Barium iron catalysts

If dry, ammonia-free amide is desired, the stirrer and condenser are removed from the reactor and replaced by wellfitting rubber stoppers, one of which carries a delivery tube. At this point some of the iron catalyst and the more soluble impurities could be removed simply by decanting the supernatant liquid, which would then require caution in disposal. In any case, the reactor is allowed to stand in a well-ventilated hood overnight for evaporation of ammonia. Outward flow of ammonia prevents access of air to the amide, but a drying tube filled with barium oxide may be used as an added precaution. Next day, a vacuum is drawn on the residue for 10 to 30 minutes, and the vacuum is broken with dry nitrogen gas, which is then led through... 

According to the Table, the metals with toxic are those with the d-orbits all occupied or occupied by one electron each orbit. Contrarily, if the d orbit is completely empty, the metal is non-toxic. The atomic weight of the non-toxic metals may be small, also have large such as zirconium, barium, cerium, and thorimn. For the iron catalyst, except in the four rows (Cu+ etc ), potassium, aluminmn, magnesium, calcium, barium, zirconium, lanthanum are widely used as promoters. Consequently, Table 8.28 provides a useful guideline for the selection of catalyst supports and promoters, the preparation of catalysts with more than two components, the identification of catalyst poisons, and the selection of materials for reactor construction. 

Ruthenirrm, promoted by alkali metals and barium and then supported on carbon, has provided a significant increase in activity compared with iron catalysts. The high cost of rathenium when compared with iron must have led to it being used with the cheap support material. In retrospect, the complex interaction between carbon, alkali metal and barium with the active mthenium led to the development of a successful catalyst. A magnesimn oxide support has now been claimed to give a longer life than caibon. ... 

Nitrates. Iron(II) nitrate hexahydrate [14013-86-6], Fe(N03)2 6H20, is a green crystalline material prepared by dissolving iron in cold nitric acid that has a specific gravity of less than 1.034 g/cm. Use of denser, more concentrated acid leads to oxidation to iron(III). An alternative method of preparation is the reaction of iron(II) sulfate and barium or lead nitrate. The compound is very soluble in water. Crystallisation at temperatures below — 12°C affords an nonahydrate. Iron(II) nitrate is a useful reagent for the synthesis of other iron-containing compounds and is used as a catalyst for reduction reactions. 

The acetylacetonates are stable in air and readily soluble in organic solvents. From this standpoint, they have the advantage over the alkyls and other alkoxides, which, with the exception of the iron alkoxides, are not as easily soluble. They can be readily synthesized in the laboratory. Many are used extensively as catalysts and are readily available. They are also used in CVD in the deposition of metals such as iridium, scandium and rhenium and of compounds, such as the yttrium-barium-copper oxide complexes, used as superconductors. 1 1 PI Commercially available acetyl-acetonates are shown in Table 4.2. 

In all these studies which were carried out over the five-year period, 1904-1909, the effects of catalysts on these fixations of nitrogen were investigated. For the barium compounds, iron oxide acted as a catalyst. For the titanium nitrides, various other metal oxides as well as a number of inorganic salts proved to be effective. For the silicium nitrides and aluminum nitrides, again metal oxides and salts had beneficial effects but in other proportions and to another extent than found for the titanium nitrides. Often, two or more catalysts were added to the reaction mixtures with beneficial effects, but no systematic quantitative comparisons were carried out at this time. Table I lists some of these experiments. 

An acetylene may be reduced to an olefin by sodium in liquid ammonia, ° by electrolytic reduction at a spongy nickel cathode, or by partial hydrogenation over metal catalysts. Catalysts for the hydrogenation include nickel, ° iron, colloidal palladium, and palladium on barium sulfate or calcium carbonate. Pure trans olefins are obtained from dialkylacetylenes by reduction with sodium in liquid ammonia. The yields ate better than 90%. Catalytic hydrogenation leads to mixtures of cis and trans olefins in which the cis isomers predominate. ° Mono- and di-arylacetylenes have also been reduced. ... 

Iridium on barium sulfate or calcium carbonate [1, 519, before Iron], The most stereoselective reduction of the methylene compound (1) to the 16/3-methyl compound (2) was accomplished by use of iridium deposited on barium sulfate or calcium carbonate less than 2% of the 16a-methyl isomer was formed. Platinum catalysts were less stereoselective.1... 

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