Synthesis Of High-performance Heteropolyanion-based Ionic Liquids And Applications In Heterogeneous Catalysis

At present,ionic liquids（ILs）are a hot area of research of green chemistry and chemical process.Functionalized ionic liquids,as a kind of clean solvent and new catalyst,have many advantages of high chemical stability,regulable property and devisable structure,which have been widely used in esterification,oxidation and condensation reaction,being given more attention by many scholars at home and abroad.Therefore,it is very important to investigate a kind of effective,reusable and less environmental pollution ionic liquids,which is required to satisfy principles of green chemistry.This paper had developed high-performance heteropolyanion-based ILs by combining organic cations of ILs and Keggin heteropolyanions.These ILs were characterized and applied in heterogeneous catalysis.The main contents are as following:1.First,a series of dual-SO₃H functionalized heteropolyanion-based ionic liquids（HPA-ILs）were obtained by combining organic cations and Keggin heteropolyanions.And on this basis,a series of Br?nsted–Lewis acidic functionalized heteropolyanion-based ionic liquids（BLA-HPA-ILs）were obtained by adding metal oxide.These ILs were characterized by FT-IR,Py-IR,TG,NH₃-TPD,³¹P MAS NMR,SEM and ¹H NMR,et al.2.Hydrolysis of cyclohexyl acetate into cyclohexanol was systemically studied using a series of dual-SO₃H HPA-ILs catalysts.Compared with traditional acidic catalysts,such as H₂SO₄,H₃PMo₁₂O₄₀,H₃PW₁₂O₄₀ and H₄SiW₁₂O₄₀0 and kinds of HPA-ILs which have only single-SO₃H,[Bis-Bs-BDMAEE]HPMo₁₂O₄₀0 performs excellent catalytic activity.The impact for the reaction of various parameters of catalyst dosage,reaction temperature,initial reactant molar ratio,reaction time were also investigated in detail.The conversion of cyclohexyl acetate was 90.56%and the selectivity of cyclohexanol was 94.86%under the appropriate conditions:the dosage of[Bis-Bs-BDMAEE]HPMo₁₂O₄₀0 11 wt%,the reaction temperature363.15 K,volume ratio of water and cyclohexyl acetate 3:1 and the reaction time 6 h.ComparedwithtraditionalacidiccatalystsofH2SO4andH3PMo12O40,[Bis-Bs-BDMAEE]HPMo₁₂O₄₀0 was heterogeneous catalysts,which could be reused in the next run by simple filtration.Moreover,[Bis-Bs-BDMAEE]HPMo₁₂O₄₀ reused for five times without any obvious decrease of cyclohexanol yield,which showed that[Bis-Bs-BDMAEE]HPMo₁₂O₄₀0 have good reusability.3.BLA-HPA-ILs were synthesized by sulfonated bis（2-dimethylaminoethy）and different Keggin heteropolyanions and metal oxide,had been applied in synthesis of cyclohexyl acetate through esterification reaction of cyclohexene with acetic acid.Compared with traditional acidic catalysts,[Bis-Bs-BDMAEE]HPW₁₂O₄₀·1/2Cu shows the highest catalytic activities.The impact for the reaction of various parameters of catalyst dosage,reaction temperature,initial reactant molar ratio were also investigated in detail.The conversion of cyclohexene was 65.92%and the selectivity of cyclohexyl acetate was 98.61%under the appropriate conditions:the dosage of[Bis-Bs-BDMAEE]HPW₁₂O₄₀·1/2Cu 7 wt%,the reaction temperature 363.15 K,molar ratio of acetic acetate and cyclohexene 3:1 and the reaction time7 h.The esterification reaction is exothermal reaction,the reaction enthalpy and entropy were-43.70 kJ/mol and-115.07 J/（mol·K）,respectively.A pseudo-homogeneous（PH）kinetic model was applied,and the calculated apparent activation energy of the forward and reverse reaction were 56.21 kJ/mol and 92.34 kJ/mol,respectively;the forward and reverse reaction pre-exponential factor were 6.68×10⁵ L/（mol·g·min）and 1.52×10¹¹ L/（mol·g·min）,respectively.Moreover,[Bis-Bs-BDMAEE]HPW12O40·1/2Cu could be easily recovered,and reused for six times without any obvious decrease of catalytic activity,showing promising potential for application.4.BLA-HPA-ILsweresynthesizedbysulfonated N,N,N’,N’’,N’’-Pentamethyldiethylenetriamine and different Keggin heteropolyanions and metal oxide,have been applied in synthesis of isobornyl acetate through esterification reaction of camphene with acetic acid.Compared with traditional acidic catalysts,[Bis-Bs-PMDETA]H₂SiW₁₂O₄₀·3/4Zn shows the highest catalytic activities.The impact for the reaction of various parameters of catalyst dosage,reaction temperature,initial reactant molar ratio,reaction time were also investigated in detail.The conversion of camphene was81.58%and the selectivity of isobornyl acetate was 93.76%under the appropriate conditions:the dosage of[Bis-Bs-PMDETA]H₂SiW₁₂O₄₀·3/4Zn 7 wt%,the reaction temperature 333.15K,molar ratio of acetic acetate and camphene 3:1 and the reaction time 3 h.Moreover,[Bis-Bs-PMDETA]H₂SiW₁₂O₄₀·3/4Zn could be easily recovered,and reused for six times withoutanyobviousdecreaseofcatalyticactivity,whichshowedthat[Bis-Bs-PMDETA]H₂SiW₁₂O₄₀·3/4Zn is suitable catalyst for synthesis of isobornyl acetate through esterification reaction of camphene with acetic acid.