Butane Residue Test Results

[Gray Wolf]

The boiling point is where internal vapor pressure exceeds atmospheric pressure of 14.7 psi holding it in check.

Liquids can't exceed their boiling points, unless you pressurize them. That is because boiling liberates the heat of vaporization and cools down the pool.

We run our collection pots at 85F when distilling, but the internal temperature doesn't reach that until the propane and butane are essentially gone, leaving Pentane at 100F, as the next lowest boiling point.

If we never take the collection pot pressure below zero gauge (14.7 psi atmospheric pressure), and don't reach 100F internal temperature, the Pentane and larger molecules are left behind.

 

[SkyHighLer]

^ And the isopentane?

"Boiling point 27.8 to 28.2 °C; 81.9 to 82.7 °F; 300.9 to 301.3 K"

https://en.wikipedia.org/wiki/Isopentane


Also, since this is so confusing, when you say "We run our collection pots at 85F," does that mean you maintain an actual water bath temp of 85F near the pot?

And if you're pumping unlimited energy into the water bath to keep the temp of the water near the collection pot at 85F (assuming you have a powerful temp controlled heater and circulating pump,) how do you know you're boiling solvent isn't roiling too high, and passing some of the impurities along?

I'm asking in all seriousness, I think if I were to operate a CLS I'd need to see the degree of boil off, I don't like doing much of anything, except copulating, blind.

 

[Old Gold]

^ And the isopentane?

"Boiling point 27.8 to 28.2 °C; 81.9 to 82.7 °F; 300.9 to 301.3 K"

https://en.wikipedia.org/wiki/Isopentane


Also, since this is so confusing, when you say "We run our collection pots at 85F," does that mean you maintain an actual water bath temp of 85F near the pot?

And if you're pumping unlimited energy into the water bath to keep the temp of the water near the collection pot at 85F (assuming you have a powerful temp controlled heater and circulating pump,) how do you know you're boiling solvent isn't roiling too high, and passing some of the impurities along?

I'm asking in all seriousness, I think if I were to operate a CLS I'd need to see the degree of boil off, I don't like doing much of anything, except copulating, blind.

My concerns exactly.
And GW: Isn't the heat being applied to a potential azeotrope, with a lower boiling point than the pure n-pentane or iso-butane would have alone (and higher than pure n-butane)?

 

[Gray Wolf]

^ And the isopentane?

"Boiling point 27.8 to 28.2 °C; 81.9 to 82.7 °F; 300.9 to 301.3 K"

https://en.wikipedia.org/wiki/Isopentane


Also, since this is so confusing, when you say "We run our collection pots at 85F," does that mean you maintain an actual water bath temp of 85F near the pot?

And if you're pumping unlimited energy into the water bath to keep the temp of the water near the collection pot at 85F (assuming you have a powerful temp controlled heater and circulating pump,) how do you know you're boiling solvent isn't roiling too high, and passing some of the impurities along?

I'm asking in all seriousness, I think if I were to operate a CLS I'd need to see the degree of boil off, I don't like doing much of anything, except copulating, blind.

A valid point, though Isopentane has never shown up in any of the analysis, at the test cut off limits. That may reflect the frequency of its presence in the gas we use, or that by stopping at zero gauge, the pot temperature never catches up.

I also misspoke, in that 85F is the upper range of 70 to 85F. Below 70F and it takes forever. 70/85F is also the range we run the pot for collection, unless we are churning out bulk oil.

The internal and external pot temperatures are not the same. Even sitting in 85F water, we form heavy ice rings around the pot when the propane content is high.

As long as you are boiling, the pot solution temperature will be at the boiling point of the solution at that pressure. The heat isn't to boil the mixture, it is to offset the refrigeration of boiling under vacuum, so that the solution temperature doesn't fall so low that the process grinds to a virtual halt.

We've tried several systems for heating the water. Silicone heat mats with aquarium pump, Sous Vide, and controlled hot water circulation system.

The controlled system worked best, and consisted of a pump pushing water through a 6" X 12 or 24" sanitary tube, with a heating element and thermocouple inside. The temperature is controlled by PID and the circulation has a manifold that directs the flow under the collection pot.

Here is a dirty peeecture of my first prototype for collection pot heat. I used a similar one for jacketed column heat, but used 6Kw heating elements, instead of only 2Kw for the pot.

 

[SkyHighLer]

^ A solid answer to part of my question, you're measuring the temperature of the water bath. You input massive energy into the system, and you could input more (you speed up the transfer of energy by raising the temperature of the water bath when you "are churning out bulk oil."

GW, from above post, "I also misspoke, in that 85F is the upper range of 70 to 85F. Below 70F and it takes forever. 70/85F is also the range we run the pot for collection, unless we are churning out bulk oil."


Which begs a basic question you didn't answer, is there a limit to the amount of energy you can input via the water bath before liquid in the collection pot is aspirated during recovery?

 

[Gray Wolf]

^ A solid answer to part of my question, you're measuring the temperature of the water bath. You input massive energy into the system, and you could input more (you speed up the transfer of energy by raising the temperature of the water bath when you "are churning out bulk oil."

GW, from above post, "I also misspoke, in that 85F is the upper range of 70 to 85F. Below 70F and it takes forever. 70/85F is also the range we run the pot for collection, unless we are churning out bulk oil."


Which begs a basic question you didn't answer, is there a limit to the amount of energy you can input via the water bath before liquid in the collection pot is aspirated during recovery?

I suspect violently boiling butane is more likely to pick up and transport other molecules, than a light simmer. I have no empirical data to support that thought.

For sure, when the butane evaporates away, the temperature will start to rise, and the pressure will start to drop. Both good indicators to stop.

 

[SkyHighLer]

I came across this little ditty from a year ago by A6 Grower,

"I distill at 60F, theres really no reason to go higher. It also makes it easier at the end to stop when you have a small puddle of liquid left. Pour the last bit out or just let it evap in a safe place. Clean everything up and your should be good."

https://www.icmag.com/ic/showthread.php?p=7221528&highlight=recovery+tank+valves#post7221528

 

[Old Gold]

I also suspect that the more rapidly you boil (higher heat transfer to the boiling liquid), the less control over a collectible fraction you will have.
Violently boiling butane definitely recovers more monoterpenes than a slowly simmered solution, as evidenced by a connoisseur's nose.

^An internal thermometer that catches the temperature spike is key, and I would think that an honest internal temperature of 32°F (plus a small "spike") at precisely 0psi would be the ideal finishing point.

 

[SkyHighLer]

The whole residual solvent spiel from Analytical 360, and no mention of non-volatile residue, because the state regulatory board makes no mention of it, other than the 99% or purer solvent 'suggestion.'



"What are residual solvents?

Hydrocarbon gases like butane and propane and organic solvents like ethanol, isopropanol and hexane are used to extract the essential oils out of cannabis to create highly concentrated, purified extracts. Residual Solvents are the solvents that remain in cannabis oils, shatters, waxes and budders after these extractions or after post-extraction processes such as winterization. Often the solvents used are not completely removed by purging with vacuum or heating, and so they can remain in the products that are smoked or inhaled by users in appreciable quantities. We test concentrates for residual solvents so that consumers have the best possible information available when choosing a finished extract.

The benefits of concentrates for users are obvious—high concentrations of cannabinoids can be delivered; a smaller amount of material is smoked for the amount of THC/CBD consumed, so that less toxins may be inhaled by users. The potent extracts can also be used to make edibles with high levels of cannabinoids for oral consumption. In some extracts, terpenes are also highly concentrated, invoking the full entourage effect, giving the maximal effect and superior taste.

What solvents are safe and at what levels?
Solvents commonly used for extraction include butane, propane, hexane, acetone and ethanol. The safety of many of these solvents has been studied. The US pharmacopeia has set guidelines as to what amount of a particular solvent a person can be exposed to on a daily basis without developing complications due to overexposure. The types of solvents are divided into three classes. Class 1 organics should never be used. Class 2 organics are not recommended for use outside of a Good Manufacturing Practice environment where these substances are tightly controlled and continuously monitored due to their dangerous effects. Class 3 are solvents that present no known human health hazard at levels normally accepted in pharmaceuticals. However, there are no long-term toxicity or carcinogenicity studies for many of the solvents in Class 3, and so safe levels for chronic use of these products have not been established.

Class 3 solvents commonly used for making extracts are Isopropanol, Ethanol, Acetone, Heptane, and Ethyl Ether and are regarded as presenting low toxic potential. Permitted daily exposure limits (PDEs) for these solvents have been published, and they have been shown to have low acute toxicity and no genotoxicity in studies on animals and in humans, and so are permitted at reasonable levels. Propane and Butane, two of the major solvents used for preparing extracts, are not on the Class 3 list but are regarded as safe.

The Washington State Liquor Control Board requires that solvent-based extracts using hydrocarbon gases that include n-Butane, Propane, Heptane and other solvents for use in inhalable extracts must be of at least 99% purity and that the products must undergo a residual solvent test. Under WAC Chapter 314-55-104, the parts per million for one gram of finished extract cannot exceed 500 ppm of residual solvent or gas when quality assurance tested per RCW 69.50.348, which is about 10 times lower than the limits set forth for Class 3 residual solvents by the FDA/International Conference on Harmonization. This recommendation is based on a 10 gram per day consumption level for a 50 kg person (50 mg/day). Extracts made from food grade ethanol, glycerin, propylene glycol, or CO2 of at least 99% purity do not require residual solvent testing.

Residual solvents are typically not acutely toxic but may have a long term effect on exposed individuals. An exposed person may exhibit eye, nose, and throat irritation, nausea, headaches, dizziness, fatigue, and allergic skin reaction. Propane and Butane are made by distillation of crude oil or refined natural gas, and are odorless, flammable hydrocarbon gases commonly used in lighter fluid, for fuel, for adhesives, cleaning solvents and degreasers. All of these products have been used for intoxication in their own right, and the effects of these include dizziness, euphoria, nausea, confusion and headaches and at higher levels can cause central nervous depression, respiratory and cardiac arrest. The key to using solvents safety in extracts is to use only very pure Class 3 solvents or highly purified propane and butane.

Butane
The MSDS for Power Butane 5x says it contains n-Butane, Isobutane, Propane, and other materials at no greater than 2% concentration (would need to be at least 99% hydrocarbon solvent under WA State law) but this varies from product to product. This agrees with our assessment of Mega Plus 5x lighter fluid which contains 4.8% Propane, 17.3% Isobutane, 76.5 % Butane, 1.3% Isopentane and 0.12% Pentane, along with another unidentified broad peak that represents roughly 1%. It is important to use hydrocarbon gases that come with an MSDS, which is required to list all components that comprise > 1% of the material and carcinogens that comprise > 0.1% of the material, since these are toxic at very low concentrations. 5x Butane and even 99.999% Butane contain significant amounts of the solvents Isopentane and Pentane and this unidentified solvent. After purging, the heavier Isopentane and Pentane remain in concentrates at higher concentrations than Propane and Butane because of their higher boiling points, and so are often present in larger quantities. These solvents are not particularly acutely toxic. This finding is of concern, however, because some preparations of Butane may contain small amounts of Benzene and 1,3-Butadiene, both of which are carcinogenic. How much of these materials may remain in concentrates after the lower boiling point materials are purged is currently under investigation in our lab using our new method. Our data also shows that with proper purging and product control residual solvents can be almost completely removed from concentrates.

What are unsafe solvents to use?
Naphtha and Hexane are other solvents used for extracting cannabinoids and are worthy of mention. Hexane is a petroleum distillate containing 6 carbon atoms, and is neurotoxic. Chronic exposure results in myelin sheath and axon degeneration. It has also been linked to Parkinson’s disease. Naphtha, found in kerosene, paint thinner, and used as a fuel, is also a petroleum distillate and contains heavier hydrocarbons such as n-Octane, n-Nonane, cycloalkanes, and branched alkanes of similar molecular weight. Naphtha and other byproducts found in the mixture are potentially cancer-causing. Because of these data, we do not recommend the use of these solvents for making concentrates.

What we offer
Analytical360 offers a validated testing method to determine the amount of residual solvents introduced during processing of concentrates. By monitoring the ppm levels of solvents we can will help identify raw materials and products that are free of harmful contamination. We are currently testing for residual solvents using GC-FID coupled with headspace sampling which is the technique recommended by USP 467 for residual solvents in pharmaceuticals. We have developed an in-house method that allows us to detect the light gases not included in USP 467. We are currently testing for propane, isobutane, n-butane, isopentane, n-pentane, isopropanol, ethanol, acetone, hexane and naphtha all in one assay.

The method currently utilized by Analytical 360 for testing residual solvents is the Gas Chromatography (GC) unit coupled with a headspace sampler and a Flame Ionization Detector (FID). Gas Chromatography is used in analytical chemistry for separating and measuring compounds that can be easily vaporized without decomposition. This test allows chemists to determine the purity of a particular substance, or identify and measure the individual components of a mixture. The process separates compounds on the basis of boiling point, or vapor pressure, similar to fractional distillation. An FID operates by detecting the ions formed from the combustion of the injected organic compounds with Hydrogen gas. The amount of detected ions is proportional to the concentration of each organic species in the mobile phase gas stream. As compounds elute off the column as determined based on their relative vapor pressures, their amounts are determined by the collection of ions by a high voltage detector. The current across the detector is directly proportional to the rate of ionization – which in turn depends upon the concentration of hydrocarbon in the sample. The ratio between the signal produced and the quantity is generally equal to number of carbon atoms for hydrocarbons. Oxygenates and other species that contain heteroatoms tend to have a lower response factor. Carbon monoxide and carbon dioxide are not detectable by FID.

Reference: AHPA Guidance on Residual Solvents in Extracts"

http://analytical360.com/cannabis-analysis-laboratory/residual-solvent-testing


USP 467 referenced above,

http://www.usp.org/sites/default/files/usp_pdf/EN/USPNF/generalChapter467Current.pdf



I have repeatedly spoken with the cannabis testing labs, they won't even discuss NVR testing without full funds upfront.

 

[CrazyKappa]

Thank you so much for this, it has helped alot. I do not have a CLS yet, but did just buy a closed pressurized column from best value vacs, and it can be upgraded to a CLS later. I will be taking every percation however, as its still open blasting, just with better recovery rates, and the option to upgrade later.

Its been some time since you reviewed butane cans, who do you feel has the best value at the moment? I have a fair amount of trim to run, just ordered a 2lb sleeved column, and a 5gal vac chamber.

I want a good deal, but i dont want to regret it either, as ill prob need a master case to get the job done. I cant take the chance of funky butane... Any advice would be very much appreciated!

Thank you very much!

 

[SkyHighLer]

Master case... why not just buy a tank or two from BVV, the USA grade preferably, though the slightly cheaper refrigerant grade (R-600 and R-290) should be ok. Unless you're going to distill it, please test any refrigerant grade first before using any given lot. Go back a few posts to where I have my simple test procedure posted up, and do it, or don't open extract with the bulk tanks coming out of Asia.

What are you seeing tempting deals on?

Link to my test procedure,

https://www.icmag.com/ic/showpost.php?p=7683783&postcount=666

 

[CrazyKappa]

I was looking at neon 5x for $175, neon 7x for $205, neon 11x $240, whip-it 5x $260. Though after talking to my partner, he just wants to run like a lb of trim at first, so for now, i will likely just pick up 3 cases.

Who is the best of the cheaper brands, a 50lb tank from BVV is 290 shipped, only its only equal to 65 300ml cans.

Also, lets say i only had 1/4lb of trim i wanted to run separate, will i lose efficiency by running that small of a amount in a 2lb column? I know you don't want to run 100% capacity, or it will hurt yield, but never heard anyone say there was a minimum.

 

[SkyHighLer]

Maybe $10 cheaper at Ecogreen,

https://ecogreenindustries.net/product/24lb-cylinder/

BVV has a buy two get one free deal on.

http://www.bestvaluevacs.com/buy2get1free-r600-30lb.html


Neon should be fine, check out Ignitus.

 

[CrazyKappa]

Would love to jump on that deal, but the bank just wont allow it, in the middle of a massive upgrade, and its stalled as is. What do you do with the tanks after? Do you get money for recycling them?

So you would go Ignitus over neon? Price is about the same, should i go 5x, 7x, or 11x? Do i need to worry about manufacturing dates with them, or are they pretty consistent, no smelly shit?

Thank you very much!

 

[SkyHighLer]

The head of Iginitus was formerly the American consultant with Neon in China, he knows what's going on with the entire process chain. They're both about the same cost, and probably quality.

Filtering more times doesn't necessarily increase the purity if you're not checking the results, and they don't have testing procedures with high enough resolution to do so... all they have is ASTM D2158 which just starts to measure the non-volatile residue (mystery oil) at the baseline found in the worst canned butane. So if a manufacturer's activated carbon filter stack is oozing nasties, and needs to be changed out, they'd never know it. Why I strongly suggest testing a can or tank of each lot yourself.

I noticed a new canned N-butane offering, and ordered a case for testing, and possible use,

https://www.amazon.com/gp/product/B01LXHX63T/ref=od_aui_detailpages00?ie=UTF8&psc=1

 

[SkyHighLer]

Blue Flame 11X had 0.031g of residue

Blue Flame, USA, 300ml/167g can, reads on the bottom "22821 16056 09"

Supposedly just N-butane, boil off temperature confirmation.

The substantial amount of non-volatile residue (mystery oil) was clear and odorless.

I'm stuck with the rest of the case...

 

[TerpChild]

Sky thanks for all of this work, it really is outstanding! After checking the list out i picked up whip it premium and really liked it. Just wanted to chime in as i am new on here and i really appreciate this resource, i am sure u have helped many people from wasting precious coin on dirty tane! Also showing how important it is to never assume anything and check things out for oneself. Thanks again!

 

[SkyHighLer]

You're welcome, I'm retesting those pictured next.

 

[TerpChild]

Oh cool bro! Curious about how the neon 5x will test now as a shop near my house has 12pks for $20 and masters for $140. I bought a 12pk of moorpark for $17 for my torch and to test on a small blast of trim, so i will post about how that oil comes out. But it smells fine and doesnt leave alot of residue on the mirror and ur tests were good for it so it should be fine. Curious about the other tests too! Thanks again!

 

[TerpChild]

Ok so the moorpark worked fine for my trim test run, no strange odors or tastes in the shatter.
Hey SH, any chance that you re-
tested the neons yet? There is alot of it available around me for cheap. The 11x is all over the internet but i wonder if its any cleaner than the 5x.