Not all cyclic ethers in bio-oil, like eucalyptol, could be converted
into aromatic hydrocarbons via the acid-treatment. 1,3,3- Trimethyl-2-oxabicyclo[2.2.2]octan-6-ol (TOCO) was found in the raw bio-oil and it also could be efficiently converted versus the prolonged residence time, as shown in Fig. S4. TOCO has a similar structure with eucalyptol, but it contains an additional hydroxyl group. The presumed reaction pathways for its isomerisation to terpenoids were presented in Scheme S4 in Supporting
information.