Hydrocarbons

• HYDROCARBONS

  • A major group of organic compounds.

  • Hydrocarbons are made up of only

  carbon and hydrogen

  atoms
• Hydrocarbons are further classified into aliphatic hydrocarbons (those

  • that do not contain a benzene ring) and aromatic hydrocarbons (those that contain a benzene ring)
• Aliphatic Hydrocarbons are further classified into Alkanes, Cycloalkanes, Alkenes and

  Alkynes
• Naming hydrocarbons

  
• Alkanes

  • have the general formula CnH2n+2

  • have single bonds

  • In naming alkanes, the –ane suffix(ending) is used.

  • also known as saturated hydrocarbons

  • They are referred to as saturated hydrocarbons because they contain the maximum number of hydrogen atoms that can bond to the carbon atoms present
• Cycloalkanes

  • Are alkanes whose carbon atoms are joined in rings.

  • They have the general formula CnH2n.
• Alkenes

  • Their formula is CnH2n

  • are hydrocarbons that contain at least one

  carbon-carbon double bond

  • In naming alkenes, the –ene suffix (ending) is used. • They are also called olefins.

  • Alkenes are classified as unsaturated hydrocarbons
• Parent chain

  The longest chain of carbon atoms containing both carbon atoms of the double bond
• Naming alkenes

  The parent chain is named using the same stem as the alkane having the same number of carbon atoms but the -ane suffix is replaced with -ene
• Naming alkenes with 4 or more carbon atoms

  • The position of the double bond must be indicated
  • The carbons atoms are numbered so that the first of the two that are doubly bonded is given the lower of the two possible numbers
• Rules in Naming Alkenes

  •3. Substituents are identified (as with other organic compounds) and their location is indicated by a number. Thus, the structure below is 5-methyl-2-hexene. Note that the numbering of the parent chain is always done in such a way as to give the double bond the lowest number, even if that causes a substituent to have a higher number. The double bond always has priority in numbering.
• Alkynes

  •They have the general formula CnH2n-2 •are hydrocarbons that contain at least

  one CC triple bond

  •In naming alkenes, the –yne suffix

  (ending) is used.