The Study On The Synthesis And Properties Of 2-difluoroaminomethyl-2-methyl Propane-1,3-diol Dinitrate

To increase the energy of explosives and propellants has always been the goal of scholars in explosive field. To make the plasticizer energetic is one of the technical way of improving the energy of explosives and propellants. The existing energetic groups mainly include nitric acid ester (-ONO2), nitro (-NO2), nitrate amine (-NNO2), azide (-N3), difluoroamino (-NF2) and fluorine dinitrodiphenyl (-CF(NO2)2), etc. Among them the nitric acid ester(-ONO2) group has the highest oxygen balance, and the difluoroamino group has the highest energy. To further introduce nitric acid ester group into the difluoroamino compound molecule can further improve its energy level. Based on this consideration, 2-difluoroaminomethyl-2-methylpropane-1,3-diol dinitrate (DFAMPDN) was synthesized from 3-difluoroaminomethyl-3-methyloxetane (DFAMO) via nitration reaction. The structure and properties of DFAMPDN was studied. The main work is as follows:(1) The difluoroamino compound 3-difluoroaminomethyl-3-methyloxetane (DFAMO) was synthesized via the sulfonylation, ammoniation, esterification and fluorination of 3-hydroxymethyl-3-methyloxetane. Then the difluoroamino plasticizer DFAMPDN was synthesized from DFAMO through nitration open-loop synthetic. The crude product was purified by column chromatography, and its structure was characterized by NMR, IR, EA and LC-MS, proving that the synthesized compound was DFAMPDN.(2) Based on the principle of nitration, four nitrating agent were choosen, and the influence of molar ratio, reaction temperature and reaction time on DFAMPDN yield were studied respectively. DFAMPDN yield. The result showed that when using dichloromethane as solvent, fuming nitric acid as nitrating reagent, the molar ratio of reactant DFAMO with fuming nitric acid was 5:1, reaction temperature was 20℃, reaction time was 55h, the product yield was the highest (73.1%).(3) The thermal decomposition performance of DFAMPDN and the compatibility between DFAMPDN and the common energetic components in propellant were studied by DSC method. The results showed that the decomposition onset temperature of DFAMPDN was 162.61℃, the peak temperature was 208.93℃, suggests DFAMPDN had good thermal stability. The peak decomposition temperature difference of DFAMPDN with DFAMPDN and CL-20, Al, AP, PDN hybrid system were -3.51℃,-2.12℃,-2.26℃,1.67℃ respectively, suggesting that DFAMPDN had level A compatibility with CL-20, Al, AP and PDN; The peak decomposition temperature difference of DFAMPDN with DFAMPDN and RDX, HMX, B gybrid system were 20.95℃,31.76℃,18.76℃respectively,suggesting that DRAMDN had poor compatibility,with RDX,HMX and B.