Study On The Separation Of Crude Anthracene And Solid-Liquid Equilibrium Of Anthracene,Phenanthrene And Carbazole

Crude anthracene,coal tar distilate,contains high value-added chemicals such as anthracene,phenanthrene and carbazole.In recent years,the application of anthracene,phenanthrene,carbazole and its derivatives in the field of optoelectronic information materials and functional polymers makes the market for the demand of high purity anthracene,phenanthrene and carbazole increase rapidly.Therefore,it is of great significance to explore an efficient separation process for clean utilization of coal and environmental protection.Based on the analysis of the composition of crude anthracene,the solvent suitable for this system was screened by solubility determination,and the crude anthracene was divided into two parts: the liquid layer of phenanthrene-enriched and the solid cake of anthracene-carbazole enriched.Anthracene and phenanthrene were further purified respectively.First,the composition of crude anthracene were analyzed qualitatively by GCMS,and a quantitative method was established for the determination of anthracene,phenanthrene and carbazole in crude anthracene by SE-54 capillary GC,where N,Ndimethylformamide(DMF)and internal standard method was used.The results showed that the composition of the crude anthracene were very complex and twentytwo components were identified.The average contents of three main components were 39.59% for anthracene,17.93% for phenanthrene and 15.48% for carbazole respectively.Second,the solubility of anthracene,phenanthrene and carbazole in several solvents such as toluene,xylene,n-butyl ether,cyclohexane and DMF were measured at different temperatures by solid-liquid equilibrium static method.The results showed that the solubilily was increased with the temperature increasing.The selectivity of toluene and xylene both to phenanthrene/anthracene and phenanthrene/carbazole were better and xylene with less toxicity was chosen as the suitable solvent.The solubility data measured were correlated using the modifiedApelblat equation,Van't Hoff equation,and ?-h equation respectively.It was found that the Van't Hoff equation was the appropriate model for the binary system of anthracene+solvent,there is the better correlation of modified Apelblat equation for the binary system of phenanthrene+solvent,and the ?-h equation was the suitable model for the binary system of carbazole +solvent for the selected solvents.Finally,the phenanthrene was removed from crude anthracene by dissolving with xylene,washing and crystallization and the removal ratio of phenanthrene was90.33% after two steps processing.The liquid layer of phenanthrene-enriched obtained was further concentrated by xylene recycling,washed with ethanol and dried,the purity of phenanthrene increased to 65.17%,which is up to an industrial standard.The solid cake of anthracene-carbazole enriched was treated by azeotropic distillation using ethylene glycol as an azeotrope,washing with water and recrystallization with DMF.The purity of anthracene reached 99.02% and the total recovery is 39.4%.So,anthracene,phenanthrene and carbazole in crude anthracene were separarted.