Removing chlorophyll with graphite/silica/acetonitrile

From Gray Wolf,

Suggested by Pharmer Joe for post extraction removal of chlorophyll :

Materials needed:

Flash silica
Fritted funnel
Erlymeyer flask with vacuum side arm
Vacuum pump


Dissolve oil in acetonitrile
Add 5% (oil wt) graphite and stir 1 hour
Make slurry with silica and acetonitrile
Set up filter apparatus
Pour silica slurry onto fritted funnel
When the solvent drains just above the bed surface; pour graphite mixture and apply gentle vacuum.
Clean equipment up afterwards with Acetone.

(Question to GW from SkyHighLer,)

Am I to assume pure graphite is pure graphite?

From eBay:

Pure Graphite Powder Quart/$16.99

[url]Graphite Powder Pure 44 microns - Uses include: dry lubricant, epoxy (Quart) | eBay

“Flash silica” at Sigma-Aldrich,


Seems to be the same as HiMedia’s GRM7481 available via Amazon, 500g/$27.



(GW’s reply,)

Pharmer Joe says yes.


I ordered a liter of reagent grade (ACS) acetonitrile from Right Price Chemicals, $33.74 plus $15.78 shipping and handling, $49.52 total.


(I only bought this out of curiosity, and to ensure Right Price Chemicals is still a no hassle supply house.)

It’s neither very polar or non-polar, between acetone and isopropyl alcohol.

Polarity table,

[url]Solvents and Solvent Effects in Organic Chemistry (Reichardt) : Free Download, Borrow, and Streaming : Internet Archive

The FDA Q3C residual standard tables list it as Class 2 with a maximum residual recommendation of 490 ppm, that’s why I didn’t pursue it previously, it needs a thorough purge as you would with hexane, which has a max residual recommendation of 290 ppm.


The above quotes are from this thread,


how well would a heated Bentonite and carbon scrub work? i recently made about 2 gallons of straight black looking crude mixture from kief.

1 Like

Interesting technique involving the removal of green stuff. Let me add a bit.

Chlorophyl can also be removed by preboiling the compound in isopropyl alcohol at about 95% purity cut with water for a half hour or so. Then when run through an aluminum oxide column the chlorphyll(s) will remain trapped on top of the filter along with waxes and such. If done with cryogenically cooled solvents after the boil and dumped into a precooled to cryogenic temps an alumina column the process is nearly 100% efficient.

If there is an advantage here it is that the isopropyl alcohol is relatively benign in use around humans, is cheap, and is extremely simple to do. I am not familiar with the original technique so cannot speak to the strengths there obviously but it does look very cool albeit a bit more involved.

Here is a visual on the results of the preboiled iso and compound.