The CBD industry is flourishing, conservatively projected to hit $16 billion in the United States by 2025. Already, the plant extract is being added to cheeseburgers, toothpicks and breath sprays. More than 60 percent of CBD users have taken it for anxiety, according to a survey of 5,000 people, conducted by the Brightfield Group, a cannabis market research firm. Chronic pain, insomnia and depression follow behind. Kim Kardashian West, for example, turned to the product when “freaking out” over the birth of her fourth baby. The professional golfer Bubba Watson drifts off to sleep with it. And Martha Stewart’s French bulldog partakes, too.

What is CBD?

Cannabidiol, or CBD, is the lesser-known child of the cannabis sativa plant; its more famous sibling, tetrahydrocannabinol, or THC, is the active ingredient in pot that catapults users’ “high.” With roots in Central Asia, the plant is believed to have been first used medicinally — or for rituals — around 750 B.C., though there are other estimates too.

Cannabidiol and THC are just two of the plant’s more than 100 cannabinoids. THC is psychoactive, and CBD may or may not be, which is a matter of debate. THC can increase anxiety; it is not clear what effect CBD is having, if any, in reducing it. THC can lead to addiction and cravings; CBD is being studied to help those in recovery.

What is short-path distillation?

Short-path distillation is a compact purification technique that is suitable for laboratory applications where minimal instrumentation footprint is vital. This low-pressure method uses numerous flasks and, comparatively, brief extraction feeds to separate condensate media across paths of just a few centimeters. Conventional distillation techniques frequently require much larger apparatus to realize the requisite purity levels for application-specific requirements. Short-path distillation meanwhile can realize distillate purity levels of up to 99% using many components in a smaller working space.

How Does Short-Path Distillation Work?

In a short-path distillation arrangement, a liquid solution or emulsion is suspended in an evaporating flask that is connected via a short feed to a condenser or chilling unit. The evaporating flask is positioned in a heating mantle that slowly increases the temperature of the solution to pre-defined boiling points, triggering distinct compartments of the solution to evaporate.

Vacuum conditions are used to draw vapors via the feed into the condensing unit, where the separated gas-phase compartments of the liquid solution are cooled and changed back into liquids. This distillate material is divided into distinct flasks according to their weight, enabling chemists to easily combine multiple desirable elements from a single sample.

In the case of cannabis oil distillation, short-path distillation signifies an economical solution for separating terpenoids, cannabinoids, and flavoring chemicals, and both organic and inorganic contaminants. This technique does not require extra solvents to catalyze the distillation process and can offer high evaporation rates for higher levels of distillate consolidation with good degrees of automation.

What role does short-path distillation play in cannabis applications?

The process when using THC is often called fractional short path distillation. In the distillation process, you can extract the hundreds of cannabis compounds out individually because each compound has a different boiling point. After the extraction is complete you can add together the known compounds you want to make the best product for the customer.

Due to the expensive nature of the materials involved with cannabis, the short-path distillation technique contributes to the profitability of the processing operation.

Why is it a crucial step?

The crucial aspect of distillation purification is temperature. Other physical chemistry variables contribute to the effectiveness and efficiency, but temperature is critical to achieving a high yield of desired products. Vacuum is often used to enhance the process by allowing distillation at lower temperatures thereby reducing the potential of altering the chemical makeup of the distillates.

The short- path distillation is a crucial step to get the end product, CBD oil without terpenoids, flavonoids, and contaminates (by-products like residual solvents and pesticides can be removed).

What is the difference between extraction and distillation?

Distillation and extraction are extremely similar as they are both separating compounds. The difference is: Distillation is separating compounds based on boiling points. Extraction is separating compounds based on solubility in the extraction solvent.

For the cannabis industry, extraction involves the collection of oils from the plant material. Whereas distillation describes the process of purifying the extracted oil into desired constituents which can be incorporated into marketable goods.

How does short-path distillation separate organic and inorganic compounds? Why is this important?

Short-path distillation separates components from the extracted oil by capitalizing on the differing chemical characteristics of the constituent compounds. The solubility and vapor pressure of compounds in a mixture (among other characteristics) affect the evaporation step during distillation. By selectively targeting these physical properties of the materials involved, the experimental conditions for collecting predictable and reproducible constituents can be identified.

This is done primarily through measuring the vapor temperature and/or noticing a color change. The distillation is completely reliant on temperature.