The amount of information regarding VM&P Naptha is abundant. I have found the g/ml solubility for naptha, but there seems to be little information on other solvents (although they are not only mentioned, but used).

I am specifically interested in low bp fractions of petroleum ether (25-70 degrees centigrade). There are other reports of Dichloryl Methane being a superior solvent, but I have quite a liking to the petroleum ether. (Can't beat ACS reagent grade ;-) )

My initial thoughts turned to the boiling point, specific gravity, and dielectric constant. Pentane/Hexane fractions (same as above) are much lower quantitatively in these values than VM&P naptha, which leads me to believe that it is indeed a better solvent. But *how* much better is it? Some claim pet. ether requires 50% the amount of solvent compared to naptha, which makes a hazy amount of sense and I am reluctant to trust this claim.

But, the fact I've never had an emulsion with pet. ether and that it separates with haste makes it very sexy.

If anyone can produce a value (g/ml) or some helpful wisdom, that would rock.

Thanks for tolerating my first post ;-)
-Scan Fail

Sorry, this should be in the A/B section. My apologies.

are you asking about the solubility of spice in these solvents?

Petroleum ether is a mixture of light chain hydrocarbons. Naptha is mostly hexanes with some aromatic hydrocarbons in it. Spice is soluble in both but only marginally so hence why you recrystallize with them and why you get seemingly better results when they are heated during extraction.

Spice is more soluble in toluene, ether's, chloroform, and dichloromethane. They cannot be used for recrystallizing. These solvents will also pull other impurities however. Some people like the impurities though as it makes the 'jungle spice' mixture which can always be purified further with naptha or hexane or something similar.

As far as g/mL goes I don't think there is a list out there for all solvents, someone would have to do the tests. Its a simple test though if you want to get an idea on the solubility but above is a relative picture.

The fractions in the pet. ether of this guy I was talking to is 30-60 degrees. This computes to mostly pentane and hexane and maybe a little cyclo this or that. VM&P naptha has a bp of 95 to 160. Perhaps naptha has less n-hexane that is thought.

His first thought was that the lower fractions simply have a greater amount of individual molecules per unit of volume. Could this mean that there are more "gaps" for the spice to wiggle into?

The fellow mentioned to me that he had read that 4-5 smaller extractions versus the typcial 3 was a far superior. This makes sense because of the apparent low solubility.

The 30-60 degree fraction is very nice because that guy can boil it down without blasting the spice away. He said something about vacuum distilation.

He'd be curious to see how density and and boiling point correspond to solubility.

Although density which effects boiling point plays a factor in solubility remember the age old rule 'like dissolves like'. Inter and intra-molecular interactions are also very important in solubility. This is why SWIM thinks aromatic hydrocarbons extract spice better then just chains like hexane.

SWIM agrees. Is there anyway to guess between naptha and pet. ether? SWIM has read the figure 1g/20ml for naptha. Is there any way of translating?

I'd imagine there solubility is quite similar but the only real way to know is to test it unless some else already has.