Carbon monoxide s.a. Carbonylation

Although nickel carbonyl is intensely poisonous, it is used in the Mond process for the refinement of nickel (see Section 16.3). Complex formation is also responsible for carbon monoxide s toxicity it attaches more strongly than oxygen to the iron in hemoglobin and prevents it from accepting oxygen from the air in the lungs. As a result, the victim suffocates. 

Loss of a ligand from saturated metal complexes often generates highly reactive fragments. In the absence of other reaction pathways, these fragments can condense to metal-metal bonded dimers or higher-order clusters. The best example of this reaction is loss of carbon monoxide from metal carbonyls to yield dimers and clusters. For example, photogenerated Fe(CO)4 species readily react with Fe(CO)s to yield Fe2(CO)g (equation 61). 

Despite the high tonnages of petrochemicals, the chemical industry as a whole consumes rather less than 10% of available petroleum and natural gas hydrocarbons as feedstocks, with possibly a further 4-5% as fuel. For comparison, the current consumption of gasoline alone in Western Europe exceeds 120 Mt per annum, while the U.S. figure is over 300 Mt per annum. Hence, prices of individual hydrocarbon feedstocks are largely determined by other forces the most economic feedstock/route combination has frequently changed with time, and may differ in different parts of the world. Furthermore, while a specific route may be preferred for new plants, older plants for which the capital is largely written off may well remain economically viable. Finally, special situations may prompt individual solutions. For example, Rhone-Poulenc in France derive the carbon monoxide for a very modern acetic acid plant, based on Monsanto s methanol carbonylation process, from the partial... 

Most of the world s nickel comes from deposits in Ontario, Canada. These deposits are believed to have formed from a meteorite impact (most meteorites have high nickel content). The nickel occurs as a sulfide compound mixed with copper and iron sulfides. To produce nickel, the sulfides are roasted in air to form metal oxides, and then they are reduced to the elemental metals with carbon. The metal mixture is heated in the presence of carbon monoxide, forming nickel carbonyl, which has a boiling point of 43 °C and can be collected as a gas. 

Both palladium-catalyzed carbonylative ring-forming reactions of o-iodophenols and o-iodothiophenols with allenes and carbon monoxide involve a carbopalladation step and afford l-benzopyran-4-one 47 and thiochroman-4-one 48 derivatives [61,62]. The reactions proceed in benzene at 100 °C, in autoclave at 20 atm of carbon monoxide and in the presence of Pd(OAc)2, Hiinig s base, dppb or dppf. However,... 

Pure iron, when needed, is produced on a relatively small scale by the reduction of the pure oxide or hydroxide with hydrogen, or by the carbonyl process in which iron is heated with carbon monoxide under pressure and the Fe(CO)5 so formed decomposed at 250°C to give the powdered metal. However, it is not in the pure state but in the form of an enormous variety of steels that iron finds its most widespread uses, the world s annual production being over 700 million tonnes. 

A 1,3-oxathiolane derivative (100) is formed when 2-mercaptoethanol is carbonylated by nickel carbonyl in pyridine (Scheme 118).181 It is probable that the mechanism involves carbonyl insertion into the Ni—S bond of intermediate thiolatonickel complexes and it is significant that compounds in this category (cf. 101,102) can be transformed into the cyclic thiocarbonate by treatment with carbon monoxide (Scheme 118).181... 

A somewhat related process, the cobalt-mediated synthesis of symmetrical benzo-phenones from aryl iodides and dicobalt octacarbonyl, is shown in Scheme 6.49 [100]. Here, dicobalt octacarbonyl is used as a combined Ar-I bond activator and carbon monoxide source. Employing acetonitrile as solvent, a variety of aryl iodides with different steric and electronic properties underwent the carbonylative coupling in excellent yields. Remarkably, in several cases, microwave irradiation for just 6 s was sufficient to achieve full conversion An inert atmosphere, a base or other additives were all unnecessary. No conversion occurred in the absence of heating, regardless of the reaction time. However, equally high yields could be achieved by heating the reaction mixture in an oil bath for 2 min. 

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