Synthesis And Application Of Bio-based Polyionic Liquids

The ionic liquid is a liquid ionic compound that is liquid at room temperature or below 100°C and consists of positive ions and negative ions.It has the advantages of non-volatile,non-flammable,recyclability,and high thermal stability so that widely used in catalysis,separation,electrochemical,organic synthesis,macromolecules and nanomaterials.Polyionic liquids have similar properties and applications such as polymer catalysts,ion conductive materials,antistatic materials,and antibacterial materials due to the same functional groups as ionic liquids.At present,with the development of the theoretical research and application of ionic liquids and polyionic liquids,more new types of ionic liquids and polyionic liquid materials with special functions are needed to meet the needs of various parties and to enrich the basic chemistry theory of ionic liquids and polyionic liquids.For this reason,different kinds of polyionic liquids were prepared based on cellulose by different synthesis methods.The detailed research contents of manuscript are divided as follows:1.Based on the dissolution and derivation of cellulose in reversible ionic liquid DBU/CO2/DMSO and the esterification reaction with 2,3-pyridinedicarboxylic anhydride under the homogeneous system can yield cellulose ionic liquid of pyridine carboxylic acid anion type.By acidification with a hydrohalic acid,a pyridine cationic cellulose polyionic liquid is obtained.The effects of reaction time,reaction temperature and ratio of raw materials on the degree of substitution of cellulose polyionic liquids were studied,and the optimal preparation conditions were obtained.The chemistry of cellulose polyionic liquids was investigated by FT-IR,¹H-NMR and ¹³C-NMR.The structure was characterized and DSC and TGA were used to study its thermodynamic properties.2.A new way of synthesizing cellulose polycationic ionic liquids has been adopted.That is,the microcrystalline cellulose is dissolved in the AMIMCl ionic liquid and then reacted with 2-chloroethyl isocyanate to obtain chlorinated cellulose and then quaternized with N-methylimidazole to obtain the cellulose imidazole cationic polyionic liquid.The results showed that the chlorinated cellulose could be up to 2.78when the reaction conditions were?80°C,24h,the molar ratio of 2-chloroethyl isocyanate/AGU was 2.5:1?.Its structure can be characterized by ¹H and ¹³C NMR,FTIR,TG and DSC.The experimental results show that the chlorinated cellulose obtained by this system has good thermal stability,and the resulting product has a glass transition temperature,which provides excellent conditions for its thermoplastic processing.3.Using the previously synthesized cellulose polyionic liquid as a catalyst for the reaction of epoxide and CO₂ to synthesize cyclocarbonate.After adding the epoxide and the catalyst to the reaction vessel and charging a certain amount of CO₂,the reaction is carried out at a certain temperature for a certain period of time,and then it is separated and purified to obtain pure cyclocarbonate product.Among them,the cellulose acetate polyionic liquid of the pyridine anhydride showed good catalytic activity under the conditions,and the catalytic efficiency could reach 85%at CO₂ pressure of 2 MPa,6 h and 120°C.The results show that cellulose polyionic liquids have good catalytic efficiency and catalytic activity.