Reactive Intermediates in Aliphatic Compounds

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What type of overlap creates the sigma bond in alkenes?

  • Sideways overlap of 2p orbitals
  • Perpendicular overlap of sp3 hybrid orbitals
  • Random overlap of s orbitals
  • Linear overlap of sp2 hybrid orbitals (correct)

What is the approximate bond angle in alkenes due to sp2 hybridization?

  • 180°
  • 120° (correct)
  • 109.5°
  • 90°

Which of the following reactions represents oxymercuration of alkenes?

  • C=C + HCl → C-C-Cl
  • C=C + H2O → C-C-OH
  • C=C + Hg(OAc)2 + H2O → C-C-OH + Hg(OAc) (correct)
  • C=C + BH3 → C-C-BH2

In the context of alkenes, what does syn addition mean?

<p>Addition of elements from the same side (D)</p> Signup and view all the answers

Which reaction demonstrates the process of hydration in alkenes?

<p>C=C + H2O → C-C-OH (A)</p> Signup and view all the answers

What is the primary feature of hydrobromination in alkenes?

<p>Addition of Bromine across the double bond (B)</p> Signup and view all the answers

Which type of reaction converts an alkene to a diol?

<p>Oxidation (A)</p> Signup and view all the answers

What characterizes anti addition reactions when applied to alkenes?

<p>Elements are added from opposite sides (D)</p> Signup and view all the answers

What product results from the hydrogenation of an alkene?

<p>Alkane (B)</p> Signup and view all the answers

What is the general molecular formula for alkanes?

<p>Câ‚™H(2â‚™ + 2) (D)</p> Signup and view all the answers

What type of bond characterizes alkenes?

<p>Carbon-carbon double bonds (D)</p> Signup and view all the answers

In which of the following does the term 'diene' apply?

<p>A compound with two double bonds (D)</p> Signup and view all the answers

What is the general formula for alkynes?

<p>Câ‚™H(2â‚™ - 2) (C)</p> Signup and view all the answers

Which of the following compounds is classified as an alkene?

<p>Cyclohexene (C)</p> Signup and view all the answers

How does the heat of combustion of alkanes relate to their structure?

<p>It typically increases with increasing chain length. (A)</p> Signup and view all the answers

What characteristic feature do C-nanotubes share with diamond?

<p>They consist of only carbon atoms in a unique structure. (D)</p> Signup and view all the answers

Which of the following statements about unsaturated aliphatic hydrocarbons is true?

<p>They include compounds like alkenes and alkynes. (C)</p> Signup and view all the answers

Which mechanism is commonly associated with the halogenation of alkanes?

<p>Free radical substitution (A)</p> Signup and view all the answers

What effect does branching have on the boiling point of alkanes?

<p>It generally decreases the boiling point. (C)</p> Signup and view all the answers

What does Markovnikov's rule state regarding the addition of H+ to a double bond?

<p>H+ adds to the carbon of the double bond with the greater number of hydrogens. (A)</p> Signup and view all the answers

Which of the following statements regarding carbocations is true?

<p>Stability of carbocations increases with the number of alkyl groups attached. (C)</p> Signup and view all the answers

What is hyperconjugation?

<p>The overlap of s bonding orbital of an adjacent C-H bond with the vacant p orbital of the cationic carbon. (B)</p> Signup and view all the answers

Which factor contributes to the stability of carbocations according to the inductive effect?

<p>The polarization of electrons in adjacent sigma bonds towards the positively charged carbon. (D)</p> Signup and view all the answers

Which configuration refers to a 2° (secondary) carbocation?

<p>A carbocation with two alkyl groups attached. (B)</p> Signup and view all the answers

Which statement is true regarding the formation of a product in regioselective reactions?

<p>One product is favored over others due to the mechanism of the reaction. (D)</p> Signup and view all the answers

What type of intermediate is a carbocation?

<p>Positively charged carbon atom. (A)</p> Signup and view all the answers

In terms of electronegativity, how does the stability of a carbocation change?

<p>Stability decreases as electronegativity of adjacent atoms increases. (D)</p> Signup and view all the answers

Which of the following is an example of a 3° (tertiary) carbocation?

<p>Cation with three methyl groups attached. (C)</p> Signup and view all the answers

Which of the following is NOT a reactive intermediate?

<p>Stable octet (C)</p> Signup and view all the answers

Flashcards

Alkane

A compound consisting of only carbon and hydrogen atoms, with single bonds connecting them.

Halogenation of Alkanes

The process of substituting one or more hydrogen atoms in an alkane with halogen atoms like chlorine or bromine.

Cyclohexane

A cyclic alkane with the molecular formula C6H12.

Alkene

A hydrocarbon containing at least one carbon-carbon double bond.

Signup and view all the flashcards

Alkyne

A hydrocarbon containing at least one carbon-carbon triple bond.

Signup and view all the flashcards

Diene

An alkene with two double bonds.

Signup and view all the flashcards

Triene

An alkene with three double bonds.

Signup and view all the flashcards

Polyene

A system with numerous double bonds.

Signup and view all the flashcards

Unsaturated Aliphatic Hydrocarbon

A hydrocarbon containing only carbon and hydrogen atoms, with at least one double bond.

Signup and view all the flashcards

Hydrogenation

The process of adding hydrogen atoms to a molecule, especially to an unsaturated hydrocarbon.

Signup and view all the flashcards

Pi Bond

A type of covalent bond between two carbon atoms formed by the sideways overlap of two parallel p orbitals.

Signup and view all the flashcards

Sigma Bond

A type of covalent bond between two carbon atoms formed by the overlap of two sp2 hybrid orbitals.

Signup and view all the flashcards

Alkene Addition Reaction

The process of adding a molecule to an alkene, breaking the double bond and forming a single bond.

Signup and view all the flashcards

Syn Addition

An addition reaction where the hydrogen atom and the halogen atom are added to the same side of the double bond.

Signup and view all the flashcards

Anti Addition

An addition reaction where the hydrogen atom and the halogen atom are added to opposite sides of the double bond.

Signup and view all the flashcards

Hydrochlorination

The addition of hydrogen chloride (HCl) to an alkene, forming a chloroalkane.

Signup and view all the flashcards

Hydration

The addition of water (H2O) to an alkene, forming an alcohol.

Signup and view all the flashcards

Bromination

The addition of bromine (Br2) to an alkene, forming a dibromoalkane.

Signup and view all the flashcards

Hydroboration-Oxidation

The addition of borane (BH3) to an alkene, followed by oxidation with hydrogen peroxide (H2O2) to form an alcohol.

Signup and view all the flashcards

Oxymercuration-Reduction

The addition of mercuric acetate (Hg(OAc)2) to an alkene, followed by reduction with sodium borohydride (NaBH4) to form an alcohol.

Signup and view all the flashcards

Markovnikov's Rule

A reaction where a hydrogen halide (HX) adds across a double bond, with the hydrogen attaching to the carbon with more hydrogen atoms already attached.

Signup and view all the flashcards

Regioselectivity

The type of reaction where one specific product is formed preferentially over other possible products.

Signup and view all the flashcards

Carbocation

A positively charged carbon atom. The positive charge resides on a carbon atom, making it electron deficient.

Signup and view all the flashcards

Carbocation Stability

The stability of carbocations increases as the number of alkyl groups attached to the positively charged carbon increases. This is due to the electron-releasing effect of alkyl groups.

Signup and view all the flashcards

Inductive Effect

The electron-releasing effect of alkyl groups on a carbocation, where electrons are shifted through sigma bonds due to electronegativity differences.

Signup and view all the flashcards

Hyperconjugation

A stabilizing effect that arises from the interaction of the filled bonding orbital of a C-H bond with the empty p orbital of the carbocation.

Signup and view all the flashcards

Tertiary Carbocation (3°)

A positively charged carbon atom with three bonds and a vacant p orbital. It is highly reactive.

Signup and view all the flashcards

Secondary Carbocation (2°)

A positively charged carbon atom with two bonds and a vacant p orbital. It is less stable than a tertiary carbocation.

Signup and view all the flashcards

Primary Carbocation (1°)

A positively charged carbon atom with one bond and a vacant p orbital. It is the least stable type of carbocation.

Signup and view all the flashcards

Methyl Carbocation (0°)

A positively charged carbon atom with no bonds and a vacant p orbital. It is highly unstable and very reactive.

Signup and view all the flashcards

Study Notes

Reactive Intermediates, Structure and Reactivity of Aliphatic Compounds

  • The lecture series covers reactive intermediates and aliphatic compounds.
  • Students will learn to identify functional groups in organic compounds.
  • Students will learn to predict products of reactions with aliphatic compounds.
  • Students will apply reactivity to define synthetic pathways for target aliphatic compounds.

References

  • Wade, L.G., Organic Chemistry, Prentice Hall, New Jersey, 2002
  • McMurry, J.E., Fundamentals of Organic Chemistry, Cenage, Boston, 2010
  • Moloney, M.G., Structure and Reactivity in Organic Chemistry, Wiley-Blackwell, New York, 2008

Alkanes

  • Molecular formula: CnH(2n+2)
  • Topics include structure, shape, hybridization, and examples like methane, ethane, propane, diamond, and carbon nanotubes.
  • Homework assignments include:
    • How melting and boiling points of alkanes change with their structure.
    • Explaining heat of combustion and its uses for alkanes.
    • Explaining the mechanism of halogenation of alkanes.

Unsaturated Aliphatic Hydrocarbons

  • Alkenes:
    • Contain a carbon-carbon double bond.
    • General formula: CnH2n (diene, triene, polyene, etc.).
  • Alkynes:
    • Contain a carbon-carbon triple bond.
    • General formula: CnH2n-2 (e.g., acetylene).

Structure of Alkenes

  • A double bond consists of:
    • A sigma (σ) bond formed by head-on overlap of sp2 hybrid orbitals.
    • A pi (Ï€) bond formed by sideways overlap of parallel 2p orbitals.
  • The two carbon atoms and the attached atoms lie in a plane.
  • Bond angles are approximately 120°.
  • Specific bond lengths (e.g., C=C length, etc.) are defined.

Characteristic Reactions of Alkenes

  • Various electrophilic addition reactions are discussed. Examples include:
    • Hydrochlorination
    • Oxymercuration
    • Hydration
    • Hydroboration
    • Bromination
    • Bromohydrin formation
    • Hydrogenation

Addition Reactions - Syn versus Anti

  • Addition of X and Y to a double bond can occur on the same side (syn) or opposite sides (anti).
  • Syn and anti addition are illustrated using Newman projections.

Carbocation Stability

  • Carbocations (C+) are positively charged carbon atoms.
  • Carbocation stability is discussed, including:
    • Factors influencing stability: Inductive effect, hyperconjugation.
      • Alkyl groups attached to a carbocation help stabilize it.
      • Methyl, primary, secondary, and tertiary carbocations have increasing stability; tertiary carbocations are generally the most stable.
  • The concept of carbocation stability governs the orientation of additions to double bonds.
  • Markovnikov's rule: H+ adds to the carbon with more hydrogens.

Reactive Intermediates

  • Carbocations, free radicals, carbanions, and carbenes are key reactive intermediates.
    • Carbocation: Positively charged carbon atom.
    • Free radical: Carbon atom with unpaired electron.
    • Carbanion: Negatively charged carbon atom.
    • Carbene: Carbon atom with two unpaired electrons.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Lecture 1- Dec 16 (1) PDF - Organic Chemistry

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser