A Graphene‐Based Supramolecular Nanoreactor for the Fast Synthesis of Imines in Water

Abstract

The confinement of organic synthesis within waterborne nanoreactors is regarded with increasing attention to improve its yield and reduce the environmental impact. However, many catalysts, such as graphene, are barely dispersible in aqueous media and many chemical reactions cannot be performed in the presence of water due to thermodynamic limitations. Therefore, there is an urgent need to develop novel strategies to carry out these processes in more sustainable conditions. To pursue this goal, in this work, a waterborne supramolecular nanoreactor is developed. The system comprises a polymeric micelle obtained from the self‐assembly of pyrrole‐based amphiphilic block copolymers. The active catalytic component is represented by few graphene layers, functionalized with pyrrole to enhance their interaction with the micelle core and hence their nanoencapsulation. Using this nanoreactor, it is possible to synthesize imines starting from primary amines and aldehydes or ketones with high yield and in short time (Y = 90% after 5 min) at room temperature. Moreover, an efficient strategy to recycle the reactor is proposed, thus increasing the potential of this technology.

Basified Graphene Oxide and PPO Composite Aerogel with Basified Graphene Oxide for Henry Reaction in Solvent-Free Conditions: A Green Approach

“…The well-known carbon materials are not “innocent” supports, as demonstrated by many recent publications within the carbocatalysis field. As a matter of fact, recently, they have emerged as cheap and metal-free catalysts and have attracted much attention regarding the use of graphite, graphite oxide (GO), and graphene oxide (eGO) in the oxidation reaction, − Friedel–Crafts reaction, aza-Michael addition, imination, polymerization, epoxy-ring opening reactions, , Mukaiyama–Michael reaction, , and crosslinking reaction …”

Green imine synthesis from amines using transition metal and micellar catalysis

“…Previous literature has shown that graphene layers functionalized with Scheme 54 Fluorogenic reaction of imine formation from anime salt and aldehyde, performed in water using surfactants as reported by Ladame et al 89 Scheme 55 Condensation of amines and aldehydes in a polymeric micelle from the self-assembly of pyrrole-based amphiphilic block copolymers as reported by Palmiero et al (HSAG-SP: high surface area graphiteserinol pyrrole, PEG-EP 10 : polyethylene glycol chain extended with 10 ethanol pyrrole methacrylate units). 90 Scheme 53 Oxidative homocoupling of octylamine in DDAO (dimethyldodecylamine N-oxide) surfactant solvent as reported by Savelli et al 88…”

“…In 2020, Palmiero et al reported using a micelle derived from pyrrole-based amphiphilic block copolymers with graphene for the condensation of carbonyls and amines to form imines (Scheme 55). 90 The aldehyde and amine were mixed in equimolar amounts. Graphene is a powerful catalyst for acid-catalysed reactions due to its high π-electron density, but it tends to form counterproductive agglomerates.…”

A green polyol approach for the synthesis of Cu2O NPs adhered on graphene oxide: a robust and efficient catalyst for 1,2,4-triazole and imidazo[1,2-a]pyridine synthesis

“…54,55 As compared to other supports, GO's 2D framework facilitates open access to reactants with limited mass transfer impedance 56 and it has been called a nano-reactor. 57,58 GO and its nanocomposites are finding applications in biomedical devices, 59 hydrogen storage, 60 drug delivery, 61 super-capacitors 62 and waste-water treatment. 63 A large number of GO-based nanocatalysts are prepared by immobilization of metal NPs, metal oxides, metal complexes, etc.…”