Nickel carbonyl, decomposition

Miscellaneous. Electron beams can be used to decompose a gas such as silver chloride and simultaneously deposit silver metal. An older technique is the thermal decomposition of volatile and extremely toxic gases such as nickel carbonyl [13463-39-3] Ni(CO)4, to form dense deposits or dendritic coatings by modification of coating parameters. 

In the carbonyl process, the Hquid is purified, vaporized, and rapidly heated to ca 300°C which results in the decomposition of the vapor to carbon monoxide and a fine high purity nickel powder of particle sizes <10 fim. This product is useflil for powder metallurgical appHcations (see Metallurgy, powder). Nickel carbonyl can also be decomposed in the presence of nickel powder, upon which the nickel is deposited. This process yields nickel pellets, typically about 0.8 cm dia and of >99.9 wt% purity. 

J. A. E. BeU and G. Hansen, "Properties of Nickel-Coated Carbon and Kevlar Fibers Produced by the Decomposition of Nickel Carbonyl," the 23rddntemational SAMPE Technical Conference, Anaheim, Calif, Society for the Advancement of Material and Process Engineering, Covina, Calif., Oct. 1991. 

Traditionally, pure CO is not used industrially water gas or producer gas are used instead. However, pure CO is made by thermal decomposition of nickel carbonyl ... 

Mond process The purification of nickel by the formation and decomposition of nickel carbonyl, monomer A small molecule from which a polymer is formed. Examples CH2=CH2 for polyethylene NH2(CH2)6NH2 for nylon, monoprotic acid A Bronsted acid with one acidic hydrogen atom. Example CH COOI I. monosaccharide An individual unit from which carbohydrates are considered to be composed. Example C6H(206, glucose, multiple bond A double or triple bond between two atoms. 

The most commonly used reaction is the decomposition of nickel carbonyl ... 

Although Ni(CO)4 was discovered many years ago, no neutral Ni2(CO)x compound has ever been synthesized in macroscopic amounts. However, several communications report ionic species such as [Ni2(CO)8l+, [Ni2(CO)7], and [Ni2(CO)6]+, where structures with one or two bridging carbonyls are proposed.2418 Plausible structures for neutral Ni2(CO)x (x = 5, 6, 7) have been investigated by theoretical methods, and decomposition temperatures well below room temperature have been predicted.2419,2420 Tetra-, penta-, and hexanuclear nickel carbonyl clusters have been investigated by means of molecular orbital theory. It is found that the neutral forms are more stable than the corresponding anionic forms but the anionic forms gain in stability as the nuclearity rises.2421 Nickel carbonyl cluster anions are manifold, and structural systematics have been reviewed.2422,2423 An example includes the anion [Ni9(CO)i6]2- with a close-packed two-layer metal core.2424... 

The chemical and thermal stability of the fluorophosphine complexes is markedly increased in every case over the chlorophosphine complexes, none of the latter being volatile. The stability of the fluorophophine complexes as compared with the parent carbonyl is also noteworthy. While nickel carbonyl is distillable only with considerable decomposition, tetrakis(trifluorophosphine)nickel-(0) is far more stable on distillation at atmospheric pressure, and can also conveniently be handled in a high-vacuum system. 

Attempts to purify the material further met with little success because of its extreme sensitivity toward oxygen. Recrystallization from ether, for instance, in a modified Schlenk tube (25), with exclusion of air, invariably led to an off-colored product. An attempt to sublime the product in a high vacuum resulted in complete decomposition. Analysis even on the crude product, however, confirmed its identity as a disubstituted derivative of nickel carbonyl. 

One step in the industrial refining of nickel is the decomposition of nickel carbonyl (Ni(CO)4) into nickel and carbon monoxide. In a laboratory reaction, 25.0 g nickel carbonyl yielded 5.34 g nickel. 

Although the hydrogenation of hydrogen cyanide to methylamine was achieved as early as 1863 (Debus, 1), the history of modern catalytic hydrogenation began in 1897 with the discovery by Paul Sabatier and R. Senderens of the vapor phase hydrogenation of unsaturated compounds over a nickel catalyst (Sabatier and Senderens, 2). Sabatier has said that his interest in the action of nickel was provoked by the newly discovered Mond process for the purification of nickel by the formation and decomposition of nickel carbonyl. The capacity of nickel... 

Recently, a nickel zeolite hydrogenation catalyst has been prepared by a novel route (94) involving the adsorption and decomposition of nickel carbonyl onto NaX, which would not be expected to result in the formation of acid sites. In general, the platinum metal-containing zeolites are more active than those containing other transition metals. For example, in zeolite Y the following activity series has been found,... 

Various active nickel catalysts obtained not via reduction of nickel oxide with hydrogen have been described in the literature. Among these are the catalysts obtained by the decomposition of nickel carbonyl 10 by thermal decomposition of nickel formate or oxalate 11 by treating Ni-Si alloy or, more commonly, Ni-Al alloy with caustic alkali (or with heated water or steam) (Raney Ni) 12 by reducing nickel salts with a more electropositive metal,13 particularly by zinc dust followed by activation with an alkali or acid (Urushibara Ni) 14-16 and by reducing nickel salts with sodium boro-hydride (Ni boride catalyst)17-19 or other reducing agents.20-24... 

This decomposition does not take place if a solution of iron pentacarbonyl in nickel carbonyl is exposed to light, perhaps because of the formation of a stable compound of the formula NiFe(CO)g (Dewar). 

Iron Pentacarbonyl. In its reactions with liquid dinitrogen tetroxide this compound follows the pattern outlined above, and the remarks on reactions of nickel carbonyl probably apply here also. The solvate, Fe(N03)3.N204, is produced (4). This has the structure N0+[Fe(N03)4] in the solid state it is volatile without decomposition, and is believed to be a five-coordinate complex, Fe(N0)(N03)4, in the vapor state. We have not yet succeeded in isolating the simple trinitrate, Fe(N03)3, by removal of N2O4. 

The gas phase reaction proceeds very much as described for nickel carbonyl, but the product does not contain the nitrite group (10). A smoke is formed immediately the gases come into contact, but the analysis and infrared spectrum of the solid formed show it to be the oxide-nitrate Fe0(N03). It seems likely that initial reaction involves the NO2 radical, and an iron nitrite such as Fe(N02)3 may be produced initially. The oxidation-reduction properties of the ferric and nitrite ions may render them incompatible Fe0(N03) would then be left as a decomposition product. So little is known about transition metal nitrites that this must remain conjecture at present, but it may be relevant to recall that it has not yet been possible to isolate pure samples of Fe(N03)3, A1(N03)3, or Cr(N03)3. 

Under the guidance of Ostwald s assistant, Max Bodenstein, he began as his doctor s thesis an investigation of the reaction kinetics and of the catalytic aspects involved in the formation and decomposition of nickel carbonyl. As he often mentioned in his later life, this first intimate contact with the fascinating and, in many respects, mysterious field of catalysis, left a deep impression on Mittasch. 

The mechanism of the reaction which takes place in the presence of nickel as well as certain other of the metal catalysts, has been explained by assuming that metallic carbonyls are formed by the action of carbon monoxide on the metal and that these compounds represent intermediate products in the catalyses. Evidence in support of this theory has been brought forward by Mond, Langer and Quinke,0- who studied the decomposition of carbon monoxide in contact with nickel at temperatures between 350° and 450° C. In examining the carbonized nickel catalyst at the end of the experiment these investigators discovered that when heated, it gave off a volatile inflammable nickel compound which could be condensed to a liquid and which was later identified as nickel carbonyl. Metals, such as nickel, cobalt, and iron, which form distinct metallic carbonyls are particularly active catalysts for the decomposition, a fact which adds weight to this theory. 

Ever since Parkyns (60) prepared nickel particles on oxide (A1203, Si02) surfaces by decomposition of nickel carbonyl, metal cluster compounds (alkoxides, carbonyls, organometallics, etc.) have been used increasingly for the production of laboratory metal catalysts (Table I), and several reviews have appeared on this subject (6l-65a,b). 

These topics are discussed in detail in monographs and reviews (NAS 1975, IPCS 1991, Barceloux 1999, Mastromatteo 1986, Sunderman 1984, 2001a). Nickel constitutes less than 0.008% of the Earth s crust. The world s nickel production is obtained primarily from sulfide ores (e.g., pentlandite and nickeliferous pyrrhotite) and, to lesser extent, from oxides ores (e.g., laterite). Nickel sulfide ores, usually mined underground, are crushed and ground, concentrated by physical methods, converted to nickel subsulfide matte, and roasted to nickel oxide. The nickel oxide may be refined electrolytically to yield nickel cathodes or refined by the Mond process, which involves reduction with hydrogen, reaction with carbon monoxide to yield nickel carbonyl, and thermal decomposition to deposit pure nickel. Nickel oxide ores, usually mined in open pits, are smelted to produce ferronickel for use in stainless steel. 

Mond process for nickel refining reduction of nickel oxide with hydrogen, reaction with carbon monoxide to yield nickel carbonyl, and thermal decomposition to deposit pure nickel... 

The principal use of the carbonyls is that of obtaining pure metals. The Mond process for refining nickel and the preparation of pure iron for special pui oses, such as magnet cores, involve the formation of a volatile carbonyl, transport of the vapors away from impurities in the original metal, and subsequent decomposition to obtain the pure metal. The carbonyls of chromium, molybdenum, and timgsten have been used in mass spectroscopy to determine the stable isotopes of the respective metals. Nickel carbonyl has been used to obtain metallic mirrors and to coat objects with a thin film of metal. Iron carbonyl has been used as an antiknock agent in gasoline. 

In the presence of air, nickel carbonyl forms a deposit that becomes peroxidized and may ignite. Nickel carbonyl is incompatible with mercury, nitric acid, chlorine, and other oxidizers, which may cause fires and explosions. Products of decomposition (nickel oxide and carbon monoxide) are less toxic that nickel carbonyl itself. 

INCO have developed [57] a method of coating carbon fiber with Ni using an adaptation of the carbonyl process, involving the thermal decomposition of nickel carbonyl gas ... 

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