TY - JOUR
T1 - p-Menthadienes as Biorenewable Feedstocks for a Monoterpene-Based Biorefinery
AU - Tibbetts, Joshua D.
AU - Bull, Steven D.
N1 - Funding Information:
The authors would like to thank EPSRC for funding through the Centre for Doctoral Training in Sustainable Chemical Technologies (EP/L016354/1). Södra Forestry Cooperative is thanked for supplying an authentic industrial sample of CST.
Funding Information:
The authors would like to thank EPSRC for funding through the Centre for Doctoral Training in Sustainable Chemical Technologies (EP/L016354/1). S?dra Forestry Cooperative is thanked for supplying an authentic industrial sample of CST.
PY - 2021/6/1
Y1 - 2021/6/1
N2 - A terpene-based biorefinery is described that uses crude sulfate turpentine (CST) and gum turpentine (GT) to produce mixtures of p-menthadienes (p-MeDs) as biorenewable terpene feedstocks. An acid catalyzed ring opening reaction (6 m aq. H2SO4, 90 °C) is first used to convert the major bicyclic monoterpenes (α-pinene, β-pinene, and 3-carene) in untreated CST (or GT with 5 mol% Me2S) into mixtures of monocyclic p-MeDs. These unpurified sulfurous p-MeD mixtures (α-terpinene, γ-terpinene, and isoterpinolene) are then used as feedstocks for oxidative aromatization (OA), ozonolysis, Diels–Alder, and hydrogenation reactions to produce p-cymene, fragrances, anti-oxidants, drugs, biopolymers, and biofuels. Mechanistic studies of the OA reaction used to convert the p-MeDs into p-cymene reveal that p-cymene hydroperoxide acts as an initiator to produce polar radical intermediates that are stabilized by DMSO generated in situ through aerobic oxidation of Me2S. This enables CST and GT to be converted into biorenewable p-cymene in 50–60% yields (two steps) using a process that only requires aqueous acid, oxygen, heat, and a final distillation step.
AB - A terpene-based biorefinery is described that uses crude sulfate turpentine (CST) and gum turpentine (GT) to produce mixtures of p-menthadienes (p-MeDs) as biorenewable terpene feedstocks. An acid catalyzed ring opening reaction (6 m aq. H2SO4, 90 °C) is first used to convert the major bicyclic monoterpenes (α-pinene, β-pinene, and 3-carene) in untreated CST (or GT with 5 mol% Me2S) into mixtures of monocyclic p-MeDs. These unpurified sulfurous p-MeD mixtures (α-terpinene, γ-terpinene, and isoterpinolene) are then used as feedstocks for oxidative aromatization (OA), ozonolysis, Diels–Alder, and hydrogenation reactions to produce p-cymene, fragrances, anti-oxidants, drugs, biopolymers, and biofuels. Mechanistic studies of the OA reaction used to convert the p-MeDs into p-cymene reveal that p-cymene hydroperoxide acts as an initiator to produce polar radical intermediates that are stabilized by DMSO generated in situ through aerobic oxidation of Me2S. This enables CST and GT to be converted into biorenewable p-cymene in 50–60% yields (two steps) using a process that only requires aqueous acid, oxygen, heat, and a final distillation step.
KW - biorefinery
KW - CST
KW - monoterpenes
KW - terpenes
KW - turpentine
UR - http://www.scopus.com/inward/record.url?scp=85103210752&partnerID=8YFLogxK
U2 - 10.1002/adsu.202000292
DO - 10.1002/adsu.202000292
M3 - Article
AN - SCOPUS:85103210752
SN - 2366-7486
VL - 5
JO - Advanced Sustainable Systems
JF - Advanced Sustainable Systems
IS - 6
M1 - 2000292
ER -
