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The U.S. Department of Defense (DOD) has increased the use of polymers due to their lightweight nature and high performance in composite materials, body armor, and military vehicles. Unfortunately, traditional polymers are petrole...
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The U.S. Department of Defense (DOD) has increased the use of polymers due to their lightweight nature and high performance in composite materials, body armor, and military vehicles. Unfortunately, traditional polymers are petroleum-derived, thus creating supply chain vulnerability. The DOD is looking to replace these petroleum-based polymers with less costly and more 'eco-friendly' alternatives. This research seeks to develop furan-based polymers as bio-based alternatives to nylon, Nomex, Kevlar, and other high- performance polyamides. U.S. Army Research Laboratory researchers have synthesized bio-/furan-based polyamides. Characterizations of these polymers are difficult because of their insolubility in most solvents. This work examines the use of potentiometric titration to measure the concentration of amine and carboxylic acid groups to enable measurement of the number-average molecular weight of these polymers. The method was established by conducting a series of sample titrations using the monomers and 1,6-hexamethylenediamine; succinic acid; 2,5-furandicarboxylic acid; and adipic acid (0.100 g) in various solvents.
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The paper gives results of experiments in a pilot-scale rotary kiln incinerator simulator, where a mixture of chlorinated and brominated surrogate waste was burned in the presence of injected fly-ash from a coal-fired utility boil...
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The paper gives results of experiments in a pilot-scale rotary kiln incinerator simulator, where a mixture of chlorinated and brominated surrogate waste was burned in the presence of injected fly-ash from a coal-fired utility boiler. Measurements were made of semivolatile products of incomplete combustion (PICs), polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/Fs) and mixed bromo-chloro dibenzo-p-dioxins and furans (PXDDs/Fs). The data have been analyzed statistically so that variability in the PCDDs/Fs can be accounted for by variation in the semivolatile PICs, particularly the chlorobenzenes (CBz) and chlorophenols (CPh). In addition, a statistical analysis was performed to investigate the variability of the PXDDs/Fs as a function of the concentrations of the semivolatile chlorinated, brominated, and mixed bromo-chloro organics.
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The production of light upon the electron transfer reaction of electrogenerated radical ions of tetraarylpyrroles (aryl = anisyl (TAP), phenyl (TPP), tolyl (TTP), p-chloro-phenyl (TCPP)), tetraphenylfuran (TPF), and tetraphenylthi...
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The production of light upon the electron transfer reaction of electrogenerated radical ions of tetraarylpyrroles (aryl = anisyl (TAP), phenyl (TPP), tolyl (TTP), p-chloro-phenyl (TCPP)), tetraphenylfuran (TPF), and tetraphenylthiophene (TPT) in systems containing these compounds alone in acetonitrile solutions or in mixed systems containing naphthalene, 2-5-diphenyl-1-3-4-oxadiazole, benzophenone, and tri-p-tolylamine is reported. Emission which corresponds to the fluorescence of the TAP, TPP, TTP, TPF, and TPT, as well as longer wavelength emission attributed to exciplex emission for some mixed systems, is observed. The singlet and triplet level energies of the compounds of interest are estimated and their cyclic voltammetric behavior described briefly. (Author)
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2,5-dialoxy-2,5-dihydrofurans can be prepared by conversion of furan with bromine in alkalonic solution at temperatures below -20 sup 0 C. The disadvantage of this synthesis is that very considerable quantities of bromine and auxi...
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2,5-dialoxy-2,5-dihydrofurans can be prepared by conversion of furan with bromine in alkalonic solution at temperatures below -20 sup 0 C. The disadvantage of this synthesis is that very considerable quantities of bromine and auxiliary bases are required which result in considerable waste water problems. The low temperatures required are also not very attractive from the technical point of view. These disadvantages can be overcome by preparing the 2,5-dialoxy-2,5-dihydrofurans by electrochemical oxidation of furan. A technically suitable method is described in DE-AS 27 10 420, but this method too requires furan as raw material which is expensive to handle safely. (ERA citation 12:004508)
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The reaction of methoxymethylsilylene (generated by pyrolysis of symtetramethoxydimethyldisilane) with 2,5-dimethylfuran yields 2-methoxy-2,3,6-trimethyl-1-oxo-2-silacyclohexa-3, t-diene and 2-methoxy-2,4,7-trimethyl-1, 3-dioxo-2-...
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The reaction of methoxymethylsilylene (generated by pyrolysis of symtetramethoxydimethyldisilane) with 2,5-dimethylfuran yields 2-methoxy-2,3,6-trimethyl-1-oxo-2-silacyclohexa-3, t-diene and 2-methoxy-2,4,7-trimethyl-1, 3-dioxo-2-silacyclohepta-4,6-diene. (Author)
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A radiochemical technique using 14C-labelled diethyl ether was used to prove that a chain transfer reaction to solvent occurs during the polymerisation of tetrahydrofuran by phosphorus pentafluoride. A mechanism to describe the ch...
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A radiochemical technique using 14C-labelled diethyl ether was used to prove that a chain transfer reaction to solvent occurs during the polymerisation of tetrahydrofuran by phosphorus pentafluoride. A mechanism to describe the chain transfer reaction was suggested. (Author)
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The report presents the results of testing, sampling and analysis of three resource recovery facilities burning municipal wastes for emissions of tetra chlorinated dioxins and furans in the flue gas. The stack emissions were analy...
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The report presents the results of testing, sampling and analysis of three resource recovery facilities burning municipal wastes for emissions of tetra chlorinated dioxins and furans in the flue gas. The stack emissions were analyzed by the EPA PTMAX dispersion model to determine maximum 1-hour ground level concentrations. A wide distribution of isomers were reported both for TCDDs and TCDFs. The most toxic 2378 TCDD isomer emissions from the stack ranged from 3.4 to 180 mg per ton of the fuel fired, while 2,378 TCDFs ranged from 22 to 1800 micrograms/ton.
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Heats of formation derived from the AM1 semiempirical method were used to determine the aromatic energies of the following systems: pyrimidine, pyridine, pyridazine, pyrazine, 1,2,4,5-tetraazine, phosphabenzene, 1,2- 1,3- 1,4-diph...
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Heats of formation derived from the AM1 semiempirical method were used to determine the aromatic energies of the following systems: pyrimidine, pyridine, pyridazine, pyrazine, 1,2,4,5-tetraazine, phosphabenzene, 1,2- 1,3- 1,4-diphosphabenzene, hexaazine, hexaphosphabenzene, silabenzene, thiophene, pyrrole, and furan. Two methods were employed for AE estimates. One used the heats of union of atomic pairs (with elimination of H2) of appropriate nonaromatic precursors. The other method used a comparison of the heats of hydrogenation of aromatic species to estimate the AE. Reprints. (aw)
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