Nickel carbonyl process

Novel palladium catalysts show marked improvements in both yields and selectivities, compared to nickel carbonyl catalysts utilized in eadier commercial carbonylation processes (83,84). The palladium catalysts are also expected to be less hazardous. 

Ca.rbonylProcess. Cmde nickel also can be refined to very pure nickel by the carbonyl process. The cmde nickel and carbon monoxide (qv) react at ca 100°C to form nickel carbonyl [13463-39-3] Ni(CO)4, which upon further heating to ca 200—300°C, decomposes to nickel metal and carbon monoxide. The process is highly selective because, under the operating conditions of temperature and atmospheric pressure, carbonyls of other elements that are present, eg, iron and cobalt, are not readily formed. 

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. 

The carbonyl process developed in 1899 by L. Mond is still used, though it is mainly of historic interest. In this the heated oxide is first reduced by the hydrogen in water gas (H2 + CO). At atmospheric pressure and a temperature around 50°C, the impure nickel is then reacted with the residual CO to give the volatile Ni(CO)4. This is passed over nucleating pellets of pure nickel at a temperature of 230°C when it decomposes, depositing nickel of 99.95% purity and leaving CO to be recycled. 

CVD is not a new process. As stated in the pioneer work of Powell, Oxley, andBlocher, 1 its first practical use was developed in the 1880s in the production of incandescent lamps to i mprove the strength of filaments by coating them with carbon or metal. In the same decade, the carbonyl process was developed by Ludwig Mond and others for the production of pure nickel. A number of patents were issued during that period coveringthe basis of CVD.PI... 

Preparation. High purity nickel can be produced through electrolytic process or by the carbonyl process. In the latter case carbon monoxide reacts at 50°C with impure Ni (or nickel-copper matte) to give the volatile tetracarbonyl from which the metal (99.9-99.99% purity) is obtained by decomposition at 200-230°C through the reaction ... 

Ruthenium is derived from platinum metal ores. Method of production depends on the type of ore. However, the extraction processes are simdar to those of other nohle metals (see Platinum, Rhodium and Iridium). Ruthenium, like Rhodium, may he obtained from accumulated anode sludges in electrolytic refining of nickel or copper from certain types of ores. Also, residues from refining nickel by Mond carbonyl process contain ruthenium and other precious metals at very low concentrations. The extraction processes are very lengthy, involving smelting with suitable fluxes and acid treatments. 

Sulfide ores are processed by a number of pyrometallurgical processes roasting, smelting, and converting. During these processes, sulfur and iron are removed to deld a sulfur-deficient copper-nickel matte. Especially after roasting and converting, the nickel in the matte may consist primarily of nickel subsulfide. After physical separation of the copper and nickel sulfides, the nickel is refined electrochemically or by the carbonyl process. The treatment of the matte depends on the end use of the nickel. Alternatively, the sulfide can be roasted to form a nickel oxide sinter that is used directly in steel production. 

In a similar process, nickel compounds also catalyze the carbonylation of allenyl halides, under phase-transfer conditions (PTC), to give allenyl acids in poor to reasonably good yields (equation 94)368. 

In this work the ultrafast photophysical processes associated with photoinduced CO loss will be described with particular regard to the mononuclear homoleptic carbonyls Cr(CO)6, Fe(CO)5, and Ni(CO)4. These complexes were the earliest metal carbonyls to be synthesized, indeed Fe(CO)5 and Ni(CO)4 have been known since the latter part of the nineteenth century. The carbonylation of nickel provided an important route to high purity nickel which was required by many important industrial processes. However, it is only within the last few decades that adequate models have been developed to explain the mechanisms of photoinduced CO loss from metal carbonyl complexes. 

The reaction of an aUcene (or aUcyne), CO, and H2O to directly produce a carboxylic acid is called Reppe carbony-lation chemistry or, more recently, hydrocarboxylation (see Reppe Reaction). An excellent review of palladium-catalyzed Reppe carbonylation systems has been published recently by Kiss, and coverage of this important material will not be repeated here. This catalytic reaction has been known for quite some time, although the stoichiometric Ni(CO)4-based carbonylation of acetylene was the first commercial carbonylation process implemented (equation 13). The extreme toxicity of Ni(CO)4, however, has limited practical applications (see Nickel Organometallic Chemistry). Co, Rh, and Pd catalysts have certainly replaced Ni(CO)4 in smaller-scale laboratory reactions, though for historical reasons a number of the fim-damental mechanisms discussed in this section are based on Ni(CO)4. 

Carbonylation Processes by Homogeneous Catalysis Coordination Chemistry History Coordination Numbers Geometries Iron Organometallic Chemistry Manganese Organometallic Chemistry Nickel Organometallic Chemistry Rhodium Organometallic Chemistry. 

Nickel. Nickelite, millerite, peiitlandite. xMetaliurgy of nickel. Mond process, nickel carbonyl. Nickel iViating from ammoniacal solution of ammonium nickel sulfate. Nickel sulfate, nickelous hydroxide, nickel chloride, nickelous oxide. Nirkelit oxide. Edisr>n storage cell. 

The applied nickel catalyst, promoted by copper halides, required rather severe reaction conditions T = 220 °C, F = 10 MPa), but gave good AA yields up to 90% based on acetylene. This so-called catalytic Reppe process was commercially operated in Germany, the USA, and Japan. Due to the limited availability of cheap acetylene as feedstock and the severe reaction conditions involved in the carbonylation process, this process has lost the competition with (heterogeneously catalyzed) oxidation of readily available propene, even though a perfect selectivity to AA is not achieved in the latter process. 

One of the earliest industrial CVD applications developed during this stage is a carbonyl process for refining nickel (Ni), developed by Mond in 1890 [9, 10], The famous Mond extraction process uses the following chemical reaction process ... 

The catalyst system for the modem methyl acetate carbonylation process involves rhodium chloride trihydrate [13569-65-8]y methyl iodide [74-88-4], chromium metal powder, and an alumina support or a nickel carbonyl complex with triphenylphosphine, methyl iodide, and chromium hexacarbonyl (34). The use of nitrogen-heterocyclic complexes and rhodium chloride is disclosed in one European patent (35). In another, the alumina catalyst support is treated with an organosilicon compound having either a terminal organophosphine or similar ligands and rhodium or a similar noble metal (36). Such a catalyst enabled methyl acetate carbonylation at 200°C under about 20 MPa (2900 psi) carbon monoxide, with a space-time yield of 140 g anhydride per g rhodium per hour. Conversion was 42.8% with 97.5% selectivity. A homogeneous catalyst system for methyl acetate carbonylation has also been disclosed (37). A description of another synthesis is given where anhydride conversion is about 30%, with 95% selectivity. The reaction occurs at 445 K under 11 MPa partial pressure of carbon monoxide (37). A process based on a montmorillonite support with nickel chloride coordinated with imidazole has been developed (38). Other related processes for carbonylation to yield anhydride are also available (39,40). 

Propionic acid is produced commercially by several different processes. It is a by-product of the liquid phase oxidation of hydrocarbons for the manufacture of acetic acid. It is also made from carbon monoxide and ethylene by the 0x0 process through a propionaldehyde intermediate or by the carbonylation of ethylene with a nickel-based catalyst. BASF uses the one-step Reppe carbonylation process with a nickel propionate catalyst to produce 40,000 metric tons per year of propionic acid in Ludwigshafen, Germany. The hydrocarboxylation chemistry is shown in Eq. (29) ... 

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 ... 

In addition, reductive elimination of palladium and nickel complexes to form esters (Equations 8.67 and 8.68), amides, and tiiioesters has been reported. -" The reductive eliminations of esters and amides were observed during mechanistic studies on the palladium-catalyzed formation of esters and amides from aryl halides, carbon monoxide, and alcohols or amines. This catalytic process is presented in Qiapter 17 (carbonylation processes). The reductive elimination of thioesters from nickel complexes were studied, in part, to understand the C-S bond-forming process of acetyl coenzyme A synthase. Prior to this work, an iron-mediated synthesis of p-lactams had been reported that appears to occur by reductive elimination to form the amide C-N bond of the lactam. ... 

Like many carbonylation processes, the hydrocarboxylation and hydroesterification reactions were first reported by Reppe. These first reactions involved the hydrocarboxylation of alkynes. These reactions were conducted with nickel carbonyl as catalyst and occurred with very low turnover numbers. Hydrocarboxylation and hydroesterification have now been studied extensively in both academic and industrial laboratories. As a result of these investigations, commercialization of this chemistry as part of new industrial processes has occurred, and the mechanism of these processes is now generally accepted. This section of Chapter 17 presents the scope and industrial applications of hydrocarboxylation and hydroesterification, the types of catalysts that have been used for these processes, and the elementary steps that constitute the catalytic cycle for olefin and alkyne hydroesterification. 

Nickel that is more than 99.9% pure can be produced by the carbonyl process Impure nickel combines with CO at 50 C to produce Ni(CO)4( ). The Ni(CO)4 is then heated to 200°C, causing it to decompose back into Ni(s) and CO g). (a) Write the equilibrium-constant expression for the formation of Ni(CO)4 (b) Given the temperatures used for the steps in the carbonyl process, do you think this reaction is endothermic or exothermic (c) In the early days of automobiles, nickel-plated exhaust pipes were used. Even though the equilibrium constant for the formation of Ni(CO)4 is very small at the temperature of automotive exhaust gases, the exhaust pipes quickly corroded. Explain why this occurred. 

During vapometallurgical refining, impure metal obtained by the reduction of nickel oxide is subjected to the action of carbon monoxide forming volatile nickel carbonyl [Ni(CO)4] (carbonyl or Mond process). This reaction is reversed by heat, and the nickel carbonyl decomposes to pure nickel metal and carbon monoxide. The carbonyl process produces the purest nickel (99.97% or more) [47-51]. 

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