Nickel tetracarbonyl decomposition

Carlton and Oxley A.I.Ch.E. J., 13 (86), 1967] have studied the heterogeneous catalytic decomposition of nickel tetracarbonyl over the temperature range from 100 to 225° C. 

Finely divided nickel combines with carbon monoxide to form zero valent nickel tetracarbonyl, Ni(CO)4. The reaction occurs at 50°C and one atmosphere, although it is usually carried out at 200°C under high CO pressure between 100 to 400 atm for high yield of carbonyl, and to prevent product decomposition. Carbon monoxide at ordinary pressure may be passed over freshly reduced metal to form the tetracarbonyl. 

Nickel tetracarbonyl is a highly toxic volatile colorless liquid that is shipped in cylinders pressurized with carbon monoxide.8 Its vapor is about six times as dense as air. Purification of nickel by the Mond process is based on the decomposition of Ni(CO)4, the reverse of Eq. 15.3. The yellow-red iron pentacarbonyl slowly decomposes in air and is sensitive to light and heal. In feet. Fe-jfCOJy, an orange solid, is prepared by photolysis of Fe(CO). ... 

Nickel Tetracarbonyl, Ni(CO)4, is obtained when carbon monoxide is passed over metallic nickel 3 in a finely divided condition, such as is obtained by the reduction of nickel oxide in hydrogen at 400° C., the best temperature for obtaining the carbonyl being about 30-50° C. The carbonyl is condensed in a cooled vessel. The reaction may be advantageously carried out under a pressure of 2-100 atmospheres of carbon monoxide, in which case the temperature may be raised even to 250° C. without fear of decomposition.4... 

Likewise, the direct synthesis of [M(PF3)4] (M = Ni, Pd, Pt) complexes has been achieved from the appropriate metal powder (method F), or alternatively under very mild conditions from highly reactive forms of the metal (e.g., Ni) generated either from the decomposition of nickel oxalate or nickel tetracarbonyl or activated by sulfide (method G). 

The reaction of 75 with nickel tetracarbonyl gives the cyclopentadienone-nickel complex (81), thermal decomposition of which yields the cyclopentadienone 82 . 

Properties Mobile, yellow liquid. D 1.466 (18C), bp 102.8C (749 mm Hg), decomposes at 200C, mp -21C, flash p 5F (-15C). Evolves carbon monoxide on exposure to air or to light. Soluble in nickel tetracarbonyl and most organic solvents soluble with decomposition in acids and alkalies insoluble in water. 

Mond process a chemical procedure for the purification of nickel that depends on the formation and later decomposition of a volatile compound of the metal (nickel tetracarbonyl). (13.2)... 

Passing gaseous hydrochloric acid in the solution of nickel tetracarbonyl results in the decomposition... 

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 ... 

The sulphide ore is oxidised in the presence of silica which enables the iron to be removed as a silicate slag. The nickel oxide left is reduced at 350° by water gas to an impure metal leaving the iron as ferric oxide. Purification is based on the formation and decomposition of gaseous Ni(CO)4. Carbon monoxide is passed over the impure metal at 60° and the gas containing a few per cent of the tetracarbonyl is brought into contact with agitated nickel pellets at 200°. The pellets grow as nickel is deposited on them the CO is recirculated (Fig. 258). 

In the presence of a large excess of tetracarbonyl nickel and ethanol diphenyldiazo-methane, diazofiuorene, bis-(4-methoxyphenyl)diazomethane, and ethyl diazoacetate give carbonylation products trapped by ethanol and processed into the corresponding carboxylic acid in 74,38,26, and 8.5% isolated yields, respectively, which presumably arise from a nickel carbene carbonyl intermediate that releases a substituted ketene upon decomposition at 50-66 °C. In the absence of ethanol, by refluxing a solution of 1 mol diphenylketene with 6.4 mol tetracarbonyl nickel in diethylether 35% isolated yield of diphenylketene was observed [86]. The r -(C,C)-ketene complex of nickel (31) was isolated in 17% yield from the reaction of nickelacyclobutane (29) with carbon monoxide (3 bar) at 50 °C (reaction 8.54) [87]. Complex 29 is believed to be in equilibrium with the nickel-carbene-olefrn complex 30 [88]. The nickel-ketene complex 31 was also obtained either by direct reaction of Ni(PPh3)4 with ketene or by carbonylation of the nickel-carbene complexes presumably formed from the reaction of Ni(PPh3)4 and CH2Br2 in the presence of metallic zinc [89]. 

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