{"doi":"10.15760/etd.4022","title":"Mechanistic Rationale for Toxic Aerosol Formation from Vaping and Dabbing with a Focus on Ketene Formation from Semi-Synthetic Cannabinoids","abstract":"Cannabis vaping is a relatively new route of administration that is increasingly common among youth and young adults. Cannabis vaping has been associated with cases of acute lung injury, especially among youth, and most often involves the heating and aerosolization of high-potency products having cannabinoid concentrations of ~ 50 % - 98 % w/w. Proponents argue that vaping is safer than smoking due to the characteristically lower temperatures and fewer plant materials. However, the extreme cannabinoid concentrations, along with non-natural formulations having undisclosed additives, require studies of the health effects of these products. Despite the popularity of cannabis concentrate vaping, especially among young people, research and research-informed regulatory oversight are currently lacking. The work described herein focuses on the production of toxicant emissions upon vaping semi-synthetic cannabinoids. Semi-synthetic cannabinoids are typically synthesized from hemp-derived CBD, and most are currently federally legal. They exert psychoactive and intoxicating effects that are comparable to or greater than those of Δ⁹-THC. Chapter 2 focuses on semi-synthetic acetylated cannabinoids such as delta 8 tetrahydrocannabinol (∆8-THC-OAc). Acetylated cannabinoids share a common phenyl acetate substructure with vitamin E acetate (VEA), which has been associated with E-Cigarette and Vaping Use Associated Lung Injury (EVALI). The phenyl acetate moiety of VEA releases toxic ketene upon heating and aerosolization. I provide evidence that ketene was generated from vaping and dabbing (flash vaporization on a hot surface) ∆8-THC-OAc at commonly used vape temperatures. Quantitative analysis performed via QNMR, HPLC-MS, and GC-MS led to the determination that the ketene levels generated via one dab or vape were above the exposure limits for ketene. A study concerning the mechanism of ketene formation was performed (as presented in chapter 3) utilizing cannabinol acetate (CBN-OAc). CBN-OAc-D3 was synthesized to enable tracking of deuterium loss from the acetate methyl to provide evidence for a mechanism involving ketene generation. Additional experimentation in an anerobic environment showed that O2 has a marked oxidative effect on the formation of ketene. Ultimately, a mechanism was proposed that features a β-scission reaction on the acetate moiety, resulting in ketene gas production. Another semi-synthetic cannabinoid being marketed is THC-JD or ∆8-THC-C8. The structure is ∆8-THC (a ∆9-THC isomer has also been reported) with its carbon tail extended to eight (from five) carbons. To test for the presence of THC-JD (Chapter 4), five commercial samples were acquired, and their neat e-liquids were extracted. GC-MS analysis determined that none of the commercial samples contained","journal":"PDXScholar  (Portland State University)","year":2025,"id":576247,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9554,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2025-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1191946,"name":"Kaelas Munger","orcid":"0000-0002-4360-9954","position":0,"is_corresponding":true}],"reference_count":0,"raw_metadata":null,"created_at":"2026-07-19T02:57:56.636458Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}