Proton Nuclear Magnetic Resonance‐Based Method for the Quantification of Epoxidized Methyl Oleate

Abstract

Epoxidized methyl esters (EMO) with their high oxirane ring reactivity, acts as a raw material in the synthesis of various industrial chemicals including polymers, stabilizers, plasticizers, glycols, polyols, carbonyl compounds, biolubricants etc. EMO has been generally quantified by the gas chromatography (GC) and high‐performance liquid chromatography (HPLC) techniques. Taking into the account of the limitations of these techniques, two qHNMR‐based equations have been proposed for the quantification of EMO in the mixture of EMO and methylesters (MO). The validity of the proposed method was determined using standard mixtures of MO and EMO having different molar concentrations. The developed equations have been applied on the samples of EMO prepared from oleic acid in two‐step process viz., esterification followed by epoxidation. The qHNMR‐based EMO quantification showed acceptable agreement with the results obtained from HPLC analysis.

Towards sustainable rubber compounds: The use of waste raw materials

“…The presence of the ester functionalities is corroborated by the multiplet at 1.6 ppm and the triplet at 2.27 pm, which are compatible with the methylene groups in position beta (proton f ) and alpha (protons g ), respectively, with respect to the carbonyl group of the ester moiety. Finally, the multiplets broadly defined in the regions between 4.40 and 4.00 ppm, and 3.3 and 3.00 ppm can be ascribed to methylenic groups in allylic positions of the unsaturated long carbon chains (protons h ) 63,64 . Additional support about the presence of the ester moieties from the natural wax came from 13 C NMR spectroscopy (Figure S1), in which we observed a peak at 173 ppm, which is a diagnostic resonance for the carbonyl carbon atom in esters.…”

“…The intense multiplet centered at 1.29 (protons c ) is characteristic of long carbon chains, while the triplet at 0.88 ppm (protons d ) can be assigned to the terminal methyl groups of the long carbon chains. The presence of (palmitoleate‐ and oleate‐type) internal double bonds (protons e ) is supported by the multiplets in the region between 5.35 and 5.20 ppm 63,64 . The presence of the ester functionalities is corroborated by the multiplet at 1.6 ppm and the triplet at 2.27 pm, which are compatible with the methylene groups in position beta (proton f ) and alpha (protons g ), respectively, with respect to the carbonyl group of the ester moiety.…”

“…Finally, the multiplets broadly defined in the regions between 4.40 and 4.00 ppm, and 3.3 and 3.00 ppm can be ascribed to methylenic groups in allylic positions of the unsaturated long carbon chains (protons h). 63,64 Additional support about the presence of the ester moieties from the natural wax came from 13 C NMR spectroscopy (Figure S1), in which we observed a peak at 173 ppm, which is a diagnostic resonance for the carbonyl carbon atom in esters.…”

“…The presence of (palmitoleate-and oleate-type) internal double bonds (protons e) is supported by the multiplets in the region between 5.35 and 5.20 ppm. 63,64 The presence of the ester functionalities is corroborated by the multiplet at 1.6 ppm and the triplet at 2.27 pm, which are compatible with the methylene groups in position beta (proton f ) and alpha (protons g), respectively, with respect to the carbonyl group of the ester moiety. Finally, the multiplets broadly defined in the regions between 4.40 and 4.00 ppm, and 3.3 and 3.00 ppm can be ascribed to methylenic groups in allylic positions of the unsaturated long carbon chains (protons h).…”

Understanding Marine Biodegradation of Bio-Based Oligoesters and Plasticizers

“…Figure S4: FT-IR spectra of the epoxidized oil (green), 1,4-butandiol (blue), product ECO-SRB (red), and product ECO-BDO (black). Figure S5: 1 H NMR spectrum of the product of the epoxidation reaction of oleic acid catalyzed by Novozyme 435 in 2 h; δ = 0.89 ppm, -CH3 (A); δ = 1.36 ppm -CH2- of chain, δ = 1.63 ppm -CH2- (D); δ:2,64ppm -CH2- (C); δ:2.90 ppm -CH- (D), with assignment of the signals according to [ 54 ]. Figure S6: 1 H NMR spectrum of the product obtained after 2 h of epoxidation of linoleic acid catalyzed by 450 U/g substrate of lipase, with assignment of the signals according to [ 55 ].…”