*3.3.2. FTIR analysis*

The standard Fourier Transform Infrared Spectrometer Nicolet 6700 type (FTIR) equipped with operating software Omnic from Thermo Company was used for the qualitative determination of the functional groups occurring in the hydrogenation reaction products. FTIR spectra were registered in the range of 4000–650 cm−1 with the resolution of 4 cm−1.

**Figure 7.** Chromatogram of the typical mixture of the hydrogenation products of N,N,N',N' tetracyanoethyl 1,2 ethyle‐ nediamine (TCED). GC peaks refer to: (A) n‐propylamine; solvent — 1,4‐dioxane; (B) N,N,N' triaminepropyl‐1,2‐ethyl‐ enediamine; (C) N,N,N',N' tetraaminepropyl‐1,2‐ethylenediamine.

In the FTIR spectra (**Figure 8**) of the TCA and TCED there is apparent peak at 2250 cm−1 assigned to C≡N group. In their FTIR spectra, after hydrogenation reaction of TCA and TCED nitriles in these groups almost completely disappeared, and instead broad peaks around 3350 cm−1 assigned to N—H bonds in primary amino groups are observed.

**Figure 8.** FTIR spectra of nitriles derived from ammonia (TCA) and ethylenediamine (TCED) and their hydrogenated products TAA and TAED.

#### *3.3.3. 1 H NMR analysis*

**Figure 7.** Chromatogram of the typical mixture of the hydrogenation products of N,N,N',N' tetracyanoethyl 1,2 ethyle‐ nediamine (TCED). GC peaks refer to: (A) n‐propylamine; solvent — 1,4‐dioxane; (B) N,N,N' triaminepropyl‐1,2‐ethyl‐

In the FTIR spectra (**Figure 8**) of the TCA and TCED there is apparent peak at 2250 cm−1 assigned to C≡N group. In their FTIR spectra, after hydrogenation reaction of TCA and TCED nitriles in these groups almost completely disappeared, and instead broad peaks around 3350 cm−1

**Figure 8.** FTIR spectra of nitriles derived from ammonia (TCA) and ethylenediamine (TCED) and their hydrogenated

enediamine; (C) N,N,N',N' tetraaminepropyl‐1,2‐ethylenediamine.

240 New Advances in Hydrogenation Processes - Fundamentals and Applications

products TAA and TAED.

assigned to N—H bonds in primary amino groups are observed.

For 1 H NMR analyses the NMR Bruker Ultrashield was used. All spectra were taken at the frequency of 400 MHz, CDCl3 with 0.03% TMS (v/v) was used as a solvent. Qualitative analyses were performed by using the Bruker Topspin 1 software.

The structures of final products after hydrogenation reactions were confirmed by use of 1 H NMR techniques. On the spectra recorded for TAA and TAED, there are shifts that could be assigned to protons corresponding to amine groups, meaning that the "core" molecules, ammonia and ethylenediamine, respectively, were successfully subjected to cyanoethylation reaction by acrylonitrile molecules.

The signals observed in the <sup>1</sup> H NMR spectra of TAA and TAED compounds (**Figure 9**) were taken to confirm their structures.

**Figure 9.** <sup>1</sup> H NMR (CDCl3) spectra of TAA (above) and TAED (below).

In the case of TAA: 0.98 ppm, s, 6H, –NH2; 1.50 ppm, p, –CH2–CH2; 1.70 ppm, t, 6H, N–CH2– CH2, 2.70 ppm, t, 6H, –CH2–NH2.

In the case of TAED**:** 1.36 ppm, s, 8H, –NH2; 1.60 ppm, p, –CH2–CH2; 2.46 ppm, t, 8H, N– CH2–CH2, 2.50 ppm, s, 4H, N–CH2–CH2–N, 2.75 ppm, t, 8H, –CH2–NH2.

During hydrogenation process undesired reactions take place, leading to the formation of low‐molecular weight products. After hydrogenation of poly(nitriles), besides the main products being TAA and TAED, the n‐butylamine is one of the most abundant by‐ products present in the reaction mixture. It is formed by cleavage of bond between nitrogen heteroa‐ tom and β‐carbon atom from acrylonitrile.
