Solid-state ²⁹Si NMR and FTIR analyses of lignin-silica coprecipitates

TY - JOUR

T1 - Solid-state 29Si NMR and FTIR analyses of lignin-silica coprecipitates

AU - Cabrera Orozco, Yohanna

AU - Cabrera, Andrés

AU - Larsen, Flemming Hofmann

AU - Felby, Claus

PY - 2016

Y1 - 2016

N2 - When agricultural residues are processed to ethanol, lignin and silica are some of the main byproducts. Separation of these two products is difficult and the chemical interactions between lignin and silica are not well described. In the present study, the effect of lignin-silica complexing has been investigated by characterizing lignin and silica coprecipitates by FTIR and solid state NMR. Silica particles were coprecipitated with three different lignins, three lignin model compounds, and two silanes representing silica-in-lignin model compounds. Comparison of 29Si SP/MAS NMR spectra revealed differences in the distribution of silanol hydroxyl groups among different coprecipitates. These differences are dependent on the lignin type. The results are interpreted that the underlying mechanism of the interactions is the formation of hydrogen bonds between lignin aliphatic hydroxyl or carboxyl groups and the silanols, but not a condensation of the silica-in-lignin among the silica particles and not the formation of C-O-Si bonds.

AB - When agricultural residues are processed to ethanol, lignin and silica are some of the main byproducts. Separation of these two products is difficult and the chemical interactions between lignin and silica are not well described. In the present study, the effect of lignin-silica complexing has been investigated by characterizing lignin and silica coprecipitates by FTIR and solid state NMR. Silica particles were coprecipitated with three different lignins, three lignin model compounds, and two silanes representing silica-in-lignin model compounds. Comparison of 29Si SP/MAS NMR spectra revealed differences in the distribution of silanol hydroxyl groups among different coprecipitates. These differences are dependent on the lignin type. The results are interpreted that the underlying mechanism of the interactions is the formation of hydrogen bonds between lignin aliphatic hydroxyl or carboxyl groups and the silanols, but not a condensation of the silica-in-lignin among the silica particles and not the formation of C-O-Si bonds.

KW - C NMR

KW - Si SP/MAS NMR

KW - FTIR

KW - lignin

KW - lignin-silica-interactions

KW - silans

KW - silica

KW - solid-state NMR

U2 - 10.1515/hf-2015-0165

DO - 10.1515/hf-2015-0165

M3 - Journal article

AN - SCOPUS:84983379444

SN - 0018-3830

VL - 70

SP - 709

EP - 718

JO - Holzforschung

JF - Holzforschung

IS - 8

ER -