Erik Christian Clemmensen (August 12, 1876 – May 21, 1941) was a

Danish-American Danish Americans () are Americans who have ancestral roots originated fully or partially from Denmark. There are approximately 1,300,000 Americans of Danes, Danish origin or descent. Most Danes who came to the United States after 1865 did so ...

chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a graduated scientist trained in the study of chemistry, or an officially enrolled student in the field. Chemists study the composition of ...

. He is most commonly associated with the

Clemmensen reduction Clemmensen reduction is a chemical reaction described as a Redox, reduction of ketones or aldehydes to alkanes using zinc Amalgam (chemistry), amalgam and concentrated hydrochloric acid (HCl). This reaction is named after Erik Christian Clemmensen ...

, a method for converting a

carbonyl group In organic chemistry, a carbonyl group is a functional group with the formula , composed of a carbon atom double-bonded to an oxygen atom, and it is divalent at the C atom. It is common to several classes of organic compounds (such as aldehydes ...

into a methylene group.

Biography

Erik Christian Clemmensen was born on August 12, 1876, in Odense, Denmark. He left school at the age of 15. He signed up to join an expedition on a warship, with the aim of becoming a naval officer, but illness prevented them from achieving this goal. Clemmensen studied at the Copenhagen Polytechnic Institute (now the Technical University of Denmark). He emigrated to the United States in 1900 and worked in the

pharmaceutical industry The pharmaceutical industry is a medical industry that discovers, develops, produces, and markets pharmaceutical goods such as medications and medical devices. Medications are then administered to (or self-administered by) patients for curing ...

. He joined the pharmaceutical company Parke, Davis & Co in

Detroit Detroit ( , ) is the List of municipalities in Michigan, most populous city in the U.S. state of Michigan. It is situated on the bank of the Detroit River across from Windsor, Ontario. It had a population of 639,111 at the 2020 United State ...

Michigan Michigan ( ) is a peninsular U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, Upper Midwestern United States. It shares water and land boundaries with Minnesota to the northwest, Wisconsin to the west, ...

. For the invention of the

, he received his Ph.D. in 1913 from the

University of Copenhagen The University of Copenhagen (, KU) is a public university, public research university in Copenhagen, Copenhagen, Denmark. Founded in 1479, the University of Copenhagen is the second-oldest university in Scandinavia, after Uppsala University. ...

. In 1914, he co-founded the Commonwealth Chemical Corporation in Newark, New York, along with H.G. Chapman and Rhea Chittenden, where he developed methods for the manufacture of

sodium benzoate Sodium benzoate also known as benzoate of soda is the sodium salt of benzoic acid, widely used as a food preservative (with an E number of E211) and a pickling agent. It appears as a white crystalline chemical with the formula C6H5COONa. Pro ...

vanillin Vanillin is an organic compound with the molecular formula . It is a phenolic aldehyde. Its functional groups include aldehyde, hydroxyl, and ether. It is the primary component of the ethanolic extract of the vanilla bean. Synthetic vanillin ...

, and

coumarin Coumarin () or 2''H''-chromen-2-one is an aromatic organic chemical compound with formula . Its molecule can be described as a benzene molecule with two adjacent hydrogen atoms replaced by an unsaturated lactone ring , forming a second six-me ...

. After a fire in 1929, the company was acquired by Monsanto Chemical Company and moved to

St. Louis, Missouri St. Louis ( , sometimes referred to as St. Louis City, Saint Louis or STL) is an Independent city (United States), independent city in the U.S. state of Missouri. It lies near the confluence of the Mississippi River, Mississippi and the Miss ...

. While working for Monsanto, Clemmensen helped develop the synthesis of the artificial sweetener

saccharin Saccharin, also called saccharine, benzosulfimide, or E954, or used in saccharin sodium or saccharin calcium forms, is a non-nutritive artificial sweetener. Saccharin is a sultam that is about 500 times sweeter than sucrose, but has a bitter or ...

. In 1935, he returned to New York City and founded The Clemmensen Chemical Corp. Clemmensen died on May 21, 1941, in Newark, New York.

Legacy

He is best known for the reaction that he developed while at Parke, Davis & Co. This reaction involves the reduction of

ketones In organic chemistry, a ketone is an organic compound with the structure , where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group (a carbon-oxygen double bond C=O). The simplest ketone is acetone ( ...

using a zinc amalgam and HCl. It has been employed in the preparation of polycyclic aromatics and

aromatics Aromatic compounds or arenes are organic compounds "with a chemistry typified by benzene" and "cyclically conjugated." The word "aromatic" originates from the past grouping of molecules based on odor, before their general chemical properties were ...

containing linear hydrocarbon side chains, the latter not being obtainable from a Friedel-Crafts alkylation.

References

{{DEFAULTSORT:Clemmensen, Erik Christian 1876 births 1941 deaths Danish emigrants to the United States Danish chemists