Oxidation of d‐Limonene in Presence of Low Density Polyethylene

Headspace oxygen contents of sodium citrate‐water buffers containing d‐limonene with and without low density polyethylene (LDPE) were measured on a weekly basis for 10 wk. d‐Limonene was readily sorbed into LDPE. Results indicated first order kinetics for limonene oxidation. GC/MS analyses determined production of limonene oxidation end‐products, including d‐carvone, carveol, limonene oxide, perrilaldehyde and linalool, as well as α‐terpineol, a hydrolysis product. Headspace oxygen contents of the d‐limonene/buffer (control) samples were lower thau that of the d‐limonene/buffer/LDPE samples, suggesting a higher oxidation rate in the control than in LDPE. Oxidation rate constants and half‐lives were 5.9 × 10 ‐3 log(%O 2 ) wk ‐1 , t 1/2 = 116 wk for control and 1.2 × 10 ‐3 log(%O 2 ) wk ‐1 , t 1/2 = 580 wk for LDPE samples, respectively.