Palladium-carbon catalyst

A mixture of 53.5 g (0.5 mol) of cyclopentylideneacetonitrile dissolved in 50 cc of absolute ethanol and 0.5 g of a palladium-carbon catalyst is hydrogenated with hydrogen at a pressure of about 40 lb for about 3 hours. An additional amount of 0.8 g of palladium-carbon catalyst is then added and the hydrogenation continued for about 4 hours during which time the reduction is substantially completed and the cyclopentylideneacetonitrile is converted to cyclopentylacetonitrile. The reaction mixture is filtered to remove the catalyst and the alcohol is evaporated in vacuo. 

Then 21.89 g of the hydrochloride salt was dissolved in 600 ml of 80% aqueous ethanol. With the addition of a palladium carbon catalyst, this solution was hydrogenated at room temperature under a hydrogen pressure of about 1.1 atmospheres. After 2 mols hydrogen had been absorbed, the catalyst was filtered off and the filtrate was evaporated in vacuo until crystallization occurred. Then the crystals were dissolved by heating in the smallest possible quantity of water and after cooling, the crystallized substance was filtered off, washed with water and dried in vacuo. The yield was 6.80 g, i.e., 39% of the theoretically possible yield. The resultant product recrystallized from water melted at 203° to 204°C. 

A4 carene can also be obtained from A3 carene as follows (JCS (C) 46(1966)) Dissolve 1 g A3 carene in 50 ml propionic acid and heat at a suitable temperature (e.g., one-half hour at room temperature may do) in presence of /2g Palladium-Carbon catalyst (5%) in ethanol and filter, evaporate in vacuum (can distill 63.5/19.5). See J.Soc. Cosmet. Chem. 22,249(1971) for a review of (+) A3 carene chemistry. 

Formic acid, Palladium-carbon catalyst, 0418 Formic acid, Phosphorus pentaoxide, 0418 Furan-2-amidoxime, 1872... 

Hydrogenation of the Condensation Product. The above product can be hydrogenated by using 10% palladium carbon catalyst and the methods in the reductions chapter. 

A solution of the above octene (50 g) in 100 ml of ethanol is shaken under 2-3 atmospheres of hydrogen in the presence of 0.6 g of 10% palladium-carbon catalyst, until no more hydrogen... 

N,a-DMT. JMC, 9, 343 (1966). Mix 5.5 g of indole, 15 ml of cyclohexane, and 0.5 g of clean copper. Bring this mixture to a reflux and add 2.9 g of diazoacetone dropwise. After some time, the reaction goes very rapidly and forms two layers. Filter, evaporate in vacuo to get 2 h. g of 3-indoyl-acetone. 3.3 g of 3-idoyl-acetone in 100 ml of ethanol is then reduced in the presence of an excess of methylamine (3 g), or analog, over palladium carbon catalyst (see the reductions chapter). After 2 hours the catalyst is filtered off and the solution is concentrated, acidified, extracted with ether, and the aqueous layer is made alkaline. The title product precipitated is a tan solid (2.2 g) with a melting point of 93-94° and can be recrystallized with a mixture of THF-hexane. 

Methyl-5-hepten-2-one is converted into linalool in excellent yield by base-catalyzed ethynylation with acetylene to dehydrolinalool [45]. This is followed by selective hydrogenation of the triple bond to a double bond in the presence of a palladium carbon catalyst. 

Palladium - carbon catalysts, 948, 950 Palladium catalysts, for dehydrogenation, 948... 

Aromatizations play a particularly prominent role in the synthesis of carbazoles since both the Fischer cyclization (Borsche s method) of cyclohexanones (Section 3.06.3.4.2) and the cycloaddition of 2-vinylindole (Section 3.06.6.1) yield tetrahydrocarbazoles. Both catalytic dehydrogenation over palladium/carbon catalyst and dehydrogenation with chloranil have been employed to effect aromatization (80JA4772,79JOC4402). 

Deacetylation of (R) and (S), and hydrogenolytic removal of the benzyl groups in the presence of 10% palladium-carbon catalyst gave the desired optically pure 2-deoxy-2-(R- and S 3-hydro-... 

A mixture of 53.5 g (0.5 mol) of cyclopentylideneacetonitrile dissolved in 50 cc of absolute ethanol and 0.5 g of a palladium-carbon catalyst is hydrogenated with hydrogen at a pressure of about 40 lb for about 3 hours. 

In this chapter, recent advances in our understanding of catalytic fluorination under heterogeneous conditions are surveyed from the standpoint of catalyst properties, including developments based on the use of mixed metal fluorides having different structural types, and reaction mechanisms. Much of the newer work has been the result of the need to replace chlorofluorocarbons (CFCs) by alternatives, hydrofluorocarbons (HFCs) or, more controversially, hydrochlorofluorocarbons (HCFCs), following adoption of the Montreal and successor Protocols [2,3]. Where relevant, aspects of catalytic hydrogenolysis, where fluorides have been used as replacement supports in the conventional palladium/carbon catalysts, and isomerization reactions are included. 

Chloranil in boiling xylene has been shown to be an excellent dehydrogenation agent for the preparation of carbazoles from 1,2,3,4-tetrahydro-carbazoles (75-95%). By this procedure, carbazoles substituted in the 1-, 2-, and 3-positions with alkyl, halo, alkoxyl, carboxyl, or nitro groups are readily made. The starting materials are available by ring closures of cyclohexanone-OT-phenylhydrazones. A palladium-carbon catalyst for the same purpose is also noteworthy, the yields of alkylcarbazoles being 86-100%. ... 

Azines of certain carbonyl compounds like 3 methyl-5-alkyl-2-cyclo-hexen-l-ones and the alkylated l>tetralones have been aromatized to the corresponding 3 methyl-3-alkylanilines and l aminonaphthalenes by boiling with a palladium-carbon catalyst in triethylbenzene. The yields in the first step are in the range 24% to 74% and in the second 20% to 55%. 

An interesting example of carbon-carbon bond formation represents the reaction between 3(2//)-pyridazinone and pyridine A -oxide in the presence of platinized palladium-carbon catalyst at 150°C to give, in 2% yield, 6-(pyridyl-2 )-3(2//)-pyridazinone. Pyridazine itself did not react (78YZ67). 4,5-Diacylpyridazines were prepared from pyridazine and the corresponding aldehydes according to the Minisci reaction (78M63). 

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