Thermochemical Conversion of Untreated and Pretreated Biomass for Efficient Production of Levoglucosenone and 5-Chloromethylfurfural in the Presence of an Acid Catalyst

Chandan Kundu,Mahmud Arman Kibria,Saheli Biswas,Sankar Bhattacharya

doi:10.3390/catal12020206

Abstract

Levoglucosenone (LGO) and 5-chloromethyl furfural (5-CMF) are two bio-based platform chemicals with applications in medicines, green solvents, fuels, and the polymer industry. This study demonstrates the one-step thermochemical conversion of raw and pretreated (delignified) biomass to highly-valuable two platform chemicals in a fluidized bed reactor. Hydrochloric acid gas is utilized to convert biomass thermochemically. The addition of hydrochloric acid gas facilitates the formation of LGO and CMF. Acid gas reacts with biomass to form 5-CMF, which acts as a catalyst to increase the concentration of LGO in the resulting bio-oil. The presence of higher cellulose content in delignified biomass significantly boosts the synthesis of both platform chemicals (LGO and CMF). GC-MS analysis was used to determine the chemical composition of bio-oil produced from thermal and thermochemical conversion of biomass. At 350 °C, the maximum concentration of LGO (27.70 mg/mL of bio-oil) was achieved, whereas at 400 °C, the highest concentration of CMF (19.24 mg/mL of bio-oil) was obtained from hardwood-delignified biomass. The findings suggest that 350 °C is the optimal temperature for producing LGO and 400 °C is optimal for producing CMF from delignified biomass. The secondary cracking process is accelerated by temperatures over 400 °C, resulting in a low concentration of the target platform chemicals. This work reveals the simultaneous generation of LGO and CMF, two high-value commercially relevant biobased compounds.

Highlights

Thermochemical conversion is a well-established technique that has the potential to develop biomass-derived high-value platform chemicals
The list of compounds derived from the thermochemical conversion of HW-raw biomass at 350 ◦C is shown in Table 1 and Supplementary Figure S2
Delignified biomass showed higher platform chemical concentration compared to raw biomass

Summary

Introduction

Thermochemical conversion is a well-established technique that has the potential to develop biomass-derived high-value platform chemicals. The main building blocks of biomass—cellulose, hemicellulose, and lignin—affect the target platform chemicals and make a considerable difference in their properties individually [1]. Thermochemical conversion of biomass results in bio-oil, char, and gas. Bio-oil is a complex combination of oxygen and organic molecules such as esters, organic acids, ketones, furans, and anhydrosugars [2]. Significant advancements in the fractionation and analysis of bio-oil have been accomplished. Due to the lack of selective biomass conversion and several chemical species in the complex bio-oil composition, the majority of research has prioritized qualitative analysis rather than focused quantitative analysis [3]

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