Study Of Cellulose To Transesterification By Organic Function Catalytic Conversion

Cellulose is the most important skeletal component in plants,and the most abundant biodegradable and renewable natural polymer.As a sustainable clean resources,cellulose derivative especially cellulose esters are extremely commercially important derivatives with wide applicatuin in various fields such as films,membranes,plastics and coatings.In this paper,we used microcrystalline cellulose and cotton pulp to synthesize different cellulose derivatives in the DBU/DMSO/CO2 mixed solvent system and the ionic liquid 1-allyl-3-methylimidazolium chloride(AMIMCl).Homogeneous facile transesterification of cellulose was accomplished by applying vinyl benzoate in the DMSO/DBU/CO2.A series of cellulose benzoates with degrees of substitution from 0.58 to 2.94 have been successfully synthesized.The structures and thermal properties of the cellulose benzoates have been characterized by arious analytical techniques such as NMR,FT-IR,DSC,and TGA.The key concept in this cellulose derivatization is the dual functionalities of 1,8-diazabicyclo[5.4.0]undec-7-ene(DBU),namely a solvent for reactants and an efficient catalyst for transesterification reactions.Long-chain cellulose esters and cellulose mixed esters were homogeneously synthesized in the DBU/DMSO/CO2 mixed solvent system.The structure and thermal properties of Long-chain cellulose esters are characterized by FT-IR,NMR,TGA,and DSC.Cellulose acetoacetate(CAA)was synthesized by reaction of cellulose with tert –butyl acetoacetate(t-BAA)or diketene in 1-allyl-3-methylimidazolium chloride(Amim Cl)in a single step without using any catalysts.The structure and properties of CAA are characterized by FT-IR,NMR,and solubility measurements.