Iron magnesium catalyst

During the synthesis, besides carbon nanofibers formation, a plenty of chemical transformations occurred in the catalyst incorporation of ions Fe in MgO lattice and Mg xFxO solid solution formation as well as Fe3C, y-Fe and iron-magnesium-graphite complex, being a transitional stratum between a metal particle and a carbon nanofibre formation. Were revealed inert (Mgi xFxO) and active, very fine particles of the catalyst (MgFe204) components which are involved in the process of carbon nanofibres formation. 

Magnesium compounds retard cellulose depolymerization by deactivating the transition metal catalysts. In alkaline media where hydroxy-acids or products of polysaccharide degradation are present, magnesium forms stable complexes with transition metals. The formation of iron-magnesium complexes in particular is supported by interactions approximating the coordination number of iron (6) and one half the coordination number (3). 

The action of nickel is so much more powerful than that of alumina that the dehydrating action of the latter is practically eliminated when catalysts containing mixtures of reduced nickel and alumina are used. In fact, the alumina apparently only acts as a support for the active metal. However, comparative measurements have shown that the oxides of aluminium, iron, magnesium, and calcium may act as strong promoters for nickel catalysts. This effect has been explained as a mechanical effect, viz., the development of a large surface by which relatively more active metal is effectively exposed.10 When only small amounts of oxide are present the effect is predominantly that of support. The increased addition of oxide may increase the catalytic activity up to a certain point beyond which it only serves to dilute the catalyst and reduce its selectivity. Other explanations of the promoter action postulate the removal of catalyst poisons by the oxide, or regeneration of the active metallic catalyst by oxidations and reductions.20... 

HEXACHLOROEPOXYOCTAHYDRO-e rfo,exo-DIMETHANO-NAPHTHA-LENE or HEXACHLORO-6,7-EPOXY-l,4,4A,5,6,7,8,8A-OCTA-HYDRO-l,4 5,8-DIMETHANONAPHTHALENE (60-57-1) C HgClgO Noncombustible or very difficult to bum solid. Incompatible with concentrated mineral acids, acid catalysts active metals strong oxidizers strong acids phenols, active metals and their salts (e.g., copper, iron, magnesium, potassium, sodium, zinc). Corrosive to some metals. 

ALVIT (60-57-1) Incompatible with concentrated mineral acids, acid catalysts, strong oxidizers, phenols, active metals such as copper, iron, magnesium, sodium, potassium, zinc, and their salts. 

We have studied the synthesis of fatty acids by the closed Fischer-Tropsch process, using various carbonates as promoters and meteoritic iron as catalyst. The conditions used were D2/CO mole ratio = 1 1, temperature == 400°C, and time = 24-48 hr. Sodium, calcium, magnesium, potassium, and rubidium carbonates were tested as promoters but only potassium carbonate and rubidium carbonate produced fatty acids. These compounds are normal saturated fatty adds ranging from C5 to Cis, showing a unimodal Gaussian distribution without predominance of odd over even carbon-numbered aliphatic chains. The yields in general exceed the yields of aliphatic hydrocarbons obtained under the same conditions. The fatty acids may be derived from aldehydes and alcohols produced under the influence of the promoter and subsequently oxidized to the acids. 

High pressure hydrothermal conversion of Spirulina was studied with iron as catalyst (Matsui et al., 1997). It showed that the bio-oil yield increased linearly from 54.4 to 63.7 wt. % with increasing amount of Fe(CO)5-S from 0 to 1 mmol. The conversion and gas yield were nearly constant. In a similar study, brown macroalga Laminaria saccharina was hydrothermally liquefied to bio-crude in a batch reactor (Anastasakis and Ross, 2011). A maximum bio-crude yield of 19.3 wt. % was obtained with a biomass to water ratio of 1 10 at 350°C and 15 min of residence time. The solid residue contained large proportion of calcium and magnesium, whereas the liquid phase was rich in sugars, ammonium, potassium and sodium. 

Scheme 4-252. Homocoupling of aryl bromides in the presence of an iron(lll) catalyst and magnesium.

Pyrotechnic mixtures may also contain additional components that are added to modify the bum rate, enhance the pyrotechnic effect, or serve as a binder to maintain the homogeneity of the blended mixture and provide mechanical strength when the composition is pressed or consoHdated into a tube or other container. These additional components may also function as oxidizers or fuels in the composition, and it can be anticipated that the heat output, bum rate, and ignition sensitivity may all be affected by the addition of another component to a pyrotechnic composition. An example of an additional component is the use of a catalyst, such as iron oxide, to enhance the decomposition rate of ammonium perchlorate. Diatomaceous earth or coarse sawdust may be used to slow up the bum rate of a composition, or magnesium carbonate (an acid neutralizer) may be added to help stabilize mixtures that contain an acid-sensitive component such as potassium chlorate. Binders include such materials as dextrin (partially hydrolyzed starch), various gums, and assorted polymers such as poly(vinyl alcohol), epoxies, and polyesters. Polybutadiene mbber binders are widely used as fuels and binders in the soHd propellant industry. The production of colored flames is enhanced by the presence of chlorine atoms in the pyrotechnic flame, so chlorine donors such as poly(vinyl chloride) or chlorinated mbber are often added to color-producing compositions, where they also serve as fuels. 

This is an endothermic reaction in which a volume increase accompanies dehydrogenation. The reaction is therefore favoured by operation at reduced pressure. In practice steam is passed through with the ethylbenzene in order to reduce the partial pressure of the latter rather than carrying out a high-temperature reaction under partial vacuum. By the use of selected catalysts such as magnesium oxide and iron oxide a conversion of 35-40% per pass with ultimate yields of 90-92% may be obtained. 

An expanded mica (hydrated magnesium-aluminium-iron silicate). Used in lightweight aggregates, insulation, fertilizer and soil conditioners, as a filler in rubber and paints, and as a catalyst carrier. 

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