Study On The Synthesis,swelling And Enrichment Properties And Catalytic Applications Of Acidic Poly(ionic Liquid)s

Acidic poly（ionic liquid）s（APILs）have been considered as a novel and green heterogeneous acid catalyst for its excellent properties such as abundant active sites,designable structure,recyclability and so on.However,APILs normally showed lower catalytic activities compare with homogeneous catalysts because of the lower degree of the exposure of the active sites in the reactants.Therefore,it was of great importance to find approachs to increase the contacts between active sites and reactants to improve the catalytic activities of APILs.In this thesis,a series of APILs with swelling and enrichment abilities in solvents and mixed solvents were designed and synthesized.The relationships between the swelling and enrichment abilities of the APILs and solvent properties were systematically studied.Moreover,the APILs were successfully applied as highly efficient catalysts to catalyze a variety of organic reactions.Owing to their unique swelling and enrichment properties in reactants or reaction medium,the APILs presented much higher catalytic activities than homogeneous acid catalysts.The concrete research contents were as follows:1.Syntheses,Swelling Properties and Enrichment Properties of Acidic Poly（ionic liquid）sA series of APILs based on 1-vinyl-3-（3-sulfopropyl）imidazolium（VSp Im）and sodium p-styrenesulfonate（Na SS）have been successfully synthesized.The swelling behaviours of the APILs in 18 solvents with a wide range of Hansen solubility parameters（δ_T）were investigated.These APILs exhibited distinct swelling properties of the APILs in solvents were attributed to the strong interactions between the APILs and solvent molecules,especially the hydrogen-bonding interactions,which was supported by the nuclear magnetic resonance（NMR）spectroscopy.The molar swelling ratio（Q_M）,which represents the swelling ability of the APILs in solvent,was linearly positively correlated with theδ_T value.Moreover,the enrichment behaviours of the APILs in various mixed solvents were also studied.In water/solvent monophasic mixed solvents,the enrichment factors of APIL P-[VSp Im-HSS]₃-CL1-2.5%to water were up to 39.82（water/THF）.The enrichment factor of the APILs to water was linearly positively correlated with the difference betweenδ_T（water）andδ_T（solvent）.The excellent swelling and enrichment properties of the APILs in solvents were attributed to the strong interactions between the APILs and solvent molecules,especially the hydrogen-bonding interactions,which was supported by the nuclear magnetic resonance（NMR）spectroscopy.2.Swelling-induced Self-assembly of Acidic Poly（ionic liquid）s and their Highly Efficient Catalytic Activities in Hydrolysis and Hydration ReactionsThe above-mentioned APILs with the maximum swelling abilities in water were applied as highly efficient heterogenous acid catalysts in hydrolysis and hydration reactions.These APILs had moderate and single acid strength,adjustable acid concentrations and good stabilities.These APILs spontaneously self-assembled into the unique micron-sized three-dimensional（3D）honeycomb structures when swelling in water.APILs with honeycomb structures in water exhibited much higher catalytic activities than homogeneous acid catalysts such as H₂SO₄,p-toluenesulfonic acid（p-Ts OH）and acidic ionic liquid 1‐vinyl‐3‐（3‐sulfopropyl）imidazolium hydrogen sulfate（[VSp Im]HSO₄）,in hydrolysis of cyclohexyl acetate to cyclohexanol.The concentrations of cyclohexyl acetate inside the APIL P-[VSp Im-HSS]₁-CL1-2.5%for a series of simulated reaction mixtures were 7.5-23.3 times higher than those of outside,indicating the high enrichment ability of these APILs for cyclohexyl acetate.The excellent catalytic activities of these APILs were attributed to their micron-sized3D honeycomb structures in water and the high enrichment ability for the reactants.Moreover,these APILs presented outstanding catalytic activities for the hydration of cyclohexene to cyclohexanol and the hydration of ethylene oxide to ethylene glycol.These APILs were facilely recovered via deswelling,and displayed remarkable reusability after 10 cycles.3.Water-medium Prins reaction Catalyzed by Swelling Acidic Poly（ionic liquid）sSwelling APILs with the maximum swelling abilities in water were successfully synthesizedviathefreeradicalcopolymerizationof4-vinyl-1-（3-sulfopropyl）pyridinium（VSp Py）,Na SS and crosslinker N,N’-methylenebis（acrylamide）（MBA）,followed by acidification.The synthesized swelling APILs were used as highly efficient heterogeneous acid catalysts for the water-medium Prins reaction ofα-methylstyrene and formaldehyde.The activities and selectivities of the synthesized swelling APILs were much higher than those of homogeneous acid catalysts,such as H₂SO₄,p-Ts OH and acidic ionic liquid4-vinyl-1-（3-sulfopropyl）pyridinium hydrogen sulfate（[VSp Py]HSO₄）.The excellent catalytic performance of the synthesized swelling APILs was attributed to their superior swelling and enrichment abilities to water in formalin.APIL P-[VSp Py-HSS]_0.33-MBA-5%with the largest molar swelling ratio（Q_M=1380mmol/g）in water and the highest acid concentration（3.44 mmol/g）exhibited the best catalytic performance,93%conversion ofα-methylstyrene and 96.8%selectivity of4-phenyl-4-methyl-1,3-dioxanewereobtained.Moreover,P-[VSp Py-HSS]_0.33-MBA-5%could efficiently catalyze the water-medium Prins reactions of various olefins and formaldehyde,79–89%isolated yields of 1,3-dioxane derivatives were achieved.