Gas-phase thermal reactions

The gas-phase thermal reaction of cinnamaldehyde with dimethyl diselenide at 630 °C gave benzo[ ]selenophene 2 <1998RCB447>. 

The thermal decomposition of 1,1,1,-trifluoroacetone has been studied by Fekete - , and that of fluoroacetone hemiacetal esters by Newallis et Lewis and Newman have reported on the rearrangements of fluoroesters in the gas phase. Thermal reactions of nitrogen-containing fluoro-compounds have included trifluoromethyl cyanide , hexafluoroazomethane , tetrafluorohydra-zine , fluorodiazirines , perfluoropyridazines , fluorochlorodinitrometh-ane and poly(difluoroamino)fluoromethanes - . ... 

A. E. Croce and E. Castellano [Int. J. Chem. Kinet., 14, 647 (1982)] studied the kinetics of the gas-phase thermal reaction between bis(fluoroxy)difluoromethane CF2(OF)2 and carbon monoxide over the temperature range 110 to 140°C ... 

Gas-Phase Thermal Reactions (abbreviated as GPTRs) greatly influence our daily lives in three main areas ... 

Figure 1 Elaboration and validation of a model of a gas-phase thermal reaction.

The aim of this chapter is to show both the part played by and the importance of gas-phase thermal reactions in the consumption of raw materials, the production of mechanical and thermal energy, the manufacture of chemical substances, the chemical safety, the atmospheric pollution, and, more generally, in the ecodevelopment of the planet. 

The global phenomenon is extremely difficult to model, as it involves both photochemical reactions, gas-phase thermal reactions, heterogeneous reactions (especially with ice particles), phenomena of convective and diffusive transport inside... 

The different themes discussed in this chapter, relating to gas-phase thermal reactions Use of fossil raw material. 

In the following discussion, only gaseous and liquid fuels will be considered. These give rise to gas-phase thermal reactions, following prior or in situ vaporization in the case of liquids. Solid fuels are excluded, as their reaction mechanisms are very different from those of gases. 

Three main categories of burners can be distinguished according to whether they work using gases, liquids or solids. Only the first two categories of burners give rise to gas-phase thermal reactions and will be discussed here. 

Industrial reactors using a gas phase thermal reaction handle very large quantities of materials each year. Thus the steamcracker in Example 1 works for about 300 days a year and uses about 50,000 t C2H and produces 40,000 t C2H4. Such processes must operate continuously. 

Gas-phase thermal reactions and, more particularly, the oxidation of hydrocarbons exhibit a wide variety of macroscopic behaviour patterns slow reactions which are strongly inhibited or accelerated by the addition of small quantities of additives, cool flames and oscillations, isothermal explosions, two stage autoignitions, thermal explosions and flames. 

When a gas-phase thermal reaction involves molecules of the type YH which are likely to form free radicals of the allylic type Y, which are stabilized by resonance, by the abstraction of an H atom, the terminations involving these radicals must be taken into account, i.e. ... 

The primary aim of Chapter XII is to describe the technology of the main kinds of reactors used in the laboratory to study complex gas-phase thermal reactions. 

This book is devoted to Gas-Phase Thermal Reactions (GPTRs), and especially combustion reactions, which take place in engines, burners and industrial chemical reactors to produce mechanical or thermal energy to incinerate pollutants or to manufacture chemical substances, and which play an important part due to the consequences they have on the environment fires and explosions, tropospheric pollution, greenhouse effect, hole in the stratospheric ozone layer. 

Half of these slaves are gas-phase thermal reactions. 

As far as natural gas, crude oil, energy, primary chemical substances and pollution are concerned, which are major geopolitical issues, gas-phase thermal reactions have acquired a major role in the world economy. The knowledge and command of these are of primary importance in the constant search for better performances and profitability. Now, although these reactions cause numerous and difficult problems, the spectacular progress in experimental, theoretical and computational methods obtained over the last twenty years has resulted in a thorough knowledge of their mechanisms. 

Graduate engineer of the Ecole Nationale Superieure des Industries Chimiques and Doctor of Philosophy, Guy-Marie COME is a Professor at the Universite Henri Poincare (Nancy I). In the Departement de Chimie Physique des Reactions, Unite Mixte Associee au CNRS, at the INP of Lorraine (ENSIC) and at The University of Nancy, he conducts research carried out within the framework of European and national research programmes and of industrial contracts with major firms. More particularly this research has been carried out within the scope of the valorization of natural gas, the reformulation of petrol and diesel fuel for limiting the production of pollutants and computational kinetics for generating more and more complex models on a computer. Guy-Marie COME s book is a synthesis of multidisciplinary elements which contribute to the comprehension of gas-phase thermal reactions. 

The DTA-EGD-GC on-line coupled simultaneous technique provides a microscale experimental method that is precise and rapid for the investigation of the reaction processes involved in the thermal decomposition of samples. The variations of the composition of reaction gases evolved can be traced and the mechanism of gas-solid phase and gas-gas phase thermal reactions in an inert gas or reactant gas can be studied. 

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