Synthesis And Porperties Of Heteroatom-Rich Microporous Organic Polymers

The study of microporous organic polymers(MOPs)has become a subject of intense interest and research with multidisciplinary participation in fields of nanomaterials,physical chemistry,polymer science,organic chemistry,separation science and technology,etc.Due to their important properties as pore size less than 2 nm,MOPs exhibit unprecedented properties such as large specific surface areas and extremely low density to traditional polymers,which leads to a variety of new applications in gas adsorptions/separations,organic vapor captures and heterogeneous catalysis.Except for those illustrated advantages,the excellent chemical and thermal stability endow the MOPs with promising material as high performance thermosetting resin.On the basis of rational molecular design,this dissertation is aimed to purposefully prepare a series of novel MOPs for capturing carbon dioxide;deeply discuss the relationship between monomer constructions and polymer surface areas and porosity parameters;further figure out the chemical composition and pore structures of polymeric materials' influences on the carbon dioxide adsorption/separation,hydrogen uptake and organic vapor adsorption/separation.Besides,the MOPs-based catalyst was investigated on the reaction of Suzuki-Miyaura cross-coupling reactions to evaluate the performance of heterogeneous catalysis.The main contents and results are described as follows:Synthesis and adsorption properties of triptycene-based microporous polycyanurate resins.Based on the ribbon-like stereotype of triptycene,2,6,14-triscyanatotriptycene and 2,6,14-tris-(4-cyanatophenyl)triptycene were designed and synthesized to obtain PCNs through cyanate groups cyclotrimerization.PCN-TPC and PCN-TPPC have similar porosity parameters including BET surface areas(662-686 m2/g)and pore volumes(0.48?0.55 cm3/g),but 2,6,14-tris(4-cyanatophenyl)triptycene has longer arms and larger rotation freedom,which leads to obvious interpenetration of networks and endows PCN-TPPC with smaller pore sizes and a larger amount of micropores.PCN-TPPC uptakes considerably higher benzene(77.8 wt%)than PCN-TPC at room temperature since the higher concentration of phenyl groups in PCN-TPPC enhances the ?-? interaction with benzene molecules.Besides,the adsorption capacity of benzene in PCN-TPPC is dramatically 7.2 times as high as that of cyclohexane,which is 3 times to PCN-TPC.PCN-TPC with more heteroatoms in the network skeleton displays larger uptake of CO2 and higher CO2/N2 selectivity of 16.4 wt%and 60 than PCN-TPPC,the capacity of CO2 is the highest among the published PCNs.At 77 K and 1.0 bar,PCN-TPC and PCN-TPPC both show hydrogen uptake larger than 1.20 wt%and the Qo more than 8.5 kJ/mol.Synthesis and adsorption properties of fluorinated covalent triazine-based frameworks.The incorporation of heteroatom-rich functionalities into polymer chains effectively enhance the capacity of adsorption for carbon dioxide,2,5-difluoro-1,4-dicyanobenzene and 2,5-ditrifluoromethyl-1,4-dicyano-benzene were designed and synthesized to polymerize fluorinated CTFs with BET surface areas over 1000 m2/g through thermal cyclotrnmerization.CTF-F and CTF-CF possess ultra-micropores of 0.44 nm owing to the tailoring functions by inert groups.The fluorine element provides the materials with fine hydrophobicity as their water vapor adsorbed volume at 298 K and 0.90 bar are 0.27 and 0.61 cm3/g for CTF-CF and CTF-F,respectively.Compared to CTF-1,CTF-F and CTF-CF show close affinity toward CO2 and display boosted CO2 adsorption capacity up to 21.1 wt%at 273 K and 1.0 bar.Since the polar groups play important role in enhancing selectivity for carbon dioxide over nitrogen,the CTF-F has a superior CO2/N2 selectivity to CTF-1 as the value is 44 to 22.Besides,CTF-F also shows excellent H2 storage property as the capacity is up to 2.05 wt%at 77 K and 1.0 bar.Synthesis and adsorption properties of microporous phenolic resins.Five porous phenolic networks are synthesized between tere-phthaladehyde,iso-phthaladehyd,o-phthalaldehyde,tri(4-formylphenyl)phosphine and tetra(4-formylphenyl)silicon with 2,5-di-hydroxy-1,4-benzoquinone via additional condensation.The results show that the the monomer structure is a determining factor on building microporous architectures.Tetra(4-formylphenyl)silicon has tetrahedral configuration and four reaction site,the obtained PFN-Si shows largest BET surface areas of 1091 m2/g and microporous volume of 0.26 cm3/g among the five PFNs,in addition,PFN-Si possesses micropores concentrating on 0.52 nm.O-phthaladehyde has two ortho-substituted functionalities which show large inhibition for the polymerizations which endows PFN-QO with largest pore size.PFNs exhibit excellent CO2 adsorption property with large amout of hydroxyl groups as PFN-QA uptakes 19.8 wt%of CO2 at 273 K and 1.0 bar.What's more,the H2 uptake of PFN-QA is up to 1.73 wt%at 77 K and 1.0 bar.Catalytic performance of microporous phenolic resin-based heterogeneous catalyst.Based on the above mentioned that phenolic resins with hierarchical pore sizes over a wide range from micropore to mesopore was prepared through no metal catalyst condensation,a novel heterogeneous catalysis was synthesized through the triphenylphosphine coordinate with palladium to create Pd@PFN-P,which effectively inhibits the quenching of catalyst.The pore sizes of Pd@PFN-P are remarkably enlarged compared to PFN-P and located at 5.7-42.6 nm,which facilitates the accessibility of the reactant to the active sites.The hydrophilic nature of polymer skeleton owing to the presence of abundant hydroxyl groups is advantageous for the accessibility of reactant to the catalyzing sites in the water reaction medium.The Suzuki-Miyaura reactions show that the conversions between bromobenzene derivatives and phenylboronic acid exceed 97.3%.Besides,the formation of C-C bond through the reactions of chlorobenzene and fluorobenzene with phenylboronic acid give a satisfactory conversion of 91.1 and 88.5%,respectively.More importantly,after five cycling reactions,the yields of reactions between bromobenzene and phenylboronic acid are almost unchaged.