The United States (US) has historically been the biggest importer of cannabis products until recently when the legislators legalized hemp research. Since then, the processing of cannabidiol (CBD) has played an important role in overall hemp production and profitability. In this study, with the primary goal of extraction and purification of CBD oil, the focus is on the removal of wax from the extracts of Cannabis Sativa L. (hemp). Once the extraction was carried out, the solution underwent a freezing process (-68 °C for 24hrs), leading to partial flocculation of the wax compounds such as phospholipids, heavy metals, chlorophyll, fatty acids, and other inhomogeneous biopolymers. This process was followed by low-pressure processing using wiped-film molecular distillation (WFMD) to remove terpenes (first stage) and separation of CBD-rich product from the wax (second stage). In the first stage, the decarboxylated extract was fed and processed at 400Pa, evaporation temperature of 130 °C, and internal condenser at -10°C which leaves about 20wt.% as terpenes. The obtained product was subjected to WFMD again in the reduced pressure of 40Pa to evaporate the majority of the feed at 180°C leaving about 20wt.% at the bottom as wax. The CBD content of all obtained samples was tracked using high-performance liquid chromatography (HPLC). Of the original hemp extract, the freezing method removed the only 8wt%, accounting for the majority of the co-extracted heavy metals. First-pass WFMD drew 4wt.% of the original extracts, while in the second stage, less than 20wt.% was separated as wax. On the other hand, nearly one-half of the original feed was obtained as the final product with a CBD content of over 70wt.%. This accounts for the majority of the CBD available in the extracted crude oil. It can be concluded that with the reduction of WFMD pressure, CBD can be further concentrated.

Enriching CBD in hemp extracts: Wax removal

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.