Figure 1
FTIR spectrum of RhH[P(i-Pr)3]3.
Source: Author’s contribution.
Figure 2
Effect of catalyst loading on hydrogenation of C≡Ns in NBR. (*: 0.8 mL catalyst solution [0.06 g catalyst, 0.1 mmol Rh], 100 mL 2.5 wt% NBR in THF, 60°C, 500 psig H2. **: the letters and numbers in the picture have no special meaning and only represent the experiment batch number).
Source: Author’s contribution.
Figure 3
Effect of temperature on hydrogenation of C≡Ns in NBR. (*: 0.8 mL catalyst solution [0.06 g catalyst, 0.1 mmol Rh], 100 mL 2.5 wt% NBR in THF, 500 psig H2. **: the letters and numbers in the picture have no special meaning and only represent the experiment batch number).
Source: Author’s contribution.
Figure 4
Effect of H2 pressure on hydrogenation of C≡Ns in NBR. (*: 0.8 mL catalyst solution [0.06 g catalyst, 0.1 mmol Rh], 100 mL NBR in THF [2.5 wt%], 60°C. **: the letters and numbers in the picture have no special meaning and only represent the experiment batch number).
Source: Author’s contribution.
Figure 5
Tandem hydrogenation of C═Cs and C≡Ns in NBR. (*: 0.8 mL catalyst solution [0.06 g catalyst, 0.1 mmol Rh], 100 mL NBR in THF [2.5 wt%], 60°C, 500 psig H2.).
Source: Author’s contribution.
Figure 6
Possible mechanism for tandem hydrogenation of nitrile and olefinic groups in NBR.
Source: Author’s contribution.
Figure 7
Mechanism for olefin hydrogenation using Wilkinson’s catalyst.
Source: Author’s contribution.
Table 1
Summary of additives for gel formation reduction
| Hydrogenation of C≡N | Hydrogenation of C═C | Gel formation | |
|---|---|---|---|
| Acetic acid | Terminated | Terminated | Rubber coagulated |
| Ethanol | Terminated | Terminated | Visible gel |
| Chlorobenzene, MCB | Terminated | Terminated | Visible gel |
| Methyl ethyl ketone | Slower | Slower | Visible gel |
| 2,2,6,6-Tetramethylpiperidin-1-oxyl | Slower | Slower | Visible gel |
| TPP | Terminated | Not terminated | No visible gel |
Source: Author’s contribution.
Figure 8
FTIR spectrum of hydrogenation of C≡Ns in NBR with TPP.
Source: Author’s contribution.
Figure 9
FTIR spectra of hydrogenation of nitrile and olefinic groups in NBR.
Source: Author’s contribution.