2-Methyl-2-butene acid catalyzed hydration

Acid-catalyzed hydration of alkenes (Section 6.10) The elements of water add to the double bond In accordance with Markovnikov s rule. R2C = CR2 + H2O R2CHCR2 OH Alkene Water Alcohol CH3 (CH3)2C=CHCH3 CH3CCH2CH3 M2SU4 OH 2-Methyl-2-butene 2-Methyl-2-butanol (90%)... 

Acid-catalyzed hydration reactions occur with Markovnikov orientation. For example, hydration of 2-methyl-2-butene gives 2-methyl-2-butanol, consistent with the intermediacy of the 3° 2-methyl-2-butyl carbocation. Moreover, hydration of 2-methyl-l-butene was also found to produce 2-methyl-2-butanol, and there was no indication of isomerization to 2-methyl-2-butene during hydration. These results suggest, but do not confirm, that the cationic intermediate undergoes nucleophilic attack by water faster than it loses a proton to revert to starting material. ... 

Rearrangements also occur in the acid-catalyzed hydration of alkenes, especially when a carbocation formed in the first step can rearrange to a more stable carbocation. For example, the acid-catalyzed hydration of 3-methyl-l-butene gives 2-methyl-2-butanol. In this example, the group that migrates is a hydrogen with its bonding pair of electrons, in effect, a hydride ion H . 

Propose a mechanism for the acid-catalyzed hydration of 3-methyl-l-butene to give 2-methyl-2-butanol. 

You might compare the product of oxymercuration-reduction of 3,3-methyl-l-butene with the product formed by acid-catalyzed hydration of the same alkene (Section 6.3C). In the former, no rearrangement occurs. In the latter, the major product is 2,3-dimethyl-2-butanol, a compound formed by rearrangement. The fact that no rearrangement occurs during oxymercuration-reduction indicates that at no time is a free carbocation intermediate formed. 

Methyl Isopropyl Ketone. Methyl isopropyl ketone [563-80-4] (3-methyl-2-butanone) is a colorless Hquid with a characteristic odor of lower ketones. It can be produced by hydrating isoprene over an acidic catalyst at 200—300°C (150,151) or by acid-catalyzed condensation of methyl ethyl ketone and formaldehyde to 2-methyl-l-buten-3-one, foUowed by hydrogenation to the product (152). Other patented preparations are known (155,156). Methyl isopropyl ketone is used as an intermediate in the production of pharmaceuticals and fragrances (see Perfumes), and as a solvent (157). It is domestically available from Eastman (Longview, Texas) (47). 

The acidity and basicity increase when ZnO is mixed with other oxides. ZnO —Ti02 becomes more acidic and reveals high activity for hydration of ethylene. Both acid and base amounts increase upon mixing with Si02 and isomerization of butene is catalyzed by the acid sites of ZnO — SiOz Addition of K to ZnO increased the base amount, and the catalytic activity for oxidation of formic acid sharply increased.A mixed oxide catalyst consisting of ZnO and FezOa is a good basic catalyst for the methylation by methanol of phenol to 2,6-xylenol. ... 

Methyl vinyl ketone is synthesized industrially by the hydration of vinylacetylene. The reaction is catalyzed by acetates, formates, or sulfates of mercury, silver, cadmium, copper, or zinc in the presence of acids [329,330]. The oxidation of 1-butene to methyl vinyl ketone in 72% yield by the formation of olefin mercuric salt complexes followed by the decomposition of these complexes with acid may become commercially feasible [331]. 

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