Synthesis And Application Of Cellulose Protic Ionic Liquids

Cellulose is an inexhaustible natural polymer with a wide range of sources.Preparation of metal nanoparticles has become one of the most concerned and rapidly developing fields due to large surface area and many other excellent properties of nanoparticles.The combination of cellulose and metal nanoparticles can complement each other and open up a new path for the development of new environmentally friendly functional materials.Based on CO₂/DMSO/TMG reversible dissolution system,this work derivatizes cellulose to prepare cellulose protic ionic liquids hydrogel?CPH?and supports Pd nanoparticles in situ in the hydrogel.Pd@CPH composite material was prepared.The loading ability of CPH to Pd was studied by innovative research methods.Further,Pd@CPH was applied to environmental catalysis,and the reaction kinetics was deeply studied.The significance of the introduction of protic ionic liquid functional groups was compared.The main research contents are as follows:1.Based on CO₂/DMSO/TMG derivatization dissolution system,cellulose was dissolved and derivatized with succinic anhydride and pyromellitic dianhydride to prepare a cellulose protic ionic liquids hydrogel with crosslinked structure.The synthesis of cellulose protic ionic liquids hydrogel was demonstrated by Fourier transform infrared spectroscopy?FTIR?,nuclear magnetic resonance?NMR?,scanning electron microscopy?SEM?,elemental analysis?EA?,and X-ray photoelectron spectroscopy?XPS?.The water absorption properties of the hydrogel were explored by testing the equilibrium swelling ratio of the hydrogel with different crosslinker contents.Based on cellulose protic ionic liquids hydrogel?CPH?,cellulose carboxyl hydrogel?CCH?and pure cellulose hydrogel?CH?were prepared for studying the significance of the existence of protic ionic liquid functional groups.2.Based on cellulose protic ionic liquids hydrogel,using PdCl₂ as precursor,palladium nanoparticles?Pd Nps?were loaded in situ in the three-dimensional network of the hydrogel to prepare cellulose protic ionic liquids hydrogel/Pd Nps composite.Scanning electron microscopy?SEM?,transmission electron microscopy?TEM?,high resolution transmission electron microscopy?HRTEM?,selected area electron diffraction?SAED?,energy dispersive X-ray spectroscopy?EDX?,X-ray diffraction?XRD?,X-ray photoelectron spectroscopy?XPS?were used to prove the synthesis of cellulose protic ionic liquids hydrogel/Pd Nps composite.The content of Pd in the composites were detected by inductively coupled plasma optical emission spectroscopy?ICP-OES?.Pd loading experiments were carried out with CH and CCH to obtain Pd@CCH and Pd@CH.The equilibrium swelling ratio of the hydrogel before and after loading of Pd Nps were studied in detail.3.Cellulose protic ionic liquids hydrogel/Pd Nps composites were used to catalyze the reduction reaction of p-nitrophenol?4-Np?,a common organic pollutant in water.And the Pd@CPH achieved 10 cycles without losing activity.The progress of the 4-Np reduction reaction was monitored by UV-vis.For comparison,catalytic experiments were carried out using Pd@CCH and Pd@CH.Further catalytic experiments were carried out at different temperatures,and the catalytic properties of the materials were studied in depth using the classical theory of reaction kinetics.In summary,this work creatively prepared a cellulose protic ionic liquids hydrogel,which enables the in-situ loading of metal nanoparticles in itself.And cellulose protic ionic liquids hydrogel/Pd nanoparticles composites were used for environmental catalysis.This work not only contributes new ideas to the preparation and application of cellulosic environment friendly functional materials,but also provides new solutions for the inherent problems in the field of water pollution treatment.