Product and mechanistic insights into the ozonolysis of Δ3-Carene

This study combines experimental and theoretical approaches to investigate the gas-phase ozonolysis of Δ 3 -carene, with a focus on product identification and mechanistic elucidation. Atmospheric ozonolysis was simulated using both a Teflon chamber and a jet-stirred reactor. Product characterization was achieved through vacuum ultraviolet photoionization mass spectrometry employing soft ionization techniques, combined with Hefei synchrotron radiation to acquire mass-selected photoionization efficiency spectra of Δ 3 -carene and its ozonolysis products. Structural assignments were then facilitated by theoretical calculations conducted at the M06-2X/6–311++G(d,p) level of theory. Our analysis revealed many characteristic ozonolysis products, such as formaldehyde (CH 2 O, m/z  = 30), acetone (C 3 H 6 O, m/z  = 58), nor-3-caronaldehyde (C 9 H 14 O 2 , m/z  = 154), nor-3-caralic acid (C 8 H 12 O 3 , m/z  = 156), 3-caronaldehyde (C 10 H 16 O 2 , m/z  = 168), 3-caralic acid (C 9 H 14 O 3 , m/z  = 170), and 3-caronic acid (C 10 H 16 O 3 , m/z  = 184). Moreover, the ozonolysis products, C 8 H 12 O 2 ( m/z  = 140), C 8 H 14 O 2 ( m/z  = 142), C 10 H 16 O ( m/z  = 152), and C 10 H 14 O 3 ( m/z  = 182) were identified in the experiments for the first time. Based on literature results and comprehensive analysis of the experimental data, we elucidated detailed reaction pathway mechanisms for these newly discovered products.