...
首页> 外文期刊>Journal of Macromolecular Science. Pure and Applied Chemistry >Structural Confirmation of Exo-Olefin-Coupled Polyisobutylene via Model Compound Synthesis and Characterization
【24h】

Structural Confirmation of Exo-Olefin-Coupled Polyisobutylene via Model Compound Synthesis and Characterization

机译:通过模型化合物的合成和表征确定外烯烃偶联的聚异丁烯的结构

获取原文
获取原文并翻译 | 示例
           

摘要

We report the synthesis and characterization of a model compound representing exo-olefin coupled polyisobutylene (PIB). Under certainconditions during the in situ quenching of quasiliving PIB with hindered bases to yield exo-olefin-terminated PIB, remaining PIB carbo-cations can undergo addition to exo-olefin PIB to yield coupled PIB with a molecular weight approximately double that of the primarychains. Characterization of the signals that arise in ~1H-NMR from the presence of coupled product has not yet been properly performed;the accurate chemical shifts of these products, specifically the exo-olefin product, have been in debate recently. Therefore, we carriedout the synthesis of a model compound which mimics the exo-olefin coupled product, and through variations in the synthetic methodwere able to produce a range of exo- and endo-olefin coupled product mixtures. The model compounds have been fully characterizedusing NMR techniques, and we herein conclusively report the proton shift (for 500 MHz 1H-NMR in CDCl_3) of 4.82 ppm for theexo-coupled product and that of 5.11 ppm for the endo-coupled product.
机译:我们报告了代表外烯烃耦合的聚异丁烯(PIB)的模型化合物的合成和表征。在某些条件下,用受阻碱对拟缩合PIB进行原位淬火以生成外烯烃封端的PIB时,剩余的PIB碳阳离子可以与外烯烃PIB进行加成反应,从而生成分子量约为主链分子量两倍的偶联PIB。由于偶联产物的存在,在〜1H-NMR中产生的信号的表征尚未得到适当的表征;这些产物,特别是外烯烃的产物的准确化学位移最近一直存在争议。因此,我们进行了模拟外烯烃耦合产物的模型化合物的合成,并且通过合成方法的变化,能够生产出一系列的外烯烃耦合产物和内烯烃耦合产物混合物。使用NMR技术已经对模型化合物进行了全面表征,我们在此总结性地报告了外耦合产物的质子位移(对于CDCl_3中的500 MHz 1H-NMR)为4.82 ppm,内耦合产物的质子位移为5.11 ppm。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号