Kinetics of the Epoxidation of Geraniol and Model Systems by Dimethyldioxirane

Abstract

Abstract:The mono-epoxidation of geraniol by dimethyldioxirane was carried out in various solvents. In all cases, the product ratios for the 2,3 and 6,7 mono-epoxides were in agreement with literature values. Kinetic studies were carried out at 23 ºC in the following dried solvent systems: acetone (k 2 = 1.49 M -1 s -1 ), carbon tetrachloride/acetone (9/1, k 2 =2.19 M -1 s -1 ), and methanol/acetone (9/1, k 2 = 17 M -1 s -1 ). Individual k 2 values were calculated for epoxidation of the 2,3 and 6,7 positions in geraniol. The nonconjugated diene system was modeled employing two simple independent alkenes: 2-methyl-2-pentene and 3-methyl-2-buten-1-ol by determining the respective k 2 values for epoxidation in various solvents. The kinetic results for each independent alkene showed that the relative reactivity of the two epoxidation sites in geraniol as a function of solvent was not simply a summation of the independent alkene systems.

Studies on Epoxidation of Tung oil with Hydrogen Peroxide Catalyzed by Sulfuric Acid

“…Some research has been pursued to embody "truer sustainability (continuity)" through the synthesis of epoxidized vegetable oils from non-edible feedstocks such as rubber seed oil [4,5], castor oil [6,7], mahua oil [8], and Karanja oil [9]. Similar research has been conducted on jatropha oil [10], cottonseed oil [11], nahor [12], canola oil [13], camelina oil [14], giraneol oil [15], and perrila oil [16].…”

Systematic Development of Vanadium Catalysts for Sustainable Epoxidation of Small Alkenes and Allylic Alcohols

“…Early developments emerge from the epoxidation of small alkenes through a chemical base, bearing the reaction with molecular oxygen and using silver as a catalyst (Wurtz's method [15]). Efforts then turned to the synthesis of complex epoxides using different oxidants, namely peroxyacids [16,17], oxones [18,19] and dioxiranes [20,21]. But resource concerns on the sustainability of these processes deemed them costly (in particular with molecular oxygen), with increasingly high by-product turnouts.…”

Activation Parameters for the Epoxidation of Substituted cis/trans Pairs of 1,2‐Dialkylalkenes by Dimethyldioxirane

“…The synthesis of epoxides by reaction with asymmetric dioxiranes generated in situ in biphasic systems, of value for the preparation of chiral compounds, also has been shown to be mechanistically consistent with a spiro transition‐state model 6. Recent kinetic experiments on the epoxidation of geraniol and model olefins have further investigated medium effects on the reaction with dimethyldioxirane ( 1 ) 7. The relative reactivity of epoxidation of alkenes by 1 has been modeled using various theoretical methods, including ab initio calculations 3c,8a–8c.…”