ORGCHEM(02)

• The International Union of Pure and Applied Chemistry (IUPAC) was established in 1919 to make sure that chemists around the world could communicate accurately
• Many chemicals had common names given to them by the people who discovered them based on their source or smell or color
• Common names don't tell you much about the chemical structure
• IUPAC has standard rules for naming organic chemicals
• IUPAC systematic naming steps

  1. Find the longest carbon chain and give it a root name

  2. Identify the highest priority functional group and add its suffix to the root name

  3. Identify the types of substituents and their positions on the carbon chain, then add a numbered prefix to the root name
• Root names for carbon chains

  1 carbon: meth-

  2 carbons: eth-

  3 carbons: prop-

  4 carbons: but-

  1. 12 carbons: pent-, hex-, hept-, oct-, non-, dec-, undec-, dodec-
• Hydrocarbon types


  Alkanes: only single bonds

  Alkenes: contain double bonds

  Alkynes: contain triple bonds

  Aromatics: more complicated
• Naming alkenes


  Find the longest chain with a double bond

  Number the carbons starting from the end closest to the double bond

  Use the lowest number touching the double bond and add the suffix -ene
• Naming alkynes


  Find the longest chain with a triple bond

  Number the carbons starting from the end closest to the triple bond

  Use the lowest number touching the triple bond and add the suffix -yne
• Naming substituents


  Identify the substituents and their positions

  Add numbered prefixes in alphabetical order

  Halogens get the -ine replaced with -o (e.g. chloro-, bromo-, iodo-)
• When an alkene and alkyne tie for the lowest number, the alkene takes priority
• Dichloromethane


  Alkane with two chlorine atoms attached to a single carbon
• Methylene chloride


  Common name for a CH2 group with two chlorine atoms
• Using systematic names helps chemists communicate more accurately