Original Articles: 2014 Vol: 6 Issue: 3
Quantitative determination of essential oil terpenoids by the reaction of epoxidation with peroxy decanoic acid
The iodometric titration method was used to study the kinetics of some individual terpenoids epoxidation reactions (α-pinene, limonene, limonene oxide), and the medical-grade turpentine epoxidation with the peroxy decanoic acid in the methylene chloride medium at 297-298 K. The kinetics of the reaction was shown to be governed by the second order kinetic equation. The second order effective constants of the reaction rate were determined: for α- pinene – 3.6 L mol-1 min-1 (297 K), limonene (to epoxide) – 2,1 L mol-1 min-1 (295 K), limonene oxide (to dioxide) – 0.052 L mol-1 min-1 (295 K), for turpentine – 3.9 L mol-1 min-1 (297 K). The proposed techniques of the quantitative determination of the basic substance content and determination of the iodine number of some terpenoids (α-pinene, limonene, limonene oxide) and the (medical-grade) gum turpentine were based on the data of epoxidation with the peroxy decanoic acid in the methylene chloride medium. The extraction-titrimetric technique was practiced and the possibility of quantitative determination of the (medical-grade) gum turpentine in turpentine ointment 10% (RSD = 3.2%, δ = -1.15%) was demonstrated.