The degradation of the lignin in Phyllostachys heterocycla cv. pubescens in an ethanol solvothermal system

Abstract

The degradation of lignin to small molecules is important for the use of biomass to produce biofuel, as the C/O and H/O ratios in lignin are much higher than those in cellulose and hemicellulose. The present work studied the selective degradation of the lignin in Phyllostachys heterocycla cv. pubescens in an ethanol solvothermal system. The results revealed that 45.3% of lignin was degraded at 220 °C for 2 h, while significant conversion of hemicellulose and cellulose was avoided. The cleavage of the β–O–4 linkage was found to be responsible for the dissolution of lignin from Phyllostachys heterocycla cv. pubescens into the liquid phase. The cracking of phenylpropyl side-chain C–C bonds followed the order: C_α–C_β, C₁–C_α, C_β–C_γ. A maximum yield of 10.6 wt% of 4-ethyl phenols based on the converted lignin from Phyllostachys heterocycla cv. pubescens was obtained under optimized conditions.