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首页> 外文期刊>Polymers for advanced technologies >Synthesis and NMR characterization of 6-pheny1-6-deoxy-2, 3-di-O-methylcellulose
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Synthesis and NMR characterization of 6-pheny1-6-deoxy-2, 3-di-O-methylcellulose

机译：6-苯基1-6-脱氧-2，3-二-O-甲基纤维素的合成及NMR表征

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In this study we achieved three major objectives: (a) new synthetic methods were discovered for the chemical modification of cellulose; (b) new cellulose derivatives were designed, prepared, and characterized; (c) unequivocal non-destructive means of proving chemical transformation of cellulose derivatives by one- and two-dimensional MNR methods was established. Starting with cellulose (DP{sub}W=361) and using Rogovin's guidelines for selective functionalization of cellulose [2a], 6-phenyl-6-deoxy-2, 3-di-O-methylcellulose (DP{sub}W=73.51) was obtained for the first time. The overall yield of the five-step process was (0.96×0.95×0.79×0.90×0.51) 33%, and the compound average reduction in DP{sub}W was ～27%. Elemental analysis and quantitative 13{sup left}C-NMR spectrometry were used concurrently to afford consistent and verifiable degree of substitution data for the cellulose polymers. DSC was not a sensitive technique for detecting T{sub}g values of these polymers. The T{sub}g value of 6-O-tritylcelluose (2) was found by DMA to be ～127℃, on thin films when the polymer was contaminated with triphenylmethyl compounds (ca. ＜5%), and its Young's modulus at 20℃ was 3.26×10{sup}9 Pa. For all other polymers, decomposition temperatures were obtained by DSC and TGA. The high decomposition temperature and large char value for 2,3-di-O-methylcellulose suggests that the material could have useful applications in blends with other polymers for high temperature applications. Finally, complete proton and chemical shift assignments for the 6-phenyl-6-deoxy-2,3-di-O-methyl-1,4-anhydroglusose repeating unit were made by interpreting a combination of one- and two-dimensional NMR spectra. The strategy for the interpretation of these spectra was unlike our previous experiences for deciphering complete chemical shift assignments of 2,3,6-tri-O-crotyl celluloses [8].
机译：在这项研究中，我们实现了三个主要目标：（a）发现了用于纤维素化学修饰的新合成方法; （b）设计，制备和表征新的纤维素衍生物; （c）建立了通过一维和二维MNR方法证明纤维素衍生物化学转化的明确无损手段。从纤维素（DP {sub} W = 361）开始，并使用Rogovin准则对纤维素[2a]，6-苯基-6-脱氧-2、3-二-O-甲基纤维素进行选择性官能化（DP {sub} W = 73.51 ）是首次获得。五步法的总收率为（0.96×0.95×0.79×0.90×0.51）33％，DP {sub} W的化合物平均减少量约为27％。同时使用元素分析和定量13 C-NMR光谱分析可提供一致且可验证的纤维素聚合物取代度数据。 DSC不是检测这些聚合物的Tg值的灵敏技术。通过DMA发现6-O-三苯甲基纤维素（2）的T {sub} g值为〜127℃，在薄膜上被三苯甲基化合物污染（约＜5％）时，其杨氏模量为20℃为3.26×10 {sup} 9 Pa。对于所有其他聚合物，通过DSC和TGA获得分解温度。 2,3-二-O-甲基纤维素的高分解温度和大焦炭值表明该材料在与其他聚合物共混以用于高温应用中可能具有有用的应用。最后，通过解释一维和二维NMR光谱的组合，得出了6-苯基-6-脱氧-2,3-二-O-甲基-1,4-脱水葡萄糖的重复单元的完整质子和化学位移分配。解释这些光谱的策略与我们以前的破译2，3，6-三-O-巴豆基纤维素的完整化学位移分配的经验不同[8]。

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