Organic Chemistry: Free Radical Reactions
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Questions and Answers

What is Free Radical Halogenation?

What free radical is most likely to be formed from bromination?

A tertiary radical

What is Combustion?

What is Pyrolysis (Cracking)?

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What are nucleophiles?

<p>Electron-rich species that are attracted to a positively polarized atom</p> Signup and view all the answers

What is a better nucleophile, I or F?

<p>Fluorine</p> Signup and view all the answers

What is a better leaving group, I or F?

<p>Iodine</p> Signup and view all the answers

What is an Sn1 Reaction?

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What doesn't a nucleophile play a role in the rate of an Sn1 reaction?

<p>It is not involved in the rate-determining step</p> Signup and view all the answers

What factors will help carbocation formation and therefore increase the rate of an Sn1 reaction?

<ol> <li>Highly substituted carbons. 2. Polar solvents. 3. Good leaving groups.</li> </ol> Signup and view all the answers

What is an Sn2 Reaction?

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Why is a Sn2 reaction bimolecular?

<p>Its rate-determining step is dependent on TWO species</p> Signup and view all the answers

What are the best conditions for an Sn2 reaction?

<p>A strong nucleophile with no steric hindrance.</p> Signup and view all the answers

With respect to optical activity, what do your end products of Sn1 and Sn2 reactions become?

<p>Sn1 = racemic mixture, Sn2 = inversion of configuration</p> Signup and view all the answers

What role does tosylate usually play in reactions?

<p>Acts as a good leaving group and a good protecting group.</p> Signup and view all the answers

What is Catalytic Hydrogenation?

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What is the Addition of HX to an alkene?

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What is the Addition of X2 to alkene?

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What is the Addition of H2O to an alkene?

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What is Free Radical Addition to alkene?

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What is Hydroboration?

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What is Oxidation with KMnO4 (Cold)?

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What is Oxidation with KMnO4 (Hot)?

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What is Ozonolysis?

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What is Ozonolysis with Reduction?

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What are Peroxycarboxylic acids?

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What do you use to add to polymers?

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What's another word for ethyne?

<p>Acetylene</p> Signup and view all the answers

What is the synthesis of Alkyne starting from dihalide?

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What is the synthesis of Alkyne using acetylide ion?

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What is Alkyne Reduction?

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What is Alkyne Reduction by free radical?

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What is the oxidation of Alkyne by KMnO4?

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What is Ozonolysis of Alkyne?

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What is Hydroboration of Alkyne?

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What are key reaction mechanisms for Alcohols and Ethers?

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What is Reduction to make Alcohol?

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What is Phenol Synthesis?

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What is Alcohol dehydration?

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How do you make OH- a good leaving group for Sn1 and Sn2 reactions?

<p>For Sn1 you can protonate it; for Sn2 you can convert it to tosylate.</p> Signup and view all the answers

How do you convert an alcohol into an alkyl halide with an ester as an intermediate?

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What does PCC (pyridinium chlorochromate) do?

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What is Jones reagent and what does it do?

<p>It is CrO₃, H₂SO₄ in acetone and it oxidizes primary alcohols to carboxylic acids.</p> Signup and view all the answers

Do ethers boil at high or low temperatures?

<p>Low</p> Signup and view all the answers

What is William Ether Synthesis?

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How to Cleave an Ether?

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How can we go from Epoxide to Alcohol?

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How can you get ketones or aldehydes?

<p>Oxidation of primary or secondary alcohols. Or ozonolysis of alkenes.</p> Signup and view all the answers

Study Notes

Free Radical Halogenation

  • A method of halogenating alkanes through free radical mechanisms.
  • Involves initiation, propagation, and termination steps.

Bromination and Free Radicals

  • Tertiary radicals are the most stable and favored during bromination.

Combustion

  • A chemical reaction where hydrocarbons react with oxygen, producing carbon dioxide and water.

Pyrolysis (Cracking)

  • A thermal decomposition process that breaks down large hydrocarbons into smaller, more valuable products.

Nucleophiles

  • Defined as electron-rich species seeking positively charged atoms, such as carbonyl carbons.

Nucleophilicity Comparison

  • Fluorine is a better nucleophile than iodine due to its better electron donation capabilities.

Leaving Group Efficiency

  • Iodine is a superior leaving group compared to fluorine due to its weaker bond with the carbon atom.

Sn1 Reaction

  • A nucleophilic substitution reaction that involves the formation of a carbocation as an intermediate.

Nucleophile's Role in Sn1

  • Nucleophiles do not influence the rate of an Sn1 reaction, as their involvement is not in the rate-determining step.

Factors Influencing Carbocation Formation for Sn1

  • Stability of the carbocation increases with highly substituted carbons.
  • Polar solvents help stabilize the carbocation.
  • Good leaving groups, typically weak bases, enhance the reaction rate.

Sn2 Reaction

  • A bimolecular nucleophilic substitution reaction where both substrate and nucleophile participate in the rate-determining step.

Bimolecular Nature of Sn2

  • The rate of an Sn2 reaction depends on both the substrate and the nucleophile.

Optimal Conditions for Sn2

  • Requires a strong nucleophile and minimal steric hindrance for effective backside attack.

Optical Activity in Sn Reactions

  • Sn1 results in a racemic mixture leading to loss of optical activity.
  • Sn2 results in an inversion of configuration, retaining optical activity.

Role of Tosylate

  • Serves as a good leaving group and can act as a protecting group in reactions.

Catalytic Hydrogenation

  • A reaction that involves the addition of hydrogen to alkenes or alkynes, often facilitated by a catalyst.

Alkene Addition Reactions

  • Addition of HX: Produces haloalkanes.
  • Addition of X₂: Results in vicinal dihalides.
  • Addition of H₂O: Leads to alcohol formation, typically through Markovnikov's rule.

Free Radical Addition to Alkenes

  • A mechanism wherein alkenes react with free radicals to form new products.

Hydroboration

  • A reaction that adds boron across alkenes, typically resulting in alcohols after oxidation.

Oxidation with KMnO₄

  • Cold KMnO₄ results in syn-dihydroxylation of alkenes.
  • Hot KMnO₄ leads to cleavage and strong oxidation, typically cleaving the double bond.

Ozonolysis

  • A reaction involving ozonolysis that cleaves alkenes into carbonyl compounds.

Ozonolysis with Reduction

  • Converts ozonolysis products (ozonides) into alcohols or other functional groups.

Peroxycarboxylic Acids

  • Used in reactions for oxidation and forming esters from alkenes.

Adding to Polymers

  • Free radical initiators or other reagents are typically used for polymerization processes.

Ethyne Synonym

  • Ethyne is commonly known as acetylene.

Synthesis of Alkynes

  • From dihalides through elimination of HX.
  • Using acetylide ions to form the terminal alkyne.

Reduction of Alkynes

  • Can result in alkenes or even alkanes depending on the reagents used.

Alkyne Oxidation

  • KMnO₄ oxidizes alkynes to diketones or carboxylic acids.

Hydroboration of Alkynes

  • A procedure to convert alkynes into alcohols, following the same logic as for alkenes.

Alcohols and Ethers Mechanisms

  • Various substitution and elimination reactions such as Williamson ether synthesis and dehydration are involved.

Alcohol Reduction

  • Conversion of suitable substrates into alcohols through reduction processes.

Phenol Synthesis

  • Can be achieved through various pathway routes, including hydroxylation of benzene.

Alcohol Dehydration

  • Involves elimination of water to form alkenes, typically through an acid-catalyzed mechanism.

Improving Leaving Group Status of OH

  • Protonation makes water a better leaving group in Sn1; conversion to tosylate does so for Sn2.

Alcohol to Alkyl Halide Conversion

  • Intermediate formation of esters can be used before converting to alkyl halides.

PCC Functionality

  • Pyridinium chlorochromate oxidizes primary alcohols to aldehydes and secondary alcohols to ketones.

Jones Reagent

  • Composed of CrO₃, H₂SO₄ in acetone; oxidizes primary alcohols to carboxylic acids effectively.

Ether Boiling Points

  • Ethers exhibit lower boiling points due to a lack of hydrogen bonding.

Ether Cleavage

  • Ethers can be cleaved into alcohols and alkyl halides under acidic or radical conditions.

Epoxide to Alcohol Conversion

  • Reaction with appropriate nucleophiles under acidic conditions initiates transformation.

Ketone and Aldehyde Formation

  • Results from oxidation of primary or secondary alcohols or ozonolysis of alkenes.

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Description

Explore the captivating world of free radical halogenation and related organic reactions. This quiz covers key concepts such as bromination, combustion, pyrolysis, and nucleophilicity. Test your understanding of fundamental organic chemistry principles and their applications.

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