Carbon dioxide temperature increase induction

Kach method suffers from one or more inherent sources of error. Method 1 is not readily adaptable to the determination of second explosion limits. If temperature equilibrium is reached very quickly by the gas flowing into the vessel, as the continued flow causes the pressure to increase, the system must first intersect the lower explosion limit. Method 2 can lead to large errors if explosion is preceded by an induction period. In the carbon monoxide-oxygen reaction, for example, it was found that the heating rate could considerably affect the results owing to the existence of a zone of slow reaction adjacent to the second limit and inhibition of the reaction by the product, carbon dioxide... 

The relatively easy decarboxylation of many azolecarboxylic acids is a result of inductive stabilization of intermediate zwitterions of type 608 (cf. Section 3.4.1.8.1). Kinetic studies show that oxazole-2- and -5-carboxylic acids are both decarboxylated via the zwitterionic tautomers. Thiazole-2-carboxylic acids, and to a lesser extent -5-carboxylic acids, are decarboxylated readily thiazole-4-carboxylic acids are relatively stable. Isothiazole-5-carboxylic acids are decarboxylated readily, the 3-isomers less so while the 4-isomers require high temperatures. The 1,2,4-, 1,2,5-, and 1,3,4-thiadiazolecar-boxylic acids are also easily decarboxylated their stability is increased by electron-donating substituents. Most 1,2,3-triazolecarboxylic acids lose carbon dioxide when heated above their melting points. Decarboxylation of 2-hydroxytetra-zole-5-carboxylic acid requires severe conditions (HC1, reflux, 90 h) to produce 2-hydroxytetrazole (40%) <1999TL6093>. 

The major gas-phase products of the DMTM process are carbon oxides and hydrogen, with the yield of carbon monoxide at high pressmes being several times that of carbon dioxide. The main pathways of formation of carbon dioxide in this process are apparently not directly related to carbon monoxide, since according to a number of studies, carbon dioxide is formed before carbon monoxide in the induction period [54]. With rising temperature, the yields of ethane and ethylene increase rapidly. 

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