Hydrogenation

Vegetable oils are made from cottonseed, soybean, and rapeseed (canola oil), for example; through the process of hydrogenation, oils are turned into solids. Hydrogenation is a chemical process used to “cook” the oil in reactors at high temperatures, liquefying them, cutting saturated organic compounds, and then turning them into solids. Hydrogenation reduces most, if not all, of the double carbon bonds found in the fatty acids, reforming liquid oils into solid fats. This is how margarine, Crisco, and cake frosting are made. They are able to maintain their solid state at room temperature. A saturated fat product and hydrogenated oil on a food label means their carbon bonds have been saturated with hydrogen and activated with a metal catalyst. Many pharmaceuticals are also made this way. Prior to hydrogenation, lard and other animal fats were used in cooking and baking because solid fats mix better with flour. Hydrogenation is also used in industrial manufacturing.

Background

Lard was used as a binder, smoother, and grease in cooking, making soap, and candles. The first research into hydrogenation was by Nobel Laureate Paul Sabatier in the 1890s, working on converting vapors. Wilhelm Normann converted liquid oils by hydrogenation in 1901 and opened a fat-hardening plant in Germany by 1909, partnering with Herforder Maschinenfett- und Oelfabrik Leprince & Siveke. Procter & Gamble, originally candle makers, bought Normann’s patent rights and hired a chemist to find alternatives to lard, the price of which was fixed by the meat industry. Thus began the efforts to change the food and soap industries. The chemist coagulated liquid cottonseed oil into a solid fat that worked much like lard. The name Crisco is an acronym for crystallized cottonseed oil. Procter & Gamble marketed Crisco as better for digestion, cleaner, and less expensive. The chemical cocktail industry took off in June 1911, marketing the first hydrogenated vegetable oil. Normann’s hydrogenation process was applied to whale and fish oils that were cheap to harvest from the sea and used in many foodstuffs.

Later research and development discovered that artificial trans fats are produced during the hydrogenation process. The problem researchers discovered is that trans fats lead to coronary heart disease and other diseases that are leading causes of death. Natural trans fats found in many foods do not have deleterious effects on humans, but the expanding use of artificial ones beginning in the 1950s is linked to the rise in consumption of fried fast foods, packaged snacks, and cakes. Other research reveals that trans fats produced by hydrogenation contribute to chronic diseases, including Alzheimer’s, cancer, diabetes, obesity, liver dysfunction, infertility, depression, and behavioral problems.

Hydrogenation was adapted from food production to the pharmaceutical and industrial chemical industries. It is a key technology process for reducing waste from the old chemical reduction processes. It inspired innovations in catalysis, engineering, equipment design, and analytical chemistry. These and other innovations in hydrogenation found their way into other industries in the twentieth century. Hydrogenation was found to be effective and efficient in manufacturing gasoline, products from xylene, turpentine, benzene, and petrochemical products from petroleum. In the 1980s and 1990s, hydrogenation of coal to produce liquid fuels became an industry standard, replacing or complementing the production of liquid fuels from older methods like extracting them from petroleum.

Hydrogenation Today

The process of hydrogenation is a well-established scientific method basically involving three components: the unsaturated substrate, a hydrogen source, and a catalyst. The reduction process is undertaken at differing temperatures and pressures depending on the substrate and catalyst. The current research literature covers a wide range of issues where hydrogenation is used. It is being studied for use in wastewater treatment, involving mercury in coal, for synthesizing perfume from industrial chemicals, and with coal being an important economic and environmental product, research studies on hydrogenation of coal to reduce sulfur oils for cleaner, less toxic burning are a major field of inquiry.

Over the years, the US Food and Drug Administration and other federal agencies have been studying the effects of hydrogenated oils (PHOs) on human health, and how manufactured food products like pastries, frozen pizza, and popcorn affect it. New FDA regulations want artificial trans fats out of foodstuffs before the end of the decade. Trans fats are not safe; the process of partial hydrogenation turn oils into solids, and the fatty acid molecules produced convert to trans fats, which are harmful to humans. Industry spokespeople argue this will increase costs exponentially. There will be product relabeling costs and changes in marketing, but most importantly, hydrogenation extends the shelf life of food and enhances flavors. Recent research finds that fully hydrogenated oils are not as harmful because the acids produced are different (stearic acids).

Some packaged food producers are taking it upon themselves to eliminate or reduce trans fats from partially hydrogenated oils from their restaurants and packaged goods, and they are researching new fats and oils that will replace hydrogenation to ensure good flavor levels and long shelf life. The number of products in their companies that meet FDA regulations is very small. The Center for Science in the Public Interest, a watchdog consumer advocacy group, is pushing governments to move more quickly and cut deeper into the food industry still using partially hydrogenated oils. Denmark was the first country to introduce a legal limit on industrial trans fat (2003), and the European Union later set a limit of 2 grams of industrial trans fat per 100 grams of fat in food intended for consumers.

. In the food industry, government and science are experimenting, growing soybeans with more healthy edible oils that will eliminate the need for hydrogenation. Their emphasis is on genomics and biotechnology for the commercial production of beans and seeds healthier for humans and more effective in food production. If these goals can be achieved, there will be more food available for an expanding worldwide growth in population, while cutting diseases from trans fats produced in the hydrogenation method. Obesity, as an example, is a condition that affects 890 million people worldwide, according to a 2022 report by the World Health Organization. A leading cause is that more people can afford fast and packaged foods high in saturated fats.

On the horizon are new methods of hydrogenation for industrial uses. An iron nanoparticle catalyst promises to improve the efficiency of hydrogenation drastically. Through green chemistry, sustainable hydrogenation might be cleaner, safer, and cheaper than metal catalysts like nickel and rare metals currently being used.

Bibliography

“Catalytic Hydrogenation of Alkenes.” Chemistry LibreTexts, 22 Jan. 2023, chem.libretexts.org/Bookshelves/Organic_Chemistry/Supplemental_Modules_(Organic_Chemistry)/Alkenes/Reactivity_of_Alkenes/Catalytic_Hydrogenation. Accessed 3 June 2026.

Christensen, Jen. “FDA Orders Food Manufacturers to Stop Using Trans Fat within Three Years.” CNN, 17 June 2015, edition.cnn.com/2015/06/16/health/fda-trans-fat. Accessed 5 June 2026.

El Shahed, Mahomoud S. “Hydrogenation: Slide Show.” Suez Canal University. Faculty of Petroleum & Mining Engineering. 26 May 2014. Web. 21 June 2016.

“Hydrogenation.” Britannica, britannica.com/science/hydrogenation. Accessed 3 June 2026.

Machado, Reinaldo M., et al. “Developments in Hydrogenation Technology for Fine-Chemical and Pharmaceutical Applications.” Current Opinion in Drug Discovery & Development, vol. 4, no. 6, Nov. 2001, pp. 745–55. Accessed 5 June 2026.

“Obesity and Overweight.” World Health Organization, 8 Dec. 2025, www.who.int/news-room/fact-sheets/detail/obesity-and-overweight. Accessed 4 June 2026.

Seager, Spencer L., and Michael Slabaugh. Chemistry for Today: General Organic and Biochemistry. Brooks/Cole Cengage Learning, 2014.

“Small Entity Compliance Guide: Revocation of Uses of Partially Hydrogenated Oils in Foods.” FDA, Apr. 2024, fda.gov/regulatory-information/search-fda-guidance-documents/small-entity-compliance-guide-revocation-uses-partially-hydrogenated-oils-foods. Accessed 3 June 2026.

Zhang, An, et al. “Synthesis Strategies of Supported Bimetallic Catalysts for Hydrogenation Reactions: Review and Outlook.” Catalysis Science & Technology, vol. 15, 29 Aug. 2025, pp. 6318–52, doi:10.1039/D5CY00622H. Accessed 3 June 2026.