Monday, August 10, 2015

Letter to the editor: look where some of the kidz are going

From last week's C&EN (because they're doing a double issue next week, so they're taking this week off...), an interesting letter to the editor: 
“Making Legal Marijuana Safe” outlined many issues with the current extraction solvent known as butane hash oil (BHO) (C&EN, April 20, page 27). This method requires a large up-front investment in closed-loop, high-pressure systems to contain and recover solvents. Safety concerns include explosion and fire risks for workers. 
The article then proposes a new extraction system using the greenhouse gas carbon dioxide. Although this CO2 extraction process seems to be a viable alternative, it only modestly shifts the safety risk from explosion to asphyxiation while doing nothing to eliminate the hazards of keeping gases under high pressure. Extraction by CO2 will still require closed-loop systems and large up-front capital investment to produce the desired extracts. 
A new Seattle-based company called BT Ingenuity has tackled the extraction process using a green chemistry approach. The company, founded by ACS member and ACS Medicinal Chemistry Fellow Tyrell Towle, uses a solvent that is ­biodegradable, does not bioaccumulate, and is nontoxic. The patented process does not require a closed-loop system and requires only minimal postextraction processing using Food & Drug Administration-approved ingredients. This new process eliminates the risk of both fire and asphyxiation for workers. It is highly versatile and provides control over the finished product. Finally, the solvent is recovered and can be reused in multiple extractions. 
The legal marijuana market will only continue to increase, and improved safety as well as green production processes will continue to be important for both producers and consumers. Innovative thinking will allow the industry to dramatically improve safety. 
Duncan I. Mackie
Carrboro, N.C.
Couple of things here. First, I agree that if there is one single thing that chemists getting into the cannabis industry should do, it would be to run the home butane hash oil business out of business. It's apparent to me that BHO is unsafe and causes tremendous amounts of injuries and property damage.

Secondly, I think it's interesting that Dr. Towle is quite young. I wonder how many young people are getting into the cannabis industry because of the relative lack of employment opportunities in more traditional arenas of chemistry? Also, undoubtedly, there is money to be made there. Developing... 


  1. After spending too much of my life watching South Park, my brain insists on turning Dr. Towle into Dr. Towelie....

    1. I never was that fond of the show, but you beat me to it.

  2. "BHO is unsafe and causes tremendous amounts of injuries and property damage." If only more people had realized this prior to the 2008 election...

  3. "...uses a solvent that is ­biodegradable, does not bioaccumulate, and is nontoxic." I'll bet this is ethyl acetate. This seems to be the thing these days for extracts. Claim that your extraction process is cutting edge and Green, when in fact all you are doing in a decades-old EtOAc extraction.

  4. Given the demand for products of this nature for decades, there have been plenty of homemade recipes for extracts. One popular choice is using ice, and it doesn't get any greener than water as a solvent. Perhaps someone can optimize and industrialize this process.

  5. Perhaps this is a matter of the grass being greener...