Design and preparation of nanoarchitectonics of LDH/polymer composite with particular morphology as catalyst for green synthesis of imidazole derivatives

Abstract

This paper was designed and prepared a new nanoarchitectonics of LDH/polymer composite with specific morphology. For this purpose, CTAB surfactant was used to control the morphology of layered double hydroxide (LDH) and to prepare LDH/polymer nanocomposites (LDH-APS-PEI-DTPA). The polymer was synthesized using diethylenetriaminepentaacetic acid (DTPA), polyethylenimine and used with LDH to form a nanocomposite with high thermal stability. Subsequently, the prepared nanocomposite was identified using FTIR, EDX, TGA, XRD, FESEM, and BET techniques. In addition, the prepared LDH-APS-PEI-DTPA nanocomposite was used as a heterogeneous and recyclable catalyst for the synthesis of imidazole derivatives under green conditions. The results showed that the LDH-APS-PEI-DTPA nanocomposite benefit from suitable morphology, simple preparation, high catalytic activity, and high surface area. Also, the proposed LDH-APS-PEI-DTPA heterogeneous catalyst showed high stability and reusability for five consecutive runs which was consistent with the principles of green chemistry.

Figure 1

LDH–APS–PEI–DTPA nanocomposite (1)-catalyzed synthesis of imidazole derivatives through a multicomponent reaction of benzoin (2), aldehyde derivatives (3a–k), and ammonium acetate (4) in EtOH under reflux conditions.

Figure 2

FTIR spectra of Mg–Al LDH (a) and LDH–APS–PEI–DTPA nanocomposite (b).

Figure 3

XRD patterns of Mg–Al LDH (a) and LDH–APS–PEI–DTPA nanocomposite (b).

Figure 4

FESEM images of the Mg–Al LDH (a,b,c), and LDH–APS–PEI–DTPA nanocomposite (1,d,e,f).

Figure 5

EDX spectra of LDH–APS–PEI–DTPA nanocomposite (1).

Figure 6

TGA curve of the LDH–APS–PEI–DTPA nanocomposite (1).

Figure 7

N₂ adsorption–desorption curves for the LDH–APS–PEI–DTPA nanocomposite (1).

Figure 8

The proposed mechanism for the synthesis of imidazole derivatives using benzoin in the presence of LDH–APS–PEI–DTPA nanocomposite (1) catalyst.

Figure 9

Reusability of the LDH–APS–PEI–DTPA nanocomposite (1) in the reaction with 5a.

Figure 10

Schematic preparation of LDH–APS–PEI–DTPA nanocomposite (1).