Carbonylation Iron carbonyl

Pyridazines form complexes with iodine, iodine monochloride, bromine, nickel(II) ethyl xanthate, iron carbonyls, iron carbonyl and triphenylphosphine, boron trihalides, silver salts, mercury(I) salts, iridium and ruthenium salts, chromium carbonyl and transition metals, and pentammine complexes of osmium(II) and osmium(III) (79ACS(A)125). Pyridazine N- oxide and its methyl and phenyl substituted derivatives form copper complexes (78TL1979). 

Further examples include homo-, co- and terpolymers of manganese carbonyl, iron carbonyl or cyclopentadienyl, and ruthenium-phosphine complexes [31, 59, 60]. 

EINECS 236-670-8 FER pentacarbonyle HSDB 6347 iron carbonyl Iron carbonyl (Fe(CO)6) Iron carbonyl (Fe(CO)5), (TB-5-11)- Iron carbonyl, (Fe(CO)5) Iron carbonyl, (TB-5-11)- Iron carbonyl compounds Iron pentacarbonyl Pentacarbonyliron UN1994,... 

Our studies have focussed largely on the catalysis of the shift reaction by ruthenium carbonyl and by the ruthenium carbonyl/iron carbonyl mixtures in the presence of organic amines under low pressures of CO. Representative studies are indicated in Table II where it is notable that ruthenium alone is a considerably better catalyst than is iron alone. Among the ruthenium systems, pyridine solutions are somewhat more... 

As the reverse reaction proceeds when nickel carbonyl is heated at a temperature of 150°C or more, the formation and decomposition reactions of nickel carbonyl began to be utilized in the manufacture of highly pure nickel [79a]. Following the discovery of nickel carbonyl, iron carbonyl (Fe(CO)5) [84] was found in 1891, and various other kinds of metal carbonyls have now been found [80a]. 

Cadmium dimethyl OT-Xylidine Triphenylarsine Titanium tetrachloride Tin tetraethyl Stannic chloride Diethyl selenide Bismuth triethyl Diethyl telluride Nickel carbonyl Iron carbonyl Lead tetraethyl... 

Covalent. Formed by most of the non-metals and transition metals. This class includes such diverse compounds as methane, CH4 and iron carbonyl hydride, H2Fe(CO)4. In many compounds the hydrogen atoms act as bridges. Where there are more than one hydride sites there is often hydrogen exchange between the sites. Hydrogens may be inside metal clusters. 

Iron forms the carbonyls FelCO),. Fe2(CO)g and FcjlCOlij- In iron pentacarbonyl. the iron(O) is 5-coordinated. as shown in Figure 13.5 to give a trigonal bipyramid the substance is volatile... 

The following acid-catalyzed cyclizations leading to steroid hormone precursors exemplify some important facts an acetylenic bond is less nucleophilic than an olelinic bond acetylenic bonds tend to form cyclopentane rather than cyclohexane derivatives, if there is a choice in proton-catalyzed olefin cyclizations the thermodynamically most stable Irons connection of cyclohexane rings is obtained selectively electroneutral nucleophilic agents such as ethylene carbonate can be used to terminate the cationic cyclization process forming stable enol derivatives which can be hydrolyzed to carbonyl compounds without this nucleophile and with trifluoroacetic acid the corresponding enol ester may be obtained (M.B. Gravestock, 1978, A,B P.E. Peterson, 1969). 

In addition to benzene and naphthalene derivatives, heteroaromatic compounds such as ferrocene[232, furan, thiophene, selenophene[233,234], and cyclobutadiene iron carbonyl complexpSS] react with alkenes to give vinyl heterocydes. The ease of the reaction of styrene with sub.stituted benzenes to give stilbene derivatives 260 increases in the order benzene < naphthalene < ferrocene < furan. The effect of substituents in this reaction is similar to that in the electrophilic aromatic substitution reactions[236]. 

Not all ligands use just two electrons to bond to transition metals Chromium has the electron configuration [Ar]4s 3rf (6 valence electrons) and needs 12 more to satisfy the 18 electron rule In the compound (benzene)tricarbonylchromium 6 of these 12 are the tt elec Irons of the benzene ring the remammg 6 are from the three carbonyl ligands... 

The original German process used either carbonyl iron or electrolytic iron as hydrogenation catalyst (113). The fixed-bed reactor was maintained at 50—100°C and 20.26 MPa (200 atm) of hydrogen pressure, giving a product containing substantial amounts of both butynediol and butanediol. Newer, more selective processes use more active catalysts at lower pressures. In particular, supported palladium, alone (49) or with promoters (114,115), has been found useful. 

Acetates. Anhydrous iron(II) acetate [3094-87-9J, Ee(C2H202)2, can be prepared by dissolving iron scraps or turnings in anhydrous acetic acid ( 2% acetic anhydride) under an inert atmosphere. It is a colorless compound that can be recrystaUized from water to afford hydrated species. Iron(II) acetate is used in the preparation of dark shades of inks (qv) and dyes and is used as a mordant in dyeing (see Dyes and dye intermediates). An iron acetate salt [2140-52-5] that is a mixture of indefinite proportions of iron(II) and iron(III) can be obtained by concentration of the black Hquors obtained by dissolution of scrap iron in acetic acid. It is used as a catalyst of acetylation and carbonylation reactions. 

Carbonyls. Iron pentacarbonyl [1346340-6], Fe(CO), is a toxic, yeUow-orange, oily Hquid which does not react with air at room temperature. It... 

Specific Surface. The total surface area of 1 g of powder measured ia cm /g is called its specific surface. The specific surface area is an excellent iadicator for the conditions under which a reaction is initiated and also for the rate of the reaction. It correlates in general with the average particle size. The great difference in surface area between 6-p.m reduced iron powder and 7-p.m carbonyl iron powder (Table 3) cannot be explained in terms of particle size, but mainly by the difference between the very inregular-shaped reduced and the spherical carbonyl iron powders. 

In atomization, a stream of molten metal is stmck with air or water jets. The particles formed are collected, sieved, and aimealed. This is the most common commercial method in use for all powders. Reduction of iron oxides or other compounds in soHd or gaseous media gives sponge iron or hydrogen-reduced mill scale. Decomposition of Hquid or gaseous metal carbonyls (qv) (iron or nickel) yields a fine powder (see Nickel and nickel alloys). Electrolytic deposition from molten salts or solutions either gives powder direcdy, or an adherent mass that has to be mechanically comminuted. 

The advent of a large international trade in methanol as a chemical feedstock has prompted additional purchase specifications, depending on the end user. Chlorides, which would be potential contaminants from seawater during ocean transport, are common downstream catalyst poisons likely to be excluded. Limitations on iron and sulfur can similarly be expected. Some users are sensitive to specific by-products for a variety of reasons. Eor example, alkaline compounds neutralize MTBE catalysts, and ethanol causes objectionable propionic acid formation in the carbonylation of methanol to acetic acid. Very high purity methanol is available from reagent vendors for small-scale electronic and pharmaceutical appHcations. 

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. 

Ma.nufa.cture. Nickel carbonyl can be prepared by the direct combination of carbon monoxide and metallic nickel (77). The presence of sulfur, the surface area, and the surface activity of the nickel affect the formation of nickel carbonyl (78). The thermodynamics of formation and reaction are documented (79). Two commercial processes are used for large-scale production (80). An atmospheric method, whereby carbon monoxide is passed over nickel sulfide and freshly reduced nickel metal, is used in the United Kingdom to produce pure nickel carbonyl (81). The second method, used in Canada, involves high pressure CO in the formation of iron and nickel carbonyls the two are separated by distillation (81). Very high pressure CO is required for the formation of cobalt carbonyl and a method has been described where the mixed carbonyls are scmbbed with ammonia or an amine and the cobalt is extracted as the ammine carbonyl (82). A discontinued commercial process in the United States involved the reaction of carbon monoxide with nickel sulfate solution. 

Manufacture. Trichloromethanesulfenyl chloride is made commercially by chlorination of carbon disulfide with the careful exclusion of iron or other metals, which cataly2e the chlorinolysis of the C—S bond to produce carbon tetrachloride. Various catalysts, notably iodine and activated carbon, are effective. The product is purified by fractional distillation to a minimum purity of 95%. Continuous processes have been described wherein carbon disulfide chlorination takes place on a granular charcoal column (59,60). A series of patents describes means for yield improvement by chlorination in the presence of dihinctional carbonyl compounds, phosphonates, phosphonites, phosphites, phosphates, or lead acetate (61). 

Since the discovery of nickel carbonyl in 1890 (15), carbonyls of many other metals have been prepared. Nickel and iron are the only metals that combine direcdy with CO to produce carbonyls in reasonable yields. At least one carbonyl derivative is known for every t5 -block metal. A number of the neutral complexes that have been reported ate Hsted in Table 4. 

Syntheses from Dry Metals and Salts. Only metaUic nickel and iron react direcdy with CO at moderate pressure and temperatures to form metal carbonyls. A report has claimed the synthesis of Co2(CO)g in 99% yield from cobalt metal and CO at high temperatures and pressures (91,92). The CO has to be absolutely free of oxygen and carbon dioxide or the yield is drastically reduced. Two patents report the formation of carbonyls from molybdenum and tungsten metal (93,94). Ruthenium and osmium do not react with CO even under drastic conditions (95,96). 

Reactions of acetylene and iron carbonyls can yield benzene derivatives, quinones, cyclopentadienes, and a variety of heterocycHc compounds. The cyclization reaction is useful for preparing substituted benzenes. The reaction of / fZ-butylacetylene in the presence of Co2(CO)g as the catalyst yields l,2,4-tri-/ f2 butylbenzene (142). The reaction of Fe(CO) and diphenylacetylene yields no less than seven different species. A cyclobutadiene derivative [31811 -56-0] is the most important (143—145). 

Exposure to metal carbonyls can present a serious health threat. Nickel carbonyl is considered to be one of the most poisonous inorganic compounds. However, the toxicological information available on metal carbonyls is restricted to the mote common, commercially important compounds such as Ni(CO)4 and Ee(CO). Other metal carbonyls are considered potentially dangerous, especially ia the gaseous state, by analogy to nickel and iron carbonyls. Data concerning toxicological studies on a few common metal carbonyls are Hsted ia Table 6 (185). Additional toxicity data are OSHA personal exposure limits (PEL) for Ee(CO) this is 8 h at 0.1 ppm, whereas for the much more toxic Ni(CO)4 it is 8 h at 0.001 ppm, with a toxic concentration TCLq low (of 7 mg/m ) for human inhalation. 

The toxic symptoms from inhalation of nickel carbonyl are beUeved to be caused by both nickel metal and carbon monoxide. In many acute cases the symptoms ate headache, di22iQess, nausea, vomiting, fever, and difficulty in breathing. If exposure is continued, unconsciousness follows with subsequent damage to vital organs and death. Iron pentacarbonyl produces symptoms similar to nickel carbonyl but is considered less toxic than nickel carbonyl. 

When heated to about 60°C, nickel carbonyl explodes. Eor both iron and nickel carbonyl, suitable fire extinguishers are water, foam, carbon dioxide, or dry chemical. Large amounts of iron pentacarbonyl also have been reported to ignite spontaneously (189). Solutions of molybdenum carbonyl have been reported to be capable of spontaneous detonation (190). The toxicity of industrial chemicals including metal carbonyls may be found in references 191-194. 

Carbonyl Iron Powders, General Aniline and Film Corporation, New York, 1962. 

Earlier catalysts were based on cobalt, iron, and nickel. However, recent catalytic systems involve rhodium compounds promoted by methyl iodide and lithium iodide (48,49). Higher mol wt alkyl esters do not show any particular abiUty to undergo carbonylation to anhydrides. 

There appear to be few examples of the formation of azetidin-2-ones by closure of the C(2) —C(3) bond. One reaction which fits into this category involves reaction of the iron carbonyl lactone complexes (144) with an amine to give the allyl complexes (145) which on oxidation are converted in high yield to 3-vinyl-/3-lactams (146) (80CC297). 

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