Investigation and development of solid acid catalyts from some waste biomass sources for production of 5-hydroxymethylfurfural and levulinic acid

In recent years, biomass resources that are used effectively because of their cheapness and abundant availability have started to take place the non-renewable fossil fuel resources and have become an important research topic that attracts the attention of scientists. Various materials; bio-based carbon, membrane, fiber and superhydrophobic materials prepared from biomass are used in fields such as catalysis, environmental science, energy generation and artificial intelligence. 5-HMF and LA are the promising high value added compounds obtained from lignocellulosic and cellulosic biomass sources used as an important starting chemicals for synthesis of many important chemicals such as tetrahydrofuran, succinic acid, 2,5-dimethylfuran, aminolevulinic acid, etc. In this study, it is aimed to produce 5-HMF and LA from agricultural and industrial biomass wastes in the presence of biomass-derived carbon solid acid catalyst in aqueous medium. Corn straw and wheat straw were used as lignocellulosic biomass, fluff and linter were used as cellulose biomass and microcrystalline cellulose was used as a model compound. Two different hydrothermal methods were followed for the conversion of biomass materials. In two-step conversion, first of all, biomass materials were broken to the smallest monomers by hydrolysis, followed by conversion to 5-HMF and LA. In the second method, both hydrolysis and conversion were performed together in the same medium. In both methods, different biomass materials were used, reaction time, temperature, amount of catalyst and concentration were optimized. In general, when compared to product efficiency, one-step conversion method is the most prominent one. 5-HMF and LA yields were varied to the biomass material and the catalyst that was used. Eight different heterogenous solid acid catalysts with different chemical and physical properties were prepared in our laboratory for this study. Characterization studies of catalysts and biomass materials were completed by elemental analysis, ICP-OES, FT-IR, SEM, XRD, Raman, XRF analysis. The BT300-Fe3O4 catalyst stands out in conversion of lignocellulosic biomass because of its easy separation from the reaction medium due to its magnetite property, high catalytic activity in conversion and its use at least 5 times without any activation process. The activity of the prepared catalysts compared with Amberlyst-15, the BT300S catalyst played an effective role in both decomposition to glucose and conversion to LA.