01:160:311 Lecture Notes - Lecture 10: Borate, Lithium Aluminium Hydride, Sodium Borohydride
16 Nov 2018
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Document Summary
How reduction is characterized in organic chemistry. Decrease in # bonds to en atoms. More selective in reducing aldehydes and ketones. Lialh4 can reduce carboxylic acids, epoxides, lactones, nitro groups, nitriles, azides, amides, acid chlorides and esters to primary alochols; nabh4 does not. Nabh4 rapidly reduces aldehydes and ketones, slowly reduces esters. Does not violently react when in contact with water and alcohols as lialh4 does. Lialh4 produces h2 gas when in contact with protic solvents very exothermic , will. Why nabh4 used instead of h2 flammable objects nearby will catch on fire. Hydrogenation with catalysts is more complicated - need to generate h2 gas in a balloon or in situ (in reaction mixture) using acid. Why was ethanol used as solvent instead of ether in the reaction. Because nabh4 is insoluble in ether but soluble in methanol and ethanol. Why ether must be used as a solvent if lialh4 is used.
