Raney nickel-aluminum alloy

T-l Raney Nickel Catalyst. To prepare, proceed as follows in a one liter three necked flask containing 600 ml of a 10% sodium hydroxide solution, 40 g of Raney nickel aluminum alloy (50%) is added in small portions. During the addition the temp should be 90-95° and there should be good stirring (do not use a magnetic stirring device). After the addition is complete (25 to 30 min), stir for 1 hour more, and let the nickel settle to the bottom of the flask. Decant the solution off, wash with 5 times 200 ml of water, 5 times 50 ml of ethanol, in such a way to keep the nickel always covered with liquid. The catalyst must be stored under ethanol and refrigerated. It may he stored for three months and remain active. 

In a 2-1. beaker resting on a hot plate and equipped with a mechanical stirrer are placed 150 g. of sodium hydroxide (Note 1) dissolved in 800 ml. of water and 41.4 g. (0.3 mole) of furyl-acrylic acid.1 The stirrer is started, and to the warm solution (Note 2) 100 g. of Raney nickel-aluminum alloy is added, in small portions, over a period of 4 4.5 hours (Notes 3 and 4). During the addition of the alloy, the temperature of the mixture is kept at 60-70° and then is raised to approximately 95° where it is held for an additional 2-3 hours, with stirring. From time to time sufficient water is added to the reaction mixture to maintain approximately the original volume. The hot solution is filtered by decantation, and the nickel residue (Note 5) is washed with two 50-ml. portions of hot 2% sodium hydroxide solution. The combined filtrates and washings are cooled and then immediately added slowly (Note 6), with good stirring, to 800 ml. of concentrated hydrochloric acid (Note 7). The solution at this point... 

Reductions of this type may also be carried out by the action of sodium and ammonia, sodium and alcohol, or Raney nickel-aluminum alloy and alkali. ... 

W-6 Raney nickel catalyst. In a 2-1. Erlenmeyer flask equipped with a thermometer and a stainless-steel stirrer are placed 600 ml. of distilled water and 160 g. of c.p. sodium hydroxide pellets. The solution is stirred rapidly and allowed to cool to 50° in an ice bath equipped with an ovei ow siphon. Then 125 g. of Raney nickel-aluminum alloy powder is added in small portions during a period of 25-30 minutes. The temperature is maintained at 50 2° by controlling the rate of addition of the alloy to the sodium hydroxide solution and the addition of ice to the cooling bath. When all the alloy has been added, the suspension is digested at 50 2° for 50 minutes with gentle stirring. It is usually necessary to remove the ice bath and replace it with a hot-water bath to keep the temperature constant. After this period of digestion the catalyst is washed with three 1-1. portions of distilled water by decantation (Note 1). 

Kametani and Nomura have described another very interesting catalytic reduction without the use of gaseous hydrogen. They have found that various nitriles can be reduced to amines by utilizing the hydrogen formed in situ by reacting Raney nickel-aluminum alloy with aqueous alkali. In this manner, they have prepared various benzylamines and phenylethylamines. 

The reactor is atwo-liter Erlenmeyerflaskequipped with a thermometer and a stainless steel stirrer. This flask is chained with 160 g. of NaOH and 600 ml. of water. The solid is dissolved with intensive stirring and the solution is cooled in an ice bath to 50°C. Then, 150 g. of Raney nickel-aluminum alloy (1 1) is added in small pieces. The rate of addition should be such that the temperature of the mixture remains constsnt at 50 2°C. The addition takes 20-30 minutes. The solution is then stirred for an additional 50 minutes while the temperature is kept at 50°C (first by cooling and later by heating on a water bath). The catalyst sludge product is washed three times by decantation with water. It is immediately placed in the washing tube c of the apparatus in Fig. 337 (the last of the product is transferred into c with a stream of water from a wash bottle). 

Catalytic methanation processes include (/) fixed or fluidized catalyst-bed reactors where temperature rise is controlled by heat exchange or by direct cooling using product gas recycle (2) through wall-cooled reactor where temperature is controlled by heat removal through the walls of catalyst-filled tubes (J) tube-wall reactors where a nickel—aluminum alloy is flame-sprayed and treated to form a Raney-nickel catalyst bonded to the reactor tube heat-exchange surface and (4) slurry or Hquid-phase (oil) methanation. 

Raney Not a process, but a nickel catalyst widely used for hydrogenating organic compounds. It is made from a 50/50 nickel/aluminum alloy by leaching out the aluminum with concentrated aqueous sodium hydroxide. The product has a spongy texture and is highly active. Invented by M. Raney in 1926. The business was acquired by W. R. Grace in 1963. U.S. Patent 1,628,190. 

Several reductions have been achieved by dissolving a nickel-aluminum alloy containing usually 50% of aluminum in 20-50% aqueous sodium hydroxide in the presence of a reducible compound. Since under such conditions elemental hydrogen is generated by dissolution of aluminum, and since Raney nickel is formed in this process, such reductions have to be considered catalytic hydrogenations rather than dissolving metal reductions. Their outcome certainly points to the former type. 

Raney nickel A porous nickel catalyst produced from a nickel-aluminum alloy. 

B. - o-Carboxy phenyl) propionic acid. In an open 1-1. widemouthed round-bottomed flask are placed 18 g. (0.094 mole) of 0-carboxycinnamic acid and 550 ml. of 10% sodium hydroxide solution. The mixture is warmed to 90° (Note 8) on a steam bath and stirred mechanically. The steam bath is then removed while 54 g. (Note 9) of nickel-aluminum alloy (Raney catalyst) powder is added through the open neck of the flask in small portions (from the end of a spatula) at frequent intervals (Note 10). When addition of the alloy is complete (about 50 minutes), the mixture is stirred and maintained at 90-95° for 1 hour by warming on a steam bath. Distilled water is added as needed to maintain the total volume at approximately 550 ml. The hot mixture is filtered with suction, and the metallic residue is washed with 50 ml. of hot 10% sodium hydroxide solution and two 50-ml. portions of hot water in such a manner that the solid is always... 

The Raney nickel reagent is prepared by addition of 9.5 g. of sodium hydroxide pellets over 8-10 minutes to a stirred suspension of 7.8 g of nickel-aluminum alloy (50% Ni, 50% A1 powder, purchased from Merck-Schuchardt) in 120 ml. of distilled water contained in a 250-ml. beaker. Fifteen minutes after the addition is completed, the beaker is immersed into a 70° water bath for 20 minutes. The water is decanted, and the catalyst is washed sequentially with two 20-ml. portions of distilled water and two 20-ml. portions of methanol. 

The alloy used is Raney Nickel Aluminum Catalyst Powder from the Gilman Paint and Varnish Company, Chattanooga, Tenn. It contains about 50 per cent nickel. 

Raney nickel catalyst has been prepared from the nickel-aluminum alloy 1 by the action of sodium hydroxide solution.2... 

For maximum catalytic activity, the metal usually is prepared in a finely divided state. This is achieved for platinum and palladium by reducing the metal oxides with hydrogen prior to hydrogenation of the alkene. A specially active form of nickel ( Raney nickel ) is prepared from a nickel-aluminum alloy. Sodium hydroxide is added to the alloy to dissolve the aluminum. The nickel remains as a black powder which is pyrophoric (bums in air) if not kept moist ... 

In 1925 Murray Raney (la) was granted a patent covering a new method of preparation of a nickel catalyst. A pulverized nickel-silicon alloy was reacted with aqueous sodium hydroxide to produce a pyrophoric, brownish nickel residue with superior catalytic properties. Upon investigation of other alloys of nickel and alkali-soluble metals, it was found that the aluminum alloy could be made with ease (lb) and was easily pulverized. The catalyst which is prepared by the action of aqueous sodium hydroxide on this nickel-aluminum alloy is known as... 

In 1925 and 1927 Raney patented a new method of preparation of an active catalyst from an alloy of a catalytic metal with a substance that may be dissolved by a solvent that will not attack the catalytic metal. First a nickel-silicon alloy was treated with aqueous sodium hydroxide to produce a pyrophoric nickel catalyst. Soon later, in 1927, the method was improved by treating a nickel-aluminum alloy with sodium hydroxide solution because the preparation and the pulverization of the aluminum alloy were easier. Some of most commonly used proportions of nickel and aluminum for the alloy are 50% Ni-50% Al, 42% Ni-58% Al, and 30% Ni-70% Al. The nickel catalyst thus prepared is highly active and now widely known as Raney Nickel, which is today probably the most commonly used nickel catalyst not only for laboratory uses but also for industrial applications.46... 

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