Berthelot principal

Theories of Formation of Benzene, etc.—Theories of the formation of these benzene products in the distillation of coal have been investigated principally by Berthelot, and his conclusions are, in general In the first place, coal decomposes by heat yielding simple paraffin compounds such as methane, ethylene, acetylene, alcohol, acetic acid, etc. These compounds when subjected to higher temperatures polymerize into benzene, and the higher hydrocarbons naphthalene, anthracene, phenanthrene, etc., and into derivatives of these such as phenol, aniline, pyridine, etc. 

Rochleder s liickenhafte Verbindungen . Berthelot says benzene can be regarded from two points of view. Its formation from acetylene corresponds with an incomplete hydrocarbon of the fourth order C H (C H )[—][——][—], which would explain its conversion into hexane. But benzene behaves mostly as a saturated hydrocarbon. To explain this, Berthelot assumed that one acetylene molecule plays a special part, the other two only subordinate parts, so that their tendency to saturation appears only in exceptional cases. He calls this the principe de saturation relative . The change of acetylene into benzene is compared with the reduction of acetylene to ethane C H2(H2)(H2), C"H2(C"H2)(C4H2). In 18762 he says... 

The high reactivity of fluorine which is responsible for its usefulness in inorganic thermochemistry is also the cause of the principal difficulties associated with the technique problems in selecting suitable materials for the construction of apparatus, the need for elaborate safety precautions, and difficulties in the analysis of volatile products in the presence of excess fluorine. Bombs of the conventional Berthelot type are used but are... 

Berthelot, 1894] M. Berthelot. Le principe du travail maximum et I entropie, Comtes Rendus 118 1378-1392, 1894. 

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