Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 7: Problem 157

Give the equations and mechanisms for the reactions of sodium methyl acetylide with: (a) 1-bromobutane (b) 2-bromobutane.

Short Answer

Expert verified
The reactions of sodium methyl acetylide with: a) 1-bromobutane: Equation: \( CH₃C≡CNa + CH₃CH₂CH₂CH₂Br → CH₃C≡CCH₂CH₂CH₂CH₃ + NaBr \) Mechanism (SN2): \( CH₃C≡C⁻ + CH₃CH₂CH₂CH₂Br → CH₃C≡CCH₂CH₂CH₂CH₃ + Br⁻ \) Product: 5-methyl-1-pentyne b) 2-bromobutane: Equation: \( CH₃C≡CNa + CH₃CHBrCH₂CH₃ → CH₃C≡CCH(CH₃)CH₂CH₃ + NaBr \) Mechanism (SN2): \( CH₃C≡C⁻ + CH₃CHBrCH₂CH₃ → CH₃C≡CCH(CH₃)CH₂CH₃ + Br⁻ \) Product: 4-methyl-3-hexyne

Step by step solution

01

Identify the nucleophile and electrophile

In this reaction, sodium methyl acetylide (CH3C≡CNa) is the nucleophile while 1-bromobutane (CH3CH2CH2CH2Br) is the electrophile.
02

Write the reaction equation

The reaction equation for the nucleophilic substitution of 1-bromobutane with sodium methyl acetylide is: CH₃C≡CNa + CH₃CH₂CH₂CH₂Br → CH₃C≡CCH₂CH₂CH₂CH₃ + NaBr
03

Describe the mechanism for the reaction

The mechanism for the reaction is an SN2 mechanism, which involves a single concerted step. The nucleophile (sodium methyl acetylide) attacks the electrophile (1-bromobutane) at the carbon atom bonded to the bromine atom. The bromine atom is then expelled as a leaving group. The mechanism can be represented as: 1) CH₃C≡C⁻ + CH₃CH₂CH₂CH₂Br → CH₃C≡CCH₂CH₂CH₂CH₃ + Br⁻ or with the sodium ions: 1) CH₃C≡CNa + CH₃CH₂CH₂CH₂Br → CH₃C≡CCH₂CH₂CH₂CH₃ + NaBr The product formed is 5-methyl-1-pentyne. #b) Sodium methyl acetylide with 2-bromobutane#
04

Identify the nucleophile and electrophile

In this reaction, sodium methyl acetylide (CH3C≡CNa) is the nucleophile while 2-bromobutane (CH₃CHBrCH₂CH₃) is the electrophile.
05

Write the reaction equation

The reaction equation for the nucleophilic substitution of 2-bromobutane with sodium methyl acetylide is: CH₃C≡CNa + CH₃CHBrCH₂CH₃ → CH₃C≡CCH(CH₃)CH₂CH₃ + NaBr
06

Describe the mechanism for the reaction

The mechanism for the reaction is also an SN2 mechanism, involving a single concerted step. The nucleophile (sodium methyl acetylide) attacks the electrophile (2-bromobutane) at the carbon atom bonded to the bromine atom. The bromine atom is expelled as a leaving group. The mechanism can be represented as: 1) CH₃C≡C⁻ + CH₃CHBrCH₂CH₃ → CH₃C≡CCH(CH₃)CH₂CH₃ + Br⁻ or with the sodium ions: 1) CH₃C≡CNa + CH₃CHBrCH₂CH₃ → CH₃C≡CCH(CH₃)CH₂CH₃ + NaBr The product formed is 4-methyl-3-hexyne.

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.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

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

You are given a mixture of 1 -butyne (bp \(8^{\circ}\) ) and 2 -butyne (bp \(27^{\circ}\) ). How could you separate, and then recover, each of these compounds using chemical means?

Indicate the features you would expect for the infrared and n.m.r. spectra of the following substances. (a) \(\mathrm{CH}_{3} \mathrm{C} \equiv \mathrm{CCH}_{3}\) (b) \(\mathrm{CH}_{3} \mathrm{C} \equiv \mathrm{CH}\) (expect a long-range n.m.r. coupling of \(3 \mathrm{cps}\) ) (C) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{C} \equiv \mathrm{CCH}_{2} \mathrm{CH}_{3}\)

Acetylene has an acid ionization constant \(\left(\mathrm{K}_{\mathrm{A}}\right)\) of \(\sim 10^{-22}\). (a) Calculate the concentration of acetylide ion expected to be present in a \(14 \mathrm{M}\) solution of potassium hydroxide that is \(0.01 \mathrm{M}\) in acetylene (assuming ideal solutions). (b) Outline a practical method (or methods) that you think might be suitable to determine an approximate experimental value of \(\mathrm{K}_{\mathrm{A}}\) for acetylene, remembering that water has \(\mathrm{K}_{\mathrm{A}}\) of about \(10^{-14}\). (c) Would you expect \(\mathrm{H}-\mathrm{C} \equiv \mathrm{N}\) to be a stronger acid than \(\mathrm{H}-\mathrm{C} \equiv \mathrm{C}-\mathrm{H}\) ? Why?

Describe the reduction of alkynes to obtain an alkene.

The chemical shifts ( \(2.4 \mathrm{ppm}\) ) of acetylenic hydrogens \((\mathrm{RC} \equiv \mathrm{C}-\mathrm{H})\) are considerably more toward higher magnetic fields than those of alkene hydrogens (4.6 to \(6.9 \mathrm{ppm}\) ). Show how this shielding effect might be explained in terms of the atomic orbital representation of acetylenes.
See all solutions

Recommended explanations on Chemistry Textbooks

Kinetics

Read Explanation

Inorganic Chemistry

Read Explanation

Chemical Reactions

Read Explanation

The Earths Atmosphere

Read Explanation

Chemical Analysis

Read Explanation

Ionic and Molecular Compounds

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.

Sign-up for free