Preparation And Performance Of Magnetic Nanospheres Supported Ionic Liquid Polymer Catalysts

With the rapid development of chemical industry and pharmaceutical industry,the usage amount of catalyst is increasing year by year,so the research of recyclable catalyst is of great significance in environment and economy.Magnetic nanoparticles have many advantages,such as wear resistance,corrosion resistance and magnetic responsiveness,which are widely used as catalyst carriers in the field of catalysis.In this paper,a series of composite catalysts were prepared using magnetic nanoparticles as carrier,which were modified by the surface and loaded with ionic liquid polymer with catalytic activity center.The main contents are as follows:(1)Magnetic nanospheres were prepared via a sol-gel process in a reverse microemulsion and combined with solvent-thermal technique using cobalt chloride and ferric nitrate as raw materials.The results showed that the magnetic nanoparticles prepared with the water/oil ratio(?)of 30 in pilot scale test and had well spinel structure.The magnetic nanoparticles after alkali treatment had better dispersibility and high saturation magnetic intensity,with the particle size of 10 nm.And the pilot scale production had a good repeatability.(2)The ionic liquid polymers were prepared by free radical polymerization method.Basic ionic liquid polymer catalysts with different anions were then prepared by ion exchange method.Magnetic nanoparticle supported ionic liquid polymer catalysts were obtained with the magnetic nanoparticles as carrier.The catalytic performances of catalysts were investigated by Knoevenagel condensation reaction between ethyl cyanoacetate and benzaldehyde.The catalytic activity of the three basic anions was OH > Im > Ac,which was in good agreement with alkaline of the anions.Alkaline ionic liquid polymer catalyst had good recovery usability.But the recovery of the supported ionic liquid polymer catalyst is not satisfactory,mainly due to the dissociation of Si-O-Si bonds in the alcohol solvent lead to the loss of active sites in the ionic liquid.(3)The surface of the magnetic nanoparticles was modified by silane coupling agent(KH-570).To obtain magnetic polymer microspheres with regular magnetic particle,high magnetic content and monodispersity,the feeding way of magnetic fluid,the concentration of the surfactants,the dosage of co-stablizer and the amount of magnetic fluid were discussed.The results showed that when the wetting method,the surfactant concentration of 3 g/L,The amount of magnetic fluid MCF of 0.3 g,the magnetic polymer microspheres were prepared with diameter of about 300 nm and strong magnetic response and surface hydrophobic.(4)The magnetic composite microspheres supported ionic liquid polymer catalysts were prepared by DPE controlled free radical miniemulsion polymerization,and their activity was evaluated by Knoevenagel condensation reaction.The results showed that the reusability of the magnetic composite microsphere supported ionic liquid polymer catalysts were significantly improved,but its catalytic activity was low.