Preparation Of Polycyclic Aromatical Intermediate Of Functional Polymer Material And Study On Their Reaction Mechanisms

In recent years,aromatic polymers are now invoking more and more interests because of their many advantages,such as good thermal and chemical stabilities,low density but robustness and facility to process,but their wider application is limited by the preparation of aromatic monomers(i.e,macromolecule intermediate).Such macromolecule intermediates can be synthesized by selective acylation,alkylation or coupling of aromatics,which is an important research direction of functional macromolecule intermaterials.So far,the studies of Friedel-Craft acylation,Friedel-Craft alkylation or coupling of aromatics are mainly focused on benzene and naphthalene or their ramifications,while few reports have been found in the literatures on the researchs of polycyclic aromatic hydrocarbons.In the present dissertation,the Friedel-Craft acylation and Friedel-Craft alkylation of anthracene and the coupling of acenaphthene catalysed by different catalysts(metal halid,ionic liquids and heteropoly acid)were firstly investigated.Several new functional macromolecule intermediates such as 1,2-aceanthrylenedione,9-Benzoylanthracene, 2-isopropylanthracene and 3,3'-biacenaphthene were selectively synthesized.The mechanisms of above reactions were explored by corresponding experimental results,the structure characteristics of anthracene,acenaphthene and catalysts as well as analysis of MS,FT-IR and ¹H NMR.Thus,reasonable analysises of all reaction products were realized.Some significant results are as follows:1)[Bmim]Cl-AlCl₃ ionic liquid was used as catalyst and solvent in the Friedel-Crafts acylation of anthracene with oxalyl chloride to synthesize the new functional macromolecule intermediates 1,2-aceanthrylenedione, Pure 1,2-aceanthrylenedione was prepared by extraction and recrystalling and the structure of 1,2-aceanthrylenedione was identified by GC/MS, FT-IR and ¹H NMR analysis.The effects of various reaction comditions on the the yield and selectivity of 1,2-aceanthrylenedione were studied by GC analysis.The results showed that the optimum synthesis conditions of the acylation reaction are as follow:the molar fraction of AlCl₃ in [Bmim]Cl-AlCl₃ being 0.67,n{[Bmim]Cl-AlCl₃}:n(anthracene)=2:1, n(oxalyl chloride):n(anthracene)= 2:1,the reaction temperature 45℃and the reaction time 6 h.Under those conditions,the yield of 1,2-aceanthrylenedione is 88.2%and selectivity is 98.2%.Farther more, [Bmim]Cl-AlCl₃ ionic liquid not only shows excellent catalysis activity, dual role as catalyst and solvent,but also can be reuse and has little pollution to environment.The mechanism of the Friedel-Craft acylation of anthracene with oxalyl chloride in the presence of[Bmim]Cl-AlCl₃ was explored by examining effects of various reaction conditions on the yield and selectivity of 1,2-aceanthrylenedione and the structure characteristic of anthracene as well as[Bmim]Cl-AlCl₃ Ionic Liquid.The results show that acylium cation as electrophilic reagent produced by oxalyl chloride interaction with[Bmim]Cl-AlCl₃ ionic liquid attack anthracene.It is belong to electrophilic substitution mechanism.2)The Friedel-Craft acylation of anthracene with oxalyl chloride catalysed by AlPW₁₂O₄₀heteropolyacid was studied.9-Benzoylanthracene was determined by GC/MS analysis and pure 9-benzoylanthracene was prepared.The structure of 9-benzoylanthracene was confirmed by GC/MS,FT-IR and ¹H NMR,and the effects of various reaction comditions on the the yield and selectivity of 9-benzoylanthracene was studied.The results showed that the most suitable synthesis conditions are solvent cyclohexane,n(benzoyl chloride):n(anthracene)= 2:1,catalyst mass fraction 4.5%,reaction temperature 90℃and reaction time 5 hour.Under those conditions,the yield of 9-benzoylanthracene is 47.4%and the selectivity towardes 9-benzoylanthracene is 91.8%.Additionally, AlPW₁₂O₄₀has no pollution to environment and can be easily recovered after the reaction for reused.Preparation of 9-benzoylanthracene was scientific discussed by studying the mechanism of the Friedel-Craft acylation of anthracene with oxalyl chloride catalysed by AlPW₁₂O₄₀ through analyzing the density of electron cloud and interspace obstacle of anthracene,characteristic of AlPW₁₂O₄₀and experimental results.3)The Friedel-Craft acylation of anthracene with oxalyl chloride catalysed by anhydrous AlCl₃,[Bmim]Cl-AlCl₃ ionic liquid and AlPW₁₂O₄₀heteropolyacid was studied.2-isopropylanthracene,which was used as new macromolecule intermediate was determined by GC/MS. Pure 2-isopropylanthracene was obtained by extraction and recrystalling the reaction mixture and its strcture was determined through GC/MS, FT-IR and ¹H NMR.Optimum synthesis conditions were gained by examining the effects of various reaction comditions on the yield and selectivity of 2-isopropylanthracene.Among the three catalysts, [Bmim]Cl-AlCl₃ ionic liquid has the highest catalysis activity on the Friedel-Craft acylation of anthracene with oxalyl chloride.Under the optimum reaction conditions catalysed by[Bmim]Cl-AlCl₃,yield and selectivity of 2-isopropylanthracene is 47.4%and 91.8%.The reaction mechanisms of the preparation of 2-isopropylanthracene were explained with electrophilic substitution,which was discussed from the aspect of thermodynamics control and kinetics control,erespectively.4)The coupling reaction of acenaphthene catalyzed by Lewis acids (AlCl₃,FeCl₃,BF₃-OEt₂)and ionic liquids([Bmim]Cl-AlCl₃,[Bmim]Cl-FeCl₃) were investigated at room temperature,ambient atmosphere or under microwave radiation.3,3'-biacenaphthenyls,which canbe used as new intermediate of function aromatic polymer material,was successfully synthesized.Pure 3,3'-biacenaphthenyls was purified by rotary evaporation,recrystallization and chromatography,and its structure was characterized by GC /MS,FT-IR,¹H NMR.The optimun reaction conditions were studied and the catalysis activity of different catalysts were compared.The results showed that[Bmim]Cl-FeCl₃ ionic liquid is the best effective catalysis among above of them on the preparation of 3,3'-biacenaphthenyls and under the optimum reaction conditions catalysed by[Bmim]Cl-FeCl₃,the yield of 3,3'- biacenaphthenyls is 38.5%and the selectivity towardes 3,3'- biacenaphthenyls is 99.1%.The mechanism of coupling reaction was discussed through the method of adding free radical scavenger and the analysis of MS,FTIR and ¹H NMR.The resuts suggest that the coupling reaction catalyzed by AlCl₃ and BF₃·OEt₂ are belong to typical free radical mechanism,while those of catalyzed by FeCl₃, [Bmin]Cl-AlCl₃ and[Bmin]Cl-FeCl₃ are proceed along carbonium mechanism to produce 3,3'-biacenaphthenyls.