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In situ generated amine as a Lewis base catalyst in the reaction of 3,7‐dinitro‐1,3,5,7‐tetraazabicyclo[3.3.1]nonane in nitric acid: Experimental and DFT study
Author(s) -
Zhang Yu,
Chi Guoli,
He Ying,
Xu Zishuai,
Zhang Luyao,
Luo Jun,
Zhou Baojing
Publication year - 2019
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.3958
Subject(s) - chemistry , catalysis , nitric acid , nonane , lewis acids and bases , ammonia , ammonium nitrate , amine gas treating , nitroso , hydroxymethyl , bicyclic molecule , nitration , yield (engineering) , organic chemistry , medicinal chemistry , inorganic chemistry , materials science , metallurgy
The problem how ammonium nitrate affects the nitrolysis of 3,7‐dinitro‐1,3,5,7‐tetraazabicyclo[3.3.1]nonane (DPT) in nitric acid to prepare 1,3,5,7‐tetranitro‐1,3,5,7‐tetraazacyclooctane (HMX) has puzzled chemists for decades. In this paper, experimental work and theoretical calculation are described to investigate the long‐standing challenge. The experiment results showed that ammonium nitrate or alkylammonium chlorides were in favor of the formation of 1‐nitroso‐3,5,7‐trinitro‐1,3,5,7‐tetraazacyclooctane (MNX) but hindered the conversion of MNX to HMX. A plausible catalytic mechanism was proposed. In which ammonia or amines, in situ generated from the unfavorable balance with their salts, act as Lewis base catalysts. At the same time, the DFT computation results reveal that rigid bicyclic transition states established with 1‐hydroxymethyl‐3,5,7‐trinitro‐1,3,5,7‐tetraazacyclooctane, ammonia (or amines) and three water molecules lead to very low activation energies. Then, a novel process for the preparation of MNX with excellent yield up to 78.5% was developed, which is free of the use of NaNO 2 or N 2 O 4 as nitroso resources.