Synthesis and characterization of triazole-based schiff bases as novel highly efficient organocatalysts for rapid H2 generation via NaBH4 methanolysis

Abstract

The triazole skeleton is a fundamental building block in heterocyclic chemistry and has been widely investigated for its applications in various fields such as materials science, medicinal chemistry and organic synthesis. Despite this broad utility, the use of this building group as an organocatalyst for hydrogen production is a largely neglected and under-researched topic in literature. While Schiff base-metal complexes (M = Cu, Zn, Ni, etc.) have previously been employed in sodium borohydride (NaBH4) hydrolysis reactions, it is particularly noteworthy that, for the first time, only triazole-based organocatalysts have been utilized as catalysts for hydrogen generation via the NaBH4 methanolysis. In this work, we synthesized, characterized, and optimized triazolebased organocatalysts (MF-MB-PF) and focused on as an efficient catalyst for hydrogen evolution via the alcoholysis of NaBH4. The hydrogen production performance of the MF catalyst was systematically evaluated on the basis of parameters such as catalyst type and amount used, NaBH4 concentration, different solvent systems, various methanol-water ratios, temperature conditions and catalyst reusability. The MF-catalyzed NaBH4 methanolysis reaction was completed in just 0.8 min. Moreover, the hydrogen generation rate (HGR) for the MFcatalyzed reaction was calculated to be 20,540 mL min-1gcat-1 at 30 degrees C, which is comparable to, or better than, that of most metal-free catalysts used for similar purposes. In addition, we determined the activation energy for the MF-catalyzed reaction to be 16.98 kJ/mol. The MF catalyst exhibited remarkable reusability with no significant loss in the first three cycles in the catalytic activity used for the five-cycle reaction. Additionally, the possible mechanism of the MF catalyst in the NaBH4 methanolysis reaction is discussed. Overall, this study introduces MF as a novel metal-free catalyst for hydrogen generation and highlights its potential as an efficient material.