Hey!

SWIM is going to make a first extraction, and just bought the materials, including the solvent

There were 2 possible solvents in the chemicals supply store, Naphtha and petroleum ether.. SWIM did not get to see the label of the petroleum ether, and since SWIM remembered most people talking about naphtha in the techniques, SWIM went for it


So anyways, later looking at the label of the naphta, it had the following information: 6 to 8 carbon molecules, less than 1% of benzene

SWIM looked up benzene and saw it is a carcinogenic solvent.


Did SWIM get the right thing, or is this particular naphtha SWIM has access to undesirably impure? Or can there be more impurities not written on the label that make more difference? Is this 1% benzene something very unwanted, or is it ok?

Is petroleum ether something more desirable, or it depends on the maker and so on?


Its sort of confusing because all around the net SWIM tried to find info on this and there seems to be no straight answer. Someone on some forum says naphtha leaves impurities when evaporated and that petroleum ether is better. In many other places, naphtha is written as the equivalent of petroleum ether. Also, some people say that there are just about as many naphtha types as there are producers of it, and that some are good some are bad.


SWIM could call the store that sold for me and ask questions.. Is there any question SWIM could ask them about the purity or whatever that would help?

hi there mate
if in doubt of solvent and impurities , just evap a little bit of each and check for residue
after everything evaped from the plate/evap dish.
swim uses naphtha with great results, and the spice can always be washed to purify it even further.
hope it helps

thanks a lot


btw, what u ppl think... if SWIM is gonna do the recrystallization, is it enough to clean the spice without the need for the wash? I mean, would recrystallization also clean the possible NaOH left overs, or is this only with the wash?

also, would there be any advantage in doing a simple cold distilled water wash (before or after the re-X-zation) ? Would SWIM lose much spice without it being so useful ?

personally i haven't done it myself, but just because there aren't any visible residues doesn't mean there is nothing there, right?
My chemistry knowledge is not what it used to be, but their both solvents so if their pure then it should all just evaporate right?
Basically you dont want to be taking in carcinogens. If i were you i'd stay on the safe side and go for something known and pure.
SWIM having the same problem atm, wondering which solvent to get.

Heptane

Name Brand: Bestine (100% heptane) It is used as a rubber cement thinner/remover. Art stores may carry it. It can easily be found online.

I believe it is non-carcenogenic, evaportes about 4x faster than naphtha, and is the bees knees for recrystalization. That being said, it is quite a bit more expensive than naphtha and is a little hard to find.

Hell yeah for heptane! The recrystalization just does itself. It's also highly selective as the initial extraction NP and freeze precips fine white powder. Maybe a little too selective given what people are finding out about the colored spices.
Naptha's good too - you just have to work a little harder to get clean product. I wouldn't worry about carcinogens, unless the Kingsford people dig lawsuits, I doubt they'd use it in charcoal lighter if that were a problem.
If you recrystalize, there is no need to wash.
If you must wash, make sure the pH is high. My friend just discovered that NP washes with a pH under 12 lose product.