The Study On Synthesis And Multidimensional Application Of Dopamine Quinone Functionalized Acrylic Fiber

Quaternary ammonium medical disinfectants are one of the main sources of water pollution,which is discharged into the environment with medical wastewater,causing some functions of microorganisms and plants to be affected.CO₂,as the main component of greenhouse gases,causes the acidification of the water and the increase of the atmospheric temperature of the earth.Therefore,the resource utilization of pollutants is very important to reduce environmental pollution for sustainable development.Combining the catalytic utility of quaternary ammonium compounds and rich renewable feedstock nature of CO₂,we have prepared dopamine quinone functionalized acrylic fiber(PAN_dpqF)to achieve effective absorption of dodecyl dimethyl benzyl ammonium chloride（DDBAC）,a commonly used quaternary ammonium medical disinfectant.Moreover,the PAN_dpqF with absorbed DDBAC has been used to efficiently catalyze the conversion,realizing the multi-dimensional application of functionalized fibers.The novel fiber material PAN_dpqF was well characterized by ¹³C CP-MAS NMR,XPS,FITR,and SEM.Through the adsorption selectivity test,we finally proved that PAN_dpqF had the highest adsorption capacity on DDBAC measured by UV,and the theoretical maximum saturated adsorption capacity can be reached 666.7 mg·g^-1at p H=8 and 25℃.By analyzing and comparing the XPS spectra and ¹³C CP-MAS NMR spectra before and after adsorption,the paper proposes the corresponding reactive adsorption mechanism.The Cl^-1of DDBAC attacks the carbon of the PAN_dpqF to expose the oxygen anion and the N⁺of DDBAC to electrostatically attract.DDBAC@PAN_dpqF obtained after the adsorption of benzalkonium chloride was used for the cyclization of CO₂and 2-chloromethyl propylene oxide.It is believed to function in cooperation through phenoxyanion（nucleophilic attack at epoxide）,phenolic hydroxyl（activated CO₂）and benzalkonium N⁺（stable intermediate）.Then the effects of catalytic amount,temperature and time on the reaction were investigated.As the result,the 0.8 mmol%fiber catalyst was well applicable to cyclization of CO₂and the yield could reach up to 93.7%after 15 h under mild conditions（80 ^oC,1 atm CO₂）.Finally,the applicability of 2-bromomethyloxirane,glycidol and other substituents was studied.Experiments show that the catalyst has higher catalytic performance for epoxy compounds and small sterically hindered substituents.In this thesis,the low-cost and easily available functionalized acrylic fiber not only absorbs the disinfectant DDBAC,but also makes use of its structural feature to catalyze the fixation of waste greenhouse gas CO₂into valuable chemical products.Thus,multi-dimensional application of functionalized fibers was well achieved,which provides a new idea for advanced environmental pollutant control.