Study On Acid-base Bifunctional Coordination Polymers Catalysts For Cycloadditon Of CO₂to Epichlorohydrin

There is an increasing awareness of the global warming caused by CO2accumulation in the atmosphere. Meanwhile, CO2is an attractive C1building block inorganic synthesis, given its advantages in renewability, abundance, and nontoxicity.Therefore, the development of chemical fixation of CO2has attracted much attentionin recent years. One of the most promising methodologies in this area is the synthesisof cyclic carbonates via coupling of CO2and epoxides. Many catalysts have beenreported to show catalytic activity towards this reaction. However, the requirement ofsolvent, co-catalysts as well as high pressure is essential for the reaction.Metal-organic frameworks (MOFs)，also known as coordination polymers, areconstructed by inorganic metal-ion clusters and polytopic organic linkers, allied withpotential applications in gas storage, chiral separation, sensors and catalysis and so on.In particular, MOFs have offered a potential platform for application in acid-basecatalyst, not only due to higher surface areas, various porous structures and tailoringstructure properties, but also for their activities sites could be rationally designed byintroducing functional metal ions or organic ligands. In this thesis, we constructedcoordination polymers from a multidentate carboxylic acid ligand with tertiary amineserve as acid-base catalysts for the cycloadditon of CO2to epichlorohydrin underatmospheric pressure.1. Two new1D linear chains coordination polymers,[Ni(OH)(H2pdcd)(H2O)2]·DMF (1) and [Co(OH)(H2pdcd)(H2O)2]·DMF (2)(H3pdcd=1-(4-carboxypheny)-2,5-dimethyl,1H-pyrrole-3,4-dicarboxylic acid), which weredesigned based on a tertiary amine ligand, were synthesized and characterized usingmultiple spectroscopic techniques.2. These two1D linear chains possess the properties of both Lewis acid andorganic base, which was confirmed by temperature programmed desorption ofammonia and on-line mass spectrometry (NH3-TPD-MS), pyridine-IR and selectivesorption for carbon dioxide. Due to their acid-base properties, the compoundsexhibited high catalytic activity, in the absence of co-catalysts, for solvent-free synthesis of chloropropene carbonate from CO2and epichlorohydrin underatmospheric CO2pressure. The yields of chloropropene carbonate were88%and87%for1and2, respectively, under the optimized conditions.3. A novel2D coordination polymers [Cd(pdcd)(C2H5OH)] has been synthesizedunder solvothermal conditions. The compounds activated under vacuum to removeethanol molecule exhibited the acid-base properties.