HardChemistryHigh School (11–12)Organic Compounds with Functional Groups › Alcohols, Phenols and EthersNumerical

Butan-2-ol is made from ethanol in three steps on the Grignard branch: ethanol to bromoethane (88…

Try it on paper first. A hint, the key idea and the worked solution are here when you need them.

Butan-2-ol is made from ethanol in three steps on the Grignard branch: ethanol to bromoethane ( $88\ \%$ ), bromoethane to ethylmagnesium bromide ( $90\ \%$ ), and the reagent with ethanal in excess to butan-2-ol ( $75\ \%$ , based on the Grignard reagent). Use $46.069\ \text{g/mol}$ for ethanol. Find the overall yield. Then find the amount of ethanol, for the Grignard branch only, and its mass, needed to make $0.0500\ \text{mol}$ of butan-2-ol.

Need a reminder? The key ideaShow

Work from the target backwards. A Grignard reagent adds its R group to a carbonyl carbon. A carbocation can shift a hydrogen or a methyl group to a more stable cation. The overall yield of a route is the product of its step yields, and a count of the starting material divides by that yield.

The worked solution

Have you tried it?

Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.

← All Problems

← Ethanal can be made from ethanol in two ways…Pentan-1-ol is made from 1-bromobutane. The bromide is converted to its Grignard reagent with… →

More onOrganic Compounds with Functional Groups › Alcohols, Phenols and Ethers

Discussion (0)

Loading…