Thomas Midgeley Jr. was a chemist and mechanical engineer who developed tetraethyl lead (TEL), an additive to gasoline which helped prevent the “knocking” of engines and so improved their performance and efficiency. The sale of lead additives in gasoline is banned in most countries now due to health concerns.
He also developed some of the very first chlorofluorocarbons (CFCs) which were used as stable, nontoxic, refrigerating compounds. Found to damage the ozone layer of the earth’s atmosphere in the mid 1970’s these compounds have now been phased out of use.
Throughout his life as a scientist, Midgeley received more than a hundred patents.
Early Life and Background
Thomas Midgeley Jr. was born in College Hill in Beaver Falls, Pennsylvania on the 18th of May in 1889. His father, Thomas Midgely Sr. was also an inventor principally in the field of automobile tires and his mother was Hattie Emerson. His family moved to New Jersey and then, when he was aged around six, they settled in Columbus, Ohio. At school Thomas was athletic and played in the high school baseball and football teams.
In 1905 he attended Betts Academy at Stamford, Connecticut and from his chemistry teacher he gained an interest in the periodic table which stayed with him throughout his life.
Midgeley continued his education at Cornell University, New York and graduated in 1911 with a degree in mechanical engineering. That same year he married Carrie Reynolds and they had a son and a daughter.
Early Career and Tetraethyl Lead
His first position was as a draftsman for the National Cash Register Company at Dayton, Ohio. After a year he left to help his father to improve cord tires and tread designs.
Midgley devised a simple form of hydrometer to check that there was enough alcohol in an automobile’s cooling system for freezing weather.
The tire business failed as so Midgley in 1916 took a position in the research staff at Dayton Engineering laboratories.
During the First World War he successfully researched developing an improved aviation fuel by hydrogenating benzene.
After the war Midgley concentrated on trying to solve how to avoid knocking in automobile engines, or that continuous pinging or putting sound which was observed in internal-combustion engines. He discovered that the engine knocking was caused by the fuel mixture, which did not burn evenly.
Midgley found a way to alter a gasoline’s chemical makeup by adding bromine from seawater and tetraethyl lead. His “no-knock” gasoline was invented in 1921, and naturally, drivers who were constantly experiencing this problem found this as an appealing solution to avoid engine knocking and potential permanent damage to their vehicles.
Bromine was needed in large quantities to prevent the formation of lead oxide on the engine’s valves and a cost effective method of extraction of bromine from sea water was devised.
However, the production of tetraethyl lead caused the death of at least seven workers in the 1920’s and Midgley himself took a long vacation in 1923 to recover from lead poisoning.
Midgely became vice president of the Ethyl Gasoline Corporation in 1923. In the marketing the “no-knock” formulation, was called “ethyl” and there was no mention of the lead in its composition. Automobile manufacturers and oil companies promoted the TEL additive discovered by Midgely as a top additive for ethanol-blend or ethanol fuels.
He received the 1923 Nichols Medal award for “Use of Anti-Knock Compounds in Motor Fuels”.
About a year later, Midgley wrote a paper about the hazards of lead poisoning. In the decades ahead, it was determined that lead additives to gasoline were highly toxic and were pollutants which caused blood and brain disorders in children, antisocial behavior, and also lowered IQ levels. In the 1970’s, the TEL compounds discovered by Midgely were replaced by non-lead alternatives as the negative effects of adding these compounds became widely recognized.
In 1928, Midgely was transferred to work for Frigidaire which at that time was also a subsidiary of General Motors. During his time there, he was tasked to find safer and more affordable refrigerant substitutes. Existing refrigerants used compounds such as ammonia, chloromethane and sulfur dioxide which were either flammable, toxic, or both. Because of these limitations, the search was on for an alternative safe, non-toxic refrigerant.
Midgely synthesized the colorless gas dichlorodifluoromethane which is a mixture of chlorine, carbon, and fluorine; this mixture is now known as a CFC or a chlorofluorocarbon. The trademark given for this product was “Freon” and it is was used as a refrigerant and aerosol spray propellant.
In 1974 a study by Mario Molina and F. Sherwood Rowland showed that CFC’s were causing the destruction of the ozone layer which in turn reduced the natural protection of the earth against the harmful sun rays. They found that a single chlorine atom was able to destroy around 100,000 ozone molecules before becoming inactive. Other evidence soon followed. Its manufacture was banned in developed countries in 1996, and developing countries in 2010.
Midgely also conducted extensive researches on rubber, publishing nineteen research papers. He extended the knowledge of the chemistry of vulcanization and the fundamental composition of natural and synthetic rubbers.
Life After His Inventions
The American Chemical Society awarded Midgely their Priestly Medal, their highest form of recognition in 1941. He also received the Willard Gibbs Award and was served as the Chairman of the American Chemical Society for 14 years and became their President in 1944.
From 1940 to 1944 Midgely was a director and vice president of the Ohio State University Research Foundation.
He was elected into the National Academy of Sciences in 1942.
In late 1940, he contracted polio which continued to progress and left him in the confines of his home. Even so, he was able to design a system of pulleys to allow him to move from one place to another without the need to be assisted by another person.
Like his several other inventions though, this ambulatory aid he made for himself also had its own dangers. On the second day of November 1944, he slipped and accidentally became entangled in the device’s ropes which in turn strangled him to death. He was 55 years old.