1900

Silicones

Frederick Stanley Kipping (1863–1949)

Silicon is the element directly below carbon in the periodic table, and it shares some of its properties. But despite the presence of silicon-based life forms in a wide variety of science-fictional stories, it’s a different enough element that the comparison doesn’t hold up very well. For example, the silicon-oxygen bond is very strong, and oxygen atoms tend to single-bond to another silicon atom instead of double-bonding as they can do with carbon. So you have carbon dioxide, the familiar gas that we exhale, versus silicon dioxide, which is glass. Evidently, silicon has its own way of doing things.

Those differences created difficulties for early chemists, who tried to treat silicon in chemical reactions the same way they did carbon. Englishman Frederick Stanley Kipping, the chemist most associated with the dawn of organosilicon chemistry, seems to have often had a terrible time of it. In 1900, he was able to extend Grignard-like chemistry into the silicon field, using organometallic reagents to try to make new compounds, but the products from these reactions kept condensing to thick, gluey resins and jellylike substances that were difficult or impossible to analyze with the equipment of the time. Kipping worked in the field for forty years, and at his retirement in 1936 he told an audience that “the prospect of any immediate and important advance in this section of chemistry does not seem very hopeful.”

But he lived long enough to see that he was wrong. World War II jump-started research in the field of organosilicon chemistry, as chemists at General Electric and Dow Corning had found that the organosilicon-oxygen compounds (known confusingly as silicones, a word coined by Kipping) were excellent insulators and lubricants. Kipping had never quite used the right conditions to produce some of these compounds, but building on his pioneering work, entire companies turned their attention to the new substances, which ended up being very useful indeed, with excellent stability to heat and corrosive agents. They could be made clear or opaque, with varying degrees of flexibility—similar to new forms of rubber—and their first use was in protecting airplane ignition systems from water. The use of silicones in breast implants has been controversial, but they’re also found in pacemakers and many other medical devices.

Silicone bakeware, a fate for his compounds that Kipping could never have imagined. New uses continue to be found for silicones, in the kitchen and well outside it.