Nitrogen reaction rate

The majority of the NOx produced in the combustion chamber is called thermal NOx. It is produced by a series of chemical reactions between the nitrogen (N2) and the oxygen (O2) in the air that occur at the elevated temperatures and pressures in gas turbine combustors. The reaction rates are highly temperature dependent, and the NOx production rate becomes significant above flame temperatures of about 3300 °F (1815 °C). Figure 10-19 shows schematically, flame temperatures and therefore NOx production... 

Most organic reactions are done in solution, and it is therefore important to recognize some of the ways in which solvent can affect the course and rates of reactions. Some of the more common solvents can be roughly classified as in Table 4.10 on the basis of their structure and dielectric constant. There are important differences between protic solvents—solvents fliat contain relatively mobile protons such as those bonded to oxygen, nitrogen, or sulfur—and aprotic solvents, in which all hydrogens are bound to carbon. Similarly, polar solvents, those fliat have high dielectric constants, have effects on reaction rates that are different from those of nonpolar solvent media. 

Aminolysis of esters often reveals general base catalysis and, in particular, a contribution to the reaction rate fi om terms that are second-order in the amine. The general base is believed to function by deprotonating the zwitterionic tetrahedral intermediate. Deprotonation of the nitrogen facilitates breakdown of the tetrahedral intermediate, since the increased electron density at nitrogen favors expulsion of an anion ... 

Halopyridines undergo self-quaternization on standing while the less reactive 2-halo isomers do not. However, more is involved here than the relative reactivity at the ring-positions. The reaction rate will depend on the relative riucleophilicity of the attack-ing pyridine-nitrogens (4-chloropyridine is more basic) and on the much lower steric hindrance at the 4-position. Related to this self-quatemization are the reactions of pyridine and picolines as nucleophiles with 4-chloro- and 2-chloro-3-nitropyridines. The 4-isomer (289) is. again the more reactive by 10-30-fold (Table VII, p. 276). 

When an azine-nitrogen and a leaving group are in the 2,3-relation to each other in monoaza- and polyaza-naphthalenes, there is a dramatic effect on the reaction rate (for 3-chloroisoquLnoline lO -lO -fold less than for its 1-chloro isomer and for 2-chloroquinoline 200-400-fold less than for 2-chloropyridine) due to restrictions imposed on the resonance stabilization of charge in the transition state by the bicyclic system ... 

K2C03 3 H202 contains hydrogen peroxide of crystallization and the solid phase decomposition involves the production of the free radicals OH and HOi, detected by EPR measurements [661]. a—Time curves were sigmoid and E = 138 kJ mole-1 for reactions in the range 333—348 K. The reaction rate was more rapid in vacuum than in nitrogen, possibly through an effect on rate of escape of product water, and was also determined by particle size. From microscopic observations, it was concluded that centres of decomposition were related to the distribution of dislocations in the reactant particles. 

Figure 8.62 shows the effect of temperature and of positive potential application on the reaction rates and on the nitrogen selectivity for the C3H6/N0/02 reaction.67,68 Electrochemical promotion significantly enhances both activity and N2 selectivity (e.g. from 58% to 92% at 350°C) and causes a pronounced (60°C) decrease in the light-off temperature of NO reduction in presence of 02. Positive potentials weaken the Rh=0 bond, decrease the O coverage and thus liberate surface sites for NO adsorption and dissociation. 

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