The Preparation Of Biobased Heterogeneous Solid Acid Catalysts And Their Application In The Synthesis Of Liquid Biofuels EMF

With the increasing depletion of non-renewable fossil energy,more and more attention has been paid to develop renewable biofuels.5-Ethoxymethylfurfural?EMF?,a kind of liquid biofuel which energy density is close to gasoline,has broad application prospects and can be easily prepared by the etherification reaction of 5-hydroxymethylfurfural?HMF?and ethanol.However,it is industrialized production is limited by high produced cost.For one,homogeneous liquid acid catalyst can be used to prepare EMF,but there are the troubles of environmental pollution,equipment corrosion and difficult recovery.For another,heterogeneous solid acid catalyst of marketization has the problems of low activity,poor stability and high cost.Therefore,the search for a low cost,high activity,high selectivity of heterogeneous solid acid catalyst for EMF production is imminent.In this paper,high quality carbon microspheres with aromatic carbon skeleton was firstly prepared with the abandoned Camellia oleifera shells by hydrothermal carbonization technology under the structural guidance of phloroglucinol.Then,the heterogeneous Br?nsted solid acid catalyst was prepared by sulfonation reaction which sulfonic acid groups were loaded onto the surface of the prepared carbon microspheres.This catalyst is very active in preparating EMF by the successful construct spherical microstructure and successful load sulfonic acid groups.Due to use low cost raw material,the development cost of the catalyst has a significantly decrease,thus reducing the production costs of EMF.Details are as follows:1.In order to investigate the mechanism of the formation of carbon microspheres with abandoned Camellia oleifera shells by hydrothermal carbonization technology under the influence of phloroglucinol,GC-MS was used to detect the composition of hydrothermal liquefaction.Cellulose,hemicellulose,lignin and tea saponin which were extracted from Camellia oleifera shell were reacted respectively with phloroglucinol.Combining with the results of field emission scanning electron microscopy.The formation mechanism of carbon microspheres are as follows: cellulose and hemicellulose were converted to monosaccharides?such as flucose and fructose?under hydrothermal conditions,these monosaccharides continue to dehydrate to form small molecules of furfural.Lignin were converted to monomeric phenolic compounds with ether bond breakage,pentacyclic triterpenoid structure and monosaccharides form when glycosidic bonds connect with pentacyclic triterpenoid structure in tea saponin were broken,these monosaccharides continue to dehydrate to form small molecules of furfural.Then,these small molecules of furfural,monomers of phenolic compounds and pentacyclic triterpenoid structure were converted to soluble polymer under the influence of phloroglucinol by intermolecular dehydration or polycondensation reaction of the aldol and the aldehydes and ketones.The polymer undergoes an aromatization reaction under the action of phenolic compound,explosive induced nucleation reaction begin to form when the amount of aromatic cluster compound reached the saturation threshold.Carbon microspheres that it is surface covered by active groups formed with the continuous polycondensation reaction.2.A low cost,high efficiency,high stability and high activity aromatic carbon microspheres heterogeneous solid acid catalyst loaded with sulfonic acid groups?Ar-CMSs-SO₃H?was prepared by combining hydrothermal carbonization with sulfonation reaction which used abandoned camellia oleifera shells as raw material.The research shows that the successful construction of spherical microstructure and the successful load of sulfonic acid groups respectively attributable to the guidance of phloroglucinol and the support of aromatic carbon skeleton.The optimum sulfonation temperature,sulfonation time and concentration of sulfuric acid in sulfonation reaction are 110?,6h and 6ml respectively.The optimum reaction time and the reaction temperature to prepare EMF are 12 h and 100? respectively.3.EMF can be easily prepared by HMF's etherification reaction under the action of the catalyst?Ar-CMSs-SO₃H?,and it is yield is high.But HMF is expensive,so fructose is a more economic way to prepare EMF.In order to increase catalyst activity,aromatic carbon microspheres was firstly treated by high temperature annealing at different temperatures,then the catalyst?A?x?-CMSs-SO₃ H,x indicates annealing temperature?,loading of sulfonic acid groups,was prepared by sulfonation reaction.The result shows that compared to Ar-CMSs-SO₃ H,A?350?-CMSs-SO₃ H show higher activity in the preparation of EMF when raw material is fructose.Than we explore the effect of different temperature and time,amount of catalyst and fructose concentration in the yield of EMF.The optimum reaction conditions are that the reaction temperature is 100?,the reaction time is 12 h,the amount of catalyst is 100 mg and the solvent is pure ethanol.4.Because of the significant effect of A?350?-CMSs-SO₃ H in converting glucose to fructose under the catalysis of Lewis acid and the high activity in converting fructose into EMF.The effect of direct conversion from glucose to EMF has been investigated by combining A?350?-CMSs-SO₃ H with Lewis acid.The result shows that glucose can be directly convert to EMF under the synergistic effect of A?350?-CMSs-SO₃ H and SnCl₄.