Synthesis, Characterization and Application of Poly(4-Methyl Vinylpyridinium Hydroxide)/SBA-15 Composite as a Highly Active Heterogeneous Basic Catalyst for the Knoevenagel Reaction

Abstract

In this paper poly (4-methyl vinylpyridinium hydroxide)/SBA-15 composite was prepared as a highly efficient heterogeneous basic catalyst by in situ polymerization method for the first time. It was characterized by XRD, FT-IR, BET, TGA, SEM and back titration using NaOH. This catalyst exhibited the excellent catalytic activities for the Knoevenagel condensation of various aldehydes with ethyl cyanoacetate. Over this catalyst, α,β-unsaturated carbonyl compounds were obtained in the reasonable yield at 95 o C in 10 -30 min in H2O as a solvent with a 100% selectivity to the condensation products. Catalyst could be easily recycled after the reaction and it could be reused without the significant loss of activity/selectivity performance. No by-product formation, high yields, short reaction times, mild reaction conditions and operational simplicity with reusability of the catalyst were the salient features of the present synthetic protocol. Presence of H2O as a solvent was also recognized as a "green method".

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“…Finally, quaternization of the pyridine groups with methyl iodide afforded a water‐soluble hyperbranched polyester. Quaternization is evident from the signal at 3.5 ppm in the 1 H NMR spectrum of 9 and is also supported by a new FTIR band at 1629 cm −1 , which is due to the new CN bond 25. The conversion of pyridine groups was estimated to 47% based on comparison of the 1 H NMR integrals of signals “ n ” and “ c .”…”

Suzuki-Miyaura Cross-coupling Reaction Catalyzed by Nickel Nanoparticles Supported on Poly(N-vinyl-2-pyrrolidone)/TiO2-ZrO2Composite

“…[32][33][34][35] Nevertheless, among the different researches on these materials, there are relatively a few reports on the application of organic-inorganic hybrid polymer as a heterogeneous catalyst. [36][37][38][39] Recently, in our previous studies, [40][41][42][43][44] hybrid organic-inorganic polymers were used as catalysts.…”

Palladium Nanoparticles Supported on Poly(2-hydroxyethyl methacrylate)/KIT-6 Composite as an Efficient and Reusable Catalyst for Suzuki–Miyaura Reaction in Water

“…It should be mentioned that there was very low Pd leaching during the reaction and the catalyst exhibited high stability even after nine recycles (Table 5). Compared to our previous study on prepared composites using SBA-15 [37][38][39][40][41], Pd-PHEMA/ KIT-6 shows more recyclability. It can be related to the interconnected large-pore cage-type mesoporous KIT-6 with three-dimensional (3D) porous networks in comparison to SBA-15 with a two-dimensional (2D) array of pores, because three-dimensional porous network of KIT-6 allows for a faster diffusion of reactants, avoids pore blockage, provides more adsorption sites and can prevent leaching of PHEMA and Pd nanoparticles.…”

“…Nevertheless, among the different researches on these materials, there are relatively a few reports on the application of organic-inorganic hybrid polymer as a heterogeneous catalyst [33][34][35][36]. Recently, in our previous studies [37][38][39][40][41], hybrid organic-inorganic polymers have been used as catalysts.…”

“…In our previous report, we prepared mesoporous silica/ polymer composites by using SBA-15 with 2D hexagonal (p6mm) structures [37][38][39][40]. In this study, we focused on the preparation of poly(2-hydroxyethyl methacrylate)/KIT-6 as a good support for Pd nanoparticles, and thus generated a suitable heterogeneous catalyst having a large surface area.…”