Search results
Results from the WOW.Com Content Network
Hydration is an important process in many other applications; one example is the production of Portland cement by the crosslinking of calcium oxides and silicates that is induced by water. Hydration is the process by which desiccants function. CuSO 4 ·5H 2 O is bright blue and has a rather different structure from its colourless anhydrous ...
Hydration is the mechanism by which hydraulic binders such as Portland cement develop strength. A hydraulic binder is a material that can set and harden submerged in water by forming insoluble products in a hydration reaction. The term hydraulicity or hydraulic activity is indicative of the chemical affinity of the hydration reaction. [2]
For example: ethanol, CH 3 −CH 2 −OH, is the product of the hydration reaction of ethene, CH 2 =CH 2, formed by the addition of H to one C and OH to the other C, and so can be considered as the hydrate of ethene. A molecule of water may be eliminated, for example, by the action of sulfuric acid.
The classic example of a dehydration reaction is the Fischer esterification, which involves treating a carboxylic acid with an alcohol to give an ester RCO 2 H + R′OH ⇌ RCO 2 R′ + H 2 O. Often such reactions require the presence of a dehydrating agent, i.e. a substance that reacts with water.
The reaction thus provides a more stereospecific and complementary regiochemical alternative to other hydration reactions such as acid-catalyzed addition and the oxymercuration–reduction process. The reaction was first reported by Herbert C. Brown in the late 1950s [2] and it was recognized in his receiving the Nobel Prize in Chemistry in 1979.
The reaction may otherwise involve the functional groups of the molecule, and is a versatile class of reactions that can occur in acidic or basic conditions or in the presence of a catalyst. This class of reactions is a vital part of life as it is essential to the formation of peptide bonds between amino acids and to the biosynthesis of fatty ...
The reaction proceeds by formation of vinyl alcohol, which tautomerizes to form the aldehyde. This reaction was once a major industrial process but it has been displaced by the Wacker process. This reaction occurs in nature, the catalyst being acetylene hydratase. Hydration of phenylacetylene gives acetophenone: [15]
Application of mukaiyama hydration in the total synthesis of (±)-Garsubellin A. The hydration reaction is catalyzed by Co(acac)2 (acac = 2,4-pentanedionato, better known as acetylacetonato) and carried out in the presence of air oxygen & phenylsilane. With isopropanol used as solvent, yields of 73 % are obtained.