Activation of Mn

Because of the relative instabiUty of FeO, the reduction to metallic Fe occurs at a much lower temperature and appreciable CO2 is present in the product gas. The high temperature required for the reaction of MnO and C results in the formation of essentially pure CO the partial pressures of CO2 and Mn are <0.1 kPa (1 X 10 atm). The product of this reaction is manganese carbide (7 3) [12076-37-8J, Mn C, containing 8.56% carbon. Assuming immiscibility of the metal and carbide, Mn should be obtainable by the reaction of MnO and Mn C at 1607°C. However, at this temperature and activity of Mn, the partial pressure of Mn vapor is approximately 10 kPa (0.1 atm) which would lead to large manganese losses. 

F. Yamakura, K. Kobayashi, H. Ue, and M. Konno, The pH-dependent changes of the enzymic activity and spectroscopic properties of iron-substituted manganese superoxide dismutase. A study on the metal-specific activity of Mn-containing superoxide dismutase. Eur. J. Biochem. 227, 700—706 (1995). 

Rybach, L. and Nissen, H.U. (1964). Neutron activation of Mn and Na traces in marbles worked by the Ancient Greeks. In Proceedings of Radiochemical Methods of Analysis. International Atomic Energy Agency, Vienna, pp. 105-117. 

Groppi and co-workers46,26 investigated the catalytic activity of Mn- and Fe-substituted hexaaluminates prepared via the carbonate route for CO and H2 combustion. These species are the main components of fuels from gasification of carbon and biomasses that represent an alternative to natural gas in gas turbine applications. 

Lab-scale tests over powder materials showed promising activity of Mn-substituted hexaaluminates in CO/H2 combustion, suggesting their potential for use with fuels from gasification of carbon or of biomasses. 

Since this redox system is taken to be at equilibrium, there is no potential for the reaction to do work that is, = 0 (or equivalently, from equation 7.23, AG = 0). Thus equation 7.44 can be used to solve for the equilibrium activity of Mn ... 

As an alternative to porphyrin and phthalocyanine catalysts, complexes of Mn and the cyclic triamine l,4,7-trimethyl-l,4,7-tnazacyclononane (tmtacn) clearly deserve more attention [11]. In acetone and at subambient temperature, the activity of Mn-tmtacn matches that of the more active porphyrins, with 1,000 turnovers within a few hours in the styrene epoxidation [12]. Moreover, Mn-tmtacn is colorless after reaction, and because of its relatively moderate price, it has even been commercialized for a short while in laundry powders [13]. A heterogeneous version of Mn-tmtacn would obviously offer even more advantages. We have proposed an immobilization of Mn-tmtacn based on zeolite... 

The synergistic interaction for the Co/Mn/Br catalyst has been previously reported Ravens [9] based on the replacement of some of the cobalt by manganese in a Co/Br catalyst and by us [10] based on the fact that the sum of the activities of Mn/Br and Co/Br catalysts is less than the Co/Mn/Br catalyst. 

For all pH < 9.29, the activity of Mn " will predominate over that of MnHCOj and rhodochrosite solubility can be contoured in terms of Mn ". ... 

The phases, surface areas, and catalytic activities of Mn-substituted hexaaluminates with various cation compositions in the mirror plane are summarized in Table 3. The crystal structures of both BaMnAlijOig. and SrMnAluOj9.(jj are the hexaaluminate type. The surface area was quite large for hexaaluminate samples even after heating at 1,300 °C. Although the hexaaluminate phase was contained in CaMnAljjOi9. , the coexisting... 

Table 3 Phases, surface areas, and catalytic activities of Mn-substituted hexaaluminates with various cation composition in the mirror plane ...

This relationship represents the final product of the manganese oxidation cycle, and gives the limiting stoichiometry of the participating species. However, it cannot be treated meaningfully by a simple mass-law equilibrium approach to predict the kinetically controlled activities of Mn and that would be brought about by operation of the cycle. 

Of the three most studied classes of MnSOD mimics, porphyrin-type mimics are most examined with respect to peroxynitrite (41). Reactivity of metal porph5uins with perox5mitrite was originally proposed by Stem et al. (41a), where authors showed that [Fe (III)TMPyP] possesses peroxynitrite isomerase activity. However, the activity of Mn porph5uins, particularly those that show SOD... 

Rybach L, Nissai VU (1965) Neutron Activation of Mn ami Na Traces in Marbles Worked by the Ancient Greeks, in Ra ochemical Methods of Analysis, Vol. I, p. 105, Vienna, Internal. Atomic Energy Agency... 

Discussion of Experiments with U Metal Sphere. The density of thermal neutrons was obtained from three essentially independent experiments fission activity inside the sphere when sphere was at 60 cm firom source same activity for 20 cm distance of sphere from source activity of Mn detectors inside of sphere for 60 cm distance. The source means, in this connection, the front of the block, i.e., the place where the fast neutrons enter. 

Activities of Mn for three different positions of the solid-aqueous boundary... 

The results of the present project indicate, that the role of Fe is rather limited to an enhancement of the oxygen mass transfer, while acceleration of the oxidation reaction is based on the catalytic support of Mn. Catalytic acceleration is based on the activity of Mn while Fe mainly acts as an oxygen-carrier, which enhances the rate of mass transfer of oxygen. The results of this investigation confirm, that acceleration of the S(IV) oxidation at pH = 5 will be observed as long as the Fe -content is kept below 3- 10 mol/l. Additional Fe will result in a rapid break down of S(IV)-oxidation. Reason for this break down is the oxidation of Fe to Fe, followed by an immediate formation of Fe(OH)3 due to the low solubility product of Fe(OH)3. 

Activi of Mn foil in lattice / Activity of Mn foil In thermal column ... 

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