Reduction of nitric oxide

Hydroxylamine sulfate is produced by direct hydrogen reduction of nitric oxide over platinum catalyst in the presence of sulfuric acid. Only 0.9 kg ammonium sulfate is produced per kilogram of caprolactam, but at the expense of hydrogen consumption (11). A concentrated nitric oxide stream is obtained by catalytic oxidation of ammonia with oxygen. Steam is used as a diluent in order to avoid operating within the explosive limits for the system. The oxidation is followed by condensation of the steam. The net reaction is... 

From the results of other authors should be mentioned the observation of a similar effect, e.g. in the oxidation of olefins on nickel oxide (118), where the retardation of the reaction of 1-butene by cis-2-butene was greater than the effect of 1-butene on the reaction of m-2-butene the ratio of the adsorption coefficients Kcia h/Kwas 1.45. In a study on hydrogenation over C03O4 it was reported (109) that the reactivities of ethylene and propylene were nearly the same (1.17 in favor of propylene), when measured separately, whereas the ratio of adsorption coefficients was 8.4 in favor of ethylene. This led in the competitive arrangement to preferential hydrogenation of ethylene. A similar phenomenon occurs in the catalytic reduction of nitric oxide and sulfur dioxide by carbon monoxide (120a). 

Precious metal loaded ln/H-ZSM-5 for reduction of nitric oxide with methane in the presence of water vapor... 

The catalytic activity of ln/H-ZSM-5 for the selective reduction of nitric oxide (NO) with methane was improved by the addition of Pt and Ir which catalyzed NO oxidation, even in the presence of water vapor. It was also found that the precious metal, particularly Ir loaded in/H-ZSM-5 gave a low reaction order with respect to NO, and then showed a high catalytic activity for the reduction of NO at low concentrations, if compared with ln/H-ZSM-5. The latter effect of the precious metal is attributed to the enhancement of the chemisorption of NO and also to the increase in the amount of NO2 adsorbed on in sites. 

As another example from chemical kinetics, we consider the catalytic reduction of nitric oxide (NO) by hydrogen which was studied using a flow reactor operated differentially at atmospheric pressure (Ayen and Peters, 1962). The following reaction was considered to be important... 

Table 4.5 Experimental Data for the Catalytic Reduction of Nitric Oxide...

Kittrell et al. (1965a) considered three models for the description of the reduction of nitric oxide. The one given in Chapter 4 corresponds to a reaction between one adsorbed molecule of nitric oxide and one adsorbed molecule of hydrogen. This was done on the basis of the shape of the curves passing through the plotted data. 

Praliaud, H., Mikhailenko, S., Chajar, Z. et al. (1998) Surface and bulk properties of Cu—ZSM-5 and Cu/A1203 solids during redox treatments. Correlation with the selective reduction of nitric oxide by hydrocarbons, Appl. Catal. B, 16, 359. 

The first pathway proposed by Iizuka and Lunsford [17] considers the reduction of nitric oxide by CO over rhodium/Y-zeolite. It leads only to N20 as follows ... 

Frank, B., Emig, G. and Renken, A. (1998) Kinetics and mechanism of the reduction of nitric oxides by H, under lean-burn conditions on a Pt-Mo-Co/a-ARO, catalyst, Appl. Catal. B 19, 45. 

S.R. Smith and H.H. Thorp, Application of the electrocatalytic reduction of nitric oxide mediated by ferrioxamine B to the determination of nitric oxide concentrations in solution. Inorg. Chim. Acta 273, 316-319(1998). 

Richter, M., Trunschke, A., Bentrup, U., Brzezinka, K.W., Schreier, E., Schneider, M., Pohl, M.M., and Fricke, R. 2002. Selective catalytic reduction of nitric oxide by ammonia over egg-shell MnOx/NaY composite catalysts. J. Catal. 206 98-113. 

An example of a model rejection based upon temperature coefficients can be obtained from the single-site model considered by Ayen and Peters (A3) for the reduction of nitric oxide over a commercial catalyst ... 

To illustrate this criterion, consider a simulation problem chosen to be similar to the catalytic reduction of nitric oxide (A3, K11) ... 

The oxidation of carbon monoxide, 2CO + 02 — C02 is one of the reactions (apart from reduction of nitric oxides and oxidation of unbumt hydrocarbons) taking place in the car exhaust catalyst. The latter consists of small noble metal particles (Pt, Rh or Pd) on a ceramic support. The reaction proceeds through the following steps [25]... 

Amiridis, M.D., Duevel, R.V., Wachs, l.E. 1999. The effect of metal oxide additives on the activity of VjOj/TiOj catalysts for the selective catalytic reduction of nitric oxide by ammonia. Appl Catal B Environ 20 111-122. 

Burch, R. and Scire, S. Selective catalytic reduction of nitric oxide with ethane and methane on some metal exchanged ZSM-5 zeolites. Appl. Catal, B Environmental,... 

Smits, R. H. H. and Iwasawa, Y. Reaction mechanisms for the reduction of nitric oxide by hydrocarbons on Cu-ZSM-5 and related catalysts. Appl Catal, B Environmental,... 

Long, R. Q. and Yang, R. T. Selective Catalytic reduction of nitric oxide with ethylene on copper ion-exchanged Al-MCM-41 catalyst, Ind. Eng. Chem. Res., 1999, Volume 38, Issue 3, 873-878. 

Zhang, B Yamaguehi, T Kawakami, H Suzuki, T. Seleetive reduction of nitric oxide over platinum eatalysts in the presenee of sulfur dioxide and excess oxygen, Appl Catal, B Environmental, 1992, Volume 1, Issue 3, L15-L20. 

Wiehterlova, B Sobalik, Z Vondrova, A. Differences in the strueture of eopper aetive sites for deeomposition and seleetive reduction of nitric oxide with hydroearbons and ammonia, Catal. Today, 1996, Volume 29, Issues 1-4, 149-153, Seeond Japan-EC Joint Workshop on the Frontiers of Catalytic Science and Technology for Energy, Environment and Risk Prevention... 

Petunehi, JO Gustave, S Hall, WK. Studies of the selective reduction of nitric oxide by hydroearbons, Catal, B Environmental, 1993, Volume 2, Issue 4, 303-321. 

V) Flame zone When the dark-zone reactions occur rapidly after an induction period, they produce a flame zone in which the final combustion products are formed and attain a state of thermal equiUbrium. When the pressure is low, below about 1 MPa, no flame zone is produced because the reduction of nitric oxide is too slow to produce nitrogen. 

The electrochemical reduction of nitric oxide in solid-state electrochemical cell is an interesting field surveyed in [95]. The working principle of the cells is the cathodic reduction of NO to nitrogen and oxygen anions. In [95], the properties of various types of solid-state electrochemical cells used for NO reduction are presented and discussed. It is shown that the cathode materials with a high redox capacity and oxygen vacancies are most active for the electrochemical reduction of nitric oxide, whereas noble metal-based electrodes show a much lower selectivity. As an alternative route, the promotion of the reduction with a reductive agent is also considered. 

According to [96], electrochemical methods, especially the application of cyclic voltammetry, could be a powerful tool to find suitable catalysts for NO removal from combustion products. Investigation of electrocatalytic properties of vitamin B12 toward oxidation and reduction of nitric oxide was reported in [97]. The catalytic activity of meso-tetraphenyl-porphyrin cobalt for nitric oxide oxidation in methanolic solution and in Nafion film was reported in [98]. 

Pt-Rh/AROs catalysts are widely used in automotive-exhaust emission control. In these systems, Pt is generally used for the oxidation of CO and hydrocarbons and Rh is active for the reduction of nitric oxide to N2. HRTEM and AEM show two discrete particle morphologies and Pt-Rh alloy particles (Lakis et al 1995). EM studies aimed at understanding the factors leading to deactivation, surface segregation of one metal over the other and SMSI are limited. There are great opportunities for EM studies, in particular, of surface enrichment, and defects and dislocations in the complex alloy catalysts as sites for SMSI. 

Garber, E. A. E., Castignetti, D., and Hollocher, T. C. (1982). Proton translocation and proline uptake associated with reduction of nitric oxide by denitrifying Paracoccus denicrificans. Biochem. Biophys. Res. Commun. 107, 1504-1507. 

Ye, R. W., Toro-Suarez, 1., Tiedje, J. M., and Averill, B. A. (1991). H2 0 isotope exchange studies on the mechanism of reduction of nitric oxide and nitrite to nitrous oxide by denitrifying bacteria. J. Biol. Chem. 266, 12848-12851. 

Zumft, W. G., and Frunzke, K. (1982). Discrimination of ascorbate-dependent nonenzy-matic and enzymatic, membrane-bound reduction of nitric oxide in denitrifying Pseudomonas perfectomarinus. Biochim. Biophys. Acta 681, 459-468. 

Nitric oxide reduction with ammonia. Lintz and co-workers78,79 have studied the platinum catalysed reduction of nitric oxide by ammonia in the region... 

Fig. 13.6 Laboratory flow reactor experiments on selective noncatalytic reduction of nitric oxide by ammonia, with and without hydrogen addition [251]. Inlet composition NO = 225 ppm, NH3 = 450 ppm, O2 = 1.23% balance inert. Residence time 0.075 s atmospheric pressure.

---