Based on the dynamic method,a quaternary system of ammonium polyphosphate (APP)-urea ammonium nitrate (UAN,CO(NH_(2))_(2)-NH_(4)NO_(3))-potassium chloride (KCl)-H_(2)O and its subsystems (APP-[CO(NH_(2))_(2)-NH_(4)NO_...Based on the dynamic method,a quaternary system of ammonium polyphosphate (APP)-urea ammonium nitrate (UAN,CO(NH_(2))_(2)-NH_(4)NO_(3))-potassium chloride (KCl)-H_(2)O and its subsystems (APP-[CO(NH_(2))_(2)-NH_(4)NO_(3)]-H_(2)O,KCl-[CO(NH_(2))_(2)-NH_(4)NO_(3)]-H_(2)O and APP-KCl-H_(2)O) were systematically investigated at the temperature of 273.2 K.Each ternary phase diagram contains one invariant point and three crystallization regions.The crystallization regions are:(1)(NH_(4))_(3)HP_(2)O_(7),(NH_(4))_(4)P_(2)O_(7)and ((NH_(4))_(3)HP_(2)O_(7)+(NH_(4))_(4)P_(2)O_(7)) for APP-[CO(NH_(2))_(2)-NH_(4)NO_(3)]-H_(2)O diagram;(2) KCl,KNO_(3)and(KCl+KNO_(3)) for KCl-[CO(NH_(2))_(2)-NH_(4)NO_(3)]-H_(2)O diagram and (3)(NH_(4))_(3)HP_(2)O_(7),KCl and((NH_(4))_(3)HP_(2)O_(7)+KCl) for APP-KCl-H_(2)O diagram.The quaternary phase diagram of APP-[CO(NH_(2))_(2)-NH_(4)NO_(3)]-KCl-H_(2)O has no quaternary invariant point but includes four solid phase crystallization regions,i.e.,(NH_(4))_(3)HP_(2)O_(7),(NH_(4))_(4)P_(2)O_(7),KNO_(3)and KCl,in which the KNO_(3)region occupies the largest area.The maximum total nutrient content (N+P_(2)O_(5)+K_(2)O) existing as ionic forms in the APP-[CO(NH_(2))_(2)-NH_(4)NO_(3)]-H_(2)O,KCl-[CO(NH_(2))_(2)-NH_(4)NO_(3)]-H_(2)O,APP-KCl-H_(2)O and quaternary systems is 44.70%,32.86%,45.56%and 46.23%(mass),respectively,indicating that the maximum nutrient content can be reached using raw materials of the corresponding systems to prepare liquid fertilizer.In the quaternary system,the content of NH_(4)~+-N ascends with the increase of the total nutrient content,while the contents of NO_(3)^(-)-N and CO(NH_(2))_(2)-N increase with elevated total N.This work can help optimize the operating parameters for the production,storage and transportation of liquid fertilizers.展开更多
2,4,5-Triarylimidazoles could be obtained in excellent yields by the one-pot three-component condensation of benzil/benzoin, aldehydes and ammonium acetate in the presence of catalytic amount of the inexpensive, readi...2,4,5-Triarylimidazoles could be obtained in excellent yields by the one-pot three-component condensation of benzil/benzoin, aldehydes and ammonium acetate in the presence of catalytic amount of the inexpensive, readily available and non-toxic ceric (IV) ammonium nitrate (CAN) in aqueous media under ultrasound at room temperature. In this reaction the products were obtained in short reaction time and easy operation under mild conditions.展开更多
The case study is about obtaining the flow rate and saturation temperature of steam that makes it possible to heat a solution of water and ammonia nitrate (<i>ANSOL</i>) in a shell and helical coil tube he...The case study is about obtaining the flow rate and saturation temperature of steam that makes it possible to heat a solution of water and ammonia nitrate (<i>ANSOL</i>) in a shell and helical coil tube heat exchanger, within a time interval, without that the crystallization of the <i>ANSOL</i> solution occurs. The desired production per batch of the solution is 5750 kg in 80 minutes. The analysis uses the concepts of efficiency and effectiveness to determine the heat transfer rate and temperature profiles that satisfy the imposed condition within a certain degree of safety and with the lowest possible cost in steam generation. Intermediate quantities necessary to reach the objective are the Reynolds number, Nusselt number, and global heat transfer coefficient for the shell and helical coil tube heat exchanger. Initially, the water is heated for a specified period and, subsequently, the ammonium nitrate is added to a given flow in a fixed mass flow rate.展开更多
To improve the performance of solid composite propellants(SCPs)supplemented with ammonium nitrate(AN)as an oxidizer,the incorporation of energetic ingredients such as explosives,energetic binders or catalysts is a com...To improve the performance of solid composite propellants(SCPs)supplemented with ammonium nitrate(AN)as an oxidizer,the incorporation of energetic ingredients such as explosives,energetic binders or catalysts is a common effective approach.For this purpose,polyurethane(PU),a typical inert binder,was mixed with nitrocellulose(NC)as an energetic polymer.Numerous composite solid propellant compositions based on AN and NC-modified polyurethane binder with different NC ratios were prepared.The prepared formulations were characterized using Fourier transform infrared spectroscopy(FTIR),RAMAN spectroscopy,X-ray diffraction(XRD),electron densimetry,thermogravimetric(TG)analysis,and differential scanning calorimetry(DSC).A kinetic study was then performed using the iterative KissingerAkahira-Sunose(It-KAS),Flynn-Wall-Ozawa(It-FWO),and non-linear Vyazovkin integral with compensation effect(VYA/CE)methods.The theoretical performances,such as theoretical specific impulse,adiabatic flame temperature,and ideal exhaust gaseous species,were also determined using the NASA Lewis Code,Chemical Equilibrium with Application(CEA).Spectroscopic examinations revealed the existence of NC and full polymerization of PU in the prepared propellants.According to density tests,the density of the propellant increases as the nitrocellulose component increases.According to the thermal analysis and kinetics study,the increase in NC content catalyzed the thermal decomposition of the AN-based composite solid propellants.Based on the theoretical study,increasing the amount of NC in the propellant increased the specific impulse and,as a result,the overall performance.展开更多
Regio and stereoselective synthesis of substituted dihydrofurans were accomplished by eeric ammonium nitrate mediated oxidative cycloaddition of 1,3-dicarbonyls to β-aryl-α,β-unsaturated ketones in moderate yields.
A new method for the cleavage of carbohydrate benzylidene acetal has been developed using Ceric (YV) ammonium nitrate (CAN) [(NH4)2Ce(NO3)6] in CH3CN-H2O (10/1, v/v).
The explosivity experiment of anti-explosive ammonium nitrate (AEAN) shows that the explosive characteristic of AEAN is eliminated. The adiabatic decompositions of ammonium nitrate and AEAN were investigated with an a...The explosivity experiment of anti-explosive ammonium nitrate (AEAN) shows that the explosive characteristic of AEAN is eliminated. The adiabatic decompositions of ammonium nitrate and AEAN were investigated with an accelerating rate calorimeter (ARC). The curves of thermal decomposition temperature and pressure versus time, self-heating rate and pressure versus temperature for two systems were obtained. The kinetic parameters such as apparent activation energy and pre-exponential factor were calculated. The safety of AEAN was analyzed. It was indicated that AEAN has a higher thermal stability than AN. At the same time, it can be shown that the elimination of its explosive characteristic is due to the improvement on the thermal stability of AEAN.展开更多
High levels of fine particulate matter(PM_(2.5))is linked to poor air quality and premature deaths,so haze pollution deserves the attention of the world.As abundant inorganic components in PM_(2.5),ammonium nitrate(NH...High levels of fine particulate matter(PM_(2.5))is linked to poor air quality and premature deaths,so haze pollution deserves the attention of the world.As abundant inorganic components in PM_(2.5),ammonium nitrate(NH_(4)NO_(3))formation includes two processes,the diffusion process(molecule of ammonia and nitric acid move from gas phase to liquid phase)and the ionization process(subsequent dissociation to form ions).In this study,we discuss the impact of meteorological factors,emission sources,and gaseous precursors on NH4NO3 formation based on thermodynamic theory,and identify the dominant factors during clean periods and haze periods.Results show that aerosol liquid water content has a more significant effect on ammonium nitrate formation regardless of the severity of pollution.The dust source is dominant emission source in clean periods;while a combination of coal combustion and vehicle exhaust sources is more important in haze periods.And the control of ammonia emission is more effective in reducing the formation of ammonium nitrate.The findings of this work inform the design of effective strategies to control particulate matter pollution.展开更多
A variety of aromatic, aliphatic and conjugated aldehydes and alcohols were transformed to the corresponding carboxylic acids and ketones with a quantitative conversion in high yields with 70% t-BuOOH solution in wate...A variety of aromatic, aliphatic and conjugated aldehydes and alcohols were transformed to the corresponding carboxylic acids and ketones with a quantitative conversion in high yields with 70% t-BuOOH solution in water in the presence of catalytic amounts of ceric ammonium nitrate [Ce(NH4)2(NO3)6] (CAN) under room temperature conditions. The scope of our catalytic system is applicable for a wide range of aromatic, conjugated and aliphatic substrates. These aldehydes were converted to the corresponding carboxylic acids in good isolated yields in reason- able times. This method possesses a wide range of capabilities since it can be used with other functional groups which may not tolerate oxidative conditions, involves fairly simple method for work-up, exhibits chemoselectivity and proceeds under ambient conditions. The resulting products are obtained in good yields within reasonable time.展开更多
A mixture of ammonium nitrate or nitro urea and silica sulfuric acid was found to be efficient and environmentally friendly nitrating media for the preparation of orto-nitro phenols in dichloromethane at room temperat...A mixture of ammonium nitrate or nitro urea and silica sulfuric acid was found to be efficient and environmentally friendly nitrating media for the preparation of orto-nitro phenols in dichloromethane at room temperature.展开更多
Ceric ammonium nitrate (CAN) supported HY-zeolite has been used as an efficient catalyst for the one- pot synthesis of 1,8-dioxo-octahydroxanthenes from the readily available 1,3-diketone and aromatic aldehydes unde...Ceric ammonium nitrate (CAN) supported HY-zeolite has been used as an efficient catalyst for the one- pot synthesis of 1,8-dioxo-octahydroxanthenes from the readily available 1,3-diketone and aromatic aldehydes under solvent-free conditions. The present methodology is cost-effective in addition to other advantages like high yields of products in shorter reaction time and simple workup procedure without the use of any injurious solvents.展开更多
Based on a study of the relationship of ammonium nitrate (AN) explosion and its thermal stability, inert agents were added to AN for eliminating the explosive characteristic of AN and in order to be irrestorable. Th...Based on a study of the relationship of ammonium nitrate (AN) explosion and its thermal stability, inert agents were added to AN for eliminating the explosive characteristic of AN and in order to be irrestorable. The results of using a large quantity of experiments and various testing technologies show that the improvement on thermal stability of modified AN is the basic reason for eliminating explosive characteristic of AN. The modification scheme was considered to have the following features: reliable and stable technology, market-demanded product, low investment and good economic returns. And during the revamping period, the normal production of AN will not be af- fected, and the economic, social and environmental benefits are good.展开更多
O-Alkylation of oximes with N-vinylpyrrolidin-2-one or N-methyl-N-vinylacetamide was efficiently initiated by a catalytic amount of cerium(Ⅳ) ammonium nitrate(CAN),giving the corresponding oxime ether derivatives...O-Alkylation of oximes with N-vinylpyrrolidin-2-one or N-methyl-N-vinylacetamide was efficiently initiated by a catalytic amount of cerium(Ⅳ) ammonium nitrate(CAN),giving the corresponding oxime ether derivatives in good yield.展开更多
The atmospheric nitric acid, ammonia and ammonium nitrate aerosol were determined simultaneously in a Beijing site to test the equilibrium prediction. Rather good agreement between measurements and theory was found at...The atmospheric nitric acid, ammonia and ammonium nitrate aerosol were determined simultaneously in a Beijing site to test the equilibrium prediction. Rather good agreement between measurements and theory was found at ambient temperature above 9℃ at relative humidity below 70%. Below 9 ℃ the kinetic constraints preventing rapid attainment equilibrium were observed. A procedure for calculation of dependence of NH_4NO_3 aerosol dissociation constants on temperature and relative humidity was given. The seasonal variation of concentrations of NH_3, total NH_4^+ and HNO_3 was observed. The seasonal variation of concentrations of HNO_3 was caused by dissociation of NH_4NO_3 aerosol. The concentrations of NH_3 were 1-2 order higher than those of HNO_3. For formation of NH_4NO_3 aerosol the HNO_3 was the control reagent. Any increase of HNO_3 formed from NO_x would react with NH_3 to form NH4NO_3 aerosol in Beijing area except for someday in summer time.展开更多
A numerical simulation model has been developed to investigate the diffusion and reaction in diffusion denuder for reactive gases and aerosols. The analytical equation for equilibrium and kinetic equations of NH 4NO ...A numerical simulation model has been developed to investigate the diffusion and reaction in diffusion denuder for reactive gases and aerosols. The analytical equation for equilibrium and kinetic equations of NH 4NO 3, NH 3 and HNO 3 system were presented. The model results of sampling efficiencies were agree with those calculated by Gormley Kennedy equation and other models. The evaporation of NH 4NO 3 aerosol has a kinetic constraint. The kinetic constant can be estimated from evaporation data. The model results showed that an annular denuder can separate reactive gases and aerosols.展开更多
6-Substituted 5,8-O-dimethyl-1,4-naphthoquinones(6-DMNQ),the promising anticancer scaffolds,were selectively generated by oxidative demethylation of 2-substituted 1,4,5,8-tetramethoxynaphthalenes with CAN in EtOAc/H...6-Substituted 5,8-O-dimethyl-1,4-naphthoquinones(6-DMNQ),the promising anticancer scaffolds,were selectively generated by oxidative demethylation of 2-substituted 1,4,5,8-tetramethoxynaphthalenes with CAN in EtOAc/H2O in comparatively high yields.An interesting finding was that apart from the reported electron-withdrawing effects of substituents on position 2 of naphthalene ring,regioselective synthesis of 6-DMNQ was largely dependent on the steric effects in CAN-mediated oxidation.The selective cytotoxicities of 6-DMNQ from the in vitro cell-based assays were exhibited between the cancer cells and normal cells.Moreover,most of sulfur-containing 6-DMNQ derivatives displayed better anticancer activities than the corresponding oxygen-containing ones,which could provide an available strategy for the design of 6-DMNQ derivatives as potential anticancer agents.展开更多
Can soil nitrate: ammonium ratios influence plant carbon: nitrogen ratios of the early succession plant? Can plant carbon: nitrogen ratios limit the plant growth in early succession? To address these two question...Can soil nitrate: ammonium ratios influence plant carbon: nitrogen ratios of the early succession plant? Can plant carbon: nitrogen ratios limit the plant growth in early succession? To address these two questions, we performed a two-factor (soil nitrate: ammonium ratio and plant density) randomized block design and a uniform-precision rotatable central composite design pot experiments to examine the relationships between soil nitrate: ammonium ratios, the carbon: nitrogen ratios and growth rate of Artemisia sphaerocephala seedlings. Under adequate nutrient status, both soil nitrate: ammonium ratios and plant density influenced the carbon: nitrogen ratios and growth rate of A. sphaerocephala seedlings. Under the lower soil nitrate: ammonium ratios, with the increase of soil nitrate: ammonium ratios, the growth rates of plant height and shoot biomass of A. sphaerocephala seedlings decreased significantly; with the increase of plant carbon: nitrogen ratios, the growth rates of shoot biomass of A. sphaerocephala seedlings decreased significantly. Soil nitrate: ammonium ratios affected the carbon: nitrogen ratios of A. sphaerocephala seedlings by plant nitrogen but not by plant carbon. Thus, soil nitrate: ammonium ratios influenced the carbon: nitrogen ratios of A. sphaerocephala seedlings, and hence influenced its growth rates. Our results suggest that under adequate nutrient environment, soil nitrate: ammonium ratios can be a limiting factor for the growth of the early succession plant.展开更多
With the strengthened controls on SO2 emissions and extensive increases in motor vehicles'exhaust,aerosol pollution shifts from sulfate-rich to nitrate-rich in recent years in Xi'an,China.To further gain insig...With the strengthened controls on SO2 emissions and extensive increases in motor vehicles'exhaust,aerosol pollution shifts from sulfate-rich to nitrate-rich in recent years in Xi'an,China.To further gain insights into the factors on nitrate formation and efficiently mitigate air pollution,highly time-resolved observations of water-soluble inorganic ions(WSIIs)in PM_(2.5) were measured in a suburban area of Xi'an,China during wintertime.Hourly concentration of total WSIIs is 39.8μg m-3 on average,accounting for 50.3%of PM_(2.5) mass.In contrast to a slight decrease in the mass fraction of SO_(4)^(2-),NO_(3)-shows a sig-nificant increase of the PM_(2.5) contribution with the aggravation of aerosol pollution.This suggests the importance of NO_(3)-formation to haze evolution.Furthermore,homogeneous reactions govern the formation of NO_(3)-,while alkali metals such as calcium and sodium play an additional role in retaining NO_(3)-in PM_(2.5) during clean periods.However,the heterogeneous hydrolysis reaction contributed more to NO_(3)-formation during the pollution periods under high relative humidity.Our investigation reveals that temperature,relative humidity,oxidant,and ammonia emissions facilitate rapid NO_(3)-formation.Using the random forest(RF)model,NO_(3)-concentrations were successfully simulated with measured variables for the training and testing datasets(R2>0.95).Among these variables,CO,NH_(3),and NO_(2) were found to be the main factors affecting the NO_(3)-concentrations.Compared with the period without vehicle re-striction,the contributions of NO_(3)-and NH4+to PM_(2.5) mass decreased by 5.3%and 3.4%in traffic re-striction periods,respectively.The vehicle restriction leads to the decreases of precursor gases of NO_(2),SO_(2),and NH_(3) by 12.8%,5.9%,and 27.6%,respectively.The results demonstrate collaborative emission reduction of NO_(x) and NH_(3) by vehicle restrictions,and using new energy vehicles(or electric vehicles)can effectively alleviate particulate matter pollution in northwest China.展开更多
Research and development of green oxidizers and green fuels as a possible replacement for ammonium perchlorate(NH4ClO4,AP) and hydrazine(N2H4) respectively has been increased considerably in the recent years.AP and hy...Research and development of green oxidizers and green fuels as a possible replacement for ammonium perchlorate(NH4ClO4,AP) and hydrazine(N2H4) respectively has been increased considerably in the recent years.AP and hydrazine are the oxidizer and fuel entities,and used in solid and liquid rocket motors respectively.AP is highly toxic and led to adverse health effects,while hydrazine is carcinogenic in nature.AP is in use from the last several decades for rocket and space shuttle propulsion,while hydrazine is used in upper stage liquid propelled rocket motors.It’s a tough task to replace AP with the currently available green oxidizers;since their ballistic properties are weaker when compared to AP and also they can’t be successfully deployed in a solid rocket motor at present Some important available solid green oxidizers are ammonium nitrate(AN),ammonium dinitramide(ADN),hydroxyl ammonium nitrate(HAN),and hydrazinium nitroformate(HNF).However,AN is one of the cheap and readily available oxidizer,and has great potential to use in solid/liquid rocket motors.Tremendous progress has been envisaged till now,and more progress will be there in the coming future over the development of AN based green energetic materials(GEM’s).A concise overview has been presented over the development of phase stabilized ammonium nitrate(PSAN) and AN/KDN based green oxidizers in the present review paper.展开更多
基金fund supported by the National Natural Science Foundation of China (32172677)。
文摘Based on the dynamic method,a quaternary system of ammonium polyphosphate (APP)-urea ammonium nitrate (UAN,CO(NH_(2))_(2)-NH_(4)NO_(3))-potassium chloride (KCl)-H_(2)O and its subsystems (APP-[CO(NH_(2))_(2)-NH_(4)NO_(3)]-H_(2)O,KCl-[CO(NH_(2))_(2)-NH_(4)NO_(3)]-H_(2)O and APP-KCl-H_(2)O) were systematically investigated at the temperature of 273.2 K.Each ternary phase diagram contains one invariant point and three crystallization regions.The crystallization regions are:(1)(NH_(4))_(3)HP_(2)O_(7),(NH_(4))_(4)P_(2)O_(7)and ((NH_(4))_(3)HP_(2)O_(7)+(NH_(4))_(4)P_(2)O_(7)) for APP-[CO(NH_(2))_(2)-NH_(4)NO_(3)]-H_(2)O diagram;(2) KCl,KNO_(3)and(KCl+KNO_(3)) for KCl-[CO(NH_(2))_(2)-NH_(4)NO_(3)]-H_(2)O diagram and (3)(NH_(4))_(3)HP_(2)O_(7),KCl and((NH_(4))_(3)HP_(2)O_(7)+KCl) for APP-KCl-H_(2)O diagram.The quaternary phase diagram of APP-[CO(NH_(2))_(2)-NH_(4)NO_(3)]-KCl-H_(2)O has no quaternary invariant point but includes four solid phase crystallization regions,i.e.,(NH_(4))_(3)HP_(2)O_(7),(NH_(4))_(4)P_(2)O_(7),KNO_(3)and KCl,in which the KNO_(3)region occupies the largest area.The maximum total nutrient content (N+P_(2)O_(5)+K_(2)O) existing as ionic forms in the APP-[CO(NH_(2))_(2)-NH_(4)NO_(3)]-H_(2)O,KCl-[CO(NH_(2))_(2)-NH_(4)NO_(3)]-H_(2)O,APP-KCl-H_(2)O and quaternary systems is 44.70%,32.86%,45.56%and 46.23%(mass),respectively,indicating that the maximum nutrient content can be reached using raw materials of the corresponding systems to prepare liquid fertilizer.In the quaternary system,the content of NH_(4)~+-N ascends with the increase of the total nutrient content,while the contents of NO_(3)^(-)-N and CO(NH_(2))_(2)-N increase with elevated total N.This work can help optimize the operating parameters for the production,storage and transportation of liquid fertilizers.
文摘2,4,5-Triarylimidazoles could be obtained in excellent yields by the one-pot three-component condensation of benzil/benzoin, aldehydes and ammonium acetate in the presence of catalytic amount of the inexpensive, readily available and non-toxic ceric (IV) ammonium nitrate (CAN) in aqueous media under ultrasound at room temperature. In this reaction the products were obtained in short reaction time and easy operation under mild conditions.
文摘The case study is about obtaining the flow rate and saturation temperature of steam that makes it possible to heat a solution of water and ammonia nitrate (<i>ANSOL</i>) in a shell and helical coil tube heat exchanger, within a time interval, without that the crystallization of the <i>ANSOL</i> solution occurs. The desired production per batch of the solution is 5750 kg in 80 minutes. The analysis uses the concepts of efficiency and effectiveness to determine the heat transfer rate and temperature profiles that satisfy the imposed condition within a certain degree of safety and with the lowest possible cost in steam generation. Intermediate quantities necessary to reach the objective are the Reynolds number, Nusselt number, and global heat transfer coefficient for the shell and helical coil tube heat exchanger. Initially, the water is heated for a specified period and, subsequently, the ammonium nitrate is added to a given flow in a fixed mass flow rate.
文摘To improve the performance of solid composite propellants(SCPs)supplemented with ammonium nitrate(AN)as an oxidizer,the incorporation of energetic ingredients such as explosives,energetic binders or catalysts is a common effective approach.For this purpose,polyurethane(PU),a typical inert binder,was mixed with nitrocellulose(NC)as an energetic polymer.Numerous composite solid propellant compositions based on AN and NC-modified polyurethane binder with different NC ratios were prepared.The prepared formulations were characterized using Fourier transform infrared spectroscopy(FTIR),RAMAN spectroscopy,X-ray diffraction(XRD),electron densimetry,thermogravimetric(TG)analysis,and differential scanning calorimetry(DSC).A kinetic study was then performed using the iterative KissingerAkahira-Sunose(It-KAS),Flynn-Wall-Ozawa(It-FWO),and non-linear Vyazovkin integral with compensation effect(VYA/CE)methods.The theoretical performances,such as theoretical specific impulse,adiabatic flame temperature,and ideal exhaust gaseous species,were also determined using the NASA Lewis Code,Chemical Equilibrium with Application(CEA).Spectroscopic examinations revealed the existence of NC and full polymerization of PU in the prepared propellants.According to density tests,the density of the propellant increases as the nitrocellulose component increases.According to the thermal analysis and kinetics study,the increase in NC content catalyzed the thermal decomposition of the AN-based composite solid propellants.Based on the theoretical study,increasing the amount of NC in the propellant increased the specific impulse and,as a result,the overall performance.
文摘Regio and stereoselective synthesis of substituted dihydrofurans were accomplished by eeric ammonium nitrate mediated oxidative cycloaddition of 1,3-dicarbonyls to β-aryl-α,β-unsaturated ketones in moderate yields.
文摘A new method for the cleavage of carbohydrate benzylidene acetal has been developed using Ceric (YV) ammonium nitrate (CAN) [(NH4)2Ce(NO3)6] in CH3CN-H2O (10/1, v/v).
文摘The explosivity experiment of anti-explosive ammonium nitrate (AEAN) shows that the explosive characteristic of AEAN is eliminated. The adiabatic decompositions of ammonium nitrate and AEAN were investigated with an accelerating rate calorimeter (ARC). The curves of thermal decomposition temperature and pressure versus time, self-heating rate and pressure versus temperature for two systems were obtained. The kinetic parameters such as apparent activation energy and pre-exponential factor were calculated. The safety of AEAN was analyzed. It was indicated that AEAN has a higher thermal stability than AN. At the same time, it can be shown that the elimination of its explosive characteristic is due to the improvement on the thermal stability of AEAN.
基金the National Natural Science Foundation of China(No.42077191)the Fundamental Research Funds for the Central Universities(Nos.63213072,63213074)+1 种基金the GDAS’Project of Science and Technology Development(No.2021GDASYL-20210103058)the Guangdong Basic and Applied Basic Research Foundation(No.2022A1515012165),The Blue Sky Foundation.
文摘High levels of fine particulate matter(PM_(2.5))is linked to poor air quality and premature deaths,so haze pollution deserves the attention of the world.As abundant inorganic components in PM_(2.5),ammonium nitrate(NH_(4)NO_(3))formation includes two processes,the diffusion process(molecule of ammonia and nitric acid move from gas phase to liquid phase)and the ionization process(subsequent dissociation to form ions).In this study,we discuss the impact of meteorological factors,emission sources,and gaseous precursors on NH4NO3 formation based on thermodynamic theory,and identify the dominant factors during clean periods and haze periods.Results show that aerosol liquid water content has a more significant effect on ammonium nitrate formation regardless of the severity of pollution.The dust source is dominant emission source in clean periods;while a combination of coal combustion and vehicle exhaust sources is more important in haze periods.And the control of ammonia emission is more effective in reducing the formation of ammonium nitrate.The findings of this work inform the design of effective strategies to control particulate matter pollution.
文摘A variety of aromatic, aliphatic and conjugated aldehydes and alcohols were transformed to the corresponding carboxylic acids and ketones with a quantitative conversion in high yields with 70% t-BuOOH solution in water in the presence of catalytic amounts of ceric ammonium nitrate [Ce(NH4)2(NO3)6] (CAN) under room temperature conditions. The scope of our catalytic system is applicable for a wide range of aromatic, conjugated and aliphatic substrates. These aldehydes were converted to the corresponding carboxylic acids in good isolated yields in reason- able times. This method possesses a wide range of capabilities since it can be used with other functional groups which may not tolerate oxidative conditions, involves fairly simple method for work-up, exhibits chemoselectivity and proceeds under ambient conditions. The resulting products are obtained in good yields within reasonable time.
文摘A mixture of ammonium nitrate or nitro urea and silica sulfuric acid was found to be efficient and environmentally friendly nitrating media for the preparation of orto-nitro phenols in dichloromethane at room temperature.
基金financial support received from Council of Scientific and Industrial Research(No.02(0025)/ 11/EMR-Ⅱ),New Delhi
文摘Ceric ammonium nitrate (CAN) supported HY-zeolite has been used as an efficient catalyst for the one- pot synthesis of 1,8-dioxo-octahydroxanthenes from the readily available 1,3-diketone and aromatic aldehydes under solvent-free conditions. The present methodology is cost-effective in addition to other advantages like high yields of products in shorter reaction time and simple workup procedure without the use of any injurious solvents.
基金Project supported by the National Natural Science Foundation of China (No. 50174008).
文摘Based on a study of the relationship of ammonium nitrate (AN) explosion and its thermal stability, inert agents were added to AN for eliminating the explosive characteristic of AN and in order to be irrestorable. The results of using a large quantity of experiments and various testing technologies show that the improvement on thermal stability of modified AN is the basic reason for eliminating explosive characteristic of AN. The modification scheme was considered to have the following features: reliable and stable technology, market-demanded product, low investment and good economic returns. And during the revamping period, the normal production of AN will not be af- fected, and the economic, social and environmental benefits are good.
基金Project 20572040 was supported by National Natural Science Foundation of China
文摘O-Alkylation of oximes with N-vinylpyrrolidin-2-one or N-methyl-N-vinylacetamide was efficiently initiated by a catalytic amount of cerium(Ⅳ) ammonium nitrate(CAN),giving the corresponding oxime ether derivatives in good yield.
文摘The atmospheric nitric acid, ammonia and ammonium nitrate aerosol were determined simultaneously in a Beijing site to test the equilibrium prediction. Rather good agreement between measurements and theory was found at ambient temperature above 9℃ at relative humidity below 70%. Below 9 ℃ the kinetic constraints preventing rapid attainment equilibrium were observed. A procedure for calculation of dependence of NH_4NO_3 aerosol dissociation constants on temperature and relative humidity was given. The seasonal variation of concentrations of NH_3, total NH_4^+ and HNO_3 was observed. The seasonal variation of concentrations of HNO_3 was caused by dissociation of NH_4NO_3 aerosol. The concentrations of NH_3 were 1-2 order higher than those of HNO_3. For formation of NH_4NO_3 aerosol the HNO_3 was the control reagent. Any increase of HNO_3 formed from NO_x would react with NH_3 to form NH4NO_3 aerosol in Beijing area except for someday in summer time.
文摘A numerical simulation model has been developed to investigate the diffusion and reaction in diffusion denuder for reactive gases and aerosols. The analytical equation for equilibrium and kinetic equations of NH 4NO 3, NH 3 and HNO 3 system were presented. The model results of sampling efficiencies were agree with those calculated by Gormley Kennedy equation and other models. The evaporation of NH 4NO 3 aerosol has a kinetic constraint. The kinetic constant can be estimated from evaporation data. The model results showed that an annular denuder can separate reactive gases and aerosols.
基金supported by National Natural Science Foundation of China(No.81373274)Ph.D.Programs Foundation of Ministry of Education China(No.20120073110068)Shanghai Biomedical Supporting Funding(No.15431900600)
文摘6-Substituted 5,8-O-dimethyl-1,4-naphthoquinones(6-DMNQ),the promising anticancer scaffolds,were selectively generated by oxidative demethylation of 2-substituted 1,4,5,8-tetramethoxynaphthalenes with CAN in EtOAc/H2O in comparatively high yields.An interesting finding was that apart from the reported electron-withdrawing effects of substituents on position 2 of naphthalene ring,regioselective synthesis of 6-DMNQ was largely dependent on the steric effects in CAN-mediated oxidation.The selective cytotoxicities of 6-DMNQ from the in vitro cell-based assays were exhibited between the cancer cells and normal cells.Moreover,most of sulfur-containing 6-DMNQ derivatives displayed better anticancer activities than the corresponding oxygen-containing ones,which could provide an available strategy for the design of 6-DMNQ derivatives as potential anticancer agents.
基金supported in part by the National Basic Research Program of China (2009CB421303)supported by National Natural Science Foundation of China (30970546)
文摘Can soil nitrate: ammonium ratios influence plant carbon: nitrogen ratios of the early succession plant? Can plant carbon: nitrogen ratios limit the plant growth in early succession? To address these two questions, we performed a two-factor (soil nitrate: ammonium ratio and plant density) randomized block design and a uniform-precision rotatable central composite design pot experiments to examine the relationships between soil nitrate: ammonium ratios, the carbon: nitrogen ratios and growth rate of Artemisia sphaerocephala seedlings. Under adequate nutrient status, both soil nitrate: ammonium ratios and plant density influenced the carbon: nitrogen ratios and growth rate of A. sphaerocephala seedlings. Under the lower soil nitrate: ammonium ratios, with the increase of soil nitrate: ammonium ratios, the growth rates of plant height and shoot biomass of A. sphaerocephala seedlings decreased significantly; with the increase of plant carbon: nitrogen ratios, the growth rates of shoot biomass of A. sphaerocephala seedlings decreased significantly. Soil nitrate: ammonium ratios affected the carbon: nitrogen ratios of A. sphaerocephala seedlings by plant nitrogen but not by plant carbon. Thus, soil nitrate: ammonium ratios influenced the carbon: nitrogen ratios of A. sphaerocephala seedlings, and hence influenced its growth rates. Our results suggest that under adequate nutrient environment, soil nitrate: ammonium ratios can be a limiting factor for the growth of the early succession plant.
基金supported by the West Light Foundation of the Chinese Academy of Sciences (grant No.XAB2021YN05)the National Natural Science Foundation of China (grant No.41503123)the National Atmospheric Research Program (grant No.2017YFC0212200).
文摘With the strengthened controls on SO2 emissions and extensive increases in motor vehicles'exhaust,aerosol pollution shifts from sulfate-rich to nitrate-rich in recent years in Xi'an,China.To further gain insights into the factors on nitrate formation and efficiently mitigate air pollution,highly time-resolved observations of water-soluble inorganic ions(WSIIs)in PM_(2.5) were measured in a suburban area of Xi'an,China during wintertime.Hourly concentration of total WSIIs is 39.8μg m-3 on average,accounting for 50.3%of PM_(2.5) mass.In contrast to a slight decrease in the mass fraction of SO_(4)^(2-),NO_(3)-shows a sig-nificant increase of the PM_(2.5) contribution with the aggravation of aerosol pollution.This suggests the importance of NO_(3)-formation to haze evolution.Furthermore,homogeneous reactions govern the formation of NO_(3)-,while alkali metals such as calcium and sodium play an additional role in retaining NO_(3)-in PM_(2.5) during clean periods.However,the heterogeneous hydrolysis reaction contributed more to NO_(3)-formation during the pollution periods under high relative humidity.Our investigation reveals that temperature,relative humidity,oxidant,and ammonia emissions facilitate rapid NO_(3)-formation.Using the random forest(RF)model,NO_(3)-concentrations were successfully simulated with measured variables for the training and testing datasets(R2>0.95).Among these variables,CO,NH_(3),and NO_(2) were found to be the main factors affecting the NO_(3)-concentrations.Compared with the period without vehicle re-striction,the contributions of NO_(3)-and NH4+to PM_(2.5) mass decreased by 5.3%and 3.4%in traffic re-striction periods,respectively.The vehicle restriction leads to the decreases of precursor gases of NO_(2),SO_(2),and NH_(3) by 12.8%,5.9%,and 27.6%,respectively.The results demonstrate collaborative emission reduction of NO_(x) and NH_(3) by vehicle restrictions,and using new energy vehicles(or electric vehicles)can effectively alleviate particulate matter pollution in northwest China.
文摘Research and development of green oxidizers and green fuels as a possible replacement for ammonium perchlorate(NH4ClO4,AP) and hydrazine(N2H4) respectively has been increased considerably in the recent years.AP and hydrazine are the oxidizer and fuel entities,and used in solid and liquid rocket motors respectively.AP is highly toxic and led to adverse health effects,while hydrazine is carcinogenic in nature.AP is in use from the last several decades for rocket and space shuttle propulsion,while hydrazine is used in upper stage liquid propelled rocket motors.It’s a tough task to replace AP with the currently available green oxidizers;since their ballistic properties are weaker when compared to AP and also they can’t be successfully deployed in a solid rocket motor at present Some important available solid green oxidizers are ammonium nitrate(AN),ammonium dinitramide(ADN),hydroxyl ammonium nitrate(HAN),and hydrazinium nitroformate(HNF).However,AN is one of the cheap and readily available oxidizer,and has great potential to use in solid/liquid rocket motors.Tremendous progress has been envisaged till now,and more progress will be there in the coming future over the development of AN based green energetic materials(GEM’s).A concise overview has been presented over the development of phase stabilized ammonium nitrate(PSAN) and AN/KDN based green oxidizers in the present review paper.