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

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 C 10 H 16 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 ( E a ) and pre-exponential factor ( k 0 ) for each pathway were also determined.