Pd-La /spinel

In the present paper, the Pd-La/spinel catalyst for this reaction was developed. On this catalyst, the activity and selectivity were high, especially the stability was increased greatly, and it was up to 480 hours under the conditions of 220°C and LHSV=0.3h . But the high initial activity decreases along with time, which impairs the catalyst practice in industrial applications. For this reason, it is important to understand the deactivation mechanism. This work concerns an investigation into the coke formation on the Pd-La/spinel catalyst in the gas-phase amination of 2,6-DIPP. Furthermore, the correlation between coke deposition and combustion was analyzed. The results provide fundamentals not only to develop new catalysts but also to optimize the reactor operation parameters. 

Figure 1 The catalytic performance of the Pd-La/spinel catalyst for amination Reaction conditions T=220 , LHSV O.3 h H2 30 ml/min.

Figure 2 X-ray diffraction patterns of Figure 3 X-ray diffraction pattern of coke different Pd-La/spinel catalysts extracted from the coked catalyst...

Figure 6 FTIR spectrum of the coke liberated from the coked Pd-La/spinel catalyst...

It can be concluded from the catalytic performance of Pd-La/spinel catalyst and the characterization results of fresh and coked catalysts that the catalytic performance decreased along with the amination. The coke formation is the main reason for catalyst deactivation. Both XRD and IR spectra indicate that shows that the coke contains aromatic and aliphatic rings, alkyl groups, condensed ring aromatic hydrocarbon, and amine groups. 

Similar results concerning the coke structure were reported recently by J. Ruixia et aF on Pd-La/spinel catalyst, coked during the production of 2,6 diisopropylaniline at 220°C. 

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