Cailletet, Louis

Using this technique, the French physicist Louis Paul Cailletet (1832-1913) and the Swiss chemist Raoul Pictet (1846-1929) were able to liquefy such gases as oxygen, nitrogen, and carbon monoxide by 1877. Hydrogen, however, still balked their efforts. 

James Mason Grafts discover that an aluminum chloride catalyst transforms organic chlorides into hydrocarbons and acid halides into ketones. This becomes known as the Friedel-Crafts reaction and is important in chemical synthesis. French physicist Louis-Paul Cailletet and Swiss physicist Raoul Pictet liquefy ojQ gen. 

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