DCVC high column load run on crude




I gave it a read and was quite interesting. That’s the first patent I’ve ever read and the format and wording were something that I am not used too but managed to decipher some good info from it. Even though they are detailing a super/sub critical co2 based extraction and purification some of the key ideas seem relevant to extraction with any solvent.

My favourite part is:

This makes me think that by placing a small amount of silica or another of those listed substances on top of your filter it may adsorb longer chain fats and waxes without picking up too many terpenes and cannabinoids. Any idea which of these materials may be suited for such a purpose?


At first glance that claim seems a bit all inclusive? Seems they are claiming that a bit of everything in the filter matrix is the patentable idea?

Silica get will stick to things but it is in the specific application within a column in a specific and tightly packed manner in which its properties are exploitable. Without packing the gel and forcing the solvent past it then the use of it for a filter medium is very limited. Extremely limited in fact.

When I see a patent claim that attempts to include the kitchen sink as an aspect of the invention I know with certainty it is not an enforcable patent. The small snippet you included is an example and for good reason. The author of that paragraph is including a hella bunch of different concepts in filtration as one claim and goes on to say that any one of those things may or may not be used?

Of course that is just a snippet of a patent but let me share something from my days when I was an engineer of some bigger projects in industry. Way over seven figure projects. I know I am gonna have to duck some tomatoes here but what I am gonna say is true but I bet you never heard it before.

Do you know why big manufacturers get patents on just about everything? Like a car manufacturer will patent even the knobs they use. Do you know why? It has nothing to do AT ALL with stopping other manufacturers from copyng their ideas.

For a manufacturer like GM for instance a patent is simply insurance. What it does as insurance is prevent the little guys in the world from patenting the ideas they see in say for instance a GM car and then turning around and suing GM for patent infringement. Patents stop “fishing expeditions” lawsuit wise of this type for a corporation of such wealth, and the expense of a patent is trivial to the expense of defending a patent infringement suit (which the plaintif hopes will settle out of court).

So I read patents from two ways. I see it as a way for a legitimate engineer to hold off the wolves of industry which will in the end gobble up the idea anyway and as a way to insure against patent infringement suits.


My thoughts were that they were hiding their key adsorbent material in the list and the other list items were there to throw ppl off. But I have no experience so I will go with your analysis that they include everything in the patent so people can’t phish for an infringement suit.

However to me it still seems like the idea of adding some specific adsorbent to either the material column or filter matrix could help bind fats and waxes without binding too much of our target molecules. Although I do not have any experience with these adsorbents and their use with Cannabis extracts so not sure which would be most appropriate to test. I also assume that the amount added would be crucial as too much would act similarly to a chromatography column and bind all of our targets as well as contaminants to the adsorbent and would require solvent gradients to elute from the material.

So my idea is to use a small amount of adsorbent to bind unwanted and highly non-polar fats and waxes without binding terpenes and cannabinoids. This is opposed to the classic use of silica as a stationary phase to resolve individual fractions of a solution containing different polarity solutes.


@Beaker Thanks for all your documentation and sharing all this! I see you mentioned height of the column doesn’t matter much for DCVC, but diameter does. Would I be able to use my 1 liter bvv filter funnel for this? It’s 12cm inner diameter and 13cm depth from filter plate to the top. If so, how high would I need to fill it with silica?


That is scaled way up but I believe the best DCVC I run is about 3-4 inches high. I cannot see a reason atm why a longer column would benefit given the nature of DCVC but also I have no experience outside of just the quick sep funnels I use. A taller column just means more solvent needs to pull through dry and does not hurt in my opinion except it consumes more resources.

Good luck!


I had a hard time finding silica gel 60 for a reasonable price, especially if it can only be used once. This stuff looks to be roughly the same micron size. Would it work just as well?


We sell silica 60 by the kilo. @coppertop


Any thoughts on a C18 dry load? @Beaker


That’s what you want, I posted up with pictures when I received mine,


HiMedia GRM7481 product information sheet,


I have never used reverse phase gel of any kind simply because of cost. Beyond cost the concept really is identical insofar as being able to easily adjust the solvent gradient in precise steps and pulling it through. My hunch is C18 would provide a better seperation but this is pure speculation based on reports from others who have used this stuff who seem to pull off much crisper seperations. However I have not seen anyone setting up to use reverse phase for a DCVC strategy but I believe it would only enhance separations.

As I recall my cost at the hobby level was four times that of silica gel 60. :nerd_face:


The thing that pinged my interest is that C18 is adsorbent of nonpolar compounds and is reusable over 100 cycles.

Dry loading and eluting with heptane over a Si60 column would probably yield a high resolution separation between lipids and cannabinoids sans polar contaminants. @Beaker


You can get fine resolution with regular phase and yes c18 columns can get more uses out of them but they are abhorrently expensive. Can clean regular phase with polar solvent washes and then non polar wash then re load the column.

There is a recipe online somewhere for a solvent mixture called “polar express” that is wicked polar and does not or at least should not dissolve your regular phase silica.

I used it to purify sugars via reg phase silica. Ill try to find the elutent conditions when i get a minute.


This sound right for the “Polar Express”?

Jonathan Rittichier
Harvard Medical School
"I would start with a special cocktail my colleague has affectionately named Polar Express (shout-out Brennan). Like EtOAc/hexane, you have a polar and nonpolar portion for the mobile phase. But for Polar Express, your polar portion is a three solvent mix (EtOAc:EtOH:AcOH {3:1:2%}) and your nonpolar portion is hexane or heptane. I have found this to be very effective at purifying acidic compounds. Evan better than DCM:MeOH:AcOH. Please see figure two of Green Chem., 2014, 16, 4060–4075 (DOI: 10.1039/c4gc00615a). "


Yup thats it i believe