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.
Quantum chemical theoretical computation was performed on gaseous molecular reaction systems to simulate parallel synthesis of energetic primary explosive precursor 4,6-dinitrobenzofuroxan (4,6-DNBF) and its isomeric derivatives. Related polarized continuum model (PCM) and Materials Studio (MS/forcite) energies were collected via kinetic rate and thermodynamic equilibrium analyses, enabling comparison of and suggestions as to suitable reaction conditions (reaction temperature, reagent concentration, mixed acid ratio) together with feasible pathways to obtain a high production yield of the research target. In summary, at a low reaction temperature of 278 K, 1.
View Article and Find Full Text PDFMolecular 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.
View Article and Find Full Text PDFThe 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.
View Article and Find Full Text PDFIn 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.
View Article and Find Full Text PDFAmorphous 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.
View Article and Find Full Text PDFTwo 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.
View Article and Find Full Text PDFThis study uses the Gaussian 03 program and density functional theory B3LYP with three basis set methods-[B3LYP/6-311+G(d,p), B3LYP/6-31+G(2d,p), and B3LYP/6-31G(d,p)]-to model the highly energetic ionic compound diguanidinium 5,5'-azotetrazolate (GZT) to research its decomposition mechanisms and thermodynamic properties. Molecular-type cracking patterns are proposed, which were initiated by heterocyclic ring opening, sequential cracking of the two five-membered rings of GZT, and simultaneous release of N2 molecules; whereas proton transfer, bond-breaking, and atomic rearrangements were performed subsequently. Finally, 15 reaction paths and five transition states were obtained.
View Article and Find Full Text PDFA test set of 65 hydrocarbons was examined to elucidate theoretically their thermodynamic properties by performing the density-functional theory (DFT) and ab initio calculations. All the calculated data were modified using a three-parameter calibration equation and the least-squares approach, to determine accurately enthalpies of formation (DeltaH(f)), entropies (S), and heat capacities (C(p)). Calculation results demonstrated that the atomization energies of all compounds exhibited an average absolute relative error ranging between 0.
View Article and Find Full Text PDFA three-parametric modification equation and the least-squares approach are adopted to calibrating hybrid density-functional theory energies of C(1)-C(10) straight-chain aldehydes, alcohols, and alkoxides to accurate enthalpies of formation DeltaH(f) and Gibbs free energies of formation DeltaG(f), respectively. All calculated energies of the C-H-O composite compounds were obtained based on B3LYP6-311++G(3df,2pd) single-point energies and the related thermal corrections of B3LYP6-31G(d,p) optimized geometries. This investigation revealed that all compounds had 0.
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