Psilocytroph - 26-8-2008 at 19:53
Just wondering, could petroleum jelly be used as a non-polar solvent? It's melting point is just under 100*F and is insoluble in water.
not_important - 26-8-2008 at 21:50
Yes, but it's next to impossible to remove from the solutes as it doesn't evaporate and leaves films of itself on any surface it is exposed to. The
high viscosity makes for slow mixing and diffusion.
Even kerosene/lamp oil is likely to be a better choice, as it is liquid at room temperature and has lower viscosity, or butane in the winter when
temperatures drop below 0 C.
Nicodem - 27-8-2008 at 00:14
Petroleum derived solvents are mainly composed of alkanes which are too nonpolar to dissolve most organic compounds except for the ones without any
polar functional groups. Therefore, petroleum ether, naphtha and similar ones are only good to extract lipids and very nonpolar organic compounds, but
usually do not dissolve well other more polar organics except some that are liquid at room temperature.
I'm moving this to Beginnings section.
ScienceSquirrel - 27-8-2008 at 04:39
Some ointments eg Vicks Vaporub are mixtures / soulutions of aromatic compounds eg camphor in petroleum jelly.
heptane
Psilocytroph - 27-8-2008 at 18:14
would heptane (found as paint thinner) be a suitable replacement for naphtha in various alkaloid extraction techniques, or would one be better off
with dichloromethane?
not_important - 27-8-2008 at 18:49
Dependson what you are extracting, while DMC is fairly non-polar alkanes are even more so.
And you'll likely not get pure heptane from painting solvents, it will be a mix of lower alkanes not worth the effort to fully fractionate. But you
will need to distill it at least once, there are small amounts of high boilers that you'll not want remaining behind in your extracted material.
ScienceSquirrel - 28-8-2008 at 02:36
It all depends on the boiling point of the naptha that was used in the original preparation.
If they are using something like light petroleum ether then redistilled Ronsonol is a really good substitute.
Klute - 28-8-2008 at 05:33
Yes, but I suppose it's more of a suspension/emulsion than a true solution.
12AX7 - 28-8-2008 at 06:53
Well, it is anyway. Petroleum jelly is neither solid nor liquid, it's kind of between melting points. If it were a more well-defined mixture I
suppose it would be white with crystals suspended in liquid, like refrigerated olive oil, or old honey.
Tim