What We Owe to Raney® Nickel

Jul 12, 2022
5 min read

What do microwave popcorn, biscuits, margarine spreads, and coffee creamers have in common? Aside from making you hungry, these foods are made possible thanks to hydrogenation. We may not give a lot of thought to hydrogenation, but it’s used in everything from foods and makeup to petrochemical products. One widely used catalyst that makes hydrogenation […]

One widely used catalyst that makes hydrogenation possible is a metallic alloy called Raney® nickel. This nickel-aluminum alloy was invented to transform cottonseed oil from a liquid into a semi-solid shortening. A series of hydrogenation experiments by chemist Murray Raney in Chattanooga, Tennessee, between 1915 and 1926 for the Chattanooga Research Company led to its discovery.1 The first patent was issued in 1925,2 with a second in 1927.3

The discovery opened the door for hydrogenation of oils, fats, and waxes in a variety of food and industrial applications. On April 7, 2022—95 years later—the American Chemical Society granted Raney nickel National Historic Chemical Landmark status.4

What Is Hydrogenation?

We commonly think of hydrogenation as a chemical process that adds texture and shelf-life to foods, but it also extends to industrial applications.

In the food industry, hydrogenation is used to solidify liquid fats fully or partially. In the petrochemical industry, hydrogenation transforms a class of unsaturated hydrocarbons called “alkenes”5—which are used to produce alcohols, plastics, lacquers, detergents, and fuels6—into saturated and less reactive forms known as “alkanes” (e.g., paraffins) and cycloalkanes (e.g., cyclic hydrocarbons, or naphthenes).7,8

The hydrogenation process involves hydrogen and another compound. Because hydrogen is generally unreactive with organic compounds, however, a catalyst is needed. Raney nickel is widely used to make a variety of catalysts for this purpose.7

What Is Raney Nickel?

In the 1920s, when Murray Raney was experimenting with nickel alloys, he patented two versions. The first version contained equal parts nickel and silicon, which was then treated with sodium hydroxide.2 His version was found to be five times more active than the existing nickel-based industry standard. Raney continued to experiment and devised a subsequent catalyst using equal parts nickel and aluminum, which forms the basis of Raney nickel catalysts still in use today.3 Promoters such as zinc, molybdenum, and chromium are also sometimes added for different uses.9

Writing in 1940, Raney noted the importance of basic research in exploring the catalytic properties of metals:

The probability that nickel or any other metal will catalyze a given reaction is based on the great amount of work that has been done in many fields, rather than on any correlated, calculable properties of either the catalyzing substance or the reacting elements or compounds. The catalytic value of a substance is determined by trial; if it does its work, it is good.10

Since his original catalysts were devised, the world has bent Raney’s discovery to a vast array of uses. At the broadest level, Raney nickel is used today as a catalyst to help convert building-block chemicals into pharmaceuticals, food ingredients, personal care products, agrochemicals, and petroleum processing.4,11 Today, W. R. Grace & Co produces a variety of catalysts for hydrogenation and dehydrogenation using Raney nickel.

Since its discovery, Raney nickel has been used in a variety of oxidative and reductive applications including:

Novel uses of Raney Nickel

Today, new uses are being explored for Raney nickel. One application is in the emerging field of biomass conversion, where it is used as a catalyst to upgrade raw biomass into biofuels.12,13 With the admirable goal of weaning the world off fossil fuels, this use of Raney nickel may prove to be its most valuable contribution yet. Another use is as a catalyst for hydrogenation to synthesize cariprazine, an anti-psychotic drug used in the treatment of schizophrenia.14

References

What We Owe to Raney® Nickel

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