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The general chemical equation for the hydration of alkenes is the following: RRC=CH 2 + H 2 O → RRC(OH)-CH 3. A hydroxyl group (OH −) attaches to one carbon of the double bond, and a proton (H +) adds to the other. The reaction is highly exothermic. In the first step, the alkene acts as a nucleophile and attacks the proton, following ...
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.
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]
Dicalcium silicate, which reacts more slowly, only contributes to late strength. Calcium silicate hydrate (also shown as C-S-H) is a result of the reaction between the silicate phases of Portland cement and water. This reaction typically is expressed as: 2 Ca 3 SiO 5 + 7 H 2 O → 3 CaO · 2 SiO 2 · 4 H 2 O + 3 Ca(OH) 2 + 173.6 kJ
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.
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.
These hydration and dehydration conversions of CO 2 and H 2 CO 3, which are normally very slow, are facilitated by carbonic anhydrase in both the blood and duodenum. [7] While in the blood, bicarbonate ion serves to neutralize acid introduced to the blood through other metabolic processes (e.g. lactic acid , ketone bodies ); likewise, any bases ...
The equation for the partial dehydration is: CaSO 4 · 2 H 2 O → CaSO 4 · 1 / 2 H 2 O + 1 + 1 / 2 H 2 O↑. The endothermic property of this reaction is relevant to the performance of drywall, conferring fire resistance to residential and other structures.