Raney nickel naphthalenes

H-acid, l-hydroxy-3,6,8-ttisulfonic acid, which is one of the most important letter acids, is prepared as naphthalene is sulfonated with sulfuric acid to ttisulfonic acid. The product is then nitrated and neutralized with lime to produce the calcium salt of l-nitronaphthalene-3,6,8-ttisulfonic acid, which is then reduced to T-acid (Koch acid) with Fe and HCl modem processes use continuous catalytical hydrogenation with Ni catalyst. Hydrogenation has been performed in aqueous medium in the presence of Raney nickel or Raney Ni—Fe catalyst with a low catalyst consumption and better yield (51). Fusion of the T-acid with sodium hydroxide and neutralization with sulfuric acid yields H-acid. Azo dyes such as Direct Blue 15 [2429-74-5] (17) and Acid... 

Bromonaphthalene has been reduced to naphthalene in good yield by hydrogenation over Raney nickel in methanolic potassium hydroxide, by triphenyltin hydride in benzene, by magnesium in isopropyl alcohol, by sodium hydrazide and hydrazine in ether, and by copper(I) acetate in pyridine. ... 

Sumimoto introduced a new sebacic acid process including several catalytic hydrogenation reactions.342 The synthesis starts with naphthalene, which is first partially hydrogenated to tetralin over cobalt oxide or molybdenum oxide, then to decalin over ruthenium or iridium on carbon. The selectivity to cw-decalin is better than 90%. In a later phase of the synthesis 5-cyclododecen-l-one is hydrogenated over Raney nickel to obtain a mixture of cyclododecanone and cyclodode-canol in a combined yield of 90%. The selectivity of this step is not crucial since subsequent oxidation of either compound leads to the endproduct sebacic acid. 

Reduction of arenes.1 Raney nickel (Mozingo type) in combination with 2-propanol (reflux) effects reduction of aromatic rings in 2-18 hours. Naphthalene is reduced in 18 hours to tetralin (90% yield) and cis- and frans-decalin (10% yield). Anisole is reduced in 110 hours to cyclohexyl methyl ether (90% yield). Nitrobenzene is reduced quickly to aniline and then further to cyclohexylamine and cyclohexylisopropylamine. 

Naphthalene is readily hydrogenated to tetrahydronaphthalene, which is used as a paint solvent, but further reduction to produce decahydro-naphthalene (decalin) requires forcing conditions (Raney nickel catalyst at 200 °C). The first step in the reduction of naphthalene can be achieved by reaction with sodium in boiling ethanol, which produces 1,4-dihy-dronaphthalene. The tetrahydro compound is formed in the higher-boiling 3-methylbutanol (isopentyl alcohol) (Scheme 12.4). 

Naphthalene is reduced to 1,4-dihydronaphthalene by sodium and alcohol. Isomerization of this product to 3,4-dihydronaphthalene occurs with sodamide in liquid ammonia. Tetrahydronaphthalene (tetralin) is formed from naphthalene by sodium in amyl alcohol or by reduction with nickel-aluminum alloy and aqueous alkali. Catalytic hydrogenation of naphthalene can be stopped at the tetralin stage over copper chromite, Raney nickel, or alkali metal catalysts. cis-Decahydronaphthalene is produced by high-pressure hydrogenation of tetralin over Adams catalyst, whereas a mixture of cis- and trans-decalins is obtained from naphthalene under the same conditions. ... 

The hydrogenation of biphenyls over Raney nickel proceeds in a marmer similar to that observed for the hydrogenation of naphthalenes. The hydrogenation of p-phenylphenol (25) takes place over a Pd/C catalyst at 125°C... 

Naphthalene, obtained from a petroleum reformate, was chromato-graphically pure after recrystallization. The two monomethylnaph-thalenes were obtained by distillation from the same reformate. The 1-methylnaphthalene was a heart cut of 99-f% purity from a precise fractional distillation. 2-Methylnaphthalene from the same distillation was recrystallized to high purity. 1,3-Dimethylnaphthalene, 1,7-dimethylnaphthalene, and 1,8-dimethylnaphthalene were synthetic samples that were kindly donated by Dr. G. D. Johnson of Kansas State University and Dr. L. Friedman of Case Institute. The remaining isomers were obtained from commercial sources. They were treated with Raney nickel in methanol under reflux to destroy catalyst poisons such as sulfur compounds. The liquid isomers were further purified by preparative-scale gas chromatography. Octalins were prepared by reducing pure naphthalene with lithium in ethylamine (29). 

In order to reduce the crystallinity of the polyketal an unsymmetrical cyclic diketone was prepared from 2,7-dihydroxy-naphthalene. Reduction of the naphthalene nucleus with Raney nickel and hydrogen gave a 90% yield of the 2,7-decalindiol, which on oxidation with chromic acid gave a 50% yield of the 2,7-deca-lindione. When this diketone was condensed with the tetrakis-(hydroxymethyl) cyclohexane, an 89% yield of a white polymer VIII was obtained which did not melt and was soluble only in hexa-fluo ro isopropano1. 

Kekule70 recommended zinc and alkali hydroxide solutions for preparation of the so-called nascent hydrogen . Somewhat similarly, Raney nickel alloys in aqueous alkali have been used repeatedly for reductions. The aluminium that goes into solution in these reactions reduces naphthalene and its substitution products,71 cyclooctatetraene,72 and in particular 3-arylacrylic adds73 in good yield. 

For selective saturation of one of several double bonds, palladium or Raney nickel can be used. Platinum is less selective but can nevertheless sometimes be used. The reaction is interrupted after consumption of the calculated amount of hydrogen. Sulfur must be completely absent during hydrogenation of aromatic rings with platinum metals derivatives of benzene such as benzoic acid and phenol, also naphthalene, are more easily hydrogenated than benzene itself but for such cases it is often advantageous to use nickel catalysts in an autoclave. 

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. 

But with metals of higher oxidisability, in particular with aluminium, the atomic ratio percentage is much lower that the initial salt ratio. One could assume that aluminium is leached out by the alcoholate ion which results from the large excess of sodium naphthalene i.e the alcoholate ion would act in a way similar to that of the hydroxide ion in the preparation of Raney nickel. The very high value measured for the nickel surface area might support this assumption. 

With polycyclic aromatic compounds, it is often possible, by varying the conditions, to obtain either partially or completely reduced products. Naphthalene can be converted into the tetrahydro or decahydro compound over Raney nickel depending on the temperature. With anthracene and phenanthrene, the 9,10-dihydro compounds are obtained by hydrogenation over copper chromite although, in general,... 

Cobalt catalysts are generally known to be less active than nickel catalysts for the hydrogenation of aromatic compounds (see, e.g., Table 11.2).4,5 However, properly prepared reduced cobalt or Raney Co have been reported to be more active than the corresponding nickel catalysts in the hydrogenation of benzene13-15 and naphthalene.15... 

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