Spectral Study for Reaction Mechanism of Etherification of Rice Straw
|Keywords||Straw Cellulose Modification Mechanism Infrared Spectroscopy CP / MAS 13C NMR spectroscopy X-ray diffraction|
In this study, the etherification reaction to Straw be chemically modified to convert it to a certain thermoplastic polymer materials . NaOH as a swelling agent and catalyst , epichlorohydrin and benzyl chloride as an etherifying agent , cetyl bromide as a phase transfer catalyst ( for debenzylation modified) , and toluene as the solvent , the straw the etherification modified its microscopic structure has changed considerably , partly to eliminate the polarity of the straw . In this study, the rate of weight gain , infrared spectroscopy , solid CP / MAS 13C NMR spectroscopy and X -ray diffraction method of combining the analysis process and reaction mechanism of epichlorohydrin modified straw and benzyl chloride modified straw modified and research . Epichlorohydrin modified straw modification time of 1-8h modified straw weight gain rate , the results show that the growth rate increases with increasing modification time , modified straw first gain within 5h The heavy rate steadily increased to 90.12% , 5h after weight gain rate basically stable at about 93.00% . Infrared spectra and solid-state 13C nuclear magnetic resonance spectra compared before and after the modification , as well as different modified time of the infrared spectra inferred epichlorohydrin etherification straw modification reaction process is divided into two steps : The first step is broken C-Cl bond , substituted cellulose on the one-OH H ; second step is substituted into the cellulose on the epoxy ring is opened, the reaction with the cellulose molecule on another one-OH . Finally, using X-ray diffraction analysis straw modified before and after the crystallization degree of change, the lower the degree of crystallinity of the modified rice straw . For the benzyl chloride modified straw , of the modified time for the 1-10h of the weight gain rate trends and infrared spectra analysis of the modification time and modification effect relationship . The results show that the modified 1-2h , weight gain rate is substantially 0.00%; modified 3-8h , weight gain rate is increased with increasing modification time , the highest weight gain rate when 8h , 61.37% ; modified time for 9-10h , the rate of weight gain decreased. Consistent with the results observed in the IR spectrum . Reaction 2h benzyl group of samples infrared spectroscopy FIG no characteristics of a benzyl group of functional corporation 's absorption peak appears , from 4h sample of IR spectroscopy FIG start appear the characteristics of a benzyl group of functional corporation 's absorption peak , 8H sample of the benzyl group of characteristics absorption peak up to its peak strongest .