Study On Acid Catalyzed Controllable Condensation Of Furfuryl Alcohol To Produce Transport Fuel Precursor

Biomass energy is a renewable energy that can replace fossil fuels,reduce CO₂emissions.Based on the characteristics of the woody biomass polymerization structure and heat-sensitive properties,biomass resources can be converted into high value-added chemicals and transportation fuels through a series of chemical reactions.For example,5-hydroxymethylfurfural,furfural and furfuryl alcohol can be prepared through the acid catalysis of cellulose,then the C5 or C6 platform compound can transformed into alkanes suitable for gasoline,diesel and aviation fuel through chain extension and hydrodeoxygenation process.FA is bio-based platform compound derived from hemicellulose.Our research group has in-depth studied on the process conditions and the reaction mechanism of the self-condensation of FA over sulfuric acid catalyst in aqueous system.we revealed that two polymerization mechanisms,step-growth polymerization and chain-growth polymerization,coexist in FA condensation reaction process,but no method for suppressing chain-growth polymerization has been given.Based on this,this paper aims at controlling the chain-growth polymerization of molecular weight with rapid growth,controlling the controllable polymerization of carbon number distribution of condensation product molecules in the range of C₉-C₂₅,and proposes the phase separation of product and reaction system,introduction of chain transfer agent,reaction strategies such as heterogeneous catalysis?phase separation of catalyst and reaction system?significantly reduce the amount of condensation products with a molecular weight above of 3000,and increase the selectivity of C₉-C₂₅5 in products of FA condensation.The effect of the sulfonic acid-type ionic liquid catalyst with less corrosion on the condensation of FA in the aqueous system was studied.It was found that the produced oligomers were separated from aqueous reaction system automatically.The structural characterization of condensation product showed that the products obtained through FA self-condensation.Through the ionic liquid homogeneously catalysed the condensation reaction of FA,60%FA conversion and 30%the selectivity of C₉-C₂₅under the optimized experimental conditions were obtained.Next,according to the characteristics of cationic polymerization,the selectivity of C₉-C₂₅5 is increased to 45%by adding nucleophilic reagent of ethanol as a chain transfer agent.Further use of a cation exchange resin as a catalyst,and ethanol as a solvent,to reduced the contact probability between protonic acid-catalyzed sites on the solid catalyst surface and FA reactants in the liquid phase.At the same time,under the synergistic effect of ethanol,the catalytic reaction rate is reduced to 0.0907(mol·L^-1·min^-1),and the selectivity of C₉-C₂₅5 products increased from about 30%in the initial period of research to 65%.Then,the parameters such as reaction order,rate constant and activation energy under different conditions were determined,and the kinetic equation was established.It was found that the reaction order of the FA in the water system was one order,while the reaction order of the furfuryl alcohol in the solvent system containing ethanol was two.The structure of the condensation product was detected by infrared spectroscopy?FTIR?and gas chromatography mass spectrometry?GC-MS?analysis of the condensation products.It was confirmed that the FA self-condensation reaction occurred in the alcohol and no reaction occurred between the FA and ethanol.High performance gel permeation chromatography?GPC?detection showed that the molecular weight of the FA condensation product was a high dispersion system,and when the FA was completely converted,the number average molecular weight of the condensation product rapidly increased with the extension of the reaction time.