Butane Honey Oil(BHO), essential oils extracted from cannabis, is one of the many uses for butane extraction systems. These systems vary greatly in method and efficiency. From Open Blast Extractors, to Closed Loop Extractors. Passive and active recovery. Butane results in one of the cleanest extractions of any solvent, making it an ideal method for extraction.
What are Solvents?
Essentially, a solvent is a substance that dissolves a solute, resulting in a solution (Solute + Solvent = Solution). In a solution, all of the ingredients are uniformly distributed at a molecular level and no residue remains. Solvents can generally be classified as polar and non-polar. In the case of cannabis, the solutes we are looking to dissolve are the cannabinoids, terpenes, and other active ingredients. Butane with create a solution with these compounds while leaving the solid plant matter behind. after the solution is made, the solvent must be purged, resulting in Honey Oil. Butane(along with propane, octane, and hexane) are hydrocarbons, meaning that they are composed entirely of carbon and hydrogen. Cannabinoids, and terpenes, have large hydrocarbon profiles. As a result hydrocarbon based extraction methods are particularly exceptional methods. There are many different solvents, however we will only be covering butane(and briefly, other hydrocarbons) in this post.
Butane as a Solvent
Butane is an organic alkane with four carbon atoms, gaseous at room temperature and atmospheric pressure. Highly flammable, colorless and easily liquefied. Butane (and n-Butane) are non polar hydrocarbon solvents that dissolve cannabinoids and terpenes extremely efficiently. No unwanted byproducts result in this solution. Having a very low boiling point, butane can be easily and efficiently purged from resulting BHO. Bonded hydrogen and carbon share two electrons, but not evenly. These electrons spend most of their time closer to the carbon. Since electrons have a negative charge, a charge differential is created. This differential is what is termed a dipole moment. Thus, when two hydrocarbon molecules with dipole moments get near to each other, they are attracted (termed London Dispersion Force). When running a BHO extractor, the butane will surround and penetrate the plant matter. Cannabinoids and terpenes then separate from the plant matter into a solution. The resulting solution should then be placed in a vacuum oven in order to purge the remaining butane from the essential oils.
Basics of a BHO Extractor
BHO extraction has a number of different methods, and systems. From Open Blast to Closed Loop (and a myriad of variations in each). The basic principle of a BHO extractor is to fill a column with prepared plant matter, and flood the column with your hydrocarbon solvent (butane, n-butane, etc..) and then collect the solution in some sort of collection vessel. In the case of open blast, the expelled solution would be collected on a pad or in a dish of some sort. In the case of a closed loop system (active or passive recovery) a collection pot is part of the system, and the solution will be collected in said collection pot. The solution will then be removed from the collection vessel and transferred to a vacuum oven to purge the remaining butane.
Cannbinoids and Terpenes
?-9-tetrahydrocannabinol (THC) Boiling point: 157C / 315 degree Fahrenheit ( Merck 200C @0.02). Properties: Euphoriant, Analgesic, Antiinflammatory, Antioxidant, Antiemetic
cannabidiol (CBD) Boiling point: 160-180*C / 320-356 degree Fahrenheit Properties: Anxiolytic, Analgesic, Antipsychotic, Antiinflammatory, Antioxidant, Antispasmodic
Cannabinol (CBN) Boiling point: 185*C / 365 degree Fahrenheit Properties: Oxidation, breakdown, product, Sedative, Antibiotic
cannabichromene (CBC) Boiling point: 220*C / 428 degree Fahrenheit Properties: Antiinflammatory, Antibiotic, Antifungal
cannabigerol (CBG) Boiling point: MP52 Properties: Antiinflammatory, Antibiotic, Antifungal
?-8-tetrahydrocannabinol (?-8-THC) Boiling point: 175-178*C / 347-352.4 degree Fahrenheit Properties: Resembles ?-9-THC, Less psychoactive, More stable Antiemetic
tetrahydrocannabivarin (THCV) Boiling point: < 220*C / <428 degree Fahrenheit Properties: Analgesic, Euphoriant
Terpenoid essential oils, their boiling points, and properties
ß-myrcene Boiling point: 166-168*C / 330.8-334.4 degree Fahrenheit Properties: Analgesic. Antiinflammatory, Antibiotic, Antimutagenic
ß-caryophyllene Boiling point: 119*C / 246.2 degree Fahrenheit Properties: Antiinflammatory, Cytoprotective (gastric mucosa), Antimalarial
d-limonene Boiling point: 177*C / 350.6 degree Fahrenheit Properties: Cannabinoid agonist?, Immune potentiator, Antidepressant, Antimutagenic
linalool Boiling point: 198*C / 388.4 degree Fahrenheit Properties: Sedative, Antidepressant, Anxiolytic, Immune potentiator
pulegone Boiling point: 224*C / 435.2 degree Fahrenheit Properties: Memory booster?, AChE inhibitor, Sedative, Antipyretic
1,8-cineole (eucalyptol) Boiling point: 176*C / 348.8 degree Fahrenheit Properties: AChE inhibitor, Increases cerebral, blood flow, Stimulant, Antibiotic, Antiviral, Antiinflammatory, Antinociceptive
a-pinene Boiling point: 156*C / 312.8 degree Fahrenheit Properties: Antiinflammatory, Bronchodilator, Stimulant, Antibiotic, Antineoplastic, AChE inhibitor
a-terpineol Boiling point: 217-218*C / 422.6-424.4 degree Fahrenheit Properties: Sedative, Antibiotic, AChE inhibitor, Antioxidant, Antimalarial
terpineol-4-ol Boiling point: 209*C / 408.2 degree Fahrenheit Properties: AChE inhibitor. Antibiotic
p-cymene Boiling point: 177*C / 350.6 degree Fahrenheit Properties: Antibiotic, Anticandidal, AChE inhibitor
Flavonoid and phytosterol components, their boiling points, and properties
apigenin Boiling point: 178*C / 352.4 degree Fahrenheit Properties: Anxiolytic, Antiinflammatory, Estrogenic
quercetin Boiling point: 250*C / 482 degree Fahrenheit Properties: Antioxidant, Antimutagenic, Antiviral, Antineoplastic
cannflavin A Boiling point: 182*C / 359.6 degree Fahrenheit Properties: COX inhibitor, LO inhibitor
ß-sitosterol Boiling point: 134*C / 273.2 degree Fahrenheit Properties: Antiinflammatory, 5-a-reductase, inhibitor
Butane Safety
First and foremost, Butane is HIGHLY flammable, and explosive when in a confined space. it requires only a 1.86% to 8.41% atmospheric concentration and an ignition source (of which there are plenty!). It is recommended to never use butane extractors in a closed, confined, or indoor space. Outdoors in the open air is the safest method. Plastic non sparking fans should be used to keep pooling of butane to a minimum. The concentration of butane can be kept diluted below combustion limits , by using a fan to disperse vapors as they accumulate. DO NOT. repeat DO NOT smoke in the vicinity of an extractor, or any other source of inflammable gases or liquids. in fact, leave your lighter in another location. Plastic clothing, and other forms of static charge can also generate a spark sufficient to ignite butane. Always keep a fire extinguisher and blanket on hand to handle any unexpected flames.
Sources:
https://medmen.com/blog/extraction-101-cannabis-extraction-methods-part-2/
https://en.wikipedia.org/wiki/Butane
http://cannlabs.com/extraction/
https://en.wikipedia.org/wiki/Solvent