Study On Resource Utilization Of Anthracene Residue To Extract Phenanthrene And Co-product 9-fluorene Formic Acid

Anthracene residue is a typical industrial organic solid waste produced during extracting anthracene and carbazole from crude anthracene,which is composed of fluorene（10～20%）and phenanthrene（40～50%）and a small amount of anthracene and carbazole.Because the physical properties of fluorene and phenanthrene are very similar,traditional physical separation methods are difficult to achieve the effective separation.Anthracene residue often discarded or used as cheap fuel to burn without effective utilization,which causes serious environmental pollution and resource waste.9-fluorene formic acid,a derivative of fluorene,is an important chemical raw material,which widely used in organic synthesis,pharmaceutical synthesis and molecular biology fields,such as the preparation of dyes,paints,resins,pesticides and other chemical products.The research applied reaction-separation coupling technology to transform fluorene in anthracene residue and CO₂into 9-fluorene formic acid with alkali carbonate catalyst.There are some shortcomings such as low yield,poor repeatability,and potential safety risks during the synthesis of 9-fluorene formic acid from fluorene and CO.Therefore,it is essencial to develop a controllable synthetic route with safety and environment friendly.The effective separation of 9-fluorene formic acid and phenanthrene was realized according the difference of solubility between them in alkali-water solvent.The main contents and results of this paper are as follows:（1）Synthesis of 9-fluorene formic acid from fluorene and CO₂with K₂CO₃as catalyst.With DMSO as solvent,molar ratio of material n_fluorene:n _catalyst:n _PTC=1:6:1.5,reacted for 3 h at 40 ^oC under 0.1 MPa CO₂,the yield of 9-fluorene formic acid can reach 64.61%.The carbonation degree of K₂CO₃was accelerated with the increase of CO₂pressure.The cyclic catalytic effect of K₂CO₃decreased due to the formation of less alkalinity KHCO₃.The catalytic activity could partially recover after regeneration,while decreased gradually with the increase of regeneration times.The yield of 9-fluorene formic acid firstly increased and then decreased with the decrease of particle size.The yield of 9-fluorene formic acid is40.07%by 40%K₂CO₃/γ-Al₂O₃.High loadings,high calcination temperature and long calcination time reduce the catalytic effect.The activity of K₂CO₃/γ-Al₂O₃could not recovered completely by regeneration,but its recycling performance was better than K₂CO₃.（2）Cs₂CO₃catalyzed the synthesis of 9-fluorene formic acid from fluorene and CO₂.Using Cs₂CO₃,the reaction rate and equilibrium yield of 9-fluorene formic acid synthesized from fluorene and CO₂were greatly improved.At 40 ^oC,0.1 MPa CO₂,DMSO as solvent,molar ratio of material n_fluorene:n _catalyst:n _PTC=1:6:1,the yield of 9-fluorene formic acid can reach 95.76%.Cs₂CO₃can maintain excellent catalytic performance after three cycles of regeneration.Due to its strong hygroscopicity,yield slump with the decrease of particle size The yield of 9-fluorene formic acid is 47.75%by 50%Cs₂CO₃/γ-Al₂O₃.At the same time,Cs₂CO₃/γ-Al₂O₃has poor recycling performance,and the catalytic performance recovered partially through regeneration,and decreased grandually with the cycles.（3）Reaction-separation of model mixtures with fluorene and phenanthrene.With mass ratio of 1:4 as raw material,after the synthesis of 9-fluorene formic acid,a large amount of phenanthrene,which did not participate in the reaction,precipitated in a solid form.The yield of 9-fluorene formic acid catalyzed by K₂CO₃and Cs₂CO₃was 41.69%and74.58%,respectively.In order to ensure the separation,the raw material cycled twice.The separated phenanthrene with a purity of 91.58%and a recovery of 88.07%,and 9-fluorene formic acid with a purity of 98.26%and a recovery of 93.65%were obtained with K₂CO₃as catalyst.Using Cs₂CO₃as catalyst,the purity and the recovery of phenanthrene were 99.14%and 95.00%,and obtained 9-fluorene formic acid with a purity of 99.16%and a recovery of94.16%,respectively.Using M₂CO₃/γ-Al₂O₃as catalyst,the separation effect is poor due to incomplete reaction.After the first catalyst and separation,the purity and recovery of phenanthrene were 85.64%and 76.58%,and the purity and recovery of 9-fluorene formic acid were 97.67%and 94.62%with K₂CO₃/γ-Al₂O₃.Using Cs₂CO₃/γ-Al₂O₃,the purity and recovery of phenanthrene were 86.99%and 80.64%,and the purity and recovery of9-fluorene formic acid were 98.52%and 95.34%,respectively.