Palladated halloysite hybridized with photo‐polymerized hydrogel in the presence of cyclodextrin: An efficient catalytic system benefiting from nanoreactor concept

Abstract

Considering the excellent performance of halloysite as a catalyst support and in an attempt to benefit from the concept of nanoreactors in the catalysis, an innovative catalytic system has been designed, in which acrylamide and bis‐acrylamide were photo‐polymerized in the presence of palladated halloysite. The novel precipitation photo‐polymerization method avoided the formation of an extended polymeric network, but led to the formation of co‐polymer on the halloysite periphery. The co‐polymer exhibited good swellability in aqueous media and formed hydrogel. This hydrophilic environment around catalytic palladated halloysite can be considered as a nanoreactor that can concentrate the substrate and bring them into the vicinity of the palladated halloysite. This catalytic system was used for promoting hydrogenation of hydrophobic nitro arenes in aqueous media. To avoid immiscibility of hydrophobic substrates and hydrophilic nature of the nanoreactor, that emerged from swelling of hydrogel, β‐cyclodextrin (CD) was utilized as phase transfer agent. The results confirmed high catalytic activity of this catalytic system. Even highly hydrophobic substrates could tolerate hydrogenation under this protocol to furnish the corresponding product in high yield. Finally, the contribution of both CD and hydrogel to the catalysis was confirmed. Moreover, studying the recyclability of the catalyst as well as Pd leaching proved the high recyclability of the catalyst and low leaching of Pd nanoparticles.

Effect of support hydrophobicity of halloysite‐based catalysts on the polyalphaolefin hydrofinishing performance

“…To prepare Hal/Pd/CTAB, Hal was first palladated using the similar procedure used for the synthesis of Hal/Pd sample (see Section 2.3.1). [51,52] Then, the as-prepared Hal/Pd was modified with CTAB according to the previous report. [53] Briefly, a solution of CTAB (0.5 g) in distilled water was prepared.…”

Fabrication of a metal free catalyst for chemical reactions through decoration of chitosan with ionic liquid terminated dendritic moiety

“…Investigation of the catalytic activity of the catalyst (CS-D-IL) also affirmed remarkable improvement in terms of yield of reaction time, Table 1. According to the literature 30 , functional polymers can exert catalytic activity. Hence, to further study the role of the dendritic moiety in the catalysis, another control catalyst, CS-D, was designed and its activity was compared with CS.…”

K2CO3-Modified Smectites as Basic Catalysts for Glycerol Transcarbonation to Glycerol Carbonate

“…Our research group has been primarily focused on harnessing the potential of clays for the development of heterogeneous catalysts [21][22][23][24][25]. Encouraged by the promising results obtained, the team has continued their investigations into clay-based catalysts.…”