Photocatalytic Reductive Defluorination of Fluorinated Compounds in Aqueous Alcohol Suspensions of a Metal‐loaded Titanium(IV) Oxide. Issue 12 (12th May 2020)

• Record Type: Journal Article
• Authors: Fukui, Makoto; Tanaka, Atsuhiro; Kominami, Hiroshi
• Is Part Of: ChemCatChem. Volume 12:Issue 12(2020)
• Page Start: 3298
• Page End: 3305
• Publication Date: 2020-05-12
• Subjects: Photocatalyst -- TiO2 -- Metal co-catalyst -- Defluorination -- Fluorinated compounds; Catalysis -- Periodicals; 541.39505
• DOI: 10.1002/cctc.202000299
• Languages: English
• ISSNs: 1867-3880

Abstract

Abstract: Selective elimination of the fluorine element in organic fluorinated compounds under mild conditions is desired in order to resolve the environment and energy resource issues. Selective reductive defluorination of fluorine‐containing organic compounds in 2‐propanol‐water suspensions of metal‐loaded titanium(IV) oxide (TiO2 ) photocatalysts is described in this paper. The effects of different types of metal co‐catalysts, adsorption behavior of fluorobenzene (FB), stoichiometry, redox balance, scope, chemoselectivity and reaction temperature were examined. Photocatalytic defluorination of FB occurred over platinum‐loaded TiO2 at room temperature, and benzene and fluoride ion were produced with a high stoichiometry without degradation of the benzene structure, while hydrogen (H2 ) production occurred as a competitive electron‐consuming reaction. A slight elevation in the reaction temperature greatly accelerated defluorination and suppressed H2 evolution, resulting in FB defluorination free from H2 production at 333 K. Kinetic parameters of FB defluorination and H2 evolution were determined, and the results obtained are explained on the basis of these parameters. Abstract : Photocatalytic reductive defluorination : Organic fluorinated compounds were reductively converted to the corresponding organic structures and fluoride ions with high stoichiometry in aqueous 2‐propanol suspensions of a metal‐loaded TiO2 photocatalyst. A slight elevation of the reaction temperature greatly improved reaction rate and electron selectivity for defluorination. Catalytic defluorination process over Pt was the rate‐determining step.