Research On Production Of Levulinic Acid By Catalytic Hydrolysis From Cane Molasses

Nowadays,the challenges of energy and chemical products consumption are becoming increasingly severe with the depletion of non-renewable petrochemical resources such as oil and gas.The global energy crisis and the greenhouse effect are becoming more and more serious.In this case,finding alternative green and clean renewable resources is the key to solve the problem.Because of renewable biomass unique properties,widely distributed and the advantage of cheap,the method of physical,chemical or biological transformation into high value-added potential energy chemicals has aroused great attention.Levulinic acid?LA for short?is regarded as a kind of new green platform compound.Because of its unique structure and reactivity,a large number of high value-added functional chemicals can be derived through chemical reactions such as salification,esterification,hydrogenation,condensation and halogenating.In this work,the single variable method is adopted to evaluate the influence of reaction time,concentration of molasses,catalyst concentration and reaction temperature on LA yield for sugar industry by-product molasses as raw material,sulfuric acid as catalyst in the process of producing LA from biomass.The process conditions of producing LA from cane molasses step by step is initial discussed.To evaluate the level and interaction of various factors in LA producing process and to optimize the preparation conditions of LA,response surface methodology?RSM?is adopted based on the single variable method.Experimental results show the best preparation conditions:the reaction time of 4.99h,w?molasses?=40%,w?H₂SO₄?=4%,the reaction temperature of 151.45?,LA yield reaches as much as 30.96%.The first order pseudo-homogeneous kinetic equation on producing LA from cane molasses is derived on account of the kinetics data of the intermediate products in the hydrolysis reaction under different experimental conditions such as fructose,glucose 5-HMF and LA within the scope of temperature 135?¹65?,w?H₂SO₄?=1%⁵%.In addition,LA is separation and purification from hydrolysate by organic solvent extraction.The stage extraction process of extraction and purification for furan firstly and then for various acids is put forward according to the dissolution properties of the contents in hydrolytic mixture.The effect of extractant type;m?extraction system?/m?hydrolysate?;temperature;time and extraction times on the solute extraction rate.The experimental results show that furan extraction rate reaches its peak with toluene as extracting agent,m?extracting agent?/m?hydrolysate?=3:1,the extraction temperature of 25?³0?,the extraction time of 10 min for 3 times.LA extraction rate reaches its peak with TOPO as extracting agent,MIBK as diluent,deionized water for back extraction,m?extraction system?/m?hydrolysate?=3:1,the extraction temperature of 30?³5?,the extraction time of 10 min,multistage cross-flow extraction.