Nitrogen productivity modeling

Perhaps the most extensive computational study of the kinetics of NO reactions on Rh and Pd surfaces has been provided by the group of Zgrablich. Their initial simulations of the NO + CO reaction on Rh(lll) corroborated the fact that the formation of N-NO intermediate is necessary for molecular nitrogen production [83], They also concluded that an Eley-Rideal mechanism is necessary to sustain a steady-state catalytic regime. Further simulations based on a lattice-gas model tested the role of the formation of... 

Fig. 1. Abundance gradient of N/O predicted by models adopting stellar yields where rotation is not taken into account (as model 7 of [3] - thin solid line) and the same models computed with MM02 yields ([2] - thick solid line). A model where we increased only the amount of primary N in massive stars for metallicities below Z=10-B overlaps with the thick solid line shown here [1], This shows that the N/O gradient along the MW disk is affected mainly by the amount of nitrogen production in low and intermediate mass stars and not the primary N in massive stars. For the abundance data see [3] and references therein - asterisks are B stars (see Cunha, this conference).

New production models in upweUing systems usuaUy are constructed with nitrogen as the currency. Earliest simple models evolved from studies of the Pern upweUing system. For example, Dugdale and Macisaac (1971) used a relationship between... 

C2H4, 0.2%NO and 0.6%O2 with He as inert gas) was fed to the catalytic reactor. The total flow rate was kept at 1000 ml min. The analysis of the reactants and products was carried out by means of gas chromatography (Shimadzu GC-14B with two parallel columns, Poropak Q and Molecular Sieve 13X) combined with vacuum chemiluminescence spectrometry for NOx analysis (Teledyne Anal. Instrument-NOx stack gas emissions analyzer, model 911/912). The conversion yield of pollutants and nitrogen production yield measured at... 

The Michael addition of enamines to nitroalkenes proceeds with high Yyn selectivity. The Yyn selectivity is explained by an acyclic synclinal model, in which there is some favorable interaction between the nitro group and the nitrogen lone pair of the enamine group CEq. 4.67i. Both Z- and E-nitrostyrenes afford the same product in over 90% diastereoselecdvity. 

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