Nickel 11 iodide

IDAS A process for making isoprene (for the manufacture of a synthetic rubber) by the oxidative dehydrogenation of isopentene. Iodine is the initial reactant the hydrogen iodide produced in the reaction is reconverted to elemental iodine via nickel iodide. 

Isomerism of the but-3-enoic acids into the E-but-2-enoic acids is base-catalysed (Table 8.8), whereas the formation of the other isomers indicates the participation of rt-allylnickel complexes in the reaction. Potassium nickel tetracarbonyl is a considerably poorer catalyst, compared with nickel cyanide, whereas nickel sulphate and nickel iodide are ineffective catalysts. 

Adipic acid can also be made from THF, obtained from furfural. It is carbonylated in the presence of nickel carbonyl-nickel iodide catalyst. Furfural is a chemurgic product obtained by the steam-acid digestion of corn cobs, oat hulls, bagasse, or rice hulls. 

In the case of phosphine, especially tri-n-butyl and triphenyl phosphines, an active phosphine complex is formed in the reaction medium via reaction with nickel carbonyl. This complex is a very active species provided that the optimum concentration of phosphine is used. Low phosphine concentration results in a loss of the effective nickel concentration through the formation of nickel tetra-carbonyl, nickel metal or nickel iodide. The absolute concentration of phosphine is less important than the P/Ni ratio. In addition to form the stable Ni-P catalyst, the phosphine has to compete with other ligands in the reaction mixture for nickel. With high carbon monoxide partial pressure, there is more CO in solution to compete with phosphine favoring the formation of the carbonyl, which is inactive under the reaction conditions. Hence with high carbon mon-... 

This is in contrast with the rhodium system where alkali metal salts were reported to have no effect on methanol carbonylation (19). In spite of the promotion effect of lithium the nickel catalyst is not maintained in a soluble stable complex form. Precipitation of nickel iodide is common when one of the alkali metals is the only catalyst promoter. 

The activity of the nickel catalyst is affected by major variations in carbon monoxide partial pressure. With very low carbon monoxide partial pressure, nickel precipitates as a metal powder and occasionally as nickel iodide. Stability of the catalyst is improved with higher CO partial pressure up to a point above which the catalyst activity drops linearly. The optimum level of carbon monoxide is different from one catalyst mixture to another. This behavior is characteristic of all the nickel catalyzed carbonylation reactions we studied. In the Li-P system, optimum carbon monoxide partial pressure is in the range of 700 to 800 psi (Table V). On the other hand, the optimum carbon monoxide partial pressure for the Li-Sn system is in the range of 220 to 250 psi, at 160 C, and 450 psi at 180 C (Table VI). It is presumed that the retarding effect of higher carbon monoxide partial pressure is associated with stabilizing an inactive carbonyl species. 

Charged to a one liter Hastelloy-C autoclave (Autoclave Engineer), provided with a magnet-drive stirrer, a mixture of methanol (5.4 mole), methylacetate (3.5mole), methyliodide (350 mmole), nickel iodide (40 mmole), lithium iodide ( 380 mmole) and tetraphenyl tin (130 mmole). 

In general it is found that salts of strong acids yield more stable ammines than do those of weak acids, and in most cases the stability of the amminc is parallel with the stability of the corresponding ammonium salt. For instance, both hexammino-nickel iodide, [N NH JIj, and ammonium iodide decompose at higher temperatures than hexammino-nickel bromide, [Ni(NH3)0]Br2, and ammonium bromide. The more stable ammines are also the least soluble in water. 

Tetrammino-nickel iodide is claimed to be formed when slightly heated nickel iodide is exposed to the action of ammonia gas. The substance swells up and a vellowish-white powder is left.3... 

Diammino-nickel Iodide, [N NH JI, is produced by the thermal decomposition of the hexammino-derivative. From the researches of Bilt-z and Fetkenheuer,4 by thermal decomposition of the hexammino-derivative only the existence of the hexammine and the diammino-derivative are indicated. 

The double cupric, ferrous, manganous, and nickelous iodides have not been prepared the double ferrous and molybdenous iodides are wanting and the double iridious iodides have alone been prepared. 

Coal was also the feedstock for synthesis gas vide infra). Many contributions to acetylene chemistry are due to Reppe. His work on new homogeneous metal (mainly nickel) catalysts for acetylene conversion, carried out in the period from 1928 to 1945, was not published until 1948. Under the influence of nickel iodide catalysts, acetylene, water and CO were found to give acrylic acid. A process based on this chemistry was commercialized in 1955. 

Nickelous Iodide or Nickel Di-iodide, Nil, may be obtained by heating reduced nickel with iodine, or by dissolving the hydroxide in... 

It has been noted that unlike the palladium and platinum complexes, the nickel derivatives afford nickel iodide instead of the free metal. The reaction is accompanied by carbon monoxide evolution, which is increased in the presence of iodine. Independently of the stoichiometric ratio of Pd to Fe employed, the reaction consumes approximately half the amount of allyl-palladium compound. Hence the present authors assume that iron enneacarbonyl produces two moieties under the conditions of reaction ... 

Na2CH204 sodium carbonate monohydrate 5968-11-6 25.00 2.2500 1 3146 NiH12l206 nickel iodide hexahydrate 7790-34-3 25.00 5.8300 1... 

Two catalyst systems, RhCl and allyl nickel iodide which give high trans polymer were examined and found to give identical, stereorandom results. Examination of recovered monomer shows no isomerization the stereorandomness of the bond forming event must be inherent to the mechanism. 

Catalysts which lead to cis polymer show a significantly higher stereoselectivity in the bond forming reaction. When (ir-allyl nickel iodide)2 modified with TiCl is employed, the 1, 2 deuterium stereochemistry is 70% dl, and 30% meso as revealed by analysis of succinic anhydride. In addition, monomer isomerization is extensive, and could account for a large fraction of the meso structures which are formed, j ke use of (ir-allyl nickel trifluoroacetate)2 as catalyst led to a similar result (32% meso), accompanied by little if any monomer isomerization. Thus, it appears that in reactions to form cis polymer, some, but not always all, of the stereochemical information present in the starting diene is preserved in the polymer. In contrast, none of the initial diene stereochemistry can be detected in the trans polymer. 

A sample of a deuteriated polymer produced by reaction of cis,cis-1,4-d2 butadiene with ir-allyl nickel iodide/TiCl catalyst was oxidatively cleaved and cyclized to d2-succinic anhydride, as described elsewhere in this section. C-NMR (chloro-form-d, 50 MHz, H ) resonance at 6 28.02 (t, J 21 Hz) ppm. 

TT-Allyl nickel iodide was prepared by the method of Wilke Polymerizations using this catalyst were carried out with either butadiene or cis,cis-1,4-d -butadiene as monomer, in the manner described previously in this section. Representative experimental details are given below ... 

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