Design And Preparation Of Ionic Conjugated Microporous Polymers And Their Application In Catalysis And Separation

Conjugated microporous polymers(Conjugated Microporous Polymers,CMPs)are the subclass of porous organic polymers(POPs)materials with permanent microporous structure composed of conjugated skeletons.Due to its diverse molecular design,CMPs are widely used in many fields such as adsorption,heterogeneous catalysis,and separation.The introduction of ionic groups into the skeleton not only provides more possibilities for the molecular structure diversity of conjugated microporous polymers,but also brings new functions and tunable pores to the materials themselves.In this paper,a series of novel imidazolium ionic conjugated microporous polymers(i CMPs)were designed and prepared,and the chemical structures and morphologies of i CMPs were characterized.The catalytic performance of i CMPs in carbon dioxide cycloaddition reaction was studied,and the ion-ieving performance of i CMPs for different valence ions after preparing macroscopic ionic conjugated microporous polymer membranes was explored.The specific research contents are as follows:(1)In view of the traditional preparation process of conjugated microporous polymers generally requires noble metal catalysts and anhydrous and anaerobic harsh conditions,a simple one-pot method to obtain ionic conjugated microporous polymers by Debus-Radziszewski reaction is proposed.This method is not only simple and rapid in the preparation process of polymers,but also can obtain ionic skeleton structure by one-pot method.The prepared i CMPs exhibit a highest BET(Brunauer-Emmett-Teller)specific surface area of 361 m2 g-1 and a highest CO2 adsorption capacity of 5.5 wt % at 373 K.In addition,through simple halogen ion exchange,ionic conjugated microporous polymers(i CMP-1,2,3 @Cl)showed excellent catalytic ability for the cycloaddition of carbon dioxide.The i CMPs were used to catalyze the cycloaddition of CO2 and epichlorohydrin.The results showed that i CMP-1 @ Cl had the highest catalytic activity,and more than 95 % yield of cyclic carbonate was obtained under the conditions of CO2 pressure of 1MPa,catalyst dosage of 2 wt %,temperature of 130 °C and reaction time of 8 h.In the five-cycle catalytic experiment under this optimal condition,the catalyst still maintained good catalytic performance,reflecting its advantages as heterogeneous catalyst.In addition,by replacing a series of epoxide substrates,the catalyst also showed catalytic universality for this model reaction,which provided ionic conjugated microporous polymer as a new catalyst for porous CO2 cycloaddition reaction.(2)In order to overcome the limitations of ionic conjugated microporous polymers in constructing macroscopic architectures,i.e.,film,aerogel,etc.,a template method combined with the Debus-Radziszewski reaction were applied to grow ionic conjugated microporous polymer film(i CMPMs)onto the graphene oxide film modified with amino group.The polymer film prepared by this method has good uniformity and compactness,among them,i CMPM-2@HCl had a specific rejection effect on Mg2+.The experiment showed that in the electrically driven ionsieving test,the separation ratio of i CMPM-2@HCl to H+/Mg2+ was 3.0,which was significantly better than 1.9 of graphene oxide film(GOM).The ion permeation rate test under concentrationdriven also showed that the separation ratio of i CMPM-2@HCl to Li+/ Mg2+ was 3.4,which was better than 2.0 of GOM.In this paper,ionic conjugated microporous polymers and ionic conjugated microporous polymer membranes had been prepared by newly introduced methods and strategies,which provided ideas for the preparation and application of conjugated microporous polymers and their membrane materials.