Preparation Of Modular Biobased Acid Catalytic Membrane And Its Performance In The Direct Conversion Of Monosaccharides To Liquid Biofuel EMF

In recent years,with the rapid development of traditional heavy industrialization,the massive consumption of fossil energy on the earth has led to the intensification of the energy crisis and the continuous deterioration of the ecological environment.Therefore,the use of abundant renewable resources stored in nature to accelerate development new green renewable new energy sources have become key research projects for scientific researchers.Among them,5-Ethoxymethylfurfural（EMF）is an important,high-energy-density,new-generation green liquid biofuel and diesel fuel additive,and is recognized as a potential green alternative fuel.The use of cheap sugars in ethanol systems to catalyze hydrolysis and etherification to obtain EMF through an acid catalyst is a very promising way to utilize biomass resources.which has the advantages of cheap raw materials,wide sources,simple process and so on.However,the currently reported traditional catalysts are mainly homogeneous catalysts.These homogeneous catalysts are extremely soluble in the liquid phase reaction system,difficult to separate and recover and easy to corrode,the shortcomings greatly limit its practical application in industry although they can catalyze the production of EMF from biomass in high yields.In addition,most of the reported heterogeneous solid powder catalysts have the disadvantage of lower EMF yields,which may be caused by the easy aggregation of powder materials.Based on this background,under the condition of ensuring the high yield of EMF,this paper aims to study the preparation of a new type of low-cost,high-yield,high-selectivity modular heterogeneous catalytic membrane for the catalysis of cheap and readily available fructose or glucose synthesis green liquid biofuel EMF,It is of great significance to realize large-scale and efficient production of EMF in an economic and environmentally friendly way in the future.In this paper,a kind of aromatic carbon microspheres with high quality and high stability were prepared by simple hydrothermal carbonization method using biomass waste camellia husk as raw material,and then combined with a high molecular polymer PVDF material,a modular heterogeneous PVDF composite membrane was successfully prepared by the phase inversion method.Finally,the corresponding new modular heterogeneous acid catalytic membrane（BCMSs-SO₃H@PVDF）was successfully prepared by loading Br（?）nsted acid or Lewis acid on the surface and inside of the membrane.The specific research content is as follows:First,a modular heterogeneous Br（?）nsted acid catalytic membrane（BCMSs-SO₃H@PVDF）was successfully prepared through a simple hydrothermal-phase inversion-sulfonation process by using biomass waste camellia husk and polymer PVDF powder as raw materials.Then,it was applied in ethanol phase system to heat and catalyze fructose to prepare green liquid biofuel EMF.The results show that most of the carbon microspheres on this modular heterogeneous Br（?）nsted acid catalytic membrane are wrapped in the pores,and the acid sites on the catalytic membrane can be efficiently contact with the substrate molecules of the reaction due to the large number of sponge-like macropores inside the membrane,thereby promoting the catalytic efficiency.In addition,the optimal conditions for the preparation of the catalytic membrane and the catalytic reaction were also explored,the results show that the optimal conditions are:the loading of carbon microspheres on the surface of the membrane is 1.0 g,the thickness of the membrane is 400μm,the pore-forming dose is 0 g,and the catalyzed reaction temperature is 100°C.and the catalyzed time is 36 h,the yield of EMF is up to 81.99%in this conditions.Although the yield of EMF obtained by catalyzing fructose is high,the price of fructose is still relatively expensive,which still makes it difficult to mass produce industrially.Therefore,on the basis of the previous work,we continue to conduct in-depth exploration.the cheaper and more readily available glucose was selected as the reaction substrate for the conversion of EMF.First,we used the modular heterogeneous Br（?）nsted acid catalytic membrane prepared in the previous work,a modular heterogeneous Lewis acid catalytic membrane was successfully prepared by supporting Cr（OH）₃ powder with Lewis acidic acid sites on the surface through sulfonic acid groups by a simple impregnation method,and then combined with the modular heterogeneous Br（?）nsted acid catalytic membrane to form a combined catalytic membrane,which was used to catalyze the conversion of glucose to green liquid biofuel EMF by the one-pot two-step method.Subsequently,the optimal preparation conditions of this modular heterogeneous Lewis acid catalytic membrane were explored.It was found that,the temperature was 60°C and the amount of acetic acid was 1 ml during the loading of Cr（OH）₃,The obtained EMF yield was 23.58%.