Berthelot's Pathway from Synthesis to Thermochemistry

Abstract

Why did Marcellin Berthelot turn away from his successful research in organic synthesis around 1864 to devote himself to the difficult and uncertain path of thermochemistry? Jean Jacques and others have argued that Berthelot's shift can be seen as a result of his flawed understanding of the emerging atomistically based theories of structural chemistry; a sense that he was being left behind by this field, it is maintained, led him to try something different. In contrast, I will argue that thermochemistry was a logical progression of Berthelot's overarching desire to predict chemical action, a great challenge in the middle of the nineteenth century. Berthelot hoped and expected that synthesis and chemical industry would transform the conditions of our existence. He asked such questions as: What substances can we expect to create? From which reagents? And most important: how can we tell in advance whether a particular chemical reaction will occur?