A new energetic material,4,5-dimethoxy-2-（dinitromethylene）imidazolidine（DMDNI）,was synthesized by the reaction of 4,5-dihydroxyl-2-（dinitromethylene）-imidazolidine（DDNI） and methanol,and structurally characte...A new energetic material,4,5-dimethoxy-2-（dinitromethylene）imidazolidine（DMDNI）,was synthesized by the reaction of 4,5-dihydroxyl-2-（dinitromethylene）-imidazolidine（DDNI） and methanol,and structurally characterized by single crystal X-ray diffraction.DMDNI crystallized in triclinic space group P1,with crystal data a=0.4324（4） nm,b=1.3599（11） nm,c=1.7503（14） nm,α=77.406（14）°,β=84.494（15）°,γ=87.976（14）°,V=0.9997（14） nm 3,Z=4,μ=0.140 mm-1,F（000）=488,D c =1.556 g/cm ^3,R 1 =0.0773 and wR 2 =0.1574.Thermal decomposition of DMDNI was studied,and its thermal decomposition process was divided into two stages.The first stage was a melting process and the second stage was an exothermic decomposition process.The enthalpy,apparent activation energy and pre-exponential constant of the exothermic decomposition reaction are-491.5 J/g,142.3 kJ/mol and 10 14.24 s^-1,respectively.The critical temperature of thermal explosion is 162.47 °C.DMDNI has a lower thermal stability than DDNI but it is close to that of 4,5-diacetoxyl-2-（dinitromethylene）-imidazolidine（DADNI）.展开更多
Poly(2,5-dimethoxyaniline) (PDMA) has been synthesized by chemical oxidative polymerization technique using varying ratio (wt/wt) of binary oxidants;ferric chloride (FeCl3) and ammonium persulfate (APS). Fourier trans...Poly(2,5-dimethoxyaniline) (PDMA) has been synthesized by chemical oxidative polymerization technique using varying ratio (wt/wt) of binary oxidants;ferric chloride (FeCl3) and ammonium persulfate (APS). Fourier transform infrared (FT-IR) and ultraviolet-visible (Uv-vis) spectroscopic investigations provide the evidence of the presence of both benzenoid and quinoid ring units. The thermal analysis and structural characterization data suggests that the oxidant ratio greatly controls the molecular ordering in PDMA. Surface morphology shows the existence of both amorphous and crystalline domains wherein the crystalline domain size depends on the oxidant ratio. The dc conductivity (σdc) of PDMA is also a function of binary oxidant ratio and at FeCl3:APS (50:50), it increases by two orders of magnitude. Films of PDMA synthesized using FeCl3:APS (50:50) binary oxidant exhibits a decrease in the surface current on exposure to ammonia gas.展开更多
基金Supported by the National Natural Science Foundation of China(No.20803058)the Basal Science Foundation of National Defense(No.B0920110005)+1 种基金the Science Program Foundation of Shaanxi Province,China(No.2011kjxx31)the Education Committee Foundation of Shaanxi Province,China(No.2010JK881)
文摘A new energetic material,4,5-dimethoxy-2-（dinitromethylene）imidazolidine（DMDNI）,was synthesized by the reaction of 4,5-dihydroxyl-2-（dinitromethylene）-imidazolidine（DDNI） and methanol,and structurally characterized by single crystal X-ray diffraction.DMDNI crystallized in triclinic space group P1,with crystal data a=0.4324（4） nm,b=1.3599（11） nm,c=1.7503（14） nm,α=77.406（14）°,β=84.494（15）°,γ=87.976（14）°,V=0.9997（14） nm 3,Z=4,μ=0.140 mm-1,F（000）=488,D c =1.556 g/cm ^3,R 1 =0.0773 and wR 2 =0.1574.Thermal decomposition of DMDNI was studied,and its thermal decomposition process was divided into two stages.The first stage was a melting process and the second stage was an exothermic decomposition process.The enthalpy,apparent activation energy and pre-exponential constant of the exothermic decomposition reaction are-491.5 J/g,142.3 kJ/mol and 10 14.24 s^-1,respectively.The critical temperature of thermal explosion is 162.47 °C.DMDNI has a lower thermal stability than DDNI but it is close to that of 4,5-diacetoxyl-2-（dinitromethylene）-imidazolidine（DADNI）.
文摘Poly(2,5-dimethoxyaniline) (PDMA) has been synthesized by chemical oxidative polymerization technique using varying ratio (wt/wt) of binary oxidants;ferric chloride (FeCl3) and ammonium persulfate (APS). Fourier transform infrared (FT-IR) and ultraviolet-visible (Uv-vis) spectroscopic investigations provide the evidence of the presence of both benzenoid and quinoid ring units. The thermal analysis and structural characterization data suggests that the oxidant ratio greatly controls the molecular ordering in PDMA. Surface morphology shows the existence of both amorphous and crystalline domains wherein the crystalline domain size depends on the oxidant ratio. The dc conductivity (σdc) of PDMA is also a function of binary oxidant ratio and at FeCl3:APS (50:50), it increases by two orders of magnitude. Films of PDMA synthesized using FeCl3:APS (50:50) binary oxidant exhibits a decrease in the surface current on exposure to ammonia gas.
