Impact of drying on the catalyst profile in supported impregnation catalysts

Monitoring Transport Phenomena of Paramagnetic Metal‐Ion Complexes Inside Catalyst Bodies with Magnetic Resonance Imaging

“…Formation of these com- 6 ] 2 + and citric acid is described by Equations (1) and (2). Coordination of Co 2 + probably takes place through two carboxylate groups and the hydroxyl group, as shown in Figure 1.…”

“…From these plots, the nature and concentration of the different components in the impregnation solutions used in this study could be derived. Cobalt:citrate solutions at pH 1 (CoCApH1) were found to contain [CoA C H T U N G T R E N N U N G (H 2 O) 6 ] 2 + and a varying …”

“…[2][3] A number of studies in this field have led to a basic understanding of the physicochemical processes that take place during the preparation of supported catalyst bodies. [4][5][6][7][8] Models have even been derived that allow one to describe the effect of parameters such as the drying rate and the metal ion/support interaction on the macrodistribution of the metal-ion precursor in the dried catalyst bodies. [4,6,7] Industrial impregnation solutions usually consist of a number of components, each with its own interaction with the support surface.…”

“…[4][5][6][7][8] Models have even been derived that allow one to describe the effect of parameters such as the drying rate and the metal ion/support interaction on the macrodistribution of the metal-ion precursor in the dried catalyst bodies. [4,6,7] Industrial impregnation solutions usually consist of a number of components, each with its own interaction with the support surface. Besides metal precursor salts, organic complexing agents such as citric acid and nitrilotriacetic acid are often added to impregnation solutions.…”

“…[12][13][14][15][16] The possibility to monitor the transport of different components inside catalyst bodies in a noninvasive manner was previously illustrated in a study in which the distribution of phosphate and Pt complexes was determined in a direct manner with a multinuclear (e.g., 31 P and 195 Pt) MRI technique. [17] Recently, we briefly reported how the distribution of paramagnetic [CoA C H T U N G T R E N N U N G (H 2 O) 6 ] 2 + complexes after impregnation of support bodies can be monitored quantitatively in a noninvasive manner via their destructive effect on the 1 H NMR signal of the water solvent in MRI measurements. [18] Here we present a full account and show that this novel MRI method in the field of heterogeneous catalysis is generally applicable to monitoring the macrodistribution of different types of Co 2 + complexes inside Co/Al 2 O 3 catalyst bodies.…”