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Hydrocarbon extraction

Hydrocarbons are organic compounds that are made of only hydrogen and carbon atoms. The most commonly used hydrocarbons for extraction are butane and propane. The process begins with the extractor {call-out, text:A person performing the extraction procedure} filling a stainless-steel column with ground plant material which is then hooked up to a tank filled with butane or propane. The gasses wash over the plant material in that column, dissolving the trichomes. The mixture flows down the column by gravity into a collection chamber at the bottom of the extraction column. Once the wash is complete, the extractor closes the valves for the hydrocarbon and the column. Then the collection chamber is detached from the extraction column and the mixture is poured onto a dish, commonly a borosilicate (heat-resistant) glass tray. The tray is placed inside of a temperature-controlled vacuum oven to begin pulling the vacuum on the mixture. This lowers the boiling point {call-out, text:The temperature at which a liquid changes to a gas} of any compounds in the mixture with the goal of removing butane and propane from the extract. Once the temperature inside the oven is stable, the vacuum valve is opened on the oven to pull a vacuum. This allows for the off-gassing of any compounds that have a boiling point lower than the temperature inside the oven. This process is often referred to as ‘purging’.1 Once the purging is complete, the pressure inside the oven is brought back to normal atmospheric pressure, after which the oven can be opened and the extract can be removed. References:
  1. Azmir, J.; Zaidul, I. S. M.; Rahman, M. M.; Sharif, K. M.; Mohamed, A.; Sahena, F.; Jahurul, M. H. A.; Ghafoor, K.; Norulaini, N. A. N.; Omar, A. K. M. (2013). Techniques for extraction of bioactive compounds from plant materials: A review. Journal of Food Engineering, 117(4), 426--436.