what is raney nickel used for
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This reference article is mainly selected from the English Wikipedia with only minor checks and changes (see www.wikipedia.org for details of authors and sources) and is available under the. In 1924 a 1:1 ratio Ni/Si alloy was produced, which after treatment with sodium hydroxide, was found to be five times more active than the best catalyst used in the hydrogenation of cottonseed oil. But what Raney nickel is used most for is its unusual property of reducing C-S bonds to C-H bonds. A practical example of the use of Raney nickel in industry is shown in the following reaction, where benzene is reduced to cyclohexane. Raney nickel /ˈreɪniː ˈnɪkəl/, also called spongy nickel, is a fine-grained solid composed mostly of nickel derived from a nickel–aluminium alloy. It is very efficient. The removal of the aluminum results in a higher surface area for the Raney nickel, which gives high catalytic activity. [CDATA[ Murray Raney graduated as a Mechanical Engineer from the University of Kentucky in 1909. After this reaction cyclohexane may be used in the synthesis of adipic acid, a raw material used in the industrial production of polyamides such as nylon. These properties are a direct result of the activation process and contribute to a relatively high catalytic activity. It can be noted that Raney nickel is sometimes referred to as “sponge metal catalyst” and as “skeletal catalyst”. The initial material is a nickel–aluminium alloy containing 50% by weight of each metal. Care should be taken when handling these raw materials during laboratory preparation of Raney nickel. Due to its large surface area and high volume of contained hydrogen gas, dry, activated Raney nickel is a pyrophoric material that should be handled under an inert atmosphere. Raney Nickel catalyst, is extremely fine powdered nickel. This results in the formation of sodium aluminate and hydrogen gas, as shown in the chemical equation provided below. Raney nickel is named after its developer – the American mechanical engineer Murray Raney. The primary application of this solid is its use as a reagent & catalyst for many hydrogenation reactions in the field of organic chemistry. Alternatively, the more generic terms " skeletal catalyst" or "sponge-metal catalyst" may be used to refer to catalysts that have physical and chemical properties similar to those of Raney nickel. Several grades are known, of which most are gray solids. What it’s used for: Like palladium on carbon (Pd/C) and platinum on carbon (Pt/C), Raney nickel can be used for the hydrogenation of alkenes and alkynes. Among the different known grades of this substance, the majority exist as grey solids under ambient conditions. A high catalytic activity, coupled with the fact that hydrogen is absorbed within the pores of the catalyst during activation, makes Raney nickel a useful catalyst for many hydrogenation reactions. This resistance allows Raney nickel to be stored and reused for an extended period; however, fresh preparations are usually preferred for laboratory use. //]]>. In addition to being a catalyst, Raney nickel will also act as a reagent to desulfurize organic compounds. The aluminium which remains helps to preserve the pore structure of the overall catalyst. Since Raney is a registered trademark of W. R. Grace and Company, only those products by its Grace Davison division are properly called "Raney nickel". Some widely used promoters are zinc, molybdenum and chromium. For this reason commercial Raney nickel is available in both "active" and "inactive" forms. The properties of Raney nickel are highly dependent on the activation process followed during the production phase. This powder may be screened for a specific particle size range depending on the application the catalyst may be required for. Commercially available Raney nickel has an average nickel surface area of 100 m² per gram of catalyst. The key characteristics of nickel in these catalysts are its ability to absorb huge quantities of hydrogen, which therefore increases how efficient reactions are. A patent for this discovery was issued in December 1925. During the activation process, aluminium is leached out the NiAl3 and Ni2Al3 phases that are present in the alloy, while most of the aluminium that remains does so in the form of NiAl. When BET measurements are conducted on with the help of a gas that tends to get preferentially adsorbed on the surface of certain metals (such as hydrogen), it is usually observed that the majority of the surface area of Raney nickel grains is made up of nickel.

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