Eucalyptus red grandis pretreatment with protic ionic liquids: effect of severity and influence of sub/super-critical CO2 atmosphere on pretreatment performance.

Francisco Malaret,Wei-Chien Tu,Joana M Lopes,Florence J V Gschwend,Jason P Hallett

doi:10.1039/d0ra02040k

Abstract

Deconstruction of lignocellulosic biomass with low-cost ionic liquids (ILs) has proven to be a promising technology that could be implemented in a biorefinery to obtain renewable materials, fuels and chemicals. This study investigates the pretreatment efficacy of the ionoSolv pretreatment of Eucalyptus red grandis using the low-cost ionic liquid triethylammonium hydrogen sulfate ([N2220][HSO4]) in the presence of 20 wt% water at 10% solids loading. The temperatures investigated were 120 °C and 150 °C. Also, the influence of performing the pretreatment under sub-critical and supercritical CO2 was investigated. The IL used is very effective in deconstructing eucalyptus, producing cellulose-rich pulps resulting in enzymatic saccharification yields of 86% for some pretreatment conditions. It has been found that under a CO2 atmosphere, the ionoSolv process is pressure independent. The good performance of this IL in the pretreatment of eucalyptus is promising for the development of a large-scale ionoSolv pretreatment processes.

Highlights

Lignocellulosic biomass is comprised of three biopolymers, namely cellulose, hemicellulose and lignin
Deconstruction of lignocellulosic biomass with low-cost ionic liquids (ILs) has proven to be a promising technology that could be implemented in a biorefinery to obtain renewable materials, fuels and chemicals
This study investigates the pretreatment efficacy of the ionoSolv pretreatment of Eucalyptus red grandis using the low-cost ionic liquid triethylammonium hydrogen sulfate ([N2220][HSO4]) in the presence of 20 wt% water at 10% solids loading

Summary

Introduction

Lignocellulosic biomass is comprised of three biopolymers, namely cellulose, hemicellulose and lignin. In order to achieve this, it is necessary to rst deconstruct and/or fractionate biomass though a process known as pretreatment.[1] Different pretreatment methods, such as steam explosion,[2] AFEX,[3] concentrated acid,[4] dilute acid,[5] hot water,[6] organosolv[7,8] and ionic liquid (IL) pretreatments,[9,10,11] including the ionoSolv process,[12,13,14,15] affect lignin content and structure, and cellulose crystallinity, accessibility and hydrolysis kinetics in different ways. This IL presents low toxicity and viscosity, but despite promising results there are some limiting factors for industrial application, such as high IL cost and stability[24] and the requirement for very low water content for optimum performance

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Conclusion