Morpholine-Modified Pd/γ-Al2O3@ASMA Pellet Catalyst with Excellent Catalytic Selectivity in the Hydrogenation of p-Chloronitrobenzene to p-Chloroaniline

Abstract

An amino poly (styrene-co-maleic anhydride) polymer (ASMA) encapsulated γ-Al 2 O 3 pellet material has been synthesized successfully. After loading with Pd species and modified with morpholine, the inorganic-organic hybrid material shows an excellent catalytic property in the selective hydrogenation of p-chloronitrobenzene (p-CNB) to p-chloroaniline (p-CAN). In this procedure, morpholine can connect with the polymer layer in a form of amide bond and acts as an unparalleled immobilized dechlorination inhibitor, which can avoid further dechlorination efficiently and keeps stability due to the repulsive effect from the surviving C-O-C bond. The catalyst as prepared was characterized by using XRD, TGA, SEM, TEM, FT-IR, and ICP-OES, and it was further tested in the selective hydrogenation of p-CNB. It shows a supreme catalytic activity (almost 100%) and selectivity (up to 99.51%) after recycling for even 10 times, much superior to the blank alumina supported palladium (47.09%).

Efficient Sorbitol Producing Process through Glucose Hydrogenation Catalyzed by Ru Supported Amino Poly (Styrene-co-Maleic) Polymer (ASMA) Encapsulated on γ-Al2O3

“…As reported by the literature, grafting a multifunctional shell, such as ZrO2 [8], or introducing nitrogen atoms [9], the dispersion of Ru nanoparticles (Ru NPs) on the support could be promoted [8]. In our previous work, the amino poly (styrene-co-maleic) polymer (ASMA) has verified its plausibility to coordinate with the electro-deficient noble metal ions firmly [32]. The discrete functional groups with -OH and -NH2 groups could precisely serve as the target spot to conjugate Ru cations.…”

“…This may indicate that the assembling of Ru NPs mainly on the external surface is firmly bounded by the polymer shell through the -NH 2 and -OH groups. It could restrain the random deposition of Ru NPs clusters in the support's pores [32].…”

“…This may indicate that the assembling of Ru NPs mainly on the external surface is firmly bounded by the polymer shell through the -NH2 and -OH groups. It could restrain the random deposition of Ru NPs clusters in the support's pores [32]. The N2 absorption-desorption isotherms of 5%Ru/γ-Al2O3@ASMA and Ru/Al2O3 samples are depicted in Figure 2a, presenting the type V hysteresis loop, according to the IUPAC.…”

“…[39], the resulted shaped samples present its feasibility because the size of the resulted pellet or granules could decrease the pressure drop resulted from the hydrodynamics, which could guarantee the access to the continuous flow process [40]. Among all these shaped subjects, the sphere-like γ-Al 2 O 3 pellets have verified its superiority attributed to the high surface area [41], strong mechanical solidity [42], and a defined diameter [32], which is frequently used in trickle bed reactors [40,43].…”

“…Based on the analysis above, to construct a core-shell-like structure with a rigid-shaped core encapsulating the multifunctional shell could satisfy these demands. With the high dispersion of Ru induced by the electron-donating groups on the multifunctional shell, the Ru NPs can be homogenously dispersed on the external surface with the outward direction [32]. At the same time, the rigid core could serve as the shaped subject to bear the harsh conditions, especially to avoid the complex hydrodynamics influence and minimize the pressure drop in the bed column due to the huddle packing of powder catalysts in the bed [17,44,45].…”