Swelling Ability Of Acidic Poly(ionic Liquid)s And Their Catalytic Activity For The Addition Reaction Of Olefins And Aliphatic Acids

Acidic poly(ionic liquid)s are a class of poly(ionic liquid)s that introduce acidic sites into their structures through anion exchange or the direct polymerization of acidic ionic liquid monomer.They combine the properties of ionic liquids,acidic sites and heterogeneity of polymer to achieve efficient catalytic activity and excellent recyclable performance of the catalyst.Swelling poly(ionic liquid)s can allow the solvent penetrate into interior structure of poly(ionic liquid)s,thereby expanding them into a three-dimensional network.In the field of catalysis,swell can promote the close contact between catalytic active sites in the structure of poly(ionic liquid)s and reactants,thus performing good catalytic activity.Herein,this thesis aims at synthesizing a series of acidic poly(ionic liquid)s that can swell in solvents and having a strong desire to employing their swelling properties in reactants to efficiently catalyze the addition reaction of aliphatic acids and olefins.And the main work are as follows:(1)An overview of swelling properties of swelling poly(ionic liquid)s and their applications,synthesis and applications of acidic poly(ionic liquid)s and the situation of the reaction of aliphatic acids with olefins.(2)A series of poly(ionic liquid)s with different length of side chain and cross-linker density were synthesized through free radical copolymerization,employing 1-vinyl-3-alkyl-imidalizulm bromide and sodium acrylate as co-polymerized monomer,DVB as cross-linker and AIBN as the initiator;then prepared acidic poly(ionic liquid)s containing hydrogen sulfate anion as acidic active center through anion exchange with sulfuric acid.The structure and morphological features were characterized by FT-IR,13 C Solid MAS NMR,TGA,SEM and Cyro-SEM,indicated the formation of three-dimensional network after swelling in formic acid.By testing swelling degree of acidic poly(ionic liquid)s and analyzing their relationship between swelling degree and solvent parameter such as polarity,dispersion,hydrogen bond,etc.,we found that acidic poly(ionic liquid)s could swell in fatty acids,alcohol and other solvents which tend to form hydrogen bond with imidazolium cation on acidic poly(ionic liquid)s.In addition,as the length of the side chain of acidic poly(ionic liquid)s increases,swelling degree in methylene chloride and chloroform gradually increases while swelling degree in water gradually decreases.This is because the hydrophilicity is weakened and the hydrophobicity is enhanced(3)Based on swelling properties in aliphatic acids,acidic poly(ionic liquid)PILs-C8-2.5DVB-HSO4 was employed as catalyst for the addition reaction of aliphatic acids and olefins,results suggested PILs-C8-2.5DVB-HSO4 exhibit excellent catalytic performance in the reaction of cyclohexene with formic acid and the conversion of cyclohexene reached 93% under the optimal reaction conditions.Compared to other catalysts,sulfuric acid and 4-Toluene sulfonic acid,PILs-C8-2.5DVB-HSO4 performed good catalytic activity and recyclable performance;meanwhile,the catalytic activity was much higher than heterogeneous catalyst,Amberlyst-15.The higher catalytic activity is closely related to its swelling properties in formic acid,which causes the acidic active site to be sufficiently exposed to the substrate to promote the contact of the acidic active site with substrates.