Does gasoline turn to "varnish" over time?
sschumsky
time, it is said that it turns to "varnish". Is this true or a
misnomer?
If it does turn to "varnish", is it because of evaporation? If so,
does it lose octane? Does it lose hydrocarbons or hydrogen atoms or
what?
Are there stages that gasoline goes through on its way to "varnish"
such as changes in chemical or empirical formulas?
Is there some way to test if gasoline has changed to "varnish" or
something that isn't good to run in your engine any more?
Thanks,
Steve Schumsky
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raconte
> When gasoline sits in a tank or container for an extended poriod of
> time, it is said that it turns to "varnish". Is this true or a
> misnomer?
>
makers. It doesn't become a polyurethane based word preservative, but
it does come out of solution, coating metal parts with a brownish
tint. So varnish is as good a name as any.
> If it does turn to "varnish", is it because of evaporation? If so,
> does it lose octane? Does it lose hydrocarbons or hydrogen atoms or
> what?
>
that is gasoline, partly the reaction with air of the hydrocarbons in
gasoline, maybe more likely reactions between air and additives to
gasoline.
> Are there stages that gasoline goes through on its way to "varnish"
> such as changes in chemical or empirical formulas?
>
I don't know. The various reactions are probably pretty complicated.
I just want to let you know that properties of gasoline useful for
internal combustion engines aren't based on simple stoichiometry of
one or two components. The blending of various hydrocarbons and
additives gives it a certain octane rating -- it's not C6H12 spiked
with x % of octane. P.S. octane increasing additives reduce engine
knock by limiting combustion, they're likely less volatile than other
components.
> Is there some way to test if gasoline has changed to "varnish" or
> something that isn't good to run in your engine any more?
>
Nothing simple that I can think of, except that if it doesn't work in
the lawnmower or outboard engine, throw it away, and buy fresh stuff.
If it screws up your car, complain to the gas station. Gasoline is
expensive world-wide these days, so I can imagine why you're so
interested in reclaiming this gasoline, but it may not be practical,
or even possible without specialty equipment.
jason cooper
: When gasoline sits in a tank or container for an extended poriod of
: time, it is said that it turns to "varnish". Is this true or a
: misnomer?
Check out:
http://www.chevron.com/prodserv/fuels/bulletin/longterm_gasoline/
It seems to answer all of your questions. The "background
information" section is particularly informative (but not
technical) on the chemistry of the thing.
-----------------------------------------------------------------
. . . Except when they don't,
Because sometimes they won't. - Dr. Seuss
-----------------------------------------------------------------
Jason Cooper jco...@acs.ucalgary.ca
donald j haarmann
> When gasoline sits in a tank or container for an extended poriod of
> time, it is said that it turns to "varnish". Is this true or a
> misnomer?
>
[snip]
My experience has been ... the gum that forms creates a mechanical problem.
It blocks the flow of gasoline thorough the carburetor. You can try carburetor
cleaner... however... mechanical removal may be needed.
You can buy products to stop this. "Store-X" "Stab-Bil" are common ones.
I don't know what is in them other than "petroleum distillate".
Also there are products to treat diesel fuel .... which has even bigger problems!
Algae &c..
--
donald j haarmann - independently dubious
William A. Noyes
"donald j haarmann" <donald-...@worldnet.att.net> wrote in message
news:7j3xc.44989$_k3.1...@bgtnsc05-news.ops.worldnet.att.net...
> "sschumsky" <ssch...@yahoo-dot-com.no-spam.invalid
>
> > When gasoline sits in a tank or container for an extended poriod of
> > time, it is said that it turns to "varnish". Is this true or a
> > misnomer?
> >
>
> [snip]
>
>
> My experience has been ... the gum that forms creates a mechanical
problem.
> It blocks the flow of gasoline thorough the carburetor. You can try
carburetor
> cleaner... however... mechanical removal may be needed.
>
> You can buy products to stop this. "Store-X" "Stab-Bil" are common ones.
> I don't know what is in them other than "petroleum distillate".
As I recall the active ingredient in butylated hydroxytoluene (BHT). It
is a common and widely used antioxidant. Use in everything from
potato chips to gasoline.
Steve Turner
<donald-...@worldnet.att.net> wrote:
>My experience has been ... the gum that forms creates a mechanical problem.
>It blocks the flow of gasoline thorough the carburetor. You can try carburetor
>cleaner... however... mechanical removal may be needed.
Carburetor? CARBURETOR???? Wow, I just about fell off my dinosaur
when I read that! I remember them things. Cranky, expensive to
repair, full of black magic... :)
Steve Turner
raconte
> Check out:
>
> http://www.chevron.com/prodserv/fuels/bulletin/longterm_gasoline/
>
> It seems to answer all of your questions. The "background
> information" section is particularly informative (but not
> technical) on the chemistry of the thing.
Hmmm...the people at Chevron use the term "gum" for solid formation in
gasoline. Attn sschumsky: No filtering it out and trying to chew it,
please.
Mark Tarka
Keep in mind, that "gasoline" is a "cut" from the
distillation of oil ... small amounts of heavier
materials are gonna get carried over in that crude
process. That's the stuff, I bet, that is the
gum or varnish you're concerned with. The different
grades of gas are "blends", I bet, and probably all
have the same varnish/gum problem. Anyone with
better info?
On the other hand, purchasing 55 gal. drums
of nitromethane.... Vaaaroooooooooommmmmmmmmmm.
Mark (Gas is $2, here, up from 1.60, to finance the war, right?
'Cuse me, Mr. President, but _your_ ass is in jeapordy :-)
Lifetime Luddite Membership No. 00-000-06
Tony
Got a Fuel-Injected lawn mower, have we?
Cheers,
Tony.
Steve Turner
Yep, and it's a diesel. Sorry, that's Diesel. 30 horses worth and a
5' cut. :)
Steve Turner
Chris R. Lee
"Mark Tarka" <mark_...@yahoo.com> a écrit dans le message de news:
6b70c71c.04060...@posting.google.com...
> rac...@hotmail.com (raconte) wrote in message
news:<a30ce47b.04060...@posting.google.com>...
> > jco...@acs4.acs.ucalgary.ca (jason cooper) wrote in message
news:<ca2d7f$84i$1...@news.ucalgary.ca>...
> >
> > > Check out:
> > >
> > > http://www.chevron.com/prodserv/fuels/bulletin/longterm_gasoline/
> > >
> > > It seems to answer all of your questions. The "background
> > > information" section is particularly informative (but not
> > > technical) on the chemistry of the thing.
> >
> > Hmmm...the people at Chevron use the term "gum" for solid formation in
> > gasoline. Attn sschumsky: No filtering it out and trying to chew it,
> > please.
>
> Keep in mind, that "gasoline" is a "cut" from the
> distillation of oil ... small amounts of heavier
> materials are gonna get carried over in that crude
> process. That's the stuff, I bet, that is the
> gum or varnish you're concerned with. The different
> grades of gas are "blends", I bet, and probably all
> have the same varnish/gum problem. Anyone with
> better info?
Gummy stuff may form a very small proportion of gasoline & it will cause
trouble if the main components evaporate off.
There's also a small proportion of unsaturated hydrocarbons. These are
volatile but during storage they tend to polymerise, just like ethylene
polymerises to polythene if the conditions are right. Additives should
prevent this reaction. The bigger & more complex the polymer molecule the
more the polymer looks like varnish rather than gum.
Conclusion: gasoline has some involatile content, which may increase during
storage.
The same reaction causes linseed oil in oil paint to harden. The stuff you
put on your window frames has more sophisticated polymerisation mechanisms.
Regards