Synthesis And Chiral Recognition Abilities Of Cellulose Derivatives With Different Molecular Weight

The chiral stationary phase prepared from cellulose phenyl carbamate derivatives can effectively separate more than 90%of the chiral compounds,and its excellent chiral separation performance has made it a research hotspot in this field.Up to now,the influence of molecular weight on the structure and abilities of cellulose phenylcarbamate derivatives is not clear,which has great limitations for the further development of the natural chiral macromolecules and their understanding of the mechanism of chiral recognition.Based on this research situation,this paper mainly studied the preparation of different molecular weight cellulose phenylcarbamate derivatives and the influence of molecular weight on the chiral recognition performance of the derivatives.At the same time,the chiral recognition process of different molecular weight cellulose phenylcarbamate derivatives for two kinds of chiral compounds with different structures were simulated by computer,and further studied their chiral recognition mechanism.First,microcrystalline cellulose with different molecular weight was prepared by acid hydrolysis,and also synthesized the cellulose phenylcarbamate derivatives of different molecular weight through carbamate reaction,then prepared the corresponding chiral stationary phases.The chemical structure,degree of substitution and molecular weight of the synthesized derivatives were systematically characterized by nuclear magnetic resonance hydrogen spectrum(~1H NMR),fourier transform infrared spectrometer(FT-IR),gel permeation chromatography(GPC),and the chiral separation of the prepared chiral stationary phase to 9 chiral compounds were carried out by high performance liquid chromatography(HPLC),for evaluating their chiral recognition performance.Then,Materials Studio software was used to simulate cellulose phenylcarbamate derivatives with different molecular weight based on the theory of molecular dynamics and molecular mechanics,and the energy difference between derivatives and different enantiomers was calculated by molecular dynamics simulation calculate the occurrence of derivatives between different enantiomers by molecular dynamics simulation,ultimately confirmed the preferential conformation of derivatives.At the same time,the results of HPLC chiral separation and simulation results were compared and analyzed,further exploring the chiral recognition mechanism of cellulose derivatives and the influence of molecular weight on the performance of chiral recognition.The results showed that the molecular weight had a great influence on the chiral recognition performance of cellulose phenylcarbamate derivatives.When the degree of polymerization was less than 77,the chiral recognition performance of cellulose derivatives increased with the increase of molecular weight;When the degree of polymerization reached 77,the effect of molecular weight on the chiral recognition performance of cellulose derivatives was gradually slowing down.Molecular simulation results showed that the introduce of phenylcarbamate side group on the position of the three cellulose sugar unitat could form regular chiral helical cavities,and was easy to form hydrogen bonds with the polar groups of enantiomeric molecules,which was an important chiral recognition site.The effects of molecular weight obtained by molecular dynamics simulation on chiral recognition performance and the elution order of enantiomers were in good agreement with the results of chromatographic separation.Molecular dynamics simulation was used to analysis the energy minimization of the conformation of cellulose derivatives,the results showed that cellulose phenylcarbamate derivatives can interact with enantiomers to form hydrogen bonds,dipole dipoles,and?-?conjugation in their chiral cavities,which had an important influence on their chiral recognition properties.