Study On The Preparation Of Acetic Acid By Pyrolysis Of Sugars Using Acetate As Catalyst

At present,acetic acid(AA)mainly produced from non-renewable resources.Preparing AA from biomass has difficulty in industry except for fermentation.This project used sugar to obtain AA.The effects of pyrolysis conditions(pyrolysis temperature,heating time,catalyst dosage,etc.)and catalytic methods(in situ catalysis,on-line catalysis,dip-molding catalysis)on the compositions and distributions of sugar pyrolysis products were studied.In addition,four kinds of monosaccharides(D-mannose,D-(-)-arabinose,1,6-anhydro-?-D-glucose and D-(+)-galactose)and furfural pyrolysis experiments were supplemented to explain the glucose pyrolysis mechanism.Thermogravimetric analysis and Py-GC/MS were used to characterize and analyze the thermal behavior of sugar and the compositions and distributions of pyrolysis products.The results and conclusions are as follows:TGA results showed that various acetates(Li+,Na+,K+,Ca2+,Mg2+,Ni2+)and carbonates(Li+,K+)would reduce the initial glucose decomposition temperature(Ti)and the maximum mass loss temperature(Tmax).When these salts were mixed with microcrystalline cellulose(MCC),except for nickel acetate,the Ti and Tmax of MCC moved to a lower temperature.The particularity of nickel acetate was due to the complexity of its own thermal decomposition..Acetate could significantly increase the yield of AA in glucose pyrolysis by changing the product generation paths,ranging from easily producing furans to AA.In the selective preparation of AA,the role of anions shouldn't be ignored.Changes in pyrolysis parameters would also affect the yield of AA.Adding a small amount of catalyst,the AA content in the products increased significantly.And as the amount of catalyst increased,the AA yield increased accordingly.This advantage weakened when the catalyst used too much.High pyrolysis temperature would increase the attaining of acetone,and the risk of catalyst decomposition.While the temperature was too low,the pyrolysis was not sufficient.MCC catalyzed-pyrolysis would also form a large amount of acetic acid.It provided a new possible way for the industrial application of biomass to gain AA.From the analysis of the pyrolysis products' compositions and distributions of four monosaccharides and furfural by acetate,it can be seen that the addition of acetate inhibits the formation of glucose to furfural or other furans,making AA become the dominant product.