Energy ketal hydrolysis

Alcohols also undergo reversible addition reactions with aldehydes and ketones. The product of addition of one mole of alcohol to an aldehyde or ketone is referred to as a hemiacetal or hemiketal, respectively. Dehydration and addition of a second mole of alcohol gives an acetal or ketal. This second phase of the process can be catalyzed only by acids, since a necessary step is elimination of hydroxide ion from a tetrahedral intermediate. There is no low-energy mechanism for base assistance of this elimination step. For this reason, acetals and ketals are stable toward hydrolysis in alkaline aqueous solution. 

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