SWIM ever thinked that Spice is a non-polar molecule because the kind of solvent used for extraction 8non-polar organic sovents)...
But, why can DCM (Dichloromethane) dissolve spice if It is a very polar solvent?

(sorry for my english, Its my best...)

it isn't.
it has electronegative (polar) elements, but both are on opposite sides of the methyl group.

it is able to undergo hydrogen bonding to some extent so it's slightly miscible in water, but is also very effective at extracting alkaloids. like chloroform, it acts like a net to pull alkaloids

It is polar... imagine the molecule in 3D, its not a cross, the Cl atoms are separated by 109 degrees (and a litle more)....
I cant talk more about chemistry; molecular geometry, sp3 hybrid, E.N., vectors addition, etc... because my english

take a look of this. Specially the table below:
WikiLink

Try not to get too caught up in chemical theory. Many chemical theories are inaccurate especially when it comes to solvent polarity.

Yes DCM is somewhat polar. It dissolves many things acetone and MEK also dissolve which solvents like heptane cannot dissolve. But it's not polar enough to be completely soluble in water. There are many polar molecules that are insoluble in DCM, such as DMT HCl. DCM dissolves nearly all non-polar molecules, so it's more non-polar than polar, from a practical point of view. There is no equation that can accurate give a solvent's polarity and predict exactly which molecules will be soluble in which solvents.

DCM can dissolve nearly all freebase alkaloids extremely well, better than highly non-polar solvents like heptane. Freebase alkaloids like mescaline and bufotenine are insoluble in heptane, but very soluble in DCM.

I'm telling you, if you attempt to understand it all, you're going to get a headache. We don't understand 100% of how molecules interact with each other. If we did we could predict all chemical reactions and all solvencies and such and we cannot. This is why chemistry is sometimes called an "art form".

Many chemists argue about chemical "facts" all the time. It seems that each person has their own idea of which chemical theories are the best and why and so on. There are certain aspects of chemistry which are hard core facts and cannot be disputed. For example, it is a fact that mescaline is soluble in xylene, but bufotenine is not. It's also a fact that mescaline is more polar than bufotenine. There are different theories available to explain why this is the exact opposite of what you'd expect, but most of them are inaccurate and don't apply to all alkaloids.

In chemistry there are two things: chemical theory, and chemical fact. Too many chemists are misguided by inaccurate theories. Don't get the two confused. Solvent polarity is based on inaccurate chemical theories that don't mach up 100% with reality.

the truly polar solvents are completely miscible with water
look at this chart
dcm has a polarity index of 3.1, dioxane is 4.8 . big difference from your wiki link.

it's all fun and good that chorines are electronegative, but the two chlorines in methylene chloride still oppose each other, and on the opposite side of the plane are just hydrogens. imagine in 3D? look at an electrostatic map, the overall molecule appears as nonpolar.

Every atom-atom bond in the molecule have a bond dipole moment, wish depends of E.N. difference between the two atoms. Each of this bond dipole moments is a vector.
So, in DCM you have 4 bonds, and therefore, 4 vectors (2 H-C and 2 C-Cl).
The 2 C-H vectors are pointing to the Carbon (for E.N. difference) and the other 2 C-Cl vectors are pointing to each Cl (same thing). Adding all you have a final vector pointing to the Chlorine side of the molecule.

...benzyme: You have to see the molecule in 3D, its a tetrahedron, nothing is oppocite. If you still dont understand let me say you that in H2O molecule the Oxigens are opposing each other too... and it is polar, or am I wrong?

Finally I learned that DCM molecule is not as polar as water, actually, has a weak polarity, but is polar, and is more polar than non-polar, and because that is clasified as polar.
VERY TNKS 69ron, I think you are right about we cant understand all about chemical interactions and solubility and sometimes we just have to follow the experience.
So I will follow your advise and I will try with naphta. I will use DCM another time in future to compare results. Or maybe I keep it for a mescaline extraction, tnks for that too

you're right that it's polar, but you are wrong about two oxygens.. it only has one oxygen.
again...look at an electrostatic potential map


there are your vectors

as you can see, DCM shows up as primarily green, a polar molecule like water would be red on one side. this indicates a flow of electrons towards that element. in dcm's case, they are distributed between the two chlorines...two polar elements, but the overall molecule is often considered nonpolar

now, you said

but with a polarity index of 3.1 (benzene is 2.7), and water being 9, it's not very polar.
relative to hexanes it's polar, but on the actual polarity index, it's more non-polar than polar.

and it's far better at pulling alkaloids than naptha

Polarity indexes are a bit crude way of estimating properties. There are more rigorous detailed mathematical descriptions of such things but there is no need to use them in many or most cases.

Regardless DCM isn't really like water. It doesn't mix well with water (although it can dissolve a bit of water). DCM mixes with many non polar solvents. Like dissolves like its non polar.

Anyway CHCl3 and DCM are both excellent solvents for many freebased alkaloids. Why? Unless you plan on detailed mathematical explanations who cares?

precisely, all of the polar solvents are proton acceptors/donors. dcm holds its hydrogens tightly, and doesn't easily lend them to hydrogen-bonding with polar solvents.
though swim noticed how easily it mixes with varsol, another non-polar.. something he wished it wouldn't do

Hahaha, just to make things even worse, why polar solvents like alcohols and ketones also dissolve spice?. And they dissolve it really well!

Sorry, writing mistake. I meaned two oppocite Hidrogens, not Oxys...
And then I said that DCM is not very polar, but It is anyway. So why do you quote me with that?

And I founded It: Chemical polarity - Wiki
It wasnt easy because I needed to put a link in english. Here says at the first part: "Molecular polarity is dependent on the difference in electronegativity between atoms in a compound and the asymmetry of the compound's structure."
Is the same I learned in highschool, pre-u, and recently again at university: So, why are you thinking on electrostatic potential maps? And the picture is not clear too...

look at the electrostatic maps on your wiki link, they all have red areas, indicating strong electron localization.
the pic I posted is clear as day, the polarity isn't as pronounced.

http://answers.yahoo.com...id=20070922124836AA7pDyY

it's not really considered a polar solvent, the dipole moment isn't that significant.
you're just going to give yourself a headache contemplating minor details, there's so much more to learn in chem

TNKS that was the answer I needed!: "You are right that the dipoles from the Chloro-Carbon Bonds do not cancel, but Chloro-Carbon Bonds are only slightly polar to begin with."
I didnt know that C-Cl E.N. difference was so little ...being Chlorine a VIIA element and 3nd period... actually the C-Cl bond is just at the edge between to be a polar or non-polar bond.

FINALLY, i agree with many of you guys; we cant know every why in chemistry.. At the less we know it works... and we can buy it

PEACE

are you learning organic chem 1?

I remember having a similar question on a biochemistry test, it's sort of a trick question. dcm behaves much differently than polar solvents. despite being somewhat polar relative to the aliphatics and aromatics because of its dipole, it's often considered a non-polar.

it's used in org 1 labs to extract caffeine from tea or coffee, the aqueous solution being the polar solvent.

DCM is extremely useful.

It evaporates REALLY FAST, boils at a very low temperature, and pulls almost everything under the sun. It’s just non-polar enough to allow A/B extractions to work, but polar enough to extract things like bufotenine, mescaline, etc., which solvents like heptane can’t extract.

The main problem with DCM is that it’s unhealthy to use it. But this is the case for most solvents. The other problem is that DCM is a GREAT SOLVENT and it pulls out almost everything. So when using it to extract alkaloids, you’ll most likely need a cleanup stage following it.

For SWIM, he’s been trying to migrate away from using DCM, but there are times when DCM is the absolute best solvent. When extracting bufotenine, SWIM always uses DCM. No other solvent works as well except chloroform. He does a thorough A/B with water and DCM and then does a xylene boil to purify the bufotenine at the end.

"The main problem with DCM is that it’s unhealthy to use it." How so ?
Iv read of there being a reaction between dcm and spice when extracting, apparently it creates some other molecule - is this true ?

there is scant evidence for this, production of an n-chloro analogue from extraction using DCM.
though there exists one paper on it, and it's also been detected in a certain tree

this theory has been tossed around, speculation that chlorination may occur under acidic conditions, but the experiment hasn't been replicated, afaik

maybe you were talking about "jungle spice"...

DCM is a suspected carcinogen that's the only safety concern. Although there is no real evidence that its a carcinogen just because its similar to chloroform people warn about it.

Get some on your hands or swallow some. You'll see right away that it's unhealthy.

As far as causing cancer goes, who knows. Many solvents are suspected of causing cancer, even naphtha.

When I say it’s unhealthy, I’m comparing it to ethanol, water, DMSO, and d-limonene. All four of those solvents are relatively safe to ingest. You should not ingest DCM.