Metal-Free Allylic Oxidation with Molecular Oxygen Catalyzed by g-C3N4 and N-Hydroxyphthalimide

Guiyin Liu,Ruiren Tang,Zhen Wang

doi:10.1007/s10562-014-1200-1

Guiyin Liu, Ruiren Tang + Show 1 more

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https://doi.org/10.1007/s10562-014-1200-1

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Journal: Catalysis Letters	Publication Date: Feb 4, 2014
Citations: 36	License type: CC BY 2.0

Affiliation: Central South University

Abstract

Polymeric graphitic carbon nitride (g-C3N4) is a layered graphite-like nitrogen-rich material, bearing the potential ability to reductively adsorb molecular oxygen for catalytic allylic oxidation. Furthermore, N-hydroxyphthalimide (NHPI) has been recognized as an efficient catalyst for aerobic oxidation of various organic compounds under mild conditions in the presence of various co-catalysts. We present here a promising strategy for employing such nitride-rich g-C3N4 combined with NHPI to form an all-organic metal-free composite and have examined its activity for allylic oxidation with molecular oxygen as the primary terminal oxidant. In the case of allylic oxidation α-isophorone catalyzed by g-C3N4/NHPI gave priority to its corresponding carbonyl compound and epoxide. The effects of various reaction conditions on the catalytic reaction were optimized, affording 74.8 % conversion with 44.4 % selectivity of ketoisophorone at 130 °C in 5 h. Repeated runs demonstrated that the catalyst was stable for at least three cycles without noticeable loss of its catalytic activity.

Highlights

Selective allylic oxidation has been studied comprehensively over the past decade, for its extensive application in organic synthesis and industrial chemistry [1, 2]
We present here a promising strategy for employing such nitride-rich g-C3N4 combined with NHPI to form an allorganic metal-free composite and have examined its activity for allylic oxidation with molecular oxygen as the primary terminal oxidant
Inspired by these previous findings, we would like to build a catalytic system of combining g-C3N4 with NHPI as catalyst and molecular oxygen as the primary terminal oxidant in the allylic oxidation under heating alone within stainless steel autoclave, which is unprecedented and seems to be a intriguing method for converting hydrocarbons into their corresponding carbonyl compounds

Summary

Introduction

Selective allylic oxidation has been studied comprehensively over the past decade, for its extensive application in organic synthesis and industrial chemistry [1, 2]. Li and co-workers [25] have applied g-C3N4 assisted by N-hydroxy compounds in selective allylic oxidation with molecular oxygen under visible light irradiation. Employing stainless steel autoclave as reaction vessel under heating alone is more convenient for industrial production Inspired by these previous findings, we would like to build a catalytic system of combining g-C3N4 with NHPI as catalyst and molecular oxygen as the primary terminal oxidant in the allylic oxidation under heating alone within stainless steel autoclave, which is unprecedented and seems to be a intriguing method for converting hydrocarbons into their corresponding carbonyl compounds

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