Whether the product obtained by the bromination of optically active (R)-2-phenylpropanoic acid under Hell-Volhard-Zelinski conditions is optically active or racemic is to be explained. Concept introduction: Hell-Volhard-Zelinski reaction takes place through the formation of an acid bromide enol intermediate. If the chiral carbon of the optically active carboxylic acid is involved in the enol formation chirality will be lost during enolization, as the double bonds are planar. Bromination of this enol can take place from either face of the enol double bond leading to the formation of a racemic mixture. If the chiral carbon does not take part in enol formation, then the resulting product will be optically active.

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Chapter 22.SE, Problem 53AP

Interpretation Introduction

Interpretation:

Whether the product obtained by the bromination of optically active (R)-2-phenylpropanoic acid under Hell-Volhard-Zelinski conditions is optically active or racemic is to be explained.

Concept introduction:

Hell-Volhard-Zelinski reaction takes place through the formation of an acid bromide enol intermediate. If the chiral carbon of the optically active carboxylic acid is involved in the enol formation chirality will be lost during enolization, as the double bonds are planar. Bromination of this enol can take place from either face of the enol double bond leading to the formation of a racemic mixture. If the chiral carbon does not take part in enol formation, then the resulting product will be optically active.

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Ethyl butyrate, CH3CH2CH2CO2CH2CH3, is an artificial fruit flavor commonly used in the food industry for such flavors as orange and pineapple. Its fragrance and taste are often associated with fresh orange juice, and thus it is most commonly used as orange flavoring.It can be produced by the reaction of butanoic acid with ethanol in the presence of an acid catalyst (H+): CH3CH2CH2CO2H(l)+CH2CH3OH(l)H+⟶CH3CH2CH2CO2CH2CH3(l)+H2O(l) a) Given 7.70 g of butanoic acid and excess ethanol, how many grams of ethyl butyrate would be synthesized, assuming a complete 100% yield? b) A chemist ran the reaction and obtained 5.25 g of ethyl butyrate. What was the percent yield? c) The chemist discovers a more efficient catalyst that can produce ethyl butyrate with a 78.0% yield. How many grams would be produced from 7.70 g of butanoic acid and excess ethanol?

Ethyl butyrate, CH3CH2CH2CO2CH2CH3, is an artificial fruit flavor commonly used in the food industry for such flavors as orange and pineapple. Its fragrance and taste are often associated with fresh orange juice, and thus it is most commonly used as orange flavoring.It can be produced by the reaction of butanoic acid with ethanol in the presence of an acid catalyst (H+): CH3CH2CH2CO2H(l)+CH2CH3OH(l)H+⟶CH3CH2CH2CO2CH2CH3(l)+H2O(l). The chemist discovers a more efficient catalyst that can produce ethyl butyrate with a 78.0% yield. How many grams would be produced from 8.50 gof butanoic acid and excess ethanol? Express your answer in grams to three significant figures.