Selective oxidation of benzene to phenol by FeCl3/mpg-C3N4 hybrids

Abstract

Existing phenol production mostly by cumene processes is a three-step route with unwanted acetone as by-product. Here, we report the FeCl 3 and mesoporous carbon nitride hybrid (FeCl 3 /mpg-C 3 N 4 ) as an active and selective photocatalyst to activate H 2 O 2 for the oxidation of benzene to phenol under visiblelight illumination. By fine-optimizing FeCl 3 loading amount in catalyst and reaction conditions, the onestep process achieved a 38% benzene conversion with 97% selectivity for phenol. The excellent catalytic performance of FeCl 3 /mpg-C 3 N 4 should be attributed to the fast reduction of Fe 3+ to Fe 2+ by photoirradiated electrons from mpg-C 3 N 4 . To further understand the reaction route, several electron spin resonance (ESR) tests were carried out, confirming mpg-C 3 N 4 promoted redox cycle of Fe 2+ /Fe 3+ in the FeCl 3 /mpg-C 3 N 4 system. Based on these results, a catalytic mechanism for the oxidation of benzene by FeCl 3 /mpg-C 3 N 4 hybrids was provided. This environmental-friendly and efficient method is expected to open up a new avenue for one-step phenol preparation.

Magnetic g-C3N4/NiFe2O4 hybrids with enhanced photocatalytic activity

“…Additionally Wang analyzed the photo-Fenton reaction routes and proved that • OH played an vital role in the oxidation process of benzene to phenol for FeCl 3 /mpg-C 3 N 4 hybrids. 46 There are related studies supporting the trapping experiment and mechanism research as well. 47,48 In Fenton and photo-Fenton reaction, iron-based species can generate highly reactive hydroxyl radicals (•OH) to treat a large variety of water pollutants.…”

Acid‐Functionalised Magnetic Ionic Liquid [AcMIm]FeCl4 as Catalyst for Oxidative Hydroxylation of Arylboronic Acids and Regioselective Friedel–Crafts Acylation

“…In addition, H 2 O 2treated [AcMIm]FeCl 4 exhibits am ultiple EPR spectrum with al ower g value (g = 1.45;F igure S7 in the Supporting Information);t his may indicatet he presence of ah ydroxyl free radical, hydroperoxyl radical or triplet oxygen diradical (oxene). [51][52][53][54][55] Also, the small and sharp peak in the EPR spectrum with a g value of approximately 4.1 signifies the presenceo fh igh-spin iron species( Figure S7 in the Supporting Information). [54] Based on the above observations, we have proposed aplausible reaction mechanism for the [AcMIm]FeCl 4 -promoted oxidativeh ydroxylation of arylboronic acids (Scheme 3).…”

Photocatalytic Properties of g-C3N4–TiO2 Heterojunctions under UV and Visible Light Conditions

“…Prime examples include that of the anatase–rutile [2] or the anatase–brookite heterojunction system [3], which both promote the effective transfer of photo-excited electrons and favor electron-hole separation. Graphitic carbon nitride ( g -C 3 N 4 ) has been shown to be efficient at producing hydrogen through the oxidation of organic species [4,5]. Therefore, a g -C 3 N 4 -doped titanium dioxide (TiO 2 ) system was chosen to be studied as a continuation of this study.…”

“…Several publications in recent years have highlighted the effectiveness of g -C 3 N 4 as a photocatalyst in areas such as the selective oxidation of alcohols and hydrocarbons [4,11], and as a good photocatalytic performer in relation to hydrogen or oxygen production via water splitting with the use of visible light irradiation [5]. It has strong reduction reaction properties owing to the high potential of the conduction band but inferior oxidation capabilities due to its valence band located at about 1.4 eV vs. NHE, resulting in a small thermodynamic driving force for water or organic pollutants oxidation.…”