Material (Polymer) Research Laboratory, Department of Chemistry, Jamia Millia Islamia Central University, New Delhi 110025, India.
Material (Polymer) Research Laboratory, Department of Chemistry, Jamia Millia Islamia Central University, New Delhi 110025, India.
Carbohydr Polym. 2018 Jan 15;180:337-347. doi: 10.1016/j.carbpol.2017.10.005. Epub 2017 Oct 6.
Gum arabic, a plant polysaccharide was oxidized with periodate to produce aldehyde groups by the cleavage of diols present in the sugar units. The oxidized gum was then iodinated with iodine monochloride (ICl) and the interaction between electrophilic iodine, I and reactive carbonyl groups of the modified gum was studied.Results of titrimetric estimation performed to determine the extent of oxidation and aldehyde content in the oxidized gum showed that degree of oxidation ranged between 19.68-50.19% which was observed to increase with periodate concentration; the corresponding aldehyde content was calculated to be 5.15-40.42%. Different strengths of ICl were used to iodinate the oxidized gum and the iodine content of the complexes varied from 6.11-11.72% as determined by iodometric titration. Structure elucidation of the iodine complexes conclusively established the attachment of ICl molecules to CHO groups. A reaction scheme has been proposed suggesting an electrophilic addition of the reagent to the aldehyde groups, a mechanism that was also supported by iodide ion release studies.
阿拉伯胶是一种植物多糖，用过碘酸盐氧化，通过糖单元中二醇的裂解产生醛基。然后用一氯化碘（ICl）对氧化胶进行碘化，研究了亲电碘（I）与改性胶的反应羰基之间的相互作用。通过滴定估计来确定氧化胶中的氧化程度和醛含量的结果表明，氧化程度在 19.68-50.19% 之间变化，这与过碘酸盐浓度呈正相关；相应的醛含量计算为 5.15-40.42%。使用不同强度的 ICl 对氧化胶进行碘化，通过碘量滴定法测定配合物的碘含量从 6.11-11.72% 不等。碘配合物的结构阐明明确确定了 ICl 分子与 CHO 基团的连接。提出了一个反应方案，建议试剂与醛基发生亲电加成，该机制也得到了碘化物离子释放研究的支持。
