In this work, comprehensive studies of 2,4-dinitroanisole(2,4DNAN) were carried out using powder thermorentgenography of the internal standard. The time of the complete polymorphic transition in the solid phase β→a ...In this work, comprehensive studies of 2,4-dinitroanisole(2,4DNAN) were carried out using powder thermorentgenography of the internal standard. The time of the complete polymorphic transition in the solid phase β→a in 2,4DNAN under various combinations of conditions has been determined. It has been established that, regardless of the season of manufacture of the substance, when it is stored for 8-9months, with a change in ambient temperature from minus 30℃ to plus 30℃, a complete polymorphic transition β→a occurs. When stored in conditions below minus 5℃, polymorphic transition does not occur. When stored in conditions above plus 30℃ in a closed container, polymorphic transition occurs within 3 weeks. The polymorphic transition is accompanied by a decrease in density by 1.3%-1.5% and an increase in melting temperature by 10-12℃, depending on the degree of purity of the starting substance. The activation energy of the molecular rearrangement was 68-70 k J/mol(16.5 ± 3 kcal/mol). The mechanism of polymorphic transition has been evaluated, which is presumably based on internal homodiffusion and energy transfer to the surface of the mass of powder particles and the product. The average activation energy of the polymorphic transition process was 110 ± 6.2 k J/mol(26.2 kcal/mol). In an open container, reactions proceed by a homogeneous mechanism, and in a closed container by a heterogeneous mechanism involving the gas phase.展开更多
2,4-Dinitroanisole(DNAN)is an important component of insensitive munitions that is anticipated to replace 2,4,6-trinitrotoluene(TNT)in munitions formulations.Photocatalyzed hydrogen peroxide(H2O2)oxidation experiments...2,4-Dinitroanisole(DNAN)is an important component of insensitive munitions that is anticipated to replace 2,4,6-trinitrotoluene(TNT)in munitions formulations.Photocatalyzed hydrogen peroxide(H2O2)oxidation experiments and chemical analyses were conducted to study the effect of initial pH and H2O2 dosage on the kinetics of DNAN decomposition and the reaction pathways.The results show that DNAN degradation followed zero-order kinetics when a 250 ppm DNAN solution was treated with ultraviolet(UV)light and 1500–4500 ppm H2O2 in an initial pH range of 4–7.However,when the H2O2 concentration was 750 ppm,DNAN degradation followed pseudo-first-order kinetics.The results indicate that DNAN can easily be oxidized by UV/H2O2 treatment.When the H2O2 dosage was 1500 ppm and the initial pH was 7,DNAN was reduced from 250 ppm to less than 1 ppm in 3 h.However,the total organic carbon(TOC)and total carbon(TC)concentrations were reduced slowly from 100 to less than 70 ppm carbon(C)in 3 h,and decreased to about 5 ppm after 9 h of treatment,suggesting the formation of other organic compounds.Those reaction intermediates were oxidized to carbon dioxide(CO2)at a slower rate than the oxidation of DNAN.CO2 was emitted from the solution because the solution pH decreased rapidly to about 3 during the UV/H2O2 oxidation.Most of the nitrogen in DNAN was converted to nitrate by UV/H2O2 oxidation after 9 h of treatment.The research results indicate that UV/H2O2 oxidation is a promising technique for the treatment of DNAN in wastewater.展开更多
2,4-dinitroanisole(DNAN)is a good replacement for 2,4,6-trinitrotoluene(TNT)in melt-cast explosives due to its superior insensitivity.With the increasing use of DNAN-based melt-cast explosives,the prediction of reacti...2,4-dinitroanisole(DNAN)is a good replacement for 2,4,6-trinitrotoluene(TNT)in melt-cast explosives due to its superior insensitivity.With the increasing use of DNAN-based melt-cast explosives,the prediction of reaction violence and hazard assessment of the explosives subjected to shock is of great significance.This study investigated the shock initiation characteristics for a DNAN-based melt-cast explosive,DHFA,using the one-dimensional Lagrangian apparatus.The embedded manganin gauges in the apparatus record the pressure histories at four Lagrangian positions and show that shock-todetonation transition in DHFA needs a high input shock pressure.The experimental data are analyzed to calibrate the Ignition and Growth model.The calibration is performed using an objective function based on both pressure history and the arrival time of shock.Good agreement between experimental and calculated pressure histories indicates the high accuracy of the calibrated parameters with the optimization method.展开更多
基金supported by the Ministry of Science and Higher Education of the Russian Federation(Agreement with Zelinsky Institute of Organic Chemistry RAS Grant No.075-15-2020-803).
文摘In this work, comprehensive studies of 2,4-dinitroanisole(2,4DNAN) were carried out using powder thermorentgenography of the internal standard. The time of the complete polymorphic transition in the solid phase β→a in 2,4DNAN under various combinations of conditions has been determined. It has been established that, regardless of the season of manufacture of the substance, when it is stored for 8-9months, with a change in ambient temperature from minus 30℃ to plus 30℃, a complete polymorphic transition β→a occurs. When stored in conditions below minus 5℃, polymorphic transition does not occur. When stored in conditions above plus 30℃ in a closed container, polymorphic transition occurs within 3 weeks. The polymorphic transition is accompanied by a decrease in density by 1.3%-1.5% and an increase in melting temperature by 10-12℃, depending on the degree of purity of the starting substance. The activation energy of the molecular rearrangement was 68-70 k J/mol(16.5 ± 3 kcal/mol). The mechanism of polymorphic transition has been evaluated, which is presumably based on internal homodiffusion and energy transfer to the surface of the mass of powder particles and the product. The average activation energy of the polymorphic transition process was 110 ± 6.2 k J/mol(26.2 kcal/mol). In an open container, reactions proceed by a homogeneous mechanism, and in a closed container by a heterogeneous mechanism involving the gas phase.
文摘2,4-Dinitroanisole(DNAN)is an important component of insensitive munitions that is anticipated to replace 2,4,6-trinitrotoluene(TNT)in munitions formulations.Photocatalyzed hydrogen peroxide(H2O2)oxidation experiments and chemical analyses were conducted to study the effect of initial pH and H2O2 dosage on the kinetics of DNAN decomposition and the reaction pathways.The results show that DNAN degradation followed zero-order kinetics when a 250 ppm DNAN solution was treated with ultraviolet(UV)light and 1500–4500 ppm H2O2 in an initial pH range of 4–7.However,when the H2O2 concentration was 750 ppm,DNAN degradation followed pseudo-first-order kinetics.The results indicate that DNAN can easily be oxidized by UV/H2O2 treatment.When the H2O2 dosage was 1500 ppm and the initial pH was 7,DNAN was reduced from 250 ppm to less than 1 ppm in 3 h.However,the total organic carbon(TOC)and total carbon(TC)concentrations were reduced slowly from 100 to less than 70 ppm carbon(C)in 3 h,and decreased to about 5 ppm after 9 h of treatment,suggesting the formation of other organic compounds.Those reaction intermediates were oxidized to carbon dioxide(CO2)at a slower rate than the oxidation of DNAN.CO2 was emitted from the solution because the solution pH decreased rapidly to about 3 during the UV/H2O2 oxidation.Most of the nitrogen in DNAN was converted to nitrate by UV/H2O2 oxidation after 9 h of treatment.The research results indicate that UV/H2O2 oxidation is a promising technique for the treatment of DNAN in wastewater.
基金Scientific Research Foundation for High-level Talents of Anhui University of Science and Technology(Grant No.2021yjrc38)Anhui Provincial Natural Science Foundation(Grant No.2208085QA27)+1 种基金National Natural Science Foundation of China(Grant Nos.11972046,12002266)the authors would like to thank these foundations for financial support.
文摘2,4-dinitroanisole(DNAN)is a good replacement for 2,4,6-trinitrotoluene(TNT)in melt-cast explosives due to its superior insensitivity.With the increasing use of DNAN-based melt-cast explosives,the prediction of reaction violence and hazard assessment of the explosives subjected to shock is of great significance.This study investigated the shock initiation characteristics for a DNAN-based melt-cast explosive,DHFA,using the one-dimensional Lagrangian apparatus.The embedded manganin gauges in the apparatus record the pressure histories at four Lagrangian positions and show that shock-todetonation transition in DHFA needs a high input shock pressure.The experimental data are analyzed to calibrate the Ignition and Growth model.The calibration is performed using an objective function based on both pressure history and the arrival time of shock.Good agreement between experimental and calculated pressure histories indicates the high accuracy of the calibrated parameters with the optimization method.
