Mechanism and kinetics of the pyrolysis of β-pinene to myrcene

- The pyrolysis of β-pinene and its primary products were investigated.
- Some small molecules and newfound C10H16 isomers were identified.
- The reaction mechanism of products from β-pinene were disscussed.
- More rigorous kinetic model is presented for the first time.
- The kinetic model of pyrolysis of β-pinene lay a foundation for process optimization.

Myrcene, an important intermediate for the production of fine chemicals and pharmaceuticals, is mainly produced by the pyrolysis of β-pinene in the industry. The study of the direct pyrolysis of β-pinene was carried out without a catalyst and carrier gas at 573-873 K and under low pressure. In order to clarify the reaction mechanism, the primary intermediates of β-pinene pyrolysis including myrcene and limonene were also used as raw materials for further pyrolysis. The identification of some small molecules and C10H16 isomers in the products proves that both decomposition reaction and ene reaction take place during the pyrolysis process. Based on the qualitative and quantitative analysis of reaction products, a reaction scheme for the pyrolysis of β-pinene was proposed. With appropriate simplification of the reaction scheme, a phenomenological kinetic model of the competitive parallel and consecutive first-order reaction was built, and exhibited good agreement with the experimental data. The activation energy (Ea) and pre-exponential factor (k0) for each pathway were also determined.