BTX from the gas-phase hydrodeoxygenation and transmethylation of guaiacol at room pressure

Highlights

The gas phase hydrodeoxygenation and transalkylation of bio-oil was studied at room pressure.

The conversion is 100%, the XHDO is 55% and the ratio of tansalkylationhydrocarbon is 22%.

The hydrogenation focuses on the Caromatic-OH and Caromatic-CH3O bone not aromatic ring.

Most of methyl or methoxyl is transferred to the phenolic or benzene ring, minimizing carbon loss.

FeH2+ from the Fe2+ chemisorbing H2 was proposed as active sites for hydrogenolysis.

Abstract

Biosourced aromatics (benzene–toluene–xylene (BTX) and phenols) could be obtained by catalytic hydrodeoxygenation (HDO) coupled with transmethylation at atmospheric pressure in a fixed-bed reactor. We choose guaiacol as a model compound to investigate the catalytic HDO over Fe/Ni/HBeta catalyst. The active amount (5%–15%), temperature (250–400 °C), and 1/WHSV (1.5–4.0) significantly influenced the hydrogenolysis of the Caromaticsingle bond

single bond

O bond and transmethylation. The mechanism showed that feed and intermediate products formed the “surface pool” on the catalyst surface, which enabled the HDO reaction by the reduced intermediate species (Z-FeH2+ and Z-NiH+). Fe/Ni/HBeta exhibited good activity for both methyl transfer and HDO. Moreover, the aromatic ring did not undergo catalytic hydrogenation, and most methyl or methoxyl molecules transferred onto the phenolic or benzene ring and remained after deoxygenation. Consequently, carbon loss was minimized, and hydrogen consumption was reduced.

Graphical abstract

Keywords

  • Lignin;
  • BTX;
  • Hydrodeoxygenation;
  • Transmethylation;
  • Fe/Ni/HBeta catalyst

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