Study On Synthesis Of Hyper-Cross-Linked Microporous Organic Polymers And Their Applications In Gas Storage And Catalysis

Microporous organic polymers with high surface area,low density and easy functionalization,are a family of porous materials including hyper-cross-linked polymers,conjugated microporous polymers,covalent organic frameworks and polymers of intrinsic microporosity,and have been widely used in gas adsorption,catalysis,photoelectricity and chemosensing.As an important branch,hyper-cross-linked polymers have diverse synthesis methodologies such as knitting method with external cross-linker,Scholl coupling reaction and solvent knitting method.However,there is a lack of comparison among these approaches,in terms of knitting ideal polymers.Besides,there are few reports relating to the effect of functional group substitution in building blocks on polymer's performance at present.Considering their significance,it is also necessary to make a further elucidation.In order to better understand the influence of synthesis methodology and functional group substitution on polymer's property,this thesis prepares some hyper-cross-linked polymers,which are characterized by FT-IR,solid state ¹³C NMR,SEM,TEM,N₂ sorption,elemental analysis and so on.After then,their applications in gas capture and separation,and catalysis are also investigated.The main contents are given as below:?1?Six hyper-cross-linked polymers based on three synthesis methodologies?knitting method with external cross-linker,Scholl coupling reaction,solvent knitting method?and two aromatic hydrocarbons?1,4-diphenylbenzene,1,3-diphenylbenzene?have been prepared,with BET surface area up to 2278 m² g^-11 and CO₂ uptake capacity of 20.89 wt%at273.15 K/1.00 bar.Regarding the porous structure,gas uptake and fluorescence properties of resultant polymers,this work has demonstrated that:?I?the solvent knitting method has a higher efficiency for knitting polymers giving better porous structures and gas uptake performances;?II?the knitting method with formaldehyde dimethyl acetal as an external cross-linker is the most time efficient;?III?the Scholl coupling reaction is able to be used to prepare fluorescent polymers.Based on proposed mechanisms,changes in structural features can also be rationally explained.?2?Polycyclic aromatic hydrocarbons?PAHs?deemed as environmental containment have not received much attention,therefore they are used to knit four hyper-cross-linked polymers.As a result,it shows that,these polymers have BET surface area up to 1788 m²g^-1,CO₂ uptake capacity of 24.79 wt%at 273.15 K/1.00 bar,H₂ adsorption of 2.20 wt%at77.3 K/1.00 bar,and CH₄ storage of 2.79 wt%at 273.15 K/1.00 bar.Studies further indicate that,PAHs containing?conjugated systems,have been found to be a class of building blocks for forming polymers with high surface area and gas uptake performance.These distinctions in polymer's CO₂ adsorption performance are mainly attributed to the BET surface area,pore size and pore size distribution of obtained polymers.?3?Three amines are selected to knit hyper-cross-linked polymers.As a result,these polymers are revealed to have BET surface area up to 1717 m² g^-1,Langmuir surface area up to 2135 m²g^-1and CO₂ uptake of 18.85 wt%at 273.15 K/1.00 bar.With functional group substitution in building blocks i.e.phenyl gradually substituted by naphthyl,the porosity and gas uptake performance of polymers can be well tuned.This is mainly because,with the substitution of phenyl by naphthyl,the total number of active sites has increased and the electron-rich characteristic of building blocks has enhanced.?4?Triphenylphosphine-based heterogeneous catalysts could effectively catalyze the coupling of aryl chloride,however the high air sensitivity is disadvantageous for the catalyst recovery and reuse.Based on low-cost triphenylphosphine analogues,eight catalysts have been prepared with surface area up to 1004 m² g^-1,exhibiting diversity in catalytic performance.Of note,the yield 99%and TOF 8800 h^-11 can be achieved within 15minutes by the Suzuki-Miyaura coupling of bromobenzene and benzoboric acid.In addition,these catalysts also present distinctions in stability after five runs.More significantly,this study has shown that,decrease the electron-rich characteristic of building blocks will be benefit for improving the reaction activity of heterogeneous catalysts in aqueous liquid.