Synthesis And Adsorption/Separation Properties Of Microporous Organic Polymers

Large amounts of CO2 emitted from anthropogenic activities have led to serious global warming. Currently, widely employed aqueous amine solution method has many drawbacks, such as corrosion and volatility of amines and high energy cost. Owing to the nanometer pore channel and higher surface area, microporous organic polymers have great potential in the fields of gas storage and separation, especially in CO2 capture and sequestration. Besides, microporous organic polymers have some advantages as easily regeneration and low energy cost in gas storage and separation. In this thesis, microporous polyimides, cyanate resins and phenolic resins were prepared on the basis of rational molecular design. The imide, triazine and phenolic hydroxyl structures in these polymers can enhance the interactions between materials and CO2, C2-C4 organic hydrocarbon gases, to improve the storage and separation properties of theses gases for microporous polyimides, cyanate resins and phenolic resins. And investigate the impacts of chemical structures and pore structures on the adsorption and separation of H2, CO2, N2, C1-C4 organic hydrocarbon gases and benzene, normal hexane, cyclohexane, water vapors through adsorption measurements of these gases and vapors. The main contents and results are as follows:Synthesis and properties of microporous polyimide and its nitration products. Two polyimides based on 1,3,5,7-tetraphenyladamantane PI-ADPM and PI-ADNT were obtained via polycondensation from 1,3,5,7-tetrakis(4-aminophenyl)adamantane with pyromellitic dianhydride and naphthalene-1,4,5,8-tetracarboxylic dianhydride, respectively. Then PI-ADNT reacted with fuming HNO3 in different time to prepare the nitro decorated polyimides with different nitro contents PI-NO2s. The results based on sorption measurements show that the pores in PI-ADPM mainly locate in the microporous region and the BET surface area is up to 868 m2 g-1. Owing to the presence of benzene ring and adamantane units in PI-ADPM, the vapor uptakes of benzene, normal hexane and cyclohexane are up to 99.2, 49.8 and 59.7 wt% at 298 K, respectively; The abundant nitrogen and oxygen atoms in the nitro decorated polyimides can enhance the interactions between polymers and CO2 molecule which lead to the higher uptake of CO2 up to 17.7 wt% from 15.0 wt% at 273 K and 1.0 bar and the initial slope selectivity of CO2/N2 and CO2/CH4 up to 56 and 21 from 32 and 11 at 273 K, respectively.Synthesis and properties of microporous cyanate resin. Four cyanate monomers, 1,3,5,7-tetrakis(4-cyanatophenyl)adamantane, tris(4-cyanatophenyl)amine,3,6-dicyanatocarb azole and 9-(4’-cyanatophenyl)-3,6-dicyanatocarbazole were designed and synthesized, and the four corresponding cyanate resins PCNs were obtained via thermal cyclotrimerization. The relationships among spatial structure and reactive group number of monomers, pore structure and adsorption/separation properties of polymers were studied and discussed. The results based on sorption measurements show that the pores in PCN-AD from the monomer with tetrahedral structure and four reactive groups mainly locate in the microporous region, and the BET surface area is up to 843 m2 g-1, the uptake of H2 is up to 1.49 wt% at 77 K and 1.0 bar, the uptake of CO2 is up to 12.8 wt% at 273 K and 1.0 bar, the vapor uptakes of benzene and cyclohexane are up to 98.0 and 57.4 wt% at 298 K, respectively; owing to the abundant nitrogen and oxygen atoms in cyanate resin which can enhance the interactions between CO2, C2, C3 organic hydrocarbon gases, the polymers exhibit excellent gas adsorption separation properties. The adsorption separation selectivities of CO2/N2, C2H6/CH4, C2H4/CH4, C3H8/CH4 and C3H6/CH4 are 112,36,32,519 and 598 at 273 K for PCN-AD, respectively.Synthesis and properties of microporous phenolic resin. Four phenolic resins PFNs were obtained via addition polycondensation from tetrakis(4-formylphenyl)silane and 1,3,5,7-tetrakis(4-formylphenyl)adamantane with phloroglucinol and resorcinol, respectively. The relationships among the reactivity and phenolic hydroxyl group of monomers and polymers, pore structure and adsorption/separation properties were studied and discussed. The results based on sorption measurements show that the pores in PFN-S1 prepared from tetrakis(4-formylphenyl)silane with phloroglucinol mainly locate in the microporous region, and the BET surface area is up to 903 m2 g-1, the uptake of H2 is up to 1.59 wt% at 77 K and 1.0 bar, the uptake of CO2 is up to 17.3 wt%at 273 K and 1.0 bar, the vapor uptake of benzne is up to 93.1 wt% at 298 K; PFN-S1 and PFN-A1 with more phenolic hydroxyl groups possess much more excellent adsorption separation properties of CO2/N2, CO2/CH4 and C2H6/CH4, C2H4/CH4, C3H8/CH4, C3H6/CH4 than PFN-S2 and PFN-A2 with less phenolic hydroxyl groups.