Catalysis of Organic..

136Aminoalcohols to Aminocarboxylic Acid SaltsHN(CH 2a CH 2d OH) 2 HN(CH 2a′ CH 2d′ OH)(CH 2c COO - ) HN(CH 2b COO-) 2(DEA) (HEG) (IDA)Reaction over the chromia-promoted catalyst proceeded in a similar way. Thespectrum at an overall conversion of 71% based on H 2 evolution is shown inFigure 4. The second spectrum here is that for the same sample but with glycine(NH 2 CH 2 COOH) added. The CH 2 lines in glycine give rise to the additional singletat ~3.00 ppm. Clearly glycine is negligible as a byproduct of reaction ofdiethanolamine. Indeed, no side products could be seen by NMR (the weak linesevident near 2.75 ppm in all spectra arise from the DSS internal standard in the D 2 Osolvent). Some oxalate may be formed but that is invisible by 1 H NMR.glycinewith glycine addedSample with glycine addedHEGIDAwithout glycineSample without glycineHEGIDA3.5 3.4 3.3 3.2 3.1 3.0 2.9 2.8 2.7 2.6 2.5(ppm)Figure 4. NMR spectra for a sample taken at 71% conversion during the reaction ofdiethanolamine over chromia-promoted copper with and without glycine added.If the lines in the four regions of Figure 3 are attributable to the a, b, c and dprotons in DEA, HEG and IDA alone, then the areas (A) are proportional to thenumber of moles of each type of proton present:A a ∝ 4n DEA + 2n HEG [5]A b ∝ 4n IDA [6]A c ∝ 2n HEG [7]