The chemical industry is mostly based on just a few simple compounds. Sulfuric acid is probably the most important, with chlorine and caustic soda close behind.
Only one of the key industrial chemicals, caustic soda, has a simple substitute available, in the form of sodium carbonate, used since ancient Egyptian times.
In 1723, the use of lead in rum stills was banned by the Massachusetts legislature, after drinkers had complained of stomach problems and partial paralysis.
In 1783, Nicolas Leblanc developed his Leblanc process to make sodium hydroxide and sodium carbonate from salt, making soap-making possible on a large scale.
In 1799, Charles Macintosh invented bleaching powder, made when chlorine is absorbed by dry slaked lime. It was patented in the name of Charles Tennant.
In 1865, the first plastic, parkesine, was made by Alexander Parkes from nitrocellulose, softened by vegetable oils and some camphor (also called xylonite).
Robert Bunsen analysed igneous rocks from Iceland and Armenia and showed the rocks came from sources which were chemically identical, founding geochemistry.