Ammonia–dimethylchloramine system: Kinetic approach in an aqueous medium and comparison with the mechanism involving liquid ammonia
作者:J. Stephan、V. Pasquet、M. Elkhatib、V. Goutelle、H. Delalu
DOI:10.1002/kin.20312
日期:2008.6
medium. Dimethylchloramine prepared in a pure state undergoes dehydrohalogenation in an alkaline medium: the principal products formed are N-methylmethanimine, 1,3,5-trimethylhexahydrotriazine, formaldehyde, and methylamine. The kinetics of this reaction was studied by UV, GC, and HPLC as a function of temperature, initial concentrations of sodium hydroxide, and chlorinated derivative. The reaction is of
在对液氨中的氨-二甲基氯胺系统进行了详尽的研究之后,比较该系统在液氨中的反应性与相同系统在水性介质中的反应性是很有趣的。以纯态制备的二甲基氯胺在碱性介质中进行脱卤化氢:形成的主要产物是 N-甲基甲亚胺、1,3,5-三甲基六氢三嗪、甲醛和甲胺。该反应的动力学通过 UV、GC 和 HPLC 作为温度、氢氧化钠初始浓度和氯化衍生物的函数进行了研究。该反应是二级反应,遵循 E2 机理(k1 = 4.2 × 10-5 M-1 s-1,ΔH○# = 82 kJ mol-1,ΔS○# = -59 J mol-1 K-1 )。二甲基氯胺氧化不对称二甲基肼涉及两个连续的过程。第一步遵循关于卤胺和肼的一级定律,导致形成氨基氮烯中间体 (k2 = 150 × 10-5 M-1 s-1)。第二步对应于在 pH 13) 下将氨基氮烯转化为甲醛二甲腙。该反应遵循一阶定律 (k3 = 23.5 × 10-5 s-1)。二甲基氯胺-氨相互作用对应于