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Title: Thermal and mechanochemical self-propagating degradation of chloro-organic compounds: The case of hexachlorobenzene over calcium hydride

Abstract

The authors report on the highly exothermic solid-state reaction between hexachlorobenzene and calcium hydride. Once ignited by a thermal spike, the reaction displays a self-sustaining character in the CaH{sub 2}/C{sub 6}Cl{sub 6} molar ratio of 3:18. The high temperatures reached, i.e., 2550--2900 K, ensure a complete breakdown of the aromatic molecule and of undesired chloro-organic congeners, with only inorganic halide salts being found among the end-products. Combustive-like reactions were also observed when reactant powders were subjected to intensive mechanical treatment by ball milling. The combustive range of mechanically driven processes falls within that found in the true self-sustaining regime even if the activation and the extinction of the reaction were ruled by completely different mechanisms. A neat correlation was worked out relating the temperatures at the combustion front to the total heat evolved in the reaction carried out in the mechanochemical mode. The same end-products were also found. The practical exploitation of a self-sustaining methodology for the disposal of hazardous organochlorine compounds seems feasible.

Authors:
; ;  [1]; ; ;  [2]
  1. Univ. degli Studi di Cagliari (Italy). Dept. di Ingegneria Chimica e Materiali
  2. Univ. degli Studi di Sassari (Italy). Dept. di Chimica
Publication Date:
OSTI Identifier:
697160
Resource Type:
Journal Article
Journal Name:
Industrial and Engineering Chemistry Research
Additional Journal Information:
Journal Volume: 38; Journal Issue: 9; Other Information: PBD: Sep 1999
Country of Publication:
United States
Language:
English
Subject:
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; CHLORINATED AROMATIC HYDROCARBONS; CALCIUM HYDRIDES; DECOMPOSITION; COMBUSTION KINETICS; WASTE PROCESSING

Citation Formats

Cao, G., Orru, R., Sannia, M., Doppiu, S., Monagheddu, M., and Cocco, G. Thermal and mechanochemical self-propagating degradation of chloro-organic compounds: The case of hexachlorobenzene over calcium hydride. United States: N. p., 1999. Web. doi:10.1021/ie980790+.
Cao, G., Orru, R., Sannia, M., Doppiu, S., Monagheddu, M., & Cocco, G. Thermal and mechanochemical self-propagating degradation of chloro-organic compounds: The case of hexachlorobenzene over calcium hydride. United States. doi:10.1021/ie980790+.
Cao, G., Orru, R., Sannia, M., Doppiu, S., Monagheddu, M., and Cocco, G. Wed . "Thermal and mechanochemical self-propagating degradation of chloro-organic compounds: The case of hexachlorobenzene over calcium hydride". United States. doi:10.1021/ie980790+.
@article{osti_697160,
title = {Thermal and mechanochemical self-propagating degradation of chloro-organic compounds: The case of hexachlorobenzene over calcium hydride},
author = {Cao, G. and Orru, R. and Sannia, M. and Doppiu, S. and Monagheddu, M. and Cocco, G.},
abstractNote = {The authors report on the highly exothermic solid-state reaction between hexachlorobenzene and calcium hydride. Once ignited by a thermal spike, the reaction displays a self-sustaining character in the CaH{sub 2}/C{sub 6}Cl{sub 6} molar ratio of 3:18. The high temperatures reached, i.e., 2550--2900 K, ensure a complete breakdown of the aromatic molecule and of undesired chloro-organic congeners, with only inorganic halide salts being found among the end-products. Combustive-like reactions were also observed when reactant powders were subjected to intensive mechanical treatment by ball milling. The combustive range of mechanically driven processes falls within that found in the true self-sustaining regime even if the activation and the extinction of the reaction were ruled by completely different mechanisms. A neat correlation was worked out relating the temperatures at the combustion front to the total heat evolved in the reaction carried out in the mechanochemical mode. The same end-products were also found. The practical exploitation of a self-sustaining methodology for the disposal of hazardous organochlorine compounds seems feasible.},
doi = {10.1021/ie980790+},
journal = {Industrial and Engineering Chemistry Research},
number = 9,
volume = 38,
place = {United States},
year = {1999},
month = {9}
}