Structural characterization and pyrolysis behavior of holocellulose obtained from lignin-first biorefinery

• Lignin-first biorefinery influenced the structure of holocellulose.
• Raney Ni holocellulose showed higher degree of crystallinity than Ru/C one.
• Raney Ni holocellulose had shorter chain length than Ru/C one.
• High char yield from pyrolysis of the resulting holocellulose was obtained.

The structural characteristics and pyrolysis behaviors of two holocelluloses obtained from lignin-first biorefinery with Ru/C or Raney Ni as catalysts were studied in this paper. The infrared spectra of the remaining solid from the lignin-first biorefinery show that both lignin and a portion of hemicellulose were decomposed. Compared with Ru/C, Raney Ni was more effective for delignification and gave a holocellulose with higher degree of crystallinity, based on both the ratio of infrared bands (1372 cm−1/2900 cm−1) and XRD analysis. The pyrolyses of holocelluloses were performed in fixed-bed and free-falling reactors, and the resulting char yields from both reactors were significantly higher than those of the parent biomass and commercial cellulose. This resulted from the cleavage of cellulose chain during the lignin-first biorefinery. Raney Ni related biorefinery cleaved cellulose chain to a higher degree.