What’s the difference between the solvent properties of
n-butane and n-propane?
?!?!?!
They are both hydrocarbons, differing only in carbon number - propane has 3, butane has 4. They really should be very similar as solvents.
The CRC Handbook (2001-2002) does not list either in its list of “Properties of common laboratory solvents” (ch 15). AFAIK, niether one is used commonly as solvents, and so there might not be much data available. If you just want to compare the physical properties of each substance, get your hands on a copy of the CRC, or try www.chemfinder.com .
BTW- why do you want to know?
I’m an asipiring… ahem… “chemist”…
As both are normally gaseous at room temperature and sea level
pressure, neither would make a useful solvent.
n-butane is liquid below 0 degrees celsius, which isn’t that hard
of a temperature to obtain.
Boiling point is not a huge concern here. If a solvent does something you want, and you have to keep things cool to use it, you work in a coldroom or under pressure.
For example, carbon dioxide is a gas at STP, yet its liquid form is used extensively as a solvent in supercritical fluid chromatography. Liquid CO[sub]2[/sub] is even used to extract caffeine from coffee .
I’ve never had the pleasure of using n-butane as a solvent myself, but I have seen big jars of the stuff sitting around in coldrooms waiting for someone else to perform extractions with. Propane, which freezes at -42.7 C, is trickier stuff, but I’m sure it’s used for something or other.
As far as the differences between propane and butane, there’s not much in general. Like the two alcohols propanol and butanol, propane and butane are pretty much interchangeable, but there are always going to be specific solvation effects between any solvent/solute pair. These are difficult to predict, but can be important in optimizing a chemical process. The usual way to determine what’s best under such circumstances is to try both solvents and see what happens.
Eight of his 21 posts are about drugs. He wants to know about solvents, and he claims he is an aspiring “chemist”. Sounds like someone wants to be a drug cook. I wouldn’t answer any more of his questions until he clears up why he needs to know this.
That’s probably safer than being an amateur explosives developer.
I think the question itself was legitimate. Let’s see if he asks about red phosphorous 
Propane and butane are used on a fairly wide scale as solvents in refineries in a process called deasphalting. The heaviest fraction of crude oil (residue) is contacted with supercritical propane or butane (in rare cases pentane), which dissolve the lighter fractions of the residue. This “deasphalted oil” is a useful feedstock in the refeinery for manufacture of lube oil or for cracking processes. The remainder is called asphalt.
There is a clear distinction between the hydrocarbons used for this process. Compared to propane, butane produces more deasphalted oil, but with heavier molecules present and therefore of lower quality. Similar for pentane versus butane.
Now let’s see whwther that is helpful in illegal drugs manufacture… 
red_dragon60: I am not planning on attempting anything, if that’s
what you’re worried about. (by the way, I don’t honestly consider
cannabis a drug).
I, for one, am reassured.
That’s kind of dumb. Caffeine, cigarettes, and alcohol are drugs, why wouldn’t cannabis be one?
Anyway, be careful with whatever you’re doing. A not too bright guy on a ‘spudgun’ list I’m on had a tank full of propane that he wanted to use as an air chamber for an air cannon. Instead of using the propane, or burning it off in a safe way, he took it outside and walked around with the tank overturned with the valve opened. He used the stream of liquid propane to freeze quite a few weeds and things before a small spark ignited it and blew him to kingdom come.
Everyting up until he blew himself up was true. He was very lucky that Darwin was looking the other way that day. Don’t play with quantities of flammable gasses while under the influence of anything.
As for the solvent qualitites of butane and propane, all I can find is stuff related to the asphalt process as described by Dragon Phoenix. What are you hoping to dissolve, or what gave you the idea that propane or butane would be good for it?
Cannabis is a plant containing a drug, not a drug
Keep in mind I’m not planning on attempting this:
Butane and isopropanol are the two most common chemicals
that are used to extract THC from cannabis. Butane is preferred,
since it doesnt extract the plant waxes. The most common
procedure is done using a copper pipe and some sort of filter,
then letting the extract sit until all the butane has evaporated.
Now every person who talks about this says that Colibri brand
butane is the best for this. The curious thing is that Colibri
butane is actually 52% n-butane, 46% propane, and 2%
isobutane. I was wondering why the propane made a difference.
Good, I am just trying to make sure we don’t have someone making a meth lab on our hands
Oh, for the love of Cecil.
Grievar, being cute about it doesn’t mean that you get to violate the rules of this message board.
Do anything even vaguely similar to this again and you’re done.
This thread is closed.