I wanted to continue the long lasting debate on wiped film vs short path for distillation of cannabinoids. I think it is an appropriate time to rekindle this debate because lab society, summit, and others are now producing 20L distillation units with high flow rates. I will start by what I see to be the pros and cons of each. Feel free to comment, criticize or critique my pro/con list.
Wiped Film:
Pros:
-Throughput
-Automation
-Shorter time cannabinoids are exposed to heat
Cons:
-Color (Orange/Red pigments)
-Sometimes requires multiple passes
Short Path:
Pros:
-Fractions (process separates other components that WF can’t)
-Color
-Reactions (Boiling Flask allows for desired reactions like Delta 9 into Delta 8 or CBD into Delta 8 (@Deleted)
Cons:
-Time (Cannabinoids are exposed to heat for longer compared to WF which can degrade product)
-Flow rate (From my research it still looks like SPD is slower than WF with larger setups)
The high throughput comes at the cost of multiple passes. 2 minimum, likely 3.
I disagree with automation. Did you mean to say continuous operation? They are not very automated and require a good amount of attention and tinkering.
Yes they have shorter residence time, but I would say it doesn’t matter that much. People get in the high 90’s with short path with little to no CBN or other.
A con I would add to WF is cost. Probably the most expensive method in the industry. People like pope will go “yeah we sell units for 40k” but it doesn’t even come with the pumps or baths and it’s a 2inch which is like 200ml/hr.
I think WF definitely has a place at the high end of the market. The only limitation in size is how much $$ you got. I mean how big realistically can a short path get. All the shit on the market right now is just lab scale stuff. Excited to see the transformation into pilot/production plants.
I would agree with @slooty that the ability to scale WFE is very enticing, however most of the smaller labs which are in-house to a vertically integrated company, versus toll processors and large scale operations or commodity refinement such as hemp, are going to do fine with SPD or SBD.
IMO another pro to WFE is that often the systems are much more modular, although the SPD sector is getting better at this, and allow for a little more plug and play. Although I would have to say this is a bit more true of stainless systems where using KF/NPT/JIC fittings without extra adapters makes them optimal. We could probably start a whole thread on SS vs Glass, even just discussing their insulative and wetting pros/cons.
A con to WFE would be that they are often very time consuming to break down and clean, especially glass. Glass WFE bodies can be quite tedious and nerve wracking to clean, an ultrasonic cleaner and a good surfactant can help mitigate this.
I would say the lower overall residence time with WFE is a pro, especially with the ability to keep your feedstock in a separate addition funnel or feedtank at an isolated and lower temperature, while also having the ability to directly change and control your residence time on the evaporator with your wiper.
When referring to the “pass” on a WFE are we talking passes per distillation at one set of parameters, or overall distillations at a variety of parameters? WFE can be adapted to a recirculating system for your raffinate allowing continuous passes on the evaporator without having to reload the feed tanks manually.
Of course as mentioned before, the cost of the WFE dosing system is the inability to perform reactions the way SPD can, although this may not matter if your operation is only focused on D9THC/CBD refinement.
Passes meaning the number of times the material has to go through the system same parameters or not. Let’s say even if a WF distills at 1.5 L/hr, you still need an extra pass or two. To get through 10L of crude it would take you 14 hours for 2 passes or 20 hours for 3 passes. Not including cleaning which everyone who runs a WF despises. A short path that could hit 1 L/hr could keep pace with that same WF at a fraction of the effort and $$.
If residence time was a huge issue I would definitely agree more with wiped film (certain natural products do degrade crazy easy), but I just don’t think that it occurs that readily at temps below 200 C without UV/Oxygen.
Short paths from my experience are not scalable past a 5 liter range. If you have having success with a short path above this range please reach out to me.
Also please do not buy a short path to run colombos SOPs you can perform these reactions without his clay or a distillation apparatus. (specifically talking about cbd to delta 8 conversion)
Do you have personal experience with a peristaltic pump on WFE? I’ve only used gear pumps and gravity fed addition funnels, I would be interested to hear the pros/cons of Gear Pumps vs Peristaltic Pumps
@Phytoalchemy while they both provide metered flow of product here are the pros and cons.
peristaltic pump pros:
cleaning a peristaltic is a breeze! just replace the tubeing.
low maintence, easy to see and replace parts
visual indication of flowing product.
low cost
self primeing
can pump into and out of an evacuated container.
cons are:
tubeing has a service life, it needs to be replaced as preventitive maintence.
wrongly selected tubeing can contaminate product/kink/colapse under vaccum.
3)some tubes are propritery to the pump, leading to a “razor and blades” sales approach to consumables.
tube can break and lead to large air leak.
one day I happened to see a rotovap running backwards, liquid evacuation tube had broke leading to the machine completly flooding the cold traps and refilling the boiling flask.
If you choose to run a pump like this it helps if it has a buddy. This is how to wire a backup pump
when the primary goes into a emergency state the backup will kick in, no lost downtime or damaged equipment.
Can confirm, unless you have a short path that can do ~1 kg/hour of flow, about 3Kg in the boiling flask (10L flask) you start to see very bad isomerization of your D9 to D8, D10, D10A…
Short path is great if you are doing small (< 1kg runs) and you know what you are doing to keep temps low and total run times short.
Wiped film is for larger scale, but to get a comparable product takes multiple passes, and I believe it also leaves behind a distinct taste to the oil. I think SPD due to the entire volume of material staying at temp for longer, removes this “card board” or “burnt” taste better.
If you ask me both are not good methods for cannabinoid production. Once people perfect product of crystal cannabinoids at scale, I see distillation going away.
Heating natural products is just never a good idea.
Maybe Flash Chromatography, Shadow. There is a a lot of really interesting things happening is the new modality flash chromatography space.
QGA, While there is not much of market today for pure “mono cannabinoids” or precise ratio formulations (by this I mean forulatons of cannabinoids where maybe 7-10 cannabinoids are added from pure stocks in precise ratios), I think this is the logical progression for the industry. A few groups have tried to go down this route, and found out that there is no profit in being too early to the party. However, I think sooner than later a group will start selling formulations of cannabinoids that produce reliable and repeatable psychotropic results. They will do this and provide double blind clinical trial data to back it up. Once someone cracks the “effect” code for cannabinoids the floodgates will open on pure cannabinoids, and we will look back at this “distillation” phase of the industry as a “in mature” age in the industry.
I think we can both agree we are at least 10 years from this being clinical trials are a long way away.
Plus prolly around 99% of people who consume these products for medicinal value do this in the abscence of blind trial. All trials do is intiate that into prescription regiments for physicians.
But yes, chemically we may be stuck seperating by cannabinoids if a natural extract but it will most likely be all synthetic chemistry instead of purifying these compounds from their natural product.
Oh i think out side the FDA clinical trials for psychotropic effects are much closer than 10 years. A number of groups are reaching the capital and technical proficiency to do.
I agree synthesis is the way forward, but it is hotly debated. Using hemp derived CBD/CBG as starting molecules is also viable.
Clinical trials are supervised by the federal government… And no clinical trials i know of will be done at the end of this year that will be very impactful, if you disagree please show me the trial
Okay i guess we will have to agree to disagree. Double blind clinical trials on average take about 7-11 years to show efficacy in humans i believe.
What is debated about synthetics exactly?
No using hemp derived products is exactly what you want to avoid as a synthetic chemist. You want to avoid any natural product extraction and start with a cheap and available starting material.
The papers have not been submitted to the IRB yet. FDA does not control whether you are allowed to do clinicals. They just control the “legality of the drug” in the market place. With cannabis its a grey area but they cant accept the study until the DEA also gets invloved also, or they reschedule cannabis. GW had to go through extensive regulatory requirements in order for their drug to get FDA approval and with DEA oversight. It can now be picked up by insurers.
