Base (chemistry)

The common (Arrhenius) definition of a base, also known as an alkaline compound, is a chemical compound that either donates hydroxide ions or absorbs hydrogen ions when dissolved in water. Bases and acids are seen as opposites because the effect of an acid is to increase the hydronium ion (H3O) concentration in water, whereas bases reduce this concentration. Arrhenius bases are water-soluble and these solutions always have a pH greater than 7.

Bases as heterogeneous catalysts

Basic substances can be used as unsoluble heterogeneous catalysts for chemical reactions. Examples are metal oxides such as magnesium oxide, calcium oxide, and barium oxide as well as potassium fluoride on alumina and some zeolites. Basic catalysts have been used for hydrogenations, the migration of double bonds, Meerwein-Ponndorf-Verlay reduction, the Michael reaction, and many other reactions.

Related Topics:
Unsoluble - Catalyst - Chemical reaction - Magnesium oxide - Calcium oxide - Barium oxide - Potassium fluoride - Alumina - Zeolite - Hydrogenation - Double bond - Meerwein-Ponndorf-Verlay reduction - Michael reaction

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