5: Alkanes and Conformations
- Page ID
- 391307
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- 5.1: Hydrocarbons and the Homologous Series
- Since we will be spending the rest of the course working with compounds with a carbon backbone, there is no time like the present to learn the homologous series, the names for simple, straight hydrocarbon chains and branches.
- 5.2: Generic (Abbreviated) Structures (aka R Groups)
- It is not always necessary to draw the entire structure of a compound. The correct use of the "R group" is explained.
- 5.3: Overview of the IUPAC Naming Strategy
- The International Union of Pure and Applied Chemistry (IUPAC) names for organic compounds all follow the same set of rules and can have up to four parts. Recognizing the overall pattern can simplify the learning process.
- 5.4: Alkanes
- Alkanes form the carbon backbone of all organic compounds.
- 5.5: Uses and Sources of Alkanes
- The primary sources for alkanes are oil and natural gas. Alkanes are important raw materials for the chemical industry and are used as fuels for motors.
- 5.6: Cycloalkanes
- The rotational limits of cycloalkanes introduce stereochemistry to some compounds. Some disubstituted cycloalkanes can exist as geometric isomers (cis/trans).
- 5.7: Haloalkane - Classification and Nomenclature
- The reactivity of the alkyl halides (haloalkanes) can be predicted using their structural classifications of primary, secondary, or tertiary.
- 5.8: Hydrocarbon Functional Groups
- Hydrocarbons are organic compounds that consist entirely of carbon and hydrogen atoms. Hydrocarbons can form different functional groups based upon their carbon bonding patterns as alkanes, alkenes, alkynes, or arenes.
- 5.9: Physical Properties of Alkanes
- Alkanes are not very reactive and have little biological activity; alkanes are colorless, odorless non-polar compounds.
- 5.10: Structure and Conformations of Alkanes
- The carbon-carbon single bonds of alkanes rotate freely. Conformers are the same molecule shown with different sigma bond rotations. Newman projections are one way to communicate bond rotation.
- 5.11: Conformations of Butane
- The conformations of butane are studied to introduce the language and energetic considerations of single bond rotation when alkyl group interactions can occur.
- 5.12: Conformations of Higher Alkanes
- Pentane and higher alkanes have conformational preferences similar to ethane and butane. Each dihedral angle tries to adopt a staggered conformation and each internal C-C bond attempts to take on an anti conformation to minimize the potential energy of the molecule.
- 5.13: Cycloalkanes and Ring Strain
- For cyclic alkanes, only partial rotation of carbon-carbon single bonds can occur. The actual shape of the carbon ring distorts from the traditional geometric shapes to reduce steric hindrance and ring strain to lower the overall potential energy of the molecule.
- 5.14: Cyclohexane Conformations
- Cyclohexane rings are notably stable. Understanding the conformations of cyclohexane and their relative energies is helpful when studying the chemistry of simple carbohydrates (monosaccharides).
- 5.15: Conformations of Monosubstituted Cyclohexanes
- For monosubstituted cyclohexanes, the axial or equatorial orientation of the substituent influences the overall potential energy of the conformation.
- 5.16: Cis-trans Isomerism in Cycloalkanes
- Stereoisomerism is possible for cycloalkanes with two different substituent groups (not counting other ring atoms). Cis and trans isomers are unique compounds.
- 5.17: Conformations of Disubstituted Cyclohexanes
- Because six-membered rings are so common among natural and synthetic compounds and its conformational features are rather well understood, we shall focus on the six-membered cyclohexane ring to study the energetic relationship of conformation and overall potential energy.
- 5.18: Additional Exercises
- This section has additional exercises for the key learning objectives of this chapter.
- 5.19: Solutions to Additional Exercises
- This section has the solutions to the additional exercises from the previous section.