Study On Directional Synthesis Of Bio-based Jet Fuel And High Value Chemical-cresol Using Lignocellulose

Biomass is the only renewable carbon resource on the earth.The efficient synthesis of bio-based jet fuels and high value chemicals from lignocellulosic biomass is of great significance for promoting carbon emission reduction and sustainable development.Up to now,due to the diversity of lignocellulosic biomass and the complexity of the reaction process,the directional synthesis of bio-jet fuel and bio-chemicals from lignocellulosic biomass remains a challenging problem.In this thesis,a new approach to the preparation of bio-jet fuels from bagasse(a typical type of lignocellulosic)was explored through the integration of bio-catalysis and thermochemical catalysis.A novel route for the selective synthesis of cresol(a high value bio-chemical)using cellulose was explored with the functional catalysts.The main findings and results are summarized as below:1.Regulatory mechanism of preparation of bio-jet fuel using bagasse(1)Based on the integration of bio-catalysis and thermal catalysis,a new strategy for the directional synthesis of bio-jet fuel using bagasse was successfully constructed.Firstly,a butanol-rich ABE(acetone/butanol/ethanol)intermediate was produced through bio-chemical reactions(enzymatic hydrolysis and fermentation),and the ABE intermediates were selectively dehydrated and polymerized to form bio-jet fuels using bifunctional catalyst of HSAPO-34/Ni@HBET.(2)An environmentally friendly deep eutectic solvent(DES)was prepared.The pretreatment of bagasse with DES significantly improved the efficiency of enzymatic hydrolysis and fermentation of bagasse.The yield of sugar reached 36.9%,and the ABE yield reached 27.6%.The characterization of biomass structure and functional groups before and after the DES pretreatment was investigated in detail.(3)One-pot synthesis of bio-jet fuels using the bagasse fermentation broth was achieved through the catalytic dehydration/polymerization using the bi-functional catalyst of HSAPO-34/Ni@HBET.The yield of bio-jet fuels reached 78.1%,and the selectivity of bio-jet fuels reached 86.2%.(4)The single bed and double bed reaction modes,the role of catalyst active sites,the effects of reaction parameters,the characterization of the catalyst,and the reusability of the catalyst have been investigated in detail.Based on the study of the structure-activity relationship of the catalyst,the main reaction path for the synthesis of bio-jet fuel from bagasse was proposed.2.Regulatory mechanism of catalytic synthesis of jet fuels from lower alcohols(1)Various catalysts for the selective synthesis of jet fuels from lower alcohols were tested.It was found that the microporous HSAPO-34 catalyst was beneficial for the selective dehydration of lower alcohols to light olefins.The synergistic effect of metal ions and the acidic site in the Ni@Fe@HBET enhanced the selectivity of jet fuels.(2)Based on the study on catalytic conversion of low-carbon alcohols and ABE model compounds,the main reaction channels in the catalytic synthesis of jet fuels using low-carbon alcohols have been revealed.(3)The catalyst stability and catalyst regeneration during the catalytic synthesis of jet fuels were investigated.The catalyst deactivation mechanism was studied through the catalyst characterization and surface intermediate analysis.3.Regulatory Mechanism of catalytic synthesis of bio-based cresol using cellulose(1)Based on coupling selective catalytic cracking of cellulose and catalytic hydroxylation of aromatic intermediates,a novel approach for the directional synthesis of bio-based cresol using cellulose was explored.(2)The ZnO/HZSM-5 catalyst used for catalytic pyrolysis of biomass was prepared.The selectivity and yield of toluene intermediates were improved through the synergistic role between the acidic sites of molecular sieves and the active sites of metal oxides.(3)The bimetallic hydroxylation catalyst of CuCr2O4@MCM-41 was designed.The synergistic role between Cu ion and Cr ion in the catalyst promoted the selective hydroxylation of toluene intermediates.The cresol selectivity reached 87.5%and the cresol yield reached 72.6%.(4)Based on the study of aromatic model compounds and the characterization of catalysts,the main reaction paths for the catalytic synthesis of bio-based cresol from cellulose have been preliminarily clarified.