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The Mechanism of Contact Elimination, A Contribution to Understanding the Function of Polar Catalysts
Author(s) -
Noller Heinrich,
Andréu Paulino,
Hunger Manfred
Publication year - 1971
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.197101721
Subject(s) - catalysis , heterolysis , chemistry , stereospecificity , reactivity (psychology) , leaving group , reaction mechanism , organic reaction , phase (matter) , product distribution , polar , elimination reaction , proton , organic chemistry , computational chemistry , medicine , physics , alternative medicine , pathology , quantum mechanics , astronomy
Abstract The current ideas of organic chemists based on the work of Ingold and his school are applied to heterogeneous catalytic eliminations (mostly from haloalkanes and aliphatic alcohols). It is deduced from the activity of the catalysts, the reactivity of the substrates (reactants), and the primary product distribution that these eliminations proceed by a heterolytic mechanism similar to that involved in the liquid phase. The activity of the catalysts (salts and oxides) increases with increasing charge and decreasing radius of the cations and with increasing basicity of the anions. The reactivity of the substrates behaves in much the same manner as in the liquid phase. In contrast with the liquid‐phase reaction, the cis‐olefins are frequently favored as primary products. The stereospecificity of the reaction is determined from the relative strengths of the interactions between the catalyst cation and the leaving group X − , and between the catalyst anion and the leaving proton. Only trans elimination has so far been found in the concerted mechanism.