In order to remove hexahydro-1,3,5-trinitro-1,3,5-triazine(RDX),the main impurity,in process of polymorphic transformation of octrahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine(HMX),the solubility ofβ-HMX and RDX in a...In order to remove hexahydro-1,3,5-trinitro-1,3,5-triazine(RDX),the main impurity,in process of polymorphic transformation of octrahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine(HMX),the solubility ofβ-HMX and RDX in acetonitrile(ACN)+water in the temperature range of 288.15-333.15 K and in nitric acid(HNO_(3))+water in the temperature range of 298.15-333.15 K were measured by laser dynamic method.The results showed that the solubility of bothβ-HMX and RDX in binary mixed solvents increased monotonously as the temperature increase at a given solvent composition or with increasing of mole fraction of solvent(ACN and nitric acid).Solubility data were well correlated by the modified Apelblat equation,Jouyban-Acree model,Yaws equation and van't Hoff equation,and the Yaws equation achieved the best fitting results according to the relative error and the mean square error root.Furthermore,the solubility ofβ-HMX and RDX in binary mixed solvent was compared,based on the solubility difference and the solvent's own properties,the best separation degree ofβ-HMX and RDX was found when the mole fraction of nitric acid was 0.22 at room temperature,which provided data support for HMX crystallization in mixed solvent.The solubility differences between RDX andβ-HMX in mixed solvents were explained from the formation of intermolecular and intramolecular hydrogen bonds.展开更多
The Disc Acceleration e Xperiment(DAX)is one of the most recent experimental methods of performance characterization of new energetic materials.A cylindrical explosive charge accelerates a thin metallic disc and its v...The Disc Acceleration e Xperiment(DAX)is one of the most recent experimental methods of performance characterization of new energetic materials.A cylindrical explosive charge accelerates a thin metallic disc and its velocity is measured continuously using photonic Doppler velocimetry.The detonation velocity is measured simultaneously.The DAX test can be used to obtain the Chapman-Jouguet(CJ)detonation pressure and to describe detonation products expansion using reduced amount of explosive.A series of DAX tests was performed at various charge diameters and disc thicknesses with Semtex 1 A plastic bonded explosive and sensitized nitromethane.The DAX-like evaluation was also applied to previously measured data of Semtex 1A and A-IX-1 explosives.The optimum disc thickness is determined by the disc to explosive mass ratio of 0.01-0.08.The repeatability of the Semtex 1 A detonation pressure results is about four times lower compared to the pressed and liquid explosives.展开更多
为研究螺杆泵送和中深孔装药时伴随的高压作用对现场混装乳化炸药基质微观结构和热稳定性的影响,采用光学显微镜、激光粒度仪、水溶性实验、热重与微商热重联用技术、Kissinger法和Ozawa法、Coats-Redfern法和?atava法,对常压、高压环...为研究螺杆泵送和中深孔装药时伴随的高压作用对现场混装乳化炸药基质微观结构和热稳定性的影响,采用光学显微镜、激光粒度仪、水溶性实验、热重与微商热重联用技术、Kissinger法和Ozawa法、Coats-Redfern法和?atava法,对常压、高压环境下基质的微观结构、粒径分布、析晶含量、热分解过程、热分解反应活化能、热分解机理函数和速率方程进行了研究。结果表明,从常压到高压,基质内相液滴出现聚合、破乳、析晶现象,粒径由3.717μm增大为4.474μm,硝酸铵晶体的析出量由0.0530 g增大为0.0640 g,乳液体系均一性减弱;基质的平均热分解起始温度T_(onset)由157.4℃升高为184.0℃,平均一阶微商热重峰温T_(p)由262.6℃升高为281.8℃,平均质量损失平均速率由0.1454%·s^(-1)升高为0.1476%·s^(-1),反应活化能由108.49 k J·mol^(-1)降低为84.74 k J·mol^(-1),高压下蒸发破乳释放的游离水可能造成了T_(onset)与T_(p)上升,热分解反应更容易发生;Ozawa法计算的活化能随着转化率增大的变化趋势不同,热分解反应的机理函数从Valensi方程变为反Jander方程,其速率方程也发生了变化。高压作用促进了基质内相液滴聚合、破乳、析晶过程,降低了热分解反应发生的活化能,减弱了体系均一性、热稳定性。展开更多
The Marplex Convention was established to prevent the manufacture of unmarked plastic explosives and stipulates that a volatile detection agent must be added at the time of manufacture.However,to-date,laboratory testi...The Marplex Convention was established to prevent the manufacture of unmarked plastic explosives and stipulates that a volatile detection agent must be added at the time of manufacture.However,to-date,laboratory testing remains the internationally accepted practice for identifying and quantifying the taggants stipulated in the Convention.In this project,portable FTIR and Raman instruments were tested for their ability to detect 2,3-dimethyl-2,3-dinitrobutane(DMDNB),the chemical marker incorporated in plastic explosives that are manufactured within Australia.While both FTIR and Raman instruments detected solid DMDNB(98%purity),field analysis of plastic explosives at an Australian Defence establishment showed that both FTIR and Raman spectra were matched the relevant explosive(RDX or PETN),rather than the DMDNB taggant.For all three plastic explosives tested,the concentration of DMDNB was measured by SPME-GC-MS to be between 1.8 and 2%,greater than the minimum 1%concentration stipulated by the Marplex Convention.Additional testing with a plastic explosive analogue confirmed that the minor absorption peaks that would characterize low concentrations of DMDNB were masked by absorption bands from other compounds within the solid.Thus,while both FTIR and Raman spectroscopy are suitable for detection of plastic explosives,neither rely on the presence of DMDNB for detection.It is likely that similar results would be found for other taggants stipulated by the Marplex Convention,given they are also present in concentrations less than 1%.展开更多
The successful synthesis of the pentazolate anion(cyclo-N-5)has been a great breakthrough in the field of energetic materials.However,the detection methods for these energetic materials based on the pentazolate anion ...The successful synthesis of the pentazolate anion(cyclo-N-5)has been a great breakthrough in the field of energetic materials.However,the detection methods for these energetic materials based on the pentazolate anion are quite rare.Herein,two fluorescent probes for cyclo-N-5anion were designed.Sensor 1(TPE2N)was synthesized with a tetraphenylethylene functionalized by two cationic groups which can generate strong electrostatic interactions with pentazolate anion and result in specific fluorescent changes.Sensor 2 was designed based on sensor 1 and supramolecular cucurbit[7]uril(CB[7]).The unique structural features of CB[7]provide sites for the interaction between the cations and N-5anion in its cavity,which would generate a platform for the detection and enhance the recognition performance.Isothermal titration calorimetry(ITC)experiment and fluorescence titration experiment indicate the binding molar ratio between sensor 1 with CB[7]is 1:2.Both sensors display typical aggregation-induced emission(AIE)features and good water-solubility.The sensors demonstrate excellent sensitivity to pentazole hydrazine salt with high enhancement constant(sensor 1:1.34×10^(6);sensor 2:3.78×10^(6))and low limit of detection(LOD:sensor 1=4.33μM;sensor 2=1.54μM).The formation of an AIE-based supramolecular sensor effectively improves the sensitivity to N-5anion.In addition,the probes also have good selectivity of N-5anion salts.The research would shed some light on the design of novel fluorescent sensors to detect pentazolate-based molecules and provides an example of supramolecular chemistry combined with fluorescent probes.展开更多
文摘In order to remove hexahydro-1,3,5-trinitro-1,3,5-triazine(RDX),the main impurity,in process of polymorphic transformation of octrahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine(HMX),the solubility ofβ-HMX and RDX in acetonitrile(ACN)+water in the temperature range of 288.15-333.15 K and in nitric acid(HNO_(3))+water in the temperature range of 298.15-333.15 K were measured by laser dynamic method.The results showed that the solubility of bothβ-HMX and RDX in binary mixed solvents increased monotonously as the temperature increase at a given solvent composition or with increasing of mole fraction of solvent(ACN and nitric acid).Solubility data were well correlated by the modified Apelblat equation,Jouyban-Acree model,Yaws equation and van't Hoff equation,and the Yaws equation achieved the best fitting results according to the relative error and the mean square error root.Furthermore,the solubility ofβ-HMX and RDX in binary mixed solvent was compared,based on the solubility difference and the solvent's own properties,the best separation degree ofβ-HMX and RDX was found when the mole fraction of nitric acid was 0.22 at room temperature,which provided data support for HMX crystallization in mixed solvent.The solubility differences between RDX andβ-HMX in mixed solvents were explained from the formation of intermolecular and intramolecular hydrogen bonds.
文摘The Disc Acceleration e Xperiment(DAX)is one of the most recent experimental methods of performance characterization of new energetic materials.A cylindrical explosive charge accelerates a thin metallic disc and its velocity is measured continuously using photonic Doppler velocimetry.The detonation velocity is measured simultaneously.The DAX test can be used to obtain the Chapman-Jouguet(CJ)detonation pressure and to describe detonation products expansion using reduced amount of explosive.A series of DAX tests was performed at various charge diameters and disc thicknesses with Semtex 1 A plastic bonded explosive and sensitized nitromethane.The DAX-like evaluation was also applied to previously measured data of Semtex 1A and A-IX-1 explosives.The optimum disc thickness is determined by the disc to explosive mass ratio of 0.01-0.08.The repeatability of the Semtex 1 A detonation pressure results is about four times lower compared to the pressed and liquid explosives.
文摘为研究螺杆泵送和中深孔装药时伴随的高压作用对现场混装乳化炸药基质微观结构和热稳定性的影响,采用光学显微镜、激光粒度仪、水溶性实验、热重与微商热重联用技术、Kissinger法和Ozawa法、Coats-Redfern法和?atava法,对常压、高压环境下基质的微观结构、粒径分布、析晶含量、热分解过程、热分解反应活化能、热分解机理函数和速率方程进行了研究。结果表明,从常压到高压,基质内相液滴出现聚合、破乳、析晶现象,粒径由3.717μm增大为4.474μm,硝酸铵晶体的析出量由0.0530 g增大为0.0640 g,乳液体系均一性减弱;基质的平均热分解起始温度T_(onset)由157.4℃升高为184.0℃,平均一阶微商热重峰温T_(p)由262.6℃升高为281.8℃,平均质量损失平均速率由0.1454%·s^(-1)升高为0.1476%·s^(-1),反应活化能由108.49 k J·mol^(-1)降低为84.74 k J·mol^(-1),高压下蒸发破乳释放的游离水可能造成了T_(onset)与T_(p)上升,热分解反应更容易发生;Ozawa法计算的活化能随着转化率增大的变化趋势不同,热分解反应的机理函数从Valensi方程变为反Jander方程,其速率方程也发生了变化。高压作用促进了基质内相液滴聚合、破乳、析晶过程,降低了热分解反应发生的活化能,减弱了体系均一性、热稳定性。
基金funded by the Defence Science Technology Group(DSTG)。
文摘The Marplex Convention was established to prevent the manufacture of unmarked plastic explosives and stipulates that a volatile detection agent must be added at the time of manufacture.However,to-date,laboratory testing remains the internationally accepted practice for identifying and quantifying the taggants stipulated in the Convention.In this project,portable FTIR and Raman instruments were tested for their ability to detect 2,3-dimethyl-2,3-dinitrobutane(DMDNB),the chemical marker incorporated in plastic explosives that are manufactured within Australia.While both FTIR and Raman instruments detected solid DMDNB(98%purity),field analysis of plastic explosives at an Australian Defence establishment showed that both FTIR and Raman spectra were matched the relevant explosive(RDX or PETN),rather than the DMDNB taggant.For all three plastic explosives tested,the concentration of DMDNB was measured by SPME-GC-MS to be between 1.8 and 2%,greater than the minimum 1%concentration stipulated by the Marplex Convention.Additional testing with a plastic explosive analogue confirmed that the minor absorption peaks that would characterize low concentrations of DMDNB were masked by absorption bands from other compounds within the solid.Thus,while both FTIR and Raman spectroscopy are suitable for detection of plastic explosives,neither rely on the presence of DMDNB for detection.It is likely that similar results would be found for other taggants stipulated by the Marplex Convention,given they are also present in concentrations less than 1%.
基金supported by the National Natural Science Foundation of China(Grant Nos.22175093 and 22007047)the Natural Science Foundation of Jiangsu Province(Grant No.BK20200474)the China Postdoctoral Science Foundation(Grant No.2022M721615)。
文摘The successful synthesis of the pentazolate anion(cyclo-N-5)has been a great breakthrough in the field of energetic materials.However,the detection methods for these energetic materials based on the pentazolate anion are quite rare.Herein,two fluorescent probes for cyclo-N-5anion were designed.Sensor 1(TPE2N)was synthesized with a tetraphenylethylene functionalized by two cationic groups which can generate strong electrostatic interactions with pentazolate anion and result in specific fluorescent changes.Sensor 2 was designed based on sensor 1 and supramolecular cucurbit[7]uril(CB[7]).The unique structural features of CB[7]provide sites for the interaction between the cations and N-5anion in its cavity,which would generate a platform for the detection and enhance the recognition performance.Isothermal titration calorimetry(ITC)experiment and fluorescence titration experiment indicate the binding molar ratio between sensor 1 with CB[7]is 1:2.Both sensors display typical aggregation-induced emission(AIE)features and good water-solubility.The sensors demonstrate excellent sensitivity to pentazole hydrazine salt with high enhancement constant(sensor 1:1.34×10^(6);sensor 2:3.78×10^(6))and low limit of detection(LOD:sensor 1=4.33μM;sensor 2=1.54μM).The formation of an AIE-based supramolecular sensor effectively improves the sensitivity to N-5anion.In addition,the probes also have good selectivity of N-5anion salts.The research would shed some light on the design of novel fluorescent sensors to detect pentazolate-based molecules and provides an example of supramolecular chemistry combined with fluorescent probes.
