Theoretical investigation on action mechanism and mollifying efficacy of propellant stabilizers.

Context: This project performed quantum chemical computation, through kinetic and thermodynamic analyses to compare relative reactivity, reaction rate, and equilibrium composition from the possible pathways in connection with stabilizer-nitrodioxide reactions to determine the stability of the materials for practical application. Corresponding achievements have promoted the use of N-methyl-p-nitroaniline (MNA) and dinitrophenyl malonamide series (M3, M4, and M5) stabilizers as high priorities for selection.

Methods: The Gaussian 09 program (G09) (Frisch et al 2009) and density functional theory (DFT) calculations with the B3LYP/6-31G(d,p) function were performed to obtain related geometric and thermodynamic energy data for the molecular systems in this study.

Graphene Wrinkles affect electronic transport in nanocomposites: Insight from molecular dynamics simulations.

Molecular dynamics (MD) simulations were carried out to study the physical properties of graphene-oxide (GO) and polydimethylsiloxane (PDMS) interfacial systems. Simulations were performed for GO molecules dispersed into short-chain, long-chain, and long-chain and cross-linked PDMS polymers. Various structural properties, dipole moments and dielectric constants of the graphene-oxide molecules were calculated, which were correlated with the electron transport properties of the GO/PDMS system.

Chemisorption and kinetic mechanisms of elemental mercury on immobilized VO/TiO at low temperatures.

To investigate the effect of low temperature and catalyst filling pattern on the adsorption of Hg° by DeNOx equipment, the chemisorption and kinetic mechanisms of Hg° adsorption on 5-30%VO/TiO immobilized on glass beads at 100-160 °C were investigated. The effects of the reaction temperature, influent Hg° concentration, and VO doping amount on the adsorption efficiency and capacity for Hg° were explored. The active sites for Hg° adsorption were further identified.

Computer simulation for the study of the liquid chromatographic separation of explosive molecules.

The application of high performance liquid chromatography (HPLC) to separate explosive chemicals was investigated by molecular dynamics (MD) simulations. The explosive ingredients including NG, RDX, HMX and TNT were assigned as solutes, while methanol (CHOH) and acetonitrile (CHCN) were assigned as solvents in the solution system. The polymeric-molecular siloxanes (SiC8) and poly-1,2-methylenedioxy-4-propenyl benzene (PISAF) compounds were treated as stationary phase in the simulation.

Computational study of Simultaneous synthesis of optically active (RS)-1,2,4-butanetriol trinitrate (BTTN).

In respective water or ethanol polarizable continuum cavity environments, simultaneous aldol condensation was performed using density functional theory (DFT) computational method to model the synthesis of optically active (RS)-1,2,4-butanetriol trinitrate (BTTN). The results of reaction energy barrier analysis suggested feasible routes with lower activation energies to obtain either the (R)- or (S)-configuration product in ethanolic solution. In addition, local analysis of average inter-particulate distances of reaction species revealed that a stronger inter-particulate interaction accompanied a shorter average distance in the ethanol system.

Comparative simulation study of chemical synthesis of functional DADNE material.

Amorphous molecular simulation to model the reaction species in the synthesis of chemically inert and energetic 1,1-diamino-2,2-dinitroethene (DADNE) explosive material was performed in this work. Nitromethane was selected as the starting reactant to undergo halogenation, nitration, deprotonation, intermolecular condensation, and dehydration to produce the target DADNE product. The Materials Studio (MS) forcite program allowed fast energy calculations and reliable geometric optimization of all aqueous molecular reaction systems (0.

Comparative theoretical kinetics and thermodynamics study on high-energy insensitive explosive 1,1-diamino-2,2-dinitroethene synthesis.

Two synthesis methods were investigated in this study in order to explore feasible reaction pathways to obtain the target DADNE product: (1) the nitration of tetrahalogen ethene and (2) the reaction of acetamidine hydrochloride with dicarbonyl dichloride. Through theoretical simulation, the findings revealed that synthesis was possible, starting from acetamidine hydrochloride in a hydrated environment, followed by subsequent reaction routes via cyclization of the methoxy-substituted acetamidine anion intermediate with oxalyl chloride to form 2-methoxy-2-methyl-imidazolan-4,5-dione, acid-catalyzed synthesis of 2-methylene-imidazolan-4,5-dione, nitration using nitric acid to obtain 2-dinitromethylene-imidazolan-4,5-dione, and hydrolysis to produce 1,1-diamino-2,2-dinitroethene. A total energy of 1048.