三氟甲磺酸催化制备环丙烷结构燃料中间体吡唑啉  

Catalytic preparation of cyclopropane-structured fuel intermediate pyrazoline by triflic acid

作　　者：张汉杰 曹宇鹏 蒋榕培[1] 孙海云[1] 方涛[1] Zhang Hanjie;Cao Yupeng;Jiang Rongpei;Sun Haiyun;Fang Tao(Beijing Key Laboratory of Research and Application for Aerospace Green Propellants,Beijing Institute of Aerospace Testing Technology,Beijing 100074,China)

机构地区：[1]北京航天试验技术研究所航天绿色推进剂研究与应用北京市重点实验室,北京100074

出　　处：《化学推进剂与高分子材料》2024年第5期22-29,共8页Chemical Propellants & Polymeric Materials

基　　金：中国航天科技集团钱学森青年基金资助。

摘　　要：通过实验对腙分子内成环制备环丙烷结构高能燃料中间体吡唑啉的酸催化剂进行了筛选,其中三氟甲磺酸的酸性最强,以其来催化合成3,5,5-三甲基-2-吡唑啉,转化率98%,选择性>99%。吡唑啉高温脱氮制备对应环丙烷结构产物,转化率>95%。此外,基于密度泛函理论B3LYP/6-311G(d,p)水平,计算了酸催化腙成环反应机理与位点,表明酸催化可以有效降低反应活化能,促进成环反应。Mulliken电荷分布分析显示,腙的质子化是该反应的关键起始步骤。上述结果表明强酸催化剂有利于加快腙转化为吡唑啉的反应速率,且腙的空间位阻是反应关键因素,空间位阻较小的底物转化率较高。该研究为吡唑啉的合成与环丙烷结构燃料的制备提供了一种可行的方法。The acid catalysts for the preparation of the cyclopropane-structured high energetic fuel intermediate pyrazoline by intramolecular cyclization of hydrazone were screened experimentally.Among them,triflic acid had the strongest acidity,and it was used to catalyze the synthesis of 3,5,5-trimethyl-2-pyrazoline with a conversion of 98%and a selectivity of more than 99%.The corresponding cyclopropane structure products were prepared by high-temperature denitrification of pyrazoline with a conversion of more than 95%.In addition,based on the density functional theory B3LYP/6-311G(d,p)level,the mechanism and sites of acid-catalyzed cyclization reaction of hydrazone were calculated,which indicated that acid catalysis could effectively reduce the activation energy of the reaction,and promote the cyclization reaction.The Mulliken charge distribution analysis showed that the protonation of hydrazone was the key initial step of the reaction.The above results showed that strong acid catalysts were favorable to accelerate the reaction rate of hydrazone to pyrazoline,and the steric hindrance of hydrazone was the key factor for the reaction.The substrates with smaller steric hindrance had higher conversion.This study provides a feasible method for the synthesis of pyrazoline and the preparation of cyclopropane structured fuels.

关 键 词：环丙烷 高能燃料 高能中间体 吡唑啉 三氟甲磺酸 

分 类 号：TQ252[化学工程—有机化工] V511[航空宇航科学与技术—航空宇航推进理论与工程]