Hydrotreatment of Kraft Lignin to Alkylphenolics and Aromatics using Ni, Mo and W Phosphides Supported on Activated Carbon

Ramesh Kumar Chowdari, Shilpa Agarwal, Hero J. Heeres* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

8 Citations (Scopus)
12 Downloads (Pure)

Abstract

The conversion of lignin to biofuels and biobased chemicals is currently attracting a lot of attention. We here report on the valorization of Kraft lignin by a catalytic hydrotreatment using Ni, Mo, and W phosphide catalysts supported on activated carbon in the absence of an external solvent. Experiments were carried out in a batch setup in the temperature range of 400-500 °C and 100 bar initial H 2 pressure. The synthesized catalysts were characterized by X-ray diffraction, nitrogen physisorption, and transmission electron microscopy. The lignin oils were analyzed extensively by different techniques such as GPC, GC-MS-FID, 13C NMR, and elemental analysis. Two-dimensional gas chromatography (GC×GC-FID) was applied to identify and quantify distinct groups of compounds (aromatics, alkylphenolics, alkanes, etc.). Mo-based catalysts displayed higher activity compared to the W-containing catalysts. The reaction parameters such as the effect of reaction temperature, reaction time, and catalyst loading were studied for two catalysts (15MoP/AC and 20NiMoP/AC), and optimized reaction conditions regarding yields of monomeric components were identified (400 °C, 100 bar H 2 at RT, 10 wt % catalyst loading on lignin intake). The highest monomer yield (45.7 wt % on lignin) was obtained for the 20NiMoP/AC (Ni 5.6 wt %, Mo 9.1 wt %, P 5.9 wt %) catalyst, which includes 25% alkylphenolics, 8.7% aromatics, and 9.9% alkanes. Our results clearly reveal that the phosphide catalysts are highly efficient catalyst to depolymerize the Kraft lignin to valuable biobased chemicals and outperform sulfided NiMo catalysts (monomer yield on lignin < 30 wt %).

Original languageEnglish
Pages (from-to)2044-2055
Number of pages12
JournalACS sustainable chemistry & engineering
Volume7
Issue number2
Early online date17 Dec 2018
DOIs
Publication statusPublished - 22 Jan 2019

Keywords

  • UT-Hybrid-D
  • Depolymerization
  • Phosphided catalysts
  • Hydrotreatment
  • Biobased chemicals
  • Kraft lignin

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