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<p>Escalating environmental issues and depletion of fossil-based reserves stimulate the need for sustainable transformation of plentiful and affordable biomass into valuable aromatic monomers. It is necessary for various industry applications. In this work, we have obtained low-molecular-weight monomeric compounds from commercial lignin by means of a low-cost catalytic depolymerization method using one of three Al-, Ti- or Zr-pillared Laponite clays as the catalyst in methanol solvent. The X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), Fourier-transform infrared spectroscopy (FTIR), temperature-programmed ammonia desorption (TPD-NH₃), and BET surface area analysis were used to characterize the synthesized Ti-Laponite materials (at 10%, 20%, 30%, and 40% loadings) as well as Al-Laponite and Zr-Laponite materials (at 30% loading).The lignin depolymerization was optimized based on different reaction conditions using an autoclave batch reactor. The resulting depolymerized products were characterized by analytical GPC, for molecular weight distribution, and by ¹³C and ¹H NMR spectroscopy, for evaluation of the carbon backbone structure. The intermediate molecular weight of lignin was significantly reduced from ~ 13,000 Da to 230 Da. The increased surface characteristics of the Ti-modified Laponite could direct selective depolymerization by cleaving the oxygen bridges (-O-) of lignin leading to the formation of low-molecular-weight compounds. Under optimal conditions (140&#xa0;°C, 10&#xa0;bar N₂ pressure), lignin conversion was &gt; 98% and the primary product was identified as 4-(3-hydroxypropyl)-catechol, as determined through gas chromatography, along with <sup>13</sup>C and <sup>1</sup>H NMR spectroscopy.</p>

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Surface enhanced cost-effective Heteroatoms pillared Laponite clay as solid acid catalyst for depolymerization of lignin into aromatic monomers

  • 期刊论文

  • 发表日期：

    2025年6月11日

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  • P. Muniyan,
  • P. Santhana Krishnan,
  • N. Rajendran,
  • K. Shanthi

摘要

Escalating environmental issues and depletion of fossil-based reserves stimulate the need for sustainable transformation of plentiful and affordable biomass into valuable aromatic monomers. It is necessary for various industry applications. In this work, we have obtained low-molecular-weight monomeric compounds from commercial lignin by means of a low-cost catalytic depolymerization method using one of three Al-, Ti- or Zr-pillared Laponite clays as the catalyst in methanol solvent. The X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), Fourier-transform infrared spectroscopy (FTIR), temperature-programmed ammonia desorption (TPD-NH₃), and BET surface area analysis were used to characterize the synthesized Ti-Laponite materials (at 10%, 20%, 30%, and 40% loadings) as well as Al-Laponite and Zr-Laponite materials (at 30% loading).The lignin depolymerization was optimized based on different reaction conditions using an autoclave batch reactor. The resulting depolymerized products were characterized by analytical GPC, for molecular weight distribution, and by ¹³C and ¹H NMR spectroscopy, for evaluation of the carbon backbone structure. The intermediate molecular weight of lignin was significantly reduced from ~ 13,000 Da to 230 Da. The increased surface characteristics of the Ti-modified Laponite could direct selective depolymerization by cleaving the oxygen bridges (-O-) of lignin leading to the formation of low-molecular-weight compounds. Under optimal conditions (140 °C, 10 bar N₂ pressure), lignin conversion was > 98% and the primary product was identified as 4-(3-hydroxypropyl)-catechol, as determined through gas chromatography, along with 13C and 1H NMR spectroscopy.