/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 40 Give the reagents and conditions... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 12: Problem 40

Give the reagents and conditions necessary for each of the following transformations and comment on the thermodynamics of each (a) cyclohexanol \(\rightarrow\) cyclohexenc; (b) cyclohexene \(\rightarrow\) cyclohexanol; (c) chlorocyclopentane \(\rightarrow\) cyclopentene; (d) cyclopentene \(\rightarrow\) chlorocyclopentane.

Short Answer

Expert verified
(a) Concentrated H2SO4 and heat; (b) H2O and H2SO4; (c) KOH in EtOH; (d) HCl.

Step by step solution

01

Title - Conversion of Cyclohexanol to Cyclohexene

The conversion of cyclohexanol to cyclohexene is an elimination reaction (E1 mechanism). Use concentrated sulfuric acid (H2SO4) as the reagent, and heat the mixture. The reaction is generally endothermic because heat is required to break the C-OH bond and form the double bond in cyclohexene.
02

Title - Conversion of Cyclohexene to Cyclohexanol

To convert cyclohexene to cyclohexanol, perform an acid-catalyzed hydration reaction. Use water (H2O) and sulfuric acid (H2SO4) as reagents. This reaction is exothermic due to the formation of a strong C-OH bond and the hydration of the double bond.
03

Title - Conversion of Chlorocyclopentane to Cyclopentene

This involves an elimination reaction (E2 mechanism). Use a strong base such as potassium hydroxide (KOH) in ethanol (EtOH). The reaction is endothermic as energy is required to remove the halogen and form the double bond.
04

Title - Conversion of Cyclopentene to Chlorocyclopentane

For this conversion, add hydrochloric acid (HCl) in an electrophilic addition reaction. The reaction is exothermic due to the formation of a new C-Cl bond by breaking the double bond in cyclopentene.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Elimination Reaction
Elimination reactions involve the removal of atoms or groups from a molecule, resulting in the formation of a double bond. These reactions are crucial in forming alkenes from alcohols or halides. For example, converting cyclohexanol to cyclohexene involves an elimination reaction. Heat and a strong acid like concentrated sulfuric acid (H2SO4) are used to break the C-OH bond, leading to the formation of a double bond in cyclohexene. This process is endothermic as it requires energy to break the bonds.
E1 Mechanism
The E1 mechanism is a two-step process commonly observed in elimination reactions. In the first step, the leaving group departs, forming a carbocation intermediate. Subsequently, a proton is removed from an adjacent carbon, creating a double bond. For instance, the conversion of cyclohexanol to cyclohexene follows an E1 mechanism. When cyclohexanol is heated with concentrated sulfuric acid, the hydroxyl group leaves, forming a carbocation. This is followed by the loss of a proton, resulting in the formation of cyclohexene.
E2 Mechanism
The E2 mechanism is a one-step process where a base removes a proton while the leaving group departs simultaneously. This concerted mechanism leads directly to the formation of a double bond. A strong base such as potassium hydroxide (KOH) in ethanol (EtOH) is used in E2 reactions. For example, converting chlorocyclopentane to cyclopentene involves an E2 mechanism. The KOH removes a proton from the carbon adjacent to the one bearing the halogen, while the halogen leaves, forming cyclopentene. This reaction is endothermic as it requires energy to break the pre-existing bonds.
Acid-Catalyzed Hydration
Acid-catalyzed hydration involves adding water to an alkene in the presence of an acid, resulting in the formation of an alcohol. This reaction is exothermic, meaning it releases energy. For example, converting cyclohexene to cyclohexanol uses water and sulfuric acid (H2SO4). The sulfuric acid protonates the double bond, making it more susceptible to nucleophilic attack by water, forming cyclohexanol. The new C-OH bond is much stronger, releasing energy during the reaction.
Electrophilic Addition
Electrophilic addition is a reaction where an electrophile adds to a double bond, resulting in the formation of a single bond. For example, converting cyclopentene to chlorocyclopentane involves electrophilic addition. Adding hydrochloric acid (HCl) to cyclopentene breaks the double bond, with the proton adding to one carbon and the chloride adding to the adjacent carbon, forming chlorocyclopentane. This reaction is exothermic as it releases energy during the formation of the new C-Cl bond.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Give the expected major product from the reaction of each alkene with (i) peroxide-free \(\mathrm{HBr}\) and (ii) \(\mathrm{HBr}\) in the presence of peroxides. (a) 1-Hexene; (b) 2-methyl-1-pentene; (c) 2-methyl-2-pentene; (d) \((Z)-3\) -hexene; (e) cyclohexene.

Would you expect the catalytic hydrogenation of a small-ring cyclic alkene such as cyclobutene to be more or less exothermic than that of cyclohexene? (Hint: Which has more bond-angle strain, cyclobutene or cyclobutane?)

Suggest a structure for a substance that, upon ozonolysis followed by treatment with \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{~S}\), gives as the sole product \(\mathrm{CH}_{3} \mathrm{COCH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CHO}\). (Hint: Begin by writing out a bond-line formula of this product so that you can clearly see its structure and number its carbon atoms.)

The stereochemical consequences of the vicinal syn dihydroxylation of alkenes are complementary to those of vicinal anti dihydroxylation. Show the products (indicate stereochemistry) of the vicinal syn dihydroxylation of cis- and trans-2-butene.

During the catalytic hydrogenation of the cis double bond in oleic acid, a naturally occurring fatty acid, the formation of some of the trans isomer is observed. Explain. Examine the mechanism Look for a pathway that could (1) allow rotation about the bond between the originally doublebonded carbons followed by (2) regeneration of a double bond with a trans configuration. \- The mechanism possesses two key features that are applicable to this problem. First, cach of the first three steps is reversible. Second, the two hydrogen atoms add to the carbons of the original double bond one at a time. Let us see how we can make use of these characteristics to define an isomerization pathway.
See all solutions

Recommended explanations on Chemistry Textbooks

Chemical Reactions

Read Explanation

Kinetics

Read Explanation

Ionic and Molecular Compounds

Read Explanation

Chemical Analysis

Read Explanation

Physical Chemistry

Read Explanation

Making Measurements

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.