Pd catalysts supported on different hydrophilic or hydrophobic carbonaceous substrate for furfural and 5-(hydroxymethyl)-furfural hydrogenation in water

Comparative study on the reaction mechanism of 5-hydroxymethyl furfural on Pd(111) and Cu(111)

CONTEXT

In this work, a comparative study on the catalytic conversion of 5-hydroxymethyl furfural (HMF) to 2,5-bis(hydroxymethyl)furan (BHMF) on precious Pd(111) and nonprecious Cu(111) was systematically performed. On the basis of the calculated activation energy (Ea) and reaction energy (Er), the optimal energy path for the hydrogenation of HMF (F-CHO) into BHMF (F-CH2OH) on Pd(111) is as follows: F-CHO + 2H → F-CHOH + H → F-CH2OH; the minimum reaction path on Cu(111) is F-CHO + 2H → F-CH2O + H → F-CH2OH. On Cu(111), the formation of F-CH2OH from F-CH2O hydrogenation is the rate-determining step because it has the highest reaction energy barrier and the smallest rate constant. The comparison of HMF hydrogenation on Pd(111) and Cu(111) reveals their inherent differences in selectivity, mainly due to the different adsorption configurations of HMF and BHMF, and it was concluded that the nonprecious Cu(111) is a promising hydrogenation catalyst for the production of BHMF from the hydrogenation of HMF.

METHODS

All plane-wave DFT calculations were performed via the Vienna ab initio simulation package (VASP). The exchange and correlation energies were computed via the generalized gradient approximation (GGA) of the Perdew, Burke, and Ernzerhof (PBE) functional with the projector augmented wave (PAW) method.

Recent advances in catalytic synthesis of 2,5-furandimethanol from 5-hydroxymethylfurfural and carbohydrates

5-Hydroxymethylfurfural (HMF) is a versatile platform chemical derived from the dehydration of renewable carbohydrates (typically glucose/fructose-based monosaccharides, oligosaccharides, and polysaccharides). Some useful compounds, such as 2,5-furandimethanol (FDM), 2,5-dimethylfuran (DMF) and 2,5-dimethyltetrahydrofuran (DMTHF), have been synthesized by reduction of HMF. Among these, FDM is a promising diol and can be further converted towards fine chemicals, liquid fuels and polymer materials. In this review, some typical catalytic systems for the synthesis of FDM from both HMF and carbohydrates were summarized. The discussion focused on controlling the reaction networks for the reduction of HMF. The reaction mechanisms and the stability of the catalysts were introduced briefly. Last but not least, the prospects of effective production of FDM were discussed as well.