Nickel, dichloro catalyst

Nickel, dichloro[ trimethylenebis] diphenyl-phosphine] ] [15629-92-2], 58, 133 Nickel, uses miscellaneous, catalysts,... 

Toyo Soda (28) operates plants where butanediol is obtained by chloration of butadiene to 1,U-dichloro-2-butene, hydrolysis of this compound to 2-butene-1,4-diol which is, finally, hydrogenated. This hydrogenation takes place in aqueous solution in the presence of a nickel-aluminium catalyst at 100°C and 270 bar. 

Alkyl- and aryl-pyridazines can be prepared by cross-coupling reactions between chloropyridazines and Grignard reagents in the presence of nickel-phosphine complexes as catalysts. Dichloro[l,2-bis(diphenylphosphino)propane]nickel is used for alkylation and dichloro[l,2-bis(diphenylphosphino)ethane]nickel for arylation (78CPB2550). 3-Alkynyl-pyridazines and their A-oxides are prepared from 3-chloropyridazines and their A-oxides and alkynes using a Pd(PPh3)Cl2-Cu complex and triethylamine (78H(9)1397). 

The electrochemistry of cobalt-salen complexes in the presence of alkyl halides has been studied thoroughly.252,263-266 The reaction mechanism is similar to that for the nickel complexes, with the intermediate formation of an alkylcobalt(III) complex. Co -salen reacts with 1,8-diiodo-octane to afford an alkyl-bridged bis[Co" (salen)] complex.267 Electrosynthetic applications of the cobalt-salen catalyst are homo- and heterocoupling reactions with mixtures of alkylchlorides and bromides,268 conversion of benzal chloride to stilbene with the intermediate formation of l,2-dichloro-l,2-diphenylethane,269 reductive coupling of bromoalkanes with an activated alkenes,270 or carboxylation of benzylic and allylic chlorides by C02.271,272 Efficient electroreduc-tive dimerization of benzyl bromide to bibenzyl is catalyzed by the dicobalt complex (15).273 The proposed mechanism involves an intermediate bis[alkylcobalt(III)] complex. 

A variety of polyaryrens are prepared by nickel-catalyzed homocoupling polycondensation. A 1,4-dichloro-phenylene monomer 180 bearing an ester substituent undergoes homocoupling in the presence of an Ni(0) catalyst... 

A solution of methyl 4,6-dichloro-4,6-dideoxy-a-D-galactopyranoside [28] (37, 1 g) in absolute ethanol (30 mL) containing triethylamine (1.3 mL) and W-4 Raney nickel catalyst... 

A solution of methyl 3,6-dichloro-3,6-dideoxy-p-D-allopyranoside [47] (25, 1.0 g) in ethanol (30 mL) containing W-4 Raney nickel catalyst [27,58] (20 mL ethanol slurry) and triethylamine (1.3 mL) was subjected to a hydrogen pressure of 45 psig for 36 h. TLC [Silica Gel G, Brinkmann 2 1 (v/v) ethyl acetate-petroleum ether (bp 60°-80°C)] showed that the starting material (R 0.42) had all reacted and revealed the presence of a new component having an Rf of 0.23. The filtered solution was concentrated to a syrup, which... 

The fourth step was the conversation of 2-[2,6-dichloro-4-nitrophenyl) imino]imidazoline (150 g, 0.55 mol) in methanol (1,5 L) to 2-[(2,6-dichloro-4-aminophenyl)imino]imidazoline by hydrogen with 30 g Raney nickel catalyst at 23°C for 22 hours. After removing the catalyst hydrogen chloride gas was bubbled into solution until pH of the reaction mixture was 1.0. The solvent was rotary removed in vacuum and the residual solid was slurried with 2-propanol (1 L). The solvent was again removed by rotary evaporation, the cream solid was triturated with 2-propanol (600 ml). After aging for 1 hour, the solid was collected by filtration, washed with 2-propanol and t-butyl methyl ether, and dried for 15 hours at 6°C and t-butyl methyl ether, and dried for 15 hours at 60°C and 20 mm Hg. Yield of dihydrochloride 167 g... 

There is little recent information in this area. The tine structure of 3-acetoxy-l, 4-dinitro-2-piperazinol (14) has been elucidated by X-ray analysis.1212 Treatment of 5,6-dichloro-3-nitro-2-pyrazinamine (15) with refluxing ethanolic sodium cyanide for 4 days induced displacement of the nitro by a cyano group as well as ethanoly-sis of one chloro substituent to afford 3-amino-6-chloro-5-ethoxy-2-pyrazinecar-bonitrile (16) in 55% yield.1313 L-Methyl-4-(/>nitrobenzoyl)pipcrazine (17) gave I -(/ -aminobenzoyl)-4-methy I piperazine (18) (75%) on refluxing in ethanolic hydrazine hydrate with a little Raney nickel catalyst for 6 h 135, cf 1032 other reduction procedures have been reported.496,1741... 

The most generally applicable catalysts are diphosphine complexes of nickel(il) halides, notably dichloro[l,3-bis(diphenylphosphino)pro-pane]nickel(n), NiCl2(dppp) , and to a lesser degree analogous palladium(n) complexes. Procedures for the latter, and tables of examples, are included in a companion volume [22], Many examples are listed in the reviews (20, 21] a procedure follows, and selected examples, mostly recent, or illustrating the range of products obtainable, are listed in Table. 8.2. ... 

Zero-valent nickel complexes are known to reduce 1,2-dihalides to olefins and to mediate C,C-coupling reactions of vinyl halides. Based on these facts, lyoda and coworkers developed a two-step, one-pot synthesis of alkyl-substituted [4]radialenes which starts from 2,3-dihalo-l,3-butadienes and 1,4-dichloro-2-butyne derivatives and circumvents the isolation of the butadiene intermediates. Furthermore, the synthesis can be made catalytic in nickel when the Ni(0) complex is generated from NiBr2(PPh3)2 with a more than stoichiometric quantity (based on the dihalide) of zinc. Again, the formation of radialene 94 must compete with that of 95 and 96. With preformed Ni(PPh3)4 and Ni(PBu3)4, the [4]radialene is normally favored in benzene solution, but formation of 95 and/or 96 becomes important in the more polar solvents THF and DMF. With a catalyst... 

Dehydrooenation 1,4-Benzoquinone. Chloranil. o-Chloranil. Copper chromite. Copper-Chromium oxide. Diethyl azodicarboxylate. 2,3-Dichloro-3,6-dicyano-I,4-benzoquinone. DIphenylpIcrylhydrazyl, N-Lithioethylenediamlne. Mercuric acetate. Nickel catalyst. Oleic add, Palladium. Perbenmic acid. Potassium l-butoxide. Pyrldinium hydrobromide per-bramlda, Balinlum. Selenium dioxide. Sodium borohydride. Sulfdr (sm 1,2-Naphthalic anhydridli preparation). Tetracyanoethylene. Thionyl chloride. Trityl perchlorate. 

Trichlorosilane and dichloro(methyl)silane375 377 react in the same way, not only with benzene, but also with other aromatic hydrocarbons such as toluene, biphenyl, and naphthalene, with boric acid, aluminum chloride, or Raney nickel as well as boron trichloride reported as catalysts. Barry et a/.378 have reviewed this direct process for synthesis of arylhalosilanes. 

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