Fig 2a Essay

Fig. 2 show the protons nuclear magnetic resonance (1H NMR) of HBA and HBA-BMF. In Fig. 2a,terminal methyl group present in fatty acid chain show the peak at around δ = 0.9 ppm.31 The proton of −CH2− groups of the fatty acid backbone and terminal methyl group attached proton show the peak between δ =1.20−1.59 ppm.30 The peak at δ = 5.4 ppm is attributed to the protons attached to the olefinic carbon atom (−CH=CH−) of fatty acid,28 this peak provides the evidence of the presence of fatty acid chain of SO in the HBA resin. The peak in the range δ =7.3−7.5 ppm associated with the aromatic protons attached to the benzene ring of phthalic anhydride present in the structure of HBA.. Presence of ester group in the HBA backbone due to the reaction …show more content…
The proton of methylene group next to ester linkages show a peak at δ = 2.3 ppm and proton of fatty acid chain next to methylene group of ester linkages show a peak at δ = 1.7 ppm. …show more content…
Presence of the prominent peak of the proton of −OCH2 confirmed the formation of HBA-BMF resin by etherification reaction of HBA with BMF. In the 13C NMR spectrum of HBA carbonyl carbon atom of ester group present in the polymeric Skelton show the peaks at δ=170 ppm (Fig. S2). Carbon Present in the aromatic ring of phthalic anhydride show the peak at δ=125−135 ppm.13, 32 Moreover; carbon attached to the oxygen atom directly show the peak in the region of δ =30−70 ppm. The peaks at δ = 0−35 ppm correspond to methyl and methylene carbon, unsaturated carbon atom of fatty acid alkyl chain in the HBA show the peak at δ = 127 ppm. The 13C NMR spectra of HBA-BMF show the similar peaks as HBA with two additional peaks around δ = 180 ppm and δ = 90 ppm attributed to the carbon atoms of the symmetrical s-triazine ring and carbon atom sandwiched between oxygen of ether group and nitrogen of BMF (−OCH2−N), respectively as shown in Fig. S3, providing an evidence for the reaction of BMF with