Alkane

• Reactionary ability of the saturated hydrocarbons (alkanes, cycloalkanes)
• Reactionary ability of the unsaturated hydrocarbons (alkenes, alkadienes, alkynes)
• Organic Chemistry is the study of carbon-based compounds and their properties
• Classes of Hydrocarbons


  • Aliphatic hydrocarbons
  • Aromatic hydrocarbons
• Types of Hydrocarbons


  • Saturated hydrocarbons
  • Unsaturated hydrocarbons
• Aliphatic Hydrocarbons


  • Alkanes
  • Alkenes
  • Alkynes
• Alkanes


  Hydrocarbons in which all the bonds are single bonds
• Alkenes


  Hydrocarbons that contain one or more carbon-carbon double bonds
• Alkynes


  Hydrocarbons that contain one or more carbon-carbon triple bonds
• Arenes is another name for aromatic hydrocarbons, which have properties much different from aliphatic hydrocarbons
• The most important aromatic hydrocarbon is benzene
• Functional Groups


  Reactive sites in hydrocarbons
• Alkanes


  Have general molecular formula CnH2n+2 where n is an integer
• The simplest alkane is methane (CH4)
• Types of Nomenclature


  • Common
  • Systematic
• Hydrocarbons can be divided into different types, depending on their bonding
• Naming Organic Molecules


  • Alkanes (carbon chain, no double or triple bonds, all single bonds)
  • Alkenes (carbon chain, contains double bond(s))
  • Alkynes (carbon chain, contains triple bond(s))
• Prefix


  Tells the number of carbons in the main chain or ring
• Prefixes


  • meth-
  • eth-
  • prop-
  • but-
  • pent-
  • hex-
  • hept-
  • oct-
  • non-
  • dec-
• Suffix


  Indicates the types of bonds present
• Suffixes


  • -ane (alkanes, all single bonds)
  • -ene (alkenes, double bond)
  • -yne (alkynes, triple bond)
• Saturated hydrocarbons are the alkanes, which are chains of carbon connected by single bonds
• Alkanes have the general molecular formula CnH2n+2
• Methane (CH4) is the simplest and most abundant alkane
• Homologous Series of Alkanes

  • Methane
  • Ethane
  • Propane
  • Butane
  • Pentane
  • Hexane
  • Heptane
  • Octane
  • Nonane
  • Decane
  • Undecane
  • Dodecane
  • Tridecane
  • Tetradecane
  • Pentadecane
• Structure of Alkanes


  • Can have simple (unbranched) or branched carbon chains
  • Unbranched alkanes are called normal or n-alkanes
  • All carbon atoms are in sp3-hybridization
  • Distance between carbon atoms is 0.154 nm, distance between carbon and hydrogen is 0.110 nm
  • Rotation can occur around C-C bonds, resulting in different conformations
• Crystal n-alkanes are zigzag-shaped, which is the most advantageous conformation
• Trivial Names


  Some alkanes have trivial names like methane, ethane, propane, n-butane, isobutane, etc.
• IUPAC Names


  Other alkanes have IUPAC names where the number of carbon atoms is specified by a prefix and the suffix -ane
• IUPAC Nomenclature of Branched Alkanes

  Choose the longest carbon chain

  2. Identify the substituent groups

  3. Number the chain to give the lowest number to the first substituent
• When the same substituent appears more than once, use multiplying prefixes like di-, tri-, tetra-

  When different substituents are present, list them in alphabetical order
• Types of Carbon Atoms

  Primary (connected to 1 carbon)

  Secondary (connected to 2 carbons)

  Tertiary (connected to 3 carbons)

  Quaternary (connected to 4 carbons)
• Isomerism in Alkanes


  • Structural isomerism (different sequence of carbon connections)

  Optical isomerism (different spatial arrangements)
• Methane is the only alkane with formula CH4, ethane the only one with C2H6, and propane the only one with C3H8. Beginning with C4H10, constitutional isomers are possible.
• 1. butane and isobutane are constitutional isomers with the same molecular formula C4H10 but different structures
• The number of isomeric alkanes increases enormously with the number of carbon atoms
• Natural Sources of Alkanes

  • Petroleum

  Natural Gas
• Fractional Distillation of Petroleum

  Petroleum ether (C5-C6)

  Benzine (C6-C10)

  Kerosene (C11-C12)

  Diesel fuel (C13-C17)

  Black oil (C18+)
• Each petroleum fraction is a mixture of hydrocarbons with similar boiling points
• Synthetic Methods for Alkanes

  Hydration of carbon(II) oxide

  2. Hydrogenation of alkenes and alkynes

  3. Wurtz reaction (alkyl halide + sodium)