Nickel carbonyls synthesis

The stoichiometric and the catalytic reactions occur simultaneously, but the catalytic reaction predominates. The process is started with stoichiometric amounts, but afterward, carbon monoxide, acetylene, and excess alcohol give most of the acrylate ester by the catalytic reaction. The nickel chloride is recovered and recycled to the nickel carbonyl synthesis step. The main by-product is ethyl propionate, which is difficult to separate from ethyl acrylate. However, by proper control of the feeds and reaction conditions, it is possible to keep the ethyl propionate content below 1%. Even so, this is significantly higher than the propionate content of the esters from the propylene oxidation route. 

Acetylene-Based Routes. Walter Reppe, the father of modem acetylene chemistry, discovered the reaction of nickel carbonyl with acetylene and water or alcohols to give acryUc acid or esters (75,76). This discovery led to several processes which have been in commercial use. The original Reppe reaction requires a stoichiometric ratio of nickel carbonyl to acetylene. The Rohm and Haas modified or semicatalytic process provides 60—80% of the carbon monoxide from a separate carbon monoxide feed and the remainder from nickel carbonyl (77—78). The reactions for the synthesis of ethyl acrylate are... 

Garboxylation Reaction. The carboxylation reaction represents the conversion of acetylene and olefins into carboxyHc acids (qv) or their derivatives. The industrially important Reppe process is used in the synthesis of P-unsaturated esters from acetylene. Nickel carbonyl is the catalyst of choice (134). 

The second approach consists of synthesizing first the complex MLra 1(L X) with the desired ratio (L )/(M) this complex bears the reactive fragment X which then reacts with the surface of the silica. This method is of limited interest, because the synthesis and isolation of these functionalized complexes is not straightforward. One of the successful examples concerns the synthesis of nickel carbonyl complexes anchored to the surface via two bonds in an attempt to increase the stability through a sort of chelate effect. Initial attempts to achieve this by the methods described in Equation(5) (initial functionalization of silica) and Equation(6) (initial functionalization of complex) failed, as demonstrated by 29Si and 31P CP MAS NMR spectroscopies.51... 

The raw material for the synthesis was methane. Powder of Nickel carbonyl (NC) or powder of nano-diamond (ND) was the catalyst. Attempts to synthesize pyro-carbon on copper powder were not successful. Powder with the composition 70%PC, 30%NC, and also the set of powders with various ratios of PC and ND were tested. Anodes made of the powder 70PC30NC showed satisfactory cycle behavior and had specific capacity 180 mAh/(g of powder) (260 mA-h/(g 0f carbon)) (Fig. 3a). The anodes made of powder xPCyND, irrespective of the components ratio, had specific capacity... 

A nickel(II) species is also though to be an intermediate in the carbonyla-tion reaction of iodobenzene with (V-methylbenzaldimine and nickel carbonyl. Two addition modes of an ensuing aroylnickel(II) complex to the C=N double bond can be envisaged as routes to l-methyl-2-phenylindol-3-one and an ethylenediamine derivative (Scheme 47).7 5 The scope of this simple indole synthesis has not been assessed. 

Probably the nickel carbonyl-catalyzed synthesis of acrylates from CO, acetylene, and hydroxylic solvent (78) involves an acetylene-hydride insertion reaction, followed by a CO insertion, and hydrolysis or acyl halide elimination. The actual catalyst in the acrylate synthesis is probably a hydride formed by the reversible addition of an acid to nickel carbonyl. 

Initial attack of hydroxide ions onto Ni(CO)4 gives as yet uncharacterized species,1 which readily condense with unreacted Ni(CO)4 to give variable mixtures of [Ni5(CO)12]2- and [Ni6(CO)12]2-. Hydrolysis of [Ni5(CO)12]2- in water produces [Ni6(CO)12]2-, according to the above reaction. The dianion [Ni CO) 2]2- is isolated as the tetramethylam-monium salt in a crystalline state in 70% yield. The [Ni6(CO)12]2 dianion is a starting material for the synthesis of several other homo- and heteromet-allic nickel carbonyl cluster complexes.1-9... 

The reaction is only partially catalytic because nickel chloride is formed in side reactions. If a reducing agent such as iron powder is added to reduce nickel(II) dichloride to nickel carbonyl with CO, higher catalytic activity is observed (22). Some examples of the 2,5-hexadienoate ester synthesis are given in Table VI. 

Polymetallic iridium carbonyl complexes, preparation, 7, 291 Polymetallic nickel—alkenes, synthesis and reactivity, 8, 139 Polymetallocenes... 

Tetrakis[phosphorus(III) chloride] nickel has been prepared by the reaction of nickel carbonyl with phosphorus-(III) chloride at room temperature.1 The synthesis of this compound as described below is based on this method. 

A more favorable synthesis of salts of the iron, cobalt and nickel carbonyl anions, which were initially prepared by disproportionation reactions of Fe(CO)5, Co2(CO)8, and Ni(CO)4 with pyridine and other amines, was found by treatment of the neutral carbonyls with alkali in aqueous or alcoholic solutions. Careful studies by Hieber revealed that Fe(CO)5 as well as Fe3(CO)12 reacted with exactly four equivalents of hydroxide ions to give the corresponding dianionic iron carbonylates (Scheme 4.4). These dianions are relatively strong bases and readily accept a proton from a water molecule to give the monoanionic hydrido carbonylates [I IFe(CO)4] and [HFe3(CO)n], respectively [36]. The related carbonylates of cobalt and manganese, [Co(CO)4] and [Mn(CO)5], were obtained by a similar way as [Fe(CO)4]2 [25]. With regard to the mechanism of Hieber s Basenreaktion , the most plausible explanation is based on an initial nucleophilic attack by the hydroxide ion at the carbon atom of a CO... 

J. C. Calabrese, L. F. Dahl, A. Cavalieri, P. Chini, G. Longoni, and S. Martinengo, Synthesis and Structure of a Hexanuclear Nickel Carbonyl Dianion, [Ni3(CO)3( j,2-CO)3]22, and Comparison with the [Pt3(CO)3(p2-CO)3]22 Dianion. An Unprecedented Case of a Metal Cluster System Possessing Different Metal Architectures for Congener Transition Metals, J. Am. Chem. Soc. 96, 2616-2618 (1974). 

The method for forming cycloolefins from bis-allylic halides and nickel carbonyl was first reported by Corey and coworkers [135] and has been appli to the synthesis of several macrocycUc natural products [136]. The 14-membered diter-pene cembrene (225) was synthesized by Dauben et al. [136b], for example. As... 

Sato and coworkers [137] reported the synthesis of macrocyclic lactones via intramolecular alkylation of n-allylic nickel complexes, based on the facile reactivity of n-allylic nickel complexes toward alkyl halides. As shown in Scheme 75, this method was applied to the synthesis of the macrolide recifeiolide 227). The linear precursor 226 in benzene was added slowly over 1 h to nickel carbonyl in benzene at 50 °C. After additional 1.5 h at 50 °C, 227 was obtained in 32% yield. 

Before the modem era of organotransition metal reactivity, it was observed that nickel carbonyl reacted with 2-methallyl chloride in methanol to give methyl 3-methyl-3-butenoate and 2,5-dimethyl-1,5-hexadiene as a by-product. In THF at 25 °C, the diene was the exclusive product. This mild formation of a carbon carbon bond, and the interest in the synthesis of terpene-based natural products led to efforts to test the scope and limitations of the process. An obvious pathway involves stepwise oxidative addition of each aUyl unit followed by Reductive Elimination. As discussed below, the key intermediates (left vague in Scheme 48) are likely to involve Ni -Ni couples. 

Synthesis of maerolides. The intramolecular coupling reaction of allylic halides (I, 722-723 2, 290-292 3, 211) has now been shown to be applicable to the synthesis of maCrocyclic lactones. Thus addition of the dibromo ester (1) to 6 eq. of nickel carbonyl in N-methylpyrrolidone effects cyclization to the macrolide (2) as the major product. 

Schrauzer and Thyret have described (528, 529, 531) the synthesis of olefin-Ni(O) complexes containing a quinone, in particular, duro-quinone, as a ligand. The red, diamagnetic duroquinone complexes are obtained by reaction of nickel carbonyl with the quinone in excess olefin. They are stable in air and soluble in polar organic solvents and water. Those olefins which form the coiiqilex contain essentially parallel double bonds, e.g., norbornadiene, dicyclopentadiene, 1,5-cycloocta-diene, 1,3,5-cyclooctatriene, or cyclooctatetraene. 

Corey and Hamanaka - employed intramolecular allylic coupling in a novel synthesis of medium-size carbocyclic systems. The doubly allylic o.ai-dihulidc (I) on cyclization with nickel carbonyl gave as the chief product the ull-trum-dimethyl-cyclododecatriene (2). eccompenled by an liomar, probably fh, iran.s.tmns. 

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