Pyrolysis in the presence of reactive gases or with catalysts

Pyrolytic reactions, mainly for analytical purposes, are commonly done in a helium atmosphere. Sometimes these reactions are done, intentionally or not, in the presence of additional reactants or in the presence of catalysts. The most common additional reactants are probably oxygen, hydrogen, and water (gas at pyrolysis temperature). Oxygen from the air and water are sometimes unintentionally present during pyrolysis. The presence of an additional reactant can modify the result of the pyrolytic reaction, either qualitatively or quantitatively. 

The presence of water as a reaction product from the pyrolytic processes or as adsorbed water on the material to be pyrolyzed is not unusual. However, in analytical pyrolysis, water is not commonly added to the sample. During some pyrolytic processes with industrial applications such as wood pyrolysis, water is sometimes added intentionally. The main effect of water during pyrolysis is hydrolysis. This takes place as the temperature elevates and can be seen in the modification of the yields of different final pyrolysis products. Therefore, the reproducibility in analytical pyrolysis may be influenced by the variability of water content of the initial sample [31]. 

One of the problems during the analysis of pyrolysates using chromatographic techniques is that polar compounds such as larger acids are not easily eluted from 

During pyrolysis, quaternary ammonium hydroxide is also decomposed. For example, the decomposition of tetramethyl ammonium hydroxide occurs by the following reaction  

Methanol and trimethylamine are therefore found in the pyrograms in addition to the compounds generated from the sample. Other small molecules can be generated from the reagent. For example, dimethyl ether can be formed by the following reaction  

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Pyrolysis in the presence of reactive gases or with catalysts... 

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