Thermal decomposition of chloropicrin, diphosgene and phosgene between 100 and 530°C

Battin‐Leclerc, Frédérique; Baronnet, F.; Paternotte, G.; Leclerc, Jean-Pierre; Gourhan, R

doi:10.1016/s0165-2370(99)00052-2

Cited by 20 publications

(31 citation statements)

References 4 publications

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“…Outra hipótese para a geração desses ácidos está relacionada com a interação do O 2 dissolvido no meio com água e ·CCl 3 , o que levaria à produção de fosgênio, o qual se degrada a CO 2 e Cl 2 , quando a temperatura está acima de 100 o C 23 .…”

Section: Resultsunclassified

Geração sonoquímica de oxidantes em solução aquosa saturada de tetracloreto de carbono

Borges¹,

Korn²

2002

Quím. Nova

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Recebido em 11/6/01; aceito em 8/11/01 SONOCHEMICAL PRODUCTION OF OXIDIZING SPECIES IN WATER SOLUTION SATURATED WITH CARBON TETRACHLORIDE. In this work the CCl 4 degradation in aqueous solution by sonication with 40 kHz commercial ultrasonic bath was investigated. Sonochemical degradation of CCl 4 occur by the cleavage of C-Cl bond into the cavitation bubbles. Oxidation reactions and the pH decreasing in the bulk solution during sonication were attributed to chlorine radicals produced by CCl 4 sonolysis, leading to increase the chloride concentration. The formation of oxidizing agents was evaluated employing I -and Fe 2+ ion solutions, converted to I 2 and HIO, and Fe 3+ , respectively. The amount of chloride and hydronium ions produced after 3 min of irradiation was 11.52 and 12.19 mmol, respectively, suggesting that the same reaction was involved to produce these ions. Fe 2+ oxidation and the pH variation were monitored to estimate chlorine radical formation rate in the presence (0.107 mmol s -1 ) and absence (0.092 mmol s -1 ) of metallic ion during the first minute of sonication.Keywords: sonochemical reactions; oxidizing species generation; carbon tetrachloride sonolysis. INTRODUÇÃOOs efeitos químicos provocados pelos ultra-sons ocorrem devido ao fenômeno da cavitação acústica, que é o processo de nucleação, crescimento e colapso de bolhas transientes em líquidos expostos a ondas ultra-sônicas de baixa frequência (< 1 MHz) 1 . As ondas ultrasônicas se propagam através de um líquido em ciclos alternados de compressão e expansão, porém, caso a onda acústica tenha pressão suficientemente alta, pode vencer as forças intermoleculares num ponto do líquido, criando uma cavidade para a qual podem se difundir, durante a etapa de expansão, os gases e vapores presentes no líquido. Na etapa de compressão os gases e vapores não retornam completamente para o líquido, resultando em aumento efetivo do tamanho da cavidade durante os ciclos seguintes de compressão e expansão até que seja atingido seu diâmetro crítico, entrando em violento colapso 2 . O colapso das bolhas transientes provoca a liberação de grande quantidade de energia, gerando temperaturas locais instantâneas muito elevadas (5200 K) e pressões da ordem de centenas de atmosferas 3,4 .O processo de cavitação e as temperaturas geradas no colapso são fortemente dependentes da pressão de vapor do solvente. Assim, moléculas de solventes com altas pressões de vapor (e.g. moléculas de água) podem penetrar nas cavidades e, no momento do colapso, sofrerem sonólise, resultando na formação de novos produtos (e.g. H 2 e H 2 O 2 ).Propriedades físico-químicas dos gases dissolvidos (condutividade térmica, capacidade calorífica, pressão parcial e solubilidade no solvente) garantirão a eficiência da cavitação e, conseqüentemen-te, da sonólise 5,6 . Em outra aproximação, sabe-se que a eficiência de cavitação depende da freqüência e amplitude das ondas acústicas, potência do sonicador, bem como da tensão superficial, força iônica e temperatura do meio solvente 7 . Também, a pre...

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Section: Resultsunclassified

Geração sonoquímica de oxidantes em solução aquosa saturada de tetracloreto de carbono

Borges¹,

Korn²

2002

Quím. Nova

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“…Methyl chloroacetate (MC) is a halogenated ester mainly used as a solvent in organic synthesis or in the preparation of several compounds [1,2]. Typically, MC is used in the preparation of (carboxymethyl) trimethylammonium chloride esters [3] or in the synthesis of octakis-(carbethoxymethoxy)calix [8]arene [4]. Additionally, methyl chloroacetate acts as an extraction solvent during the separation of neutral compounds with concentration enhancement using coupling liquid-liquid semi-microextraction with micellar electrokinetic chromatography through oncapillary decomposition [5].…”

Section: Introductionmentioning

confidence: 99%

“…The destruction of the stock of toxic chemical warfare agents, absorbed in soils or stored as unexploded ammunitions, is still an environmental challenge in many countries [6,7]. The destruction of these dangerous compounds by pyrolysis can be a valuable alternative to their incineration [8], because the absence of oxygen limits the amount of exhausted gases to be treated at the outlet of such a process and disfavors the possibility of dioxin or furan formations [9].…”

Section: Introductionmentioning

confidence: 99%

First Study of the Pyrolysis of a Halogenated Ester: Methyl Chloroacetate

Vin

Battin‐Leclerc

Herbinet

2019

Ind. Eng. Chem. Res.

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The pyrolysis of a halogenated ester, methyl chloroacetate (MC), under dilute atmosphere and quasiatmospheric pressure was studied at temperatures from 473 to 1048 K using an alumina tubular reactor. MC was chosen as a surrogate to model the thermal decomposition of ethyl bromoacetate, a chemical warfare agent. A maximum MC conversion of 99.8% was observed at a residence time of 2 s, a temperature of 1048 K, and an inlet mole fraction of 0.01. The following products were quantified: CO, CO2, HCl, methane, ethylene, ethane, propene, chloromethane, dichloromethane, vinyl chloride, chloroethane, and dichloroethane. For the first time, a detailed kinetic model of MC pyrolysis was developed and gave a good prediction of the global reactivity and the formation of most of the major products. Flow rate and sensitivity analyses were made to highlight the different pathways of decomposition during the MC pyrolysis. In a first attempt to extrapolate the results obtained with methyl chloroacetate to ethyl bromoacetate, simulations were run with a modified version of the model developed in this study taking into account the differences in bond dissociation energies induced by the change of the chlorine atom by a bromine one. Supplementary MaterialKinetic mechanism used in this work given under CHEMKIN format.Thermodynamic data of all species of the mechanism.Scheme of the experimental setup used for running pyrolysis experiments, measured temperature profile in the TR in absence of reaction, and the carbon, oxygen, and chlorine balances, SCF energy, zero-point corrected electronic energy, frequencies and geometry of molecules, radicals and transition states, calculated at the CBS-QB3 level of theory, comparison of the kinetic parameters of reaction R30 in Table 1 with literature data, experimental mole fractions of species in a tabular form.

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“…Few quantitative experimental studies have been devoted to chloropicrin thermal decomposition [7][8][9][10][11] . High toxicity of this compound induces a high level of complexity for any experiments.…”

Section: Introductionmentioning

confidence: 99%

Combustion and Pyrolysis Kinetics of Chloropicrin

Lizardo-Huerta

Sirjean

Verdier³

et al. 2018

J. Phys. Chem. A

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Chloropicrin (CClNO) is widely used in agriculture as a pesticide, weed-killer, fungicide or nematicide. It has also been used as a chemical agent during World War I. The precise understanding of its combustion chemistry for destruction processes or in the event of accidental fire of stored reserves is a major safety issue. A detailed chemical kinetic model for the combustion and pyrolysis of chloropicrin is proposed for the first time. A large number of thermo-kinetic parameters were calculated using quantum chemistry and reaction rate theory. The model was validated against experimental pyrolysis data available in the literature. It was shown that the degradation of chloropicrin is ruled by the breaking of the C-N bond followed by the oxidation of the trichloromethyl radical by NO through the formation of the adduct CClONO, which can decompose to NO, chlorine atom, and phosgene. Phosgene is much more stable than chloropicrin and its decomposition starts at much higher temperatures. Combustion and pyrolysis simulations were also compared and demonstrated that the addition of oxygen has very little effect on the reactivity or product distribution due to the absence of hydrogen atoms in chloropicrin.

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Thermal decomposition of chloropicrin, diphosgene and phosgene between 100 and 530°C

Cited by 20 publications

References 4 publications

Geração sonoquímica de oxidantes em solução aquosa saturada de tetracloreto de carbono

Geração sonoquímica de oxidantes em solução aquosa saturada de tetracloreto de carbono

First Study of the Pyrolysis of a Halogenated Ester: Methyl Chloroacetate

Combustion and Pyrolysis Kinetics of Chloropicrin

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