5: An Introduction to Organic Reactions using Free Radical Halogenation of Alkanes
- Page ID
- 136861
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)- 5.1: Types of Organic Reactions
- The four main classes of organic reactions are additions, eliminations, substitutions, and rearrangements.
- 5.2: 5.2 Reaction Mechanism Notation and Symbols
- Arrows are used by chemists to communicate electron flow in mechanisms, reaction completion/equilibrium, and resonance relationships. It is important to use accuracy when selecting the type of arrow for reactions and precision in drawing the location of the arrow head and tail for the curved arrows of electron flow.
- 5.3: the Dance of the Nucleophile and Electrophile
- Sterics and electronics are the underlying driving forces for polar organic reactions. The electron rich nucleophile (Nu:) reacts with the electron poor electrophile through a variety of pathways that can be limited and/or influenced by steric hindrance. We explore and learn the polar reaction pathways in subsequent chapters.
- 5.4: Describing a Reaction - Equilibrium and Free Energy Changes
- The relationship between equilibrium and free energy is reviewed quantitatively and applied to organic reactions conceptually.
- 5.5: Homolytic Cleavage and Bond Dissociation Energies
- The products of homolytic cleavage are radicals and the energy that is required to break the bond homolytically is called the Bond Dissociation Energy (BDE) and is a measure of the strength of the bond.
- 5.6: Reaction Energy Diagrams and Transition States
- Reaction energy diagrams efficiently and effectively communicate the thermodynamics and kinetics of chemical reactions in a single diagram. They are a useful tool in learning organic chemistry.
- 5.7: 5.7 Reactive Intermediates - Carbocations
- A carbocation is a cation in which carbon has an empty p orbital and bears a positive charge creating a highly reactive intermediate. Comparing the relative stability of reaction intermediates helps elucidate reaction mechanisms and predict major and minor products.
- 5.8: 5.8 Reactive Intermediates - Radicals
- A radical (more precisely, a free radical) is an atom, molecule, or ion that has unpaired valence electron (half filled orbital) creating a highly reactive intermediate.
- 5.9: Reactive Intermediates: Carbanions and Carbon Acids
- A carbanion is an anion in which carbon has an unshared pair of electrons and bears a negative charge creating a highly reactive intermediate.
- 5.10: The Free-Radical Halogenation of Alkanes
- Free radical halogenation of alkanes is the substitution of a single hydrogen on the alkane for a single halogen to form a haloalkane. This reaction is very important in organic chemistry because it opens a gateway to further chemical reactions. We will apply the reaction concepts discussed in this chapter to this reaction to show how empirical data supports these theories.
- 5.11: Reactivity and Selectivity
- In general, high reactivity correlates with low selectivity and vice versa. Depending on the structure of the substrate, reaction conditions can be optimized for high reactivity or high selectivity and occasionally for both.
- 5.12: A Comparison between Biological Reactions and Laboratory Reactions
- Biochemical reactions occur within our body fluids at a typical pH of 7.4 and temperature of 98.6C. Our biochemistry relies on enzymes to catalyze physiological reactions within this narrow range of environmental conditions. Synthetic organic chemists can create extreme conditions within reactions flasks to catalyze and promote chemical reactions.
- 5.13: Additional Exercises
- This section has additional exercises for the key learning objectives of this chapter.
- 5.14: Solutions to Additional Exercises
- This section has the solutions to the additional exercises from the previous section.