Substitution, theory

Dumas s Parisian school also became known as the French school of chemistry. Theophile Jules Pelouze complained about Dumas that he was using the theory of substitution to elevate himself to the position of "Chef de l Ecole" of the new organic chemistry. Adolphe Wurtz praised Dumas in saying that "the basic lines [of the substitution theory] are indelibly drawn, and it was the French School that drew them." 13... 

Therefore, one should expect to see the isotopic effect in electron-transfer reactions as being dependent on the change in the corresponding orbital energy levels of the donor and the acceptor as a result of the isotopic substitution. Theory shows that electron transfer... 

Paper 2 Auguste Laurent, Translator s Preface (by William Odling) Carbon, Metallic and Hydrogen, Oxygen, and Chlorine Substitutions Theory of Chlorine Substitutions Nitrogen Substitutions. 

The experiences which found expression in Dumas substitution theory led to a second type of names. The sensational observation of hydrogen replaced by other elements without fundamental change of type was immediately visualized by Dumas (19) as having a bearing on nomenclature. Lavoisier s binary nomenclature was now no longer sufficient. Dumas writes ... 

Among many other experiments that Hofmann undertook with aniline was treatment of the indigo-derived base with chlorine. He identified the products. They were used to demonstrate that the two main rival theories of chemical combination were entirely compatible. These were the electrochemical theory of attraction of Jons Jacob Berzelius and the substitution theory of Jean Baptiste Andr6 Dumas. This work was published in 1845 when Hofmann was at Bonn4. Hofmann then moved on to synthesis of aniline in... 

In a further discussion of the constitution of alcohol and ether Liebig attacked Dumas etherin theory (see p. 343) and defended the ethyl theory. He also attacked Dumas substitution theory in its application to the formation of chloral (see p. 361). Dumas views, Liebig said, were founded on inexact experiments and he remained silent when his errors were pointed out to him. We should be ready at every moment to change admitted hypotheses for better theories. Since Zeise s compound of platinous chloride and ethylene seemed to support the etherin theory, Liebig recalculated Zeise s analyses to show that the compound contains oxygen and is a compound of ether and not ethylene (etherin). Zeise confirmed that the compound does not contain oxygen. 

The desolvation theory has recently been extended by a solvation-substitution theory [101], It is based on the assumption that the enzyme would not be able to strip off the water which is surrounding the substrate to effect a desolvation , because this would be energetically unfavorable. Instead, the solvent is displaced by the environment of the active site of the enzyme thereby affecting solvation substitution . Thus, the (often) hydrophobic substrate replaces the water with the (often) hydrophobic site of the enzyme which favors the formation of the... 

Explain in terms of aromatic substitution theory why the substitution occurred at the position observed and why a single substitution product was obtained. Could you have predicted the result in advance ... 

In fact, technology developments emerging through alloys, blends and con osites are likely to be the major factor driving engineering plastics performance toward metals equivalency and a market opportunity delineated by the Fisher-Pry substitution theory to be as much as 18 billion pounds annually by the year 2000.1... 

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