Hydrolytic depolymerization of hydrolysis lignin: Effects of catalysts and solvents

Bioresour Technol. 2015 Aug:190:416-9. doi: 10.1016/j.biortech.2015.04.074. Epub 2015 Apr 27.

Abstract

Hydrolytic depolymerization of hydrolysis lignin (HL) in water and water-ethanol co-solvent was investigated at 250°C for 1h with 20% (w/v) HL substrate concentration with or without catalyst (H2SO4 or NaOH). The obtained depolymerized HLs (DHLs) were characterized with GPC-UV, FTIR, GC-MS, (1)H NMR and elemental analyzer. In view of the utilization of depolymerized HL (DHL) for the preparation of rigid polyurethane foams/resins un-catalyzed depolymerization of HL employing water-ethanol mixture appeared to be a viable route with high yield of DHL ∼70.5wt.% (SR yield of ∼9.8wt.%) and with Mw as low as ∼1000g/mole with suitable aliphatic (227.1mgKOH/g) and phenolic (215mgKOH/g) hydroxyl numbers. The overall % carbon recovery under the selected best route was ∼87%. Acid catalyzed depolymerization of HL in water and water-ethanol mixture lead to slightly increased Mw. Alkaline hydrolysis helped in reducing Mw in water and opposite trend was observed in water-ethanol mixture.

Keywords: Acid/base; Depolymerization; Hydrolysis lignin; Water; Water–ethanol mixture.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Catalysis
  • Gases / chemical synthesis
  • Hydrolysis
  • Lignin / chemistry*
  • Lignin / isolation & purification
  • Polymers / chemistry
  • Polyurethanes / chemical synthesis*
  • Solvents / chemistry*
  • Water / chemistry*

Substances

  • Gases
  • Polymers
  • Polyurethanes
  • Solvents
  • Water
  • Lignin