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Applications of combustion analysis

Combustion, or burning as it is more commonly known, is simply the mixing and exothermic reaction of a fuel and an oxidizer. It has been used since prehistoric times in a variety of ways, such as a source of direct heat, as in furnaces, boilers, stoves, and metal forming, or in piston engines, gas turbines, jet engines, rocket engines, guns, and explosives. Automobile engines use internal combustion in order to convert chemical into mechanical energy. Combustion is currently utilized in the production of large quantities of H 2 . Coal or coke is combusted at 1000 °C in the presence of water in a two-step reaction. The first step shown in [link] involved the partial oxidation of carbon to carbon monoxide. The second step, [link] , involves a mixture of produced carbon monoxide with water to produce hydrogen and is commonly known as the water gas shift reaction.

Although combustion provides a multitude of uses, it was not employed as a scientific analytical tool until the late 18th century.

History of combustion

In the 1780's, Antoine Lavoisier ( [link] ) was the first to analyze organic compounds with combustion using an extremely large and expensive apparatus ( [link] ) that required over 50 g of the organic sample and a team of operators.

French chemist and renowned "father of modern Chemistry" Antoine Lavoisier (1743-1794).
Lavoisier's combustion apparatus. A. Lavoisier, Traité Élémentaire de Chimie , 1789, 2 , 493-501.

The method was simplified and optimized throughout the 19 th and 20 th centuries, first by Joseph Gay-Lussac ( [link] ), who began to use copper oxide in 1815, which is still used as the standard catalyst.

French chemist Joseph Gay-Lussac (1778-1850).

William Prout ( [link] ) invented a new method of combustion analysis in 1827 by heating a mixture of the sample and CuO using a multiple-flame alcohol lamp ( [link] ) and measuring the change in gaseous volume.

English chemist, physician, and natural theologian William Prout (1785-1850).
Prout's combustion apparatus. W. Prout, Philos. T. R. Soc. Lond. , 1827, 117 , 355.

In 1831, Justus von Liebig ( [link] ) simplified the method of combustion analysis into a "combustion train" system ( [link] and [link] ) that linearly heated the sample using coal, absorbed water using calcium chloride, and absorbed carbon dioxide using potash (KOH). This new method only required 0.5 g of sample and a single operator, and Liebig moved the sample through the apparatus by sucking on an opening at the far right end of the apparatus.

German chemist Justus von Liebig (1803-1873).
Print of von Liebig's "combustion train" apparatus for determining carbon and hydrogen composition. J. Von Liebig, Annalen der Physik und Chemie , 1831,  21 .
Photo of von Liebig's "combustion train apparatus" for determining carbon and hydrogen composition. The Oesper Collections in the History of Chemistry, Apparatus Museum, University of Cincinnati, Case 10, Combustion Analysis. For a 360 o view of this apparatus, visit (External Link) .

Jean-Baptiste André Dumas ( [link] ) used a similar combustion train to Liebig. However, he added a U-shaped aspirator that prevented atmospheric moisture from entering the apparatus ( [link] ).

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Source:  OpenStax, Physical methods in chemistry and nano science. OpenStax CNX. May 05, 2015 Download for free at http://legacy.cnx.org/content/col10699/1.21
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