This study aims to produce levulinic acid (LA) from paper towel waste in environment-friendly and economically feasible conditions, and evaluate the difference using solid and aqueous Brønsted acids. Direct dehydration of glucose to LA required sufficiently strong Brønsted acidity, where Amberlyst 36 demonstrated rapid production of approximately 30 C mol% of LA in 20 min. However, the maximum yield of LA was limited by mass transfer. In contrast, the yield of LA gradually increased to over 40 C mol% in 1 M H2SO4 at 150 °C in 60 min. The SEM images revealed the conversion in dilute acids under microwave at 150 °C resulting in swelling structures of cellulose, which were similar to the pre-treatment process with concentrated acids. Further increase in reaction temperature to 200 °C significantly shortened the reaction time from 60 to 2.5 min, which saved the energy cost as revealed in preliminary cost analysis.
- Brønsted acid
- Levulinic acid
- Waste valorization
ASJC Scopus subject areas
- Environmental Engineering
- Renewable Energy, Sustainability and the Environment
- Waste Management and Disposal