Research On The Preparation Of Furfural From Sugars Degraded By Biomass And Phenol-Furfural Resin Foamed Material

With the continuous development of society,people's demand for energy is also increasing.Fossil energy is one of the main energy sources depending on at present,but it belongs to non-renewable energy,which will eventually be exhausted under continuous mining.What's worse,the extensive use of fossil energy has also caused serious environmental problems.Therefore,it is urgent to find new energy sources to replace fossil energy.Among them,biomass energy is a promising energy source.Furfural can be obtained from renewable biomass raw materials through acid catalysis.However,inorganic acids are used as catalysts in traditional production process,which exists some problems,such as serious corrosion to equipment and the production of acid waste water.In this paper,functional metal-organic frameworks?MOFs?MIL-101?Cr?-SO₃H were synthesized to catalyze sugars to furfural,and furfural was used to replace formaldehyde reacting with phenol to prepare resol phenol-furfural resin without free formaldehyde.Finally,the foaming process of the resin was investigated.This process not only realized the process of high efficiency conversion of biomass raw material to furfural,but also replaced formaldehyde with the less toxic furfural to prepare phenol-furfural resin,effectively reducing the harm of formaldehyde to human body and environment.MIL-101?Cr?-SO₃H with Lewis acid and Br?nsted acid catalytic sites was synthesized by hydrothermal method under different molar ratios of metal salt and organic ligand.The unmodified material MIL-101?Cr?and modified MIL-101?Cr?-SO₃H were characterized by a series instruments.These MOFs were used to prepare furfural from xylose and the optimum reaction conditions were:0.4 g xylose,0.27 g MIL-101?Cr?-SO₃H?molar ratio of metal salt to organic ligand was 1:1?,26 wt%NaCl,12 g mixed cyclopentyl methyl ether?CPME?and water?mass ratio 2:1?,170?,180 min.Furfural yield and xylose conversion were 70.8%and97.8%respectively.The screening conditions were further applied to the conversion of eucalyptus powder hydrolysate by changing the reaction time only.89.49%hemicellulose of eucalyptus powder could be removed by hot water prehydrolysis.The results showed that the maximum furfural yield reached 52.9%when eucalyptus powder hydrolysate reacted for 5 h.Phenol-furfural resin was prepared by phenol and substituting furfural for formaldehyde at different molar ratios.When the ratio of furfural to phenol was 1.6:1,the content of free phenol and free furfural in the resin were 3.84%,1.77%respectively and the viscosity was5228 mPa·s,which all met the performance index of standard first-order phenolic resin.When the amount of urea was 6%of the molar number of furfural,the content of free furfural decreased to 0.62%.Finally,the effects of resin viscosity,foaming mold,plasticizer content and blowing agent content on properties of foamed material were discussed.The results showed that the foaming effect was better when the resin viscosity was 5000-7000 mPa·s with3-4%plasticizer dioctyl phthalate?DOP?and 10-12%blowing agent n-pentane using plastic mold.Under the optimum conditions,the apparent density,the compressive strength,the oxygen index and the thermal conductivity of phenol-furfural foamed material were 50 kg·m^-3,0.45 MPa,40%and 0.035 W·m^-1·K^-11 respectively.This product was a high efficiency thermal insulation material.