Room Temperature Acid-Free Greener Synthesis of Imine Using Cobalt-Doped Manganese Tungstate

Abstract

Facile synthesis of an imine compound through a greener route is still a challenging task. Industrial processes rely on the age-old Schiff reaction for the synthesis of imine, which are reversible and nongreen from an environmental viewpoint. Herein, cobalt-doped manganese tungstate with two different morphologies is synthesized and demonstrated as a recyclable catalyst for imine synthesis from the condensation of an aldehyde and an amine with 73% yield of an imine in a nonaqueous and nonacidic environment at room temperature. The high catalytic activity is attributed to cobalt doping, high surface area, strong acidic site, and the polar nature of the catalyst. The stability and recyclability test shows that the catalytic activity remains the same after several cycles, which is crucial from the industrial point of view. The formation of imine is found to follow an alternative mechanism in an irreversible manner with a polar four-membered intermediate unlike the conventional method. The demonstrated process has several advantages including irreversibility, “greener”, environmental friendly, and energy-efficient.

CuO Immobilized Cellulose Paper as a Green Catalyst for the Acid/Base-Free Synthesis of Imines via a Nonconventional Approach

“…To overcome these drawbacks, the synthesis of imine in an acid-free organic medium with a non-noble metal-based catalyst has been performed in this study. According to Mal and Pradhan, the reaction follows an alternative mechanism (Figure ), which involves the direct transfer of a proton from the amine group of aniline to the oxygen of the carbonyl group. Simultaneously, C–N bond formation also takes place to form the carbinolamine intermediate via a four-membered polar transition state.…”

“…Imines are some of the most significant intermediate products used in chemistry and biology. These are generally known as Schiff bases (aromatic imines) and are highly reactive species used to produce pharmaceutically and biologically active compounds, heterocyclic chemicals, fine chemicals, dyes, and fungicides. − The traditional method for the preparation of imines is the condensation of amines with carbonyl compounds. This approach is simple, but it has two major drawbacks.…”

Synthesis and Experimental Structure of a Multifunctional Catechol‐Azomethinebenzoic Acid, DFT/DMol3 Calculations, and Molecular Docking with Hsp90

“…The formation of Schiff bases (imines) from amines and ketones or aldehydes is a very versatile reaction allowing to build‐up complex and multi‐functional organic structures from the two components [1–3] . Imines as parts of polydentate, multifunctional ligands have been extensively used in coordination chemistry with applications in catalysis, sensing, corrosion inhibition, and analytics [1,2,4,5] .…”

“…The formation of Schiff bases (imines) from amines and ketones or aldehydes is a very versatile reaction allowing to build-up complex and multi-functional organic structures from the two components. [1][2][3] Imines as parts of polydentate, multifunctional ligands have been extensively used in coordination chemistry with applications in catalysis, sensing, corrosion inhibition, and analytics. [1,2,4,5] But also, biomedically interesting purely organic structures have been build-up through the imine formation reaction and have been studied for their applications in medical diagnosis and treatment.…”