in their
pure form.. Not apart of a cleaning agent such as meths of window
cleaner etc.

Good luck, maybe you could feed us some more background information.

P.S. Clever people this is only what I remember from my A level
chemistry.. Please correct me if I've made a mistake :P.

--
Regards,
Aaron.