Gas Phase Hydrogenation of Furaldehydes via Coupling with Alcohol Dehydrogenation over Ceria Supported Au-Cu.

ABSTRACT: We have investigated the synthesis and application of Au-Cu/CeO? (Cu: Au = 2) in the continuous gas phase (P = 1 atm; T = 498 K) coupled hydrogenation of 5-hydroxymethyl-2-furaldehyde (HMF) with 2-butanol dehydrogenation. STEM-EDX analysis revealed a close surface proximity of both metals in Au-Cu/CeO? post-TPR. XPS measurements suggest (support ? metal) charge transfer to form Au^?- and strong metal-support interactions to generate Cu? and Cu?. Au-Cu/CeO? promoted the sole formation of 2,5-dihydroxymethylfuran (DHMF) and 2-butanone in the HMF/2-butanol coupling with full hydrogen utilisation. Under the same reaction conditions, Au/CeO? was fully selective to DHMF in standard HMF hydrogenation (using an external hydrogen supply), but delivered a lower production rate and utilised less than 0.2% of the hydrogen supplied. Exclusive -C=O hydrogenation and -OH dehydrogenation is also demonstrated for the coupling of a series of m-substituted (-CH?, -CH?CH?, -CH?OH, -CF?, -N(CH?)?, -H) furaldehydes with alcohol (1-propanol, 1-butanol, 2-propanol, 2-butanol, cyclohexanol) dehydrogenation over Au-Cu/CeO?, consistent with a nucleophilic mechanism. In each case, we observed a greater hydrogenation rate and hydrogen utilisation efficiency with a 3?15 times lower E-factor in the coupling process relative to standard hydrogenation. Our results demonstrate the feasibility of using hydrogen generated in situ through alcohol dehydrogenation for the selective hydrogenation of m-furaldehydes with important industrial applications.

SUBMITTER: Pischetola C 

PROVIDER: S-EPMC6278317 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature