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

Samahe Sadjadi,Fatemeh Koohestani,Majid M. Heravi

doi:10.1038/s41598-020-76795-8

Samahe Sadjadi, Fatemeh Koohestani + Show 1 more

Open Access

https://doi.org/10.1038/s41598-020-76795-8

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Abstract

In attempt to develop a biocompatible metal-free catalyst, a dendritic moiety was grown on chitosan through successive reactions with 2,4,6-trichloro-1,3,5-triazine and ethylenediamine. Subsequently, the terminal functional groups of the dendron were decorated with 1-methylimidazolium chloride. The catalyst was characterized with SEM, EDS, TGA, FTIR, XRD and mapping analysis. Then, the catalytic activity of the resultant composite was scrutinized for catalyzing Knoevenagel condensation and synthesis of xanthene derivatives in aqueous media under mild reaction condition. The results confirmed high activity of the catalyst, superior to ionic liquid free counterpart and bare chitosan. This observation was ascribed to the instinct catalytic activity of ionic liquid. Moreover, using control catalysts, it was confirmed that the presence of the dendritic moiety that could increase the content of ionic liquid on the backbone of the catalyst enhanced the catalytic activity.

Highlights

In attempt to develop a biocompatible metal-free catalyst, a dendritic moiety was grown on chitosan through successive reactions with 2,4,6-trichloro-1,3,5-triazine and ethylenediamine
CS was first functionalized with 2,4,6-trichloro-1,3,5-triazine and successively reacted with ethylenediamine and 2,4,6-trichloro-1,3,5-triazine to graft a dendron on CS
To address one of the main challenges of chitosan supported ILs, i.e. low loading of ILs, a solution is reported by introduction of dendritic moiety

Summary

Introduction

In attempt to develop a biocompatible metal-free catalyst, a dendritic moiety was grown on chitosan through successive reactions with 2,4,6-trichloro-1,3,5-triazine and ethylenediamine. The results confirmed high activity of the catalyst, superior to ionic liquid free counterpart and bare chitosan. The popularity of carbohydrates for the catalysis lies in the availability, bio-compatibility, biodegradability, tuneability and diversity of these compounds Both linear and cyclic carbohydrates have been successfully utilized for catalytic purposes[1,2,3]. Considering the environmental concerns and economic issues, use of metal-free catalysts received great attention In this regard, use of ILs can be a promising solution. The resultant composite was utilized as a bio-based and metal free catalyst for catalyzing Knoevenagel condensation of aldehydes and malonitrile in aqueous media at ambient temperature and synthesis of xanthene derivatives. At the end of this research, the recyclability of the catalyst was appraised

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