Kinetic and mechanistic aspects of myrcene production via thermal-induced β-pinene rearrangement

The production of myrcene (2) is an industrially important reaction because 2 is a building block for the syntheses of various fine chemicals. The production of 2 through rearrangement of β-pinene (1) is a process carried out at elevated temperatures in flow-type reactors made of quartz or stainless steel with residence times below 1 s. Herein the thermal rearrangements of 1 and 2 are investigated in a quartz flow-type reactor using N2 as carrier gas. Experiments were carried out in a temperature range of 300–600 °C with residence times of 0.5–2.5 s. Results showed that the main product 2 can be formed with a maximal overall yield of 77%. Consecutive reactions of 2 lead to a decrease in yield due to the formation of isomerization products. Neither the formation of gaseous or lower molecular products was observed nor polymerizations occurred in the temperature range investigated. Kinetic experiments allow for the calculation of activation parameters for the initial reactions. A reaction model of competitive parallel first-order reactions describes well the thermal reaction network of C10H16 hydrocarbons based on 1.