THC-O-Acetate is a form (ester) of THC that is 300 percent stronger than normal THC. (1) Acetic acid – the compound in table vinegar – can combine with THC to form this acetate ester.
Does a similar chemical reaction occur when we use cannabinoid acid and terpene alcohol instead of acetic acid and active THC? And can we combine common compounds in the cannabis plant to crystallize terpenes, as well as terp diamonds?
What are esters?
A common type of ester is the combination of an alcohol and an acid. Ethanol, the alcohol that people regularly consume, combines with acetic acid to form ethyl acetate. All three substances are approved as solvents for cannabis processing in Canada, but acetic acid violates most laws in the United States. (2)
Esters require highly specific conditions in order to form. You can't just put alcohol and vinegar in a glass and expect ethyl acetate to form. That being said, other alcohols (and alkyl groups) can combine with other acids under certain conditions to make different esters.
What are terpene alcohols?
Terpenes are the slightly aromatic constituents of natural essential oils. There are many different terpenes, over 30,000, in myriad plants, including cannabis. (3) Terpenes consist of a certain ratio and arrangement of hydrogen and carbon atoms. However, different terpenes fit different chemical classifications in their identity due to their molecular structure. Some terpenes are actually chemically characteristic of alcohol.
An alcohol is an organic compound that contains an additional hydroxyl group (OH) attached to a specific carbon atom within the molecule. It should be noted that this describes a few different terpenes. In addition, terpene alcohols dissolve in a very specific way, so they can hypothetically be collected and separated from other types of terpenes.
Examples of terpene alcohols
What are cannabinoid acids and can they be combined with terpene alcohols?
One of two ingredients needed to make an ester, an alcohol, is found in cannabis. The second component is a carboxylic acid, a basic molecule with a COOH group (one carbon, two oxygen atoms, and one hydrogen).
THCa and CBDa are both considered cannabinoid acids because they are both bound to carboxylic acid. But can you combine pure cannabinoid acids like THCa with certain terpene alcohols and produce unknown esters?
Are there other cannabinoid esters?
An accomplishment by the notorious cannabis chemist Professor Raphael Mechoulam involved replacing a methyl group with a CBDa molecule. (5) This created a CBD methyl ester. To make this cannabinoid ester, the methyl group (CH3) must replace a hydroxyl group (OH) on the carboxylic acid attached to a CBD molecule.
While THC-o-acetate is less of a chemical feat, making CBD methyl ester has been seen as a more well-known feat. So is it possible to replace the hydroxyl group (OH) on THCa or CBDa with a terpene alcohol instead of a methyl group? And if so, what are the properties and effects of the following connection?
Problems with cannabinoid terpene esterification
The process of making esters can involve a solvent, but typically also requires something called an acid catalyst. You can hypothetically make various solvent-free esters using pressurized hydrochloride gas. (6) However, this should only be done by a person with advanced chemical experience as it requires many subsequent steps to establish a pure and safe connection.
A commenter on Instagram cited unknown techniques for supersaturating terpenes and THCa in solvents only to create firm and uniform co-crystallizations between cannabinoid acid and terpenes. While there is no evidence that this method actually works, the exact identity of the final extraction remains a mystery.
Pentane can be used to combine an alcohol and an acid into an ester. However, to repeat a critical step, an acid catalyst is typically required for this reaction.
Another question also remains open. What happens to a terpene like myrcene if we let it stand in a highly specific solvent under the right conditions?
Check out this story to learn more about cannabinoid salts. And stay tuned to see if methylene blue can be made from certain cannabis extractions.