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一步法合成混合取代含氟环三磷腈化合物及其热稳定性研究
One-step synthesis of mixed-substituted fluorinated cyclotriphosphazene compound and its thermal stability study
【摘要】 以六氯环三磷腈为底物,八氟戊醇和间甲基苯酚为亲核试剂,采用简单的一步法合成了混合取代含氟环三磷腈化合物。与传统的分步法合成相比,一步法是所有亲核试剂一次性加入到反应体系中,按照亲核试剂与底物取代反应能力的强弱,通过调控亲核试剂浓度和反应时间控制其产物结构,减少了反应时间,缩短了反应步骤。作为对比,还合成了八氟戊醇和间甲酚单一基团全取代的两种环三磷腈化合物。通过红外光谱(FT-IR)和核磁共振磷谱(31P NMR)对产物的结构进行了表征,结果表明一步法合成的混合取代产物中八氟戊氧基和苯氧基的基团占比分别为49%和51%,而分步法为34%和66%。数均相对分子质量(Mn)测定结果表明,分步法和一步法产物的数均相对分子质量分别为1 230和1 356,表明一步法合成的环三磷腈产物中侧链八氟戊氧基大相对分子质量基团较多,与31P NMR结果一致。此外热失重(TG)结果表明,一步法和分步法样品在N2气氛热失重50%的温度分别为333和365℃,热稳定性的提高与其分子结构中苯氧基的比例增大密切相关。
【Abstract】 A one-step synthesis of mixed-substituted fluorinated cyclotriphosphazene compound was achieved using hexachloro-cyclotriphosphazene as a substrate and octafluoropentanol and 3-methylphenol as nucleophilic reagents.This approach,compared to traditional stepwise methods,involves simultaneous addition of all nucleophilic reagents to the reaction system.Control of nucleophilic reagent concentration and reaction time allows for the regulation of product structure,resulting in reduced reaction time and steps.For comparison,two cyclotriphosphazene compounds with full substitution,using octafluoropentanol and meta-methylphenol,were also synthesized.Characterizations of product structures through FT-IR and31P NMR reveal that the one-step method produces compounds with 49%octafluoropentoxy and 51%phenoxy groups,while the stepwise method yields products with 34%octafluoropentoxy and 66%phenoxy groups.Additionally,the one-step method produces cyclotriphosphazene products with higher molecular weight side chains,as evidenced by Mnvalues of1 356 compared to 1 230 for the stepwise method.TG results reveal that the temperatures at which the one-step and stepwise method samples experience 50%weight loss under N2atmosphere are 333 and 365℃,respectively.The increased thermal stability is closely related to the higher proportion of phenoxy groups in the molecular structure.
【Key words】 fluorinated cyclotriphosphazene; one-step synthesis; stepwise synthesis; structural characterization; thermal stability;
- 【文献出处】 化学研究 ,Chemical Research , 编辑部邮箱 ,2024年05期
- 【分类号】O627.51
- 【下载频次】22