The Preparation Of Acidic Ionic Liquids Polymer And Its Catalytic Application For Esterfication Reaction

As a kind of important chemical products,ester is closely related with our lives.The catalysts of esterification reaction in industry mainly are sulfuric acid and acidic resin.There are some disadvantages about these two catalysts.Sulfuric acid is not an environmental friendly catalyst and also corrosive for equipment.The mechanical strength of resin is low,and it is easy to be swelled and broken in pieces during reaction.Ionic liquids?ILs?are a new kind of green chemicals.They are widely used and studied as solvents,electrolyte and catalysts.However,it's hard to be separated,recycled and easy to be leaked when it is used as catalysts.Poly ionic liquids?PILs?are a new kind of poly-material with structural and properties characteristics of both polymers and ionic liquids,which may overcome some of the intrinsic demerits of ILs.To find out solid poly-ionic liquids with high catalytic activity,8 kinds of powder poly-imidazole acidic ionic liquids were synthesized.The catalytic performance of these catalysts was tested for esterification of succinic acid and methanol.Among these catalysts,the catalytic activity of poly-vinyl imidazole trifluoromethane sulfonic acid?P[Vim]CF₃SO₃?was best.It was characterized by FT-IR,TGA-DTA and SEM.The results showed that P[Vim]CF₃SO₃ had good thermal stability,and particle size was about200 nm.In optimal reaction conditions,the conversion of succinic acid was 96.5%.P[Vim]CF₃SO₃ was recycled for 5 times without the obvious decrease of catalytic activity.Sphere poly-pyridine trifluoromethane sulfonic acid?PV-St-CF₃SO₃?with millimeter level diameter was synthesized by free radical reaction.It was characterized by FT-IR,TGA-DTA,XRD and SEM.It showed better mechanical strength and thermal stability than commercial resin.The influence of rotate speed,dispersant amount,the ratio of monomer,solvent and reaction temperature on diameter of PV-St-CF₃SO₃ was investigated in detail.Catalysts with particular forms and sizes were synthesized in specific equipment.PV-St-CF₃SO₃ catalytic activity was tested for esterification of methacrylic acid and methanol.Reusability of this catalyst is excellent.Methylbenzene and n-heptane were added during the polymerization reaction as pore-foaming agent.Poly-N-vinyl pyrrolidone sulfuric acid ionic liquid?PVP-St-HSO₄?was synthesized by N-vinyl pyrrolidone and styrene with crosslinking agent.It was also characterized.The catalytic activity was evaluated for esterification reaction of acetic acid and butanol with cyclohexane as water carrier.It showed good catalytic performance.Thereaction conditions were optimized.Nano silica was synthesized by Stober method.Poly-ionic liquids were supported on nano silica.The supported catalysts were characterized by FT-IR,TG-DTA,SEM and TEM.The catalytic activity was evaluated for 5 kinds of esterification reaction with cyclohexane as water carrier,and the reusability was investigated.The results showed the catalytic performance of supported catalysts was worse than the bulk ones,and they also could not be recycled due to losing of catalytic activity.