Reddy Damavarapu

Equilibrium and column adsorption studies of 2,4‐dinitroanisole (DNAN) on surface modified granular activated carbons

2,4‐Dinitroanisole (DNAN) is used as a component extensively in the development of insensitive munitions. This may result in release of DNAN into the environment. Here, the results are reported of a study on the removal characteristics of DNAN through adsorption on granular activated carbon (GAC), chitosan coated granular activated carbon (CGAC), acid treated granular activated carbon (AGAC) and alkali treated granular activated carbon (BGAC) under equilibrium and column flow conditions. The effect of pH, contact time, concentration of DNAN, and presence of electrolytes on the uptake of DNAN by the adsorbents was investigated. The equilibrium data were fitted to different types of adsorption isotherms. The data were further analysed on the basis of Lagergren first‐order, pseudo second‐order and intraparticle diffusion kinetic models. Breakthrough curves were obtained based on column flow results. All the adsorbents were capable of removing about 99% of DNAN from aqueous media, except CGAC which adsorbed about 87% of DNAN.

Nucleophilic Substitution Reactions of 1-Methyl-2,4,5-trinitroimidazole (MTNI)

Abstract Nucleophilic substitution reactions on 1-methyl-2,4,5-trinitroimidazole (MTNI) are described.

Nanoscale 2CL-20·HMX high explosive cocrystal synthesized by bead milling

Energetic nanoscale 2CL-20·HMX, a cocrystal of CL-20 and HMX in a 2u2006:u20061 molar ratio, was prepared by a novel method of bead milling an aqueous suspension of e-CL-20 and β-HMX. The conversion of the coformers to the cocrystal form was monitored by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis of specimens sampled at various milling times. Complete conversion to the cocrystal form was achieved by 60 minutes of milling. Rounded 2CL-20·HMX cocrystal particles with a mean size below 200 nm were produced. A mechanism for the conversion of the coformers to the cocrystalline form is postulated based on the experimental results. As an inherently safe manufacturing method, the aqueous bead milling process has great potential in advancing cocrystal research and applications in the field of energetic materials.

Physicochemical properties of an insensitive munitions compound, N-methyl-4-nitroaniline (MNA)

Accurate information on physicochemical properties of an organic contaminant is essential for predicting its environmental impact and fate. These properties also provide invaluable information for the overall understanding of environmental distribution, biotransformation, and potential treatment processes. In this study the aqueous solubility (Sw), octanol-water partition coefficient (Kow), and Henrys law constant (K(H)) were determined for an insensitive munitions (IM) compound, N-methyl-4-nitroaniline (MNA), at 298.15, 308.15, and 318.15 K. Effect of ionic strength on solubility, using electrolytes such as NaCl and CaCl2, was also studied. The data on the physicochemical parameters were correlated using the standard Vant Hoff equation. All three properties exhibited a linear relationship with reciprocal temperature. The enthalpy and entropy of phase transfer were derived from the experimental data.

Synthesis of azido heterocycles

Abstract Syntheses of azido derivatives of hexaazaisowurtzitane, triazine, and tetrazine heterocyclic compounds are described.

Physical Properties of Select Explosive Components for Assessing Their Fate and Transport in the Environment

Information on physical properties of munitions compounds is necessary for assessing their environmental distribution and transport, and predict potential hazards. This information is also needed for selection and design of successful physical, chemical or biological environmental remediation processes. This chapter summarizes physicochemical properties relevant to distribution of select explosive components in the three environmental matrices namely, soil, water and air. Physicochemical properties including melting point (MP), boiling point (BP), aqueous solubility (Sw), water-octanol partition coefficient (KOC), Henry’s law constant (KH), vapor pressure (VP) and enthalpy of vaporization (ΔH) obtained from literature using model predictions and experimental studies are listed for a total of 16 energetic compounds. The explosive compounds included are dinitroanisole (DNAN), n-methyl-p-nitroaniline (MNA), nitro-triazolone (NTO), triaminotrinitrobenzene (TATB), cyclotetramethylene-tetranitramine (HMX), cyclotrimethylene-trinitramine (RDX), trinitrotoluene (TNT), Chinalake-20 (CL-20), Diamino-Dinitroethylene (DADE), 1,3,3-Trinitroazetidine (TNAZ), Pentaerythritol tetranitrate (PETN), 2,4-Dinitrophenol (DNP), 1-Methyl-2,4,5-trinitroimidazole (MTNI), Triacetone Triperoxide (TATP), 2,4,6-trinitrophenyl-N-methylnitramine (TETRYL), and Bis (2,2,2-trinitroethyl)-3,6-diaminotetrazine (BTAT). The prediction models considered are limited to the EPI suite, SPARC and group contribution and COSMOtherm. Results of model predictions are compared with available experimental data. This chapter is not an exhaustive review of all available literature data.

Sensitive determination of nitrophenol isomers by reverse-phase high-performance liquid chromatography in conjunction with liquid–liquid extraction

ABSTRACT A method for the highly sensitive determination of 2-, 3- and 4-nitrophenols was developed using reverse-phase high-performance liquid chromatography (RP-HPLC) with a UV photodiode array detector. Using a reverse-phase column and 40% aqueous acetonitrile as an eluent (i.e. isocratic elution), the integrated peak area of detector output was linear up to 300 mg/L and the detection limit was 150 µg/L. The sensitivity of this detection method was improved by pretreating the sample solutions with a solvent extraction procedure that makes use of the high partition coefficient of ethyl acetate (EA)/water system. To find an optimum condition for the extraction procedure, this process was simulated by plotting the concentration of nitrophenol extracted in organic solvent against the volume multiplication factor at various partition coefficient of solute. This simulation demonstrated that EA is a superior extractant to other organic solvents. With the newly developed method, the detection limit was extended to 0.3 µg/L. This method offers fast, reliable and more sensitive determination of nitrophenol isomers than any other HPLC method.