Abstract
A green, regenerative and highly active Cu(0) catalyst derived from waste fibre-based cellulose-supported poly(hydroxamic acid) was synthesized. The surface of the hydrolyzed cellulose was undergone chemical modification through graft co-polymerization using methyl acrylate. Then the poly(methyl acrylate) was further converted into poly(hydroxamic acid) bidentate chelating ligand via Wilhelm Lossen rearrangement in an alkaline hydroxylamine aqueous solution. Finally, the copper was impregnated onto the poly(hydroxamic acid) via the adsorption process forming stable five-member ring complex; Cu(II)NPs@PHA. The Cu(II)NPs@PHA is reduces into Cu(0)NPs@PHA using hydrazine hydride as a reducing agent. The Cu(0)NPs@PHA was fully characterized by FT-IR, FE-SEM & EDX, TEM, ICP-OES, TGA, XRD and XPS analyses. The cellulose-supported Cu(0)NPs@PHA was successfully applied to the Aza-Michael addition reaction with several Michael acceptors and various substituted aryl/heterocyclic/alky amine to afford the corresponding C-N product with excellent yield [aryl amine (50-95%); heterocyclic amine (50-96%); alkyl amine (80-98%)]. The Cu(0)NPs@PHA showed extraordinary stability and it was easy to recover from the reaction mixture and could be reused up to five times without loss of its original catalytic activity.
Highlights
A recyclable biomass-derived heterogeneous catalyst pave the way for significant attention in recent decades [1]
We report pandanus cellulose supported poly(hydroxamic acid) copper(0) catalyst as an efficient heterogeneous catalyst for Aza-Michael addition reaction, which can be used for syntheses of medicinal compounds such as antibiotics, auxiliaries, natural products and N-containing heterocycles [13]
The free radicals bearing anhydroglucose units (AGU) added with acrylic monomers and further initiated the free radicals on the cellulosic backbone for propagation reaction resulting in the grafting copolymer products
Summary
A recyclable biomass-derived heterogeneous catalyst pave the way for significant attention in recent decades [1]. This is due to the broad advantages of a heterogenous catalyst such as low cost, high activity, and easy recovery, potential reusability and tolerance to drastic reaction conditions [2]. Biopolymers are an attractive candidate as a solid supported material in the synthesis of heterogeneous catalyst. The biopolymers such as alginate [8], gelatin [9], chitosan [10], and cellulose [11] and etc. Among all of these biopolymers, cellulose could be the most
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
