Question

b) Which area of the spectrum did you focus on and which key piece of information (chemical shift, integration, or splitting pattern) helped you decide which spectrum belonged to which isomer? Please explain your responses.

Reaction 1: Nitration HNO3 NO2 + + H2SO4, H20 NO2 toluene NO2 ortho meta para

Answer 1

Proton NMR Spectrum for Peak A on Gas Chromatogram: ЗН Hd NO He H, H HC Ha Ho Ha Hd 1H 2H 1H 9 8 6 5 4 3 2 0 PPM Expansion of downfield signals: Ha at 7.9 ppm due to the Ortho effect of the NO2 (electron with drawing group) group, this is more down fielded. (coupling with Hb, He will give dd) H, Will give dd at at 7.55 and H. Will give td at 7.45 ppm Ha at 7.25 ppm Due to the Ortho effect of the methyl group (electron with donating group), this is more up fielded will give td due to coupling with Hb, H. He will give singlet at 2.5 ppm 1H 2H 1H dd dd,td td 8 7 dd= doublet of doublets td= triplet of doublets

Proton NMR Spectrum for Peak B on Gas Chromatogram: Hale ЗН Hc, Ha На Ho Ho H Hai NO2 2H 21 9 8 7 6 5 4 3 2 PPM Downfield signals are both doublets. H. at 7.1 ppm due to the Ortho effect of the NO2 (electron with drawing group), this is more down fielded. Will give doublet Ha at 7.25 ppm Due to the Ortho effect of the methyl group (electron with donating group), this is more up fielded will give doublet He will give singlet at 2.2 ppm

Proton NMR Spectrum for Peak Con Gas Chromatogram: 3H Hd. Ha H., Ha Ho NO2 He Н. Ho Hd 2H 1H 1H 9 8 7 6 5 4 3 2 1 0 PPM Expansion of downfield signals: 2H Hp at 7.1 ppi group, this i Ha at 7.05 p methyl grou H. at 7.3 pp Hd at 7.2 pp group), this He will gives 1H 1H We t,dt tdt 8 7 t = triplet dt = doublet of triplets