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Title: Prediction of crystal densities of organic explosives by group additivity

Abstract

The molar volume of crystalline organic compound is assumed to be a linear combination of its constituent volumes. Compounds consisting only of the elements hydrogen, carbon, nitrogen, oxygen, and fluorine are considered. The constituent volumes are taken to be the volumes of atoms in particular bonding environments and are evaluated from a large set of crystallographic data. The predicted density has an expected error of about 3%. These results are applied to a large number of explosives compounds.

Authors:
Publication Date:
Research Org.:
Los Alamos National Lab., NM (USA)
OSTI Identifier:
6254123
Report Number(s):
LA-8920
ON: DE81032016
DOE Contract Number:
W-7405-ENG-36
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE; CHEMICAL EXPLOSIVES; DENSITY; CARBON; CHEMICAL BONDS; CRYSTAL STRUCTURE; CRYSTALLOGRAPHY; CRYSTALS; EXPERIMENTAL DATA; FLUORINE; HYDROGEN; NITROGEN; ORGANIC COMPOUNDS; OXYGEN; TABLES; THEORETICAL DATA; VOLUME; DATA; ELEMENTS; EXPLOSIVES; HALOGENS; INFORMATION; NONMETALS; NUMERICAL DATA; PHYSICAL PROPERTIES; 450100* - Military Technology, Weaponry, & National Defense- Chemical Explosions & Explosives

Citation Formats

Stine, J R. Prediction of crystal densities of organic explosives by group additivity. United States: N. p., 1981. Web. doi:10.2172/6254123.
Stine, J R. Prediction of crystal densities of organic explosives by group additivity. United States. doi:10.2172/6254123.
Stine, J R. Sat . "Prediction of crystal densities of organic explosives by group additivity". United States. doi:10.2172/6254123. https://www.osti.gov/servlets/purl/6254123.
@article{osti_6254123,
title = {Prediction of crystal densities of organic explosives by group additivity},
author = {Stine, J R},
abstractNote = {The molar volume of crystalline organic compound is assumed to be a linear combination of its constituent volumes. Compounds consisting only of the elements hydrogen, carbon, nitrogen, oxygen, and fluorine are considered. The constituent volumes are taken to be the volumes of atoms in particular bonding environments and are evaluated from a large set of crystallographic data. The predicted density has an expected error of about 3%. These results are applied to a large number of explosives compounds.},
doi = {10.2172/6254123},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Aug 01 00:00:00 EDT 1981},
month = {Sat Aug 01 00:00:00 EDT 1981}
}

Technical Report:

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  • Existing methods of density prediction, which primarily involve the summation of appropriate atomic or group volumes of parts of a molecule, yield what we call a ''normal'' density for a particular chemical composition. However, the compounds of most interest as military explosives often have densities significantly above the norm and predicted densities for memebers of this group frequently are substantially underestimated. A new procedure has been developed that allows a possible crystal packing arrangement for a molecular to be determined, from which a crystal density, usually accurate to within 2% can be calculated. The technique consists of three parts: determinationmore » of a reasonable three-dimensional molecular structure; determination of several possible crystal packing arrangements (crystal structures) for this molecular structure; refinement of the unit cell parametrs, molecular orientation and position for each of the potential crystal structures. The lowest energy arrangement from step (3) is used to calculate the crystal density. The crystal densities predicted for both bicyclo-HMX and octanitrocubane are loser than those obtained from additivity methods. This result should be considered when establishing properties for further atempts to synthesize these currently unknown compounds. 15 refs., 5 figs., 10 tabs.« less
  • Conversion of Additional Programs to CRAY Vector Supercomputers and Program Enhancements, MRD-CI Calculations for the Propagation Step in Cationic Polymerization of Energetic Oxetanes, NMR Spectra of Oxetanes, Ab-Initio Atom-Class - Class Potential Functions and Independent Confirmations of the Validity of Our Ab-Initio MODPOT/VRDDO Energy Partitioned Method For Intermolecular Interactions, Geometry Optimization at the MC-SCF/CI Level, POLY-CRYST. The author developed and implemented a new approach based on localized occupied and virtual orbitals in the interaction region with the remainder of the localized molecular orbitals being folded into an effective CI. Hamiltonian. This method is completely general and applicable to reactions andmore » molecular decompositions of energetic compounds for ground and electronically excited states. We initiated a major research effort on ab-initio MRD-CI calculations on opening the ring of oxetane or protonated oxetane and on the opening of the protonated oxetane ring in the course of interaction with oxetane. We have carried out MRD-CI calculations for a great many geometries for various paths of attack for the system oxetane plus protonated oxetane ring (ring 'A') varied the internuclear distance between the rings and the angle between the plane of the oxetane (ring 'B') and the plane of the protonated oxetane ring.« less
  • Calculated equilibria in the biphenyl/ phenylcyclohexane/bicyclohexane/ hydrogen system are presented and compared with experimental values reported in the literature. Gibbs energies of formation were estimated for phenylcyclohexane and bicyclohexane using group-additivities. The results were combined with values for biphenyl obtained from experimental thermodynamics to calculate the equilibria in the system. Under thermodynamic equilibrium conditions the maximum concentration of phenylcyclohexane obtainable is approximately 60 mole per cent. As the temperature is increased this maximum concentration can only be obtained by a corresponding increase in hydrogen pressure. In a given temperature regime, too high a hydrogen pressure will facilitate the formation ofmore » the fully saturated compound, bicyclohexane, and too low a hydrogen pressure the formation of biphenyl. Equilibrium conditions for the generation of hydroaromatics have been defined. Hydrogen transfer from a donor molecule (here tetralin) to an aromatic acceptor (here biphenyl) is favored by low temperature and a large excess of the donor over the acceptor. The report concludes that an order of magnitude improvement in the additivity methodology (increase in the accuracy and precision of the group-contribution term parameters) is required to enable meaningful calculation of the conditions under which thermodynamic equilibria exist in the hydrogenation of multi-ring aromatic systems. 27 refs., 6 figs., 6 tabs.« less
  • A method is presented for calculating densities of solid or liquid fuels and explosives from additive molar volume atomic and structural increments. Selected examples of calculated densities are presented in tabular form; these agree with observed values with a mean error of less than + or - 5%. Structural parameters affecting density are presented. The scope and limitations of density calculations are discussed including structural features contributing to deviations from the additive scheme. (Author) (GRA)
  • Four mathematical models of the equation of state for LNG like mixtures are presented. The four models include an extended corresponding states model, a cell model, a hard sphere model and a revised Klosek and McKinley model. Each of the models has been optimized to the same experimental data set which included data for pure nitrogen, methane, ethane, propane, iso and normal butane, iso and normal pentane and mixtures thereof. For LNG like mixtures (mixtures of the orthobaric liquid state at temperatures of 120 K or less and containing at least 60% methane, less than 4% nitrogen, less than 4%more » each of iso and normal butane and less than 2% total of iso and normal pentane), all of the models are estimated to predict densities to within 0.1% of the true value. The revised Klosek and McKinley model is valid only for mixtures within the range of temperature and composition specified above while the other three models are valid for a broader range of pressure, temperature and composition. The experimental PVTx data set used in the optimization together with comparisons are given and listings of computer programs for each of the models are included.« less