Papers by Bogdan Dlugogorski
Catalysis Surveys from Asia, 2006
The purpose of this review article is to provide readers with an account of CFC and halon treatme... more The purpose of this review article is to provide readers with an account of CFC and halon treatment technologies as depicted in the patent and open literature. Destruction technologies, in which halons and CFCs are converted into species such as CO 2 , HX or X 2 (X = Br, Cl, F), are treated less extensively. Emphasis has been placed on conversion processes, which aim at transforming (rather than destroying) CFC or halon into environmentally benign and useful products. It has been found that catalytic hydrodehalogenation over transition metal based catalysts, Pd in particular, has great potential for conversion of CFCs and halons to hydrofluorocarbons. In this regard, the focus of this review is on catalytic hydrodehalogenation, including an assessment of reaction mechanisms, catalytic activity, selectivity and durability.
Ind Eng Chem Res, 2005
Hydrodehalogenation of CBrClF 2 , CCl 2 F 2 , CHClF 2 , and CH 2 F 2 with hydrogen has been studi... more Hydrodehalogenation of CBrClF 2 , CCl 2 F 2 , CHClF 2 , and CH 2 F 2 with hydrogen has been studied in the gas phase and over supported Pd catalysts in a tubular alumina reactor. During gas-phase reactions, selectivity to CH 2 F 2 is low for the hydrodehalogenation of CBrClF ...
ABSTRACT In this study, the decomposition of methane in a nonequilibrium plasma, where nitrogen a... more ABSTRACT In this study, the decomposition of methane in a nonequilibrium plasma, where nitrogen and oxygen were excluded from the feed mixture, was investigated. The major product species formed under conditions where the conversion level of methane was relatively high (up to 50 %) were determined. Hydrogen, acetylene, ethylene, ethane and propane were the primary gaseous species identified, and a liquid fraction was detected, which was characterised by 1H NMR and gel permeation chromatography. The product spectrum formed in the nonequilibrium plasma is compared to the species profile predicted from methane pyrolysis, where the feed composition, residence time and methane conversion levels used in the high temperature pyrolysis simulation matched those in the nonequilibrium plasma experimental reactor.
Altarawneh M and Dlugogorski B Z Formation of Dibenzofuran Dibenzo P Dioxin and Their Hydroxylated Derivatives from Catechol Physical Chemistry Chemical Physics 17 Pp 1822 1830, 2015
We present, in this study, mechanistic and kinetic accounts of the formation of dibenzofuran (DF)... more We present, in this study, mechanistic and kinetic accounts of the formation of dibenzofuran (DF), dibenzo-p-dioxin (DD) and their hydroxylated derivatives (OHs-DF/OHs-DD) from the catechol (CT) molecule, as a model compound for phenolic constituents in biomass. Self-condensation of two CT molecules produces predominantly a DD molecule via open- and closed-shell corridors. Coupling modes involving the o-semiquinone radical and the CT molecule (o-SQ/CT) generate two direct structural blocks for the formation of OHs-DF/OHs-DD structures, ether-type intermediates and di-keto moieties. The calculated reaction rate constants indicate that the fate of ether-type intermediates is to make hydroxylated diphenyl ethers rather than to undergo cyclisation reactions leading to the formation of preDF structures. Unimolecular loss of a H or OH moiety from a pivotal carbon in these hydroxylated diphenyl ethers then produces hydroxylated and non-hydroxylated DD molecules. Formation of OHs-DF initiated by o(C)-o(C) cross-linkages involving o-SQ/o-SQ and o-SQ/CT reactions incurs very similar reaction and activation enthalpies encountered in the formation of chlorinated DFs from chlorophenols.
Altarawneh M and Dlugogorski B Z Mechanisms For Formation of Pollutants in Fires in Proceeding of the Seventh International Seminar on Fire and Explosion Hazards 5 10 May Providence Ri Usa Pp 27 36, 2013
ABSTRACT This paper examines the effect of methane on the reaction of 1, 2-dichloroethane in a no... more ABSTRACT This paper examines the effect of methane on the reaction of 1, 2-dichloroethane in a non-thermal plasma in a double dielectric barrier discharge (DBD) reactor, under non oxidative conditions and at atmospheric pressure. Commercially important products such as vinyl chloride and polyvinyl chloride were produced. The addition of CH4 to the feed stream reduces the concentration of unsaturation in the polymeric material.
Industrial Engineering Chemistry Research, 1992
The initiation rate equation is obtained from the dimensionless form of eq A57. bD31'2CCo3+CArCHO... more The initiation rate equation is obtained from the dimensionless form of eq A57. bD31'2CCo3+CArCHO(s) ki Ri = (A60) rP k2'I2 Registry No. Benzaldehyde, 100-52-7; perbenzoic acid, 93-59-4. Literature Cited Bawn, C. E. H. Freeradical Reaction in Solution Initiated by Heavy Metal Ion. Discuss. Faraday Soc. 1953,14, 181-190. Blyumberg, E. A.; Malievshii, A. D.; Emanuel, N. M. Effect of Solvents on the Mechanism of Liquid-phase Oxidation of n-Butane. Int. Chem. Eng. 1964,4,400-404.
Altarawneh M Mackie J C Kennedy E M and Dlugogorski B Z a Theoretical Study of the Reactions of Ho2 in the Low Temperatures Oxidation of Benzene in Proceedings of the Australian Combustion Symposium 2007 9 11 December Sydney Nsw Australia Pp 84 88, 2007
ABSTRACT We have generated a set of thermodynamic and kinetic parameters for the reactions involv... more ABSTRACT We have generated a set of thermodynamic and kinetic parameters for the reactions involving HO2 in the very early stages of benzene oxidation at low temperatures using density functional theory (DFT). In particular, we report the rate constants for the reactions of HO2 with benzene and phenyl. The calculated reaction rate constant for the abstraction of H–C6H5 by HO2 is found to be in good agreement with the limited experimental values. HO2 addition to benzene is found to be more important than direct abstraction. We show that the reactions of HO2 with the phenyl radical generate the propagating radical OH in a highly exoergic reaction. The results presented herein should be useful in modeling the oxidation of aromatic compounds at low temperatures.
Altarawneh M and Dlugogorski B Z Formation and Chlorination of Carbazole Phenoxazine and Phenazine Environmental Science Technology 49 Pp 2215 2221, 2015
This contribution presents pathways for the formation of the three nitrogenated dioxin-like speci... more This contribution presents pathways for the formation of the three nitrogenated dioxin-like species, carbazole, phenoxazine, and phenazine via unimolecular rearrangements of diphenylamine (DPA) and its nitro substituents (NDPA). The latter represent major structural entities appearing in formulations of explosives and propellants. Intramolecular H transfer from the amine group to one of the two O atoms in the nitro group denotes the most accessible route in the unimolecular decomposition of NDPA. Further unimolecular rearrangements afford phenazine and carbazole. A loss of an ortho substituent from DPA, followed by addition of an oxygen molecule, prompts the formation of carbazole and phenoxazine in a facile mechanism. The consistency between trends in Fukui-based electrophilic indices and the experimental profiles of chlorinated carbazole, phenoxazine, and phenazine suggests the formation of these species by electrophilic substitution.
Opoku M K Dlugogorski B Z Kennedy E M and Mackie J C the Effect of Additive on Nox Emission During Thermal Decomposition of Nano Recrystallised Nitrate Salts Advances in Materials Science For Environmental and Energy Technologies Iii 250 Pp 307 319, Oct 31, 2014
This chapter contains sections titled: Introduction Experimental Discussion Conclusions Acknowled... more This chapter contains sections titled: Introduction Experimental Discussion Conclusions Acknowledgments Footnotes IntroductionExperimentalDiscussionConclusionsAcknowledgmentsFootnotes
Altarawneh M and Dlugogorski B Z a Mechanistic and Kinetic Study on the Formation of Pbdd Fs from Pbdes Environmental Science Technology 47 Pp 5118 5127, Apr 11, 2013
This study presents a detailed mechanistic and kinetic investigation that explains the experiment... more This study presents a detailed mechanistic and kinetic investigation that explains the experimentally observed high yields of formation of polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) from the polybrominated diphenyl ethers (PBDEs), commonly deployed in brominated flame retardants (BFRs). Theoretical calculations involved the accurate meta hybrid functional of M05-2X. The previously suggested pathways of debromination and generation of bromophenols/bromophenoxys/bromobenzenes were found to be unimportant corridors for the formation of PBDD/Fs. A loss of an ortho Br or H atom from PBDEs, followed by a ring-closure reaction, is the most accessible pathway for the production of PBDFs via modest reaction barriers. The initially formed peroxy-type adduct (RO₂) is found to evolve in a complex, nevertheless very exoergic, mechanism to produce PBDDs. Results indicate that, degree and pattern of bromination, in the vicinity of the ether oxygen bridge, has a minor influence on governing mechanisms and that even fully brominated isomers of BFRs are capable of forming PBDD/Fs. We thoroughly discuss bimolecular reactions of PBDEs with Br and H, as well as the Br-displacement reaction by triplet oxygen. The rate of the Br-displacement reaction significantly exceeds that of the unimolecular inititiation reactions due to loss of ortho Br or H. Results presented herein address conclusively the intriguing question of how PBDEs form PBDD/Fs, a matter that has been in the center of much debate among environmental chemists.
Fire Safety Science, 1988
Mathematical modeling of the effect of pressure on low-temperature oxidation of coal indicates th... more Mathematical modeling of the effect of pressure on low-temperature oxidation of coal indicates that, high partial pressure of oxygen significantly accelerates the physical and chemical interaction between coal and oxygen. Based on these findings, this paper develops a new test method for ranking the susceptibility of coal to spontaneous combustion, using a high-pressure technique to shorten the testing period. By combining an isothermal high-pressure fixed-bed flow reactor with appropriate diagnostic instrumentation, an experimental facility is designed to determine the rate of coal oxidation, the concentration of oxygenated products, as well as the rate of heat release during oxidation. It is expected that, when the facility is operated at a partial pressure of oxygen of 5MPa, the time needed to carry out an experiment will be shortened by 75% in comparison to the data reported in the literature at atmospheric pressure.
Altarawneh M and Dlugogorski B Z Theoretical Investigation into the Atmospheric Reactions of Fluorotelomer Alcohols With Oh Radicals Organohalogen Compounds 74 Pp 383 387, 2012
J Phys Chem a, 2006
We present an ab initio procedure for accurately calculating aqueous-phase pK a values and apply ... more We present an ab initio procedure for accurately calculating aqueous-phase pK a values and apply it to study the acidity of nitrous acid (HNO 2 , or HONO). The aqueous-phase pK a of nitrous acid was obtained from calculated gas-phase acidities and solvation free energies via a thermodynamic cycle and the solvation model chemistry of Barone et al. (J. Chem. Phys. 1997, 107, 3210). Solvation free energies were calculated at the HF/6-31G(d) level using the dielectric-polarizable continuum and the integral equation formalism-polarizable continuum solvent models (D-PCM and IEF-PCM, respectively), with the D-PCM model yielding the most accurate pK a values. For HF free energies of solvation, significant improvements in accuracy could be made by moving to the larger 6-311++G(3df,3pd) and aug-cc-pVQZ basis sets. Solvation free energies were also calculated using the density functional theory (DFT) methods B3LYP, TPSS, PBE0, B1B95, VSXC, B98 and O3LYP, with the most accurate methods being TPSS and VSXC, which provided average errors of less than 0.11 pK a units. Solvation free energies calculated with the different DFT methods were relatively insensitive to the basis set used. Our theoretical calculations are compared with experimental results obtained using stopped flow spectrophotometry. The pK a of nitrous acid was measured as 3.16 at 25°C, and the enthalpy and entropy of nitrous acid dissociation were calculated from measurements as 6.7 kJ mol -1 and -38.4 J mol -1 K -1 , respectively, between 25 and 45°C. The UV/visible absorption spectra of the nitrite ion and nitrous acid were also examined, and molar extinction coefficients were obtained for each.
Chemosphere, 2003
Gas-phase reaction of CFC-12 (CCl 2 F 2 ) with methane was carried out in a plug flow reactor ove... more Gas-phase reaction of CFC-12 (CCl 2 F 2 ) with methane was carried out in a plug flow reactor over the temperature range of 873-1123 K. The major organic halocarbons formed during the reaction were C The formation of all products except C 2 H 2 F 2 decreased with temperature, while the selectivity to C 2 H 2 F 2 (difluoroethylene) increased with temperature and reached 80% at 1123 K. Under these reaction conditions, methane acts as hydrogen and carbon source, resulting in the formation of an unsaturated C 2 hydrofluorocarbon from two C 1 precursors.
The Journal of Physical Chemistry a, Nov 1, 2006
We present an ab initio procedure for accurately calculating aqueous-phase pK a values and apply ... more We present an ab initio procedure for accurately calculating aqueous-phase pK a values and apply it to study the acidity of nitrous acid (HNO 2 , or HONO). The aqueous-phase pK a of nitrous acid was obtained from calculated gas-phase acidities and solvation free energies via a thermodynamic cycle and the solvation model chemistry of Barone et al. (J. Chem. Phys. 1997, 107, 3210). Solvation free energies were calculated at the HF/6-31G(d) level using the dielectric-polarizable continuum and the integral equation formalism-polarizable continuum solvent models (D-PCM and IEF-PCM, respectively), with the D-PCM model yielding the most accurate pK a values. For HF free energies of solvation, significant improvements in accuracy could be made by moving to the larger 6-311++G(3df,3pd) and aug-cc-pVQZ basis sets. Solvation free energies were also calculated using the density functional theory (DFT) methods B3LYP, TPSS, PBE0, B1B95, VSXC, B98 and O3LYP, with the most accurate methods being TPSS and VSXC, which provided average errors of less than 0.11 pK a units. Solvation free energies calculated with the different DFT methods were relatively insensitive to the basis set used. Our theoretical calculations are compared with experimental results obtained using stopped flow spectrophotometry. The pK a of nitrous acid was measured as 3.16 at 25°C, and the enthalpy and entropy of nitrous acid dissociation were calculated from measurements as 6.7 kJ mol -1 and -38.4 J mol -1 K -1 , respectively, between 25 and 45°C. The UV/visible absorption spectra of the nitrite ion and nitrous acid were also examined, and molar extinction coefficients were obtained for each.
Altarawneh M and Dlugogorski B Z Mechanism of Thermal Decomposition of Tetrabromobisphenol a the Journal of Physical Chemistry a 118 Pp 9338 9346, Sep 18, 2014
This study presents a detailed investigation into the gas-phase thermal decomposition of tetrabro... more This study presents a detailed investigation into the gas-phase thermal decomposition of tetrabromobisphenol A (TBBA), that is, the most widely used brominated flame retardant (BFR). Elimination of one of the methyl groups characterizes the sole dominant channel in the self-decomposition of the TBBA molecule at all temperatures. A high-pressure rate constant for this reaction is fitted to k(T) = 2.09 × 10(10)T(1.93) exp(-37000/T) s(-1). The high A factor and low activation energy for this reaction arise from the formation of a delocalized radical upon the loss of a methyl group. We calculate rate constants for the bimolecular reactions of TBBA with H, Br, and CH3 radicals. Kinetic and mechanistic data provided herein should be instrumental to gain further understanding of the fate of TBBA during thermal degradation of materials laden with this BFR.
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Papers by Bogdan Dlugogorski