Preparation Of Hierarchical Pore Melamine And Catalytic Membrane And Study Of CO₂ Catalytic Performance

A large amount of carbon dioxide(CO2)has been produced by the industrial production and human life,resulting in serious greenhouse effect and global warming and other serious climate problems,which is a serious threat to human survival and life.It is particularly important to reduce the emission of CO2,especially the carbon dioxide content in industrial waste gas.On the other hand,CO2 is also a cheap,non-toxic,stable and renewable C1 raw material.Porous organic polymers(pops)that adsorb metal ions are often used in cycloaddition catalysis of CO2.Based on this,high internal-phase emulsion polymerization was used to prepare a kind of ah-PMF with hierarchical porous structure,and a porous material with rmacropore,mesopore and micropore.Melamine and polyformaldehyde are dissolved in dimethyl sulfoxide,isomeric alkanes are used as the dispersed phase,and dimethyl sulfoxide is used as the continuous phase to make oil with high internal phase,and monomers are polymerized into dense amine materials.After metallization,it acts as a catalyst to catalyze the cycloaddition reaction of propylene oxide with CO2.In order to avoid the loss of catalyst in the separation step,a new catalytic membrane(PI-Zn@PMF)was prepared by blending the metallized porous mimetic amine with polyimide by NIPS method and chemical crosslinking.In the membrane reactor,the cycloaddition of epichiorohydiin and CO2 was carried out in the form of "flow through" at room temperature and pressure.The main research contents and conclusions were as follows:The preparation method of high iuternal phase of oil and the synthesis of dense amine with hierarchical porous structure were proposed.It was measured by solid carbon spectrum imaging(13C NMR),Fourier infrared spectroscopy(ATR-FTIR),thermogravimetric analyzer(TG),scaning electron microscope(SEM),high-resolution transmission electron microscopy(HR-TEM),X-ray photoelectron spectroscopy(XPS),X-ray diffr-action(XRD),surface area analyzer(BET),such as the melamine particles were characterized;The metal ions adsorption reached 74.9 mg/g,and cycloaddition reaction conversion rate up to 79.1%,in 100?,2 MPa,0.5 h,and the TOF value is 18388h-1.The reusability of the catalyst needs to be further improved.It has high catalytic performance in cycloaddition reactions of other epoxies,and the cost of the catalyst is very low.The price of its main monomer is one tenth of the cheapest catalyst reported so far.The preparation method of catalytic membrane(PI-Zn@PMF membrane)was proposed.The catalytic membrane was applied to the catalytic reaction of cycloaddition of CO2 in a membrane reactor.The catalytic membrane was characterized by Fourier infrared spectroscopy(ATR-FTIR),thermogravimetric analyzer(TG),scanning electron microscope(SEM),high-resolution transmission electron microscope(HR-TEM),surface area analyzer(BET)ancd water contact Angle tester.Porosity was measured by bubble point method.Fourier infrared spectroscopy(ATR-FTIR)was used to calculate the crosslinking degree.The conversion rate of the catalytic reaction was calculated by nuclear magnetic resonance(1H NMR).The 12 h conversion rate of the catalytic membrane is ab out 79.5%at 25?(and 0.1 MPa,CO2 atmosplhere,flow rate=4ml/h,TOF value of 2034h-1,while avoiding the separation step,TOF value is 4-100 fold higher than the current report.