Halogenoalkanes are named from the parent alkane, with a prefix for each halogen:fluoro- chloro- bromo- iodo- Rules:
1. Find the longest carbon chain; this gives the stem name (e.g. propane).
2. Number the chain from the end that gives the substituents the lowest numbers.
3. Put the position number in front of each prefix, e.g. 2-bromo.
4. If there are two or more of the same halogen, use di-, tri- or tetra- and give every position, e.g. 1,2-dichloro.
5. List different substituents (including alkyl groups such as methyl) in alphabetical order, ignoring di- and tri-.Examples:
• CH3CH2CH2Cl is 1-chloropropane
• CH3CHBrCH3 is 2-bromopropane
• CHCl3 is trichloromethane
• (CH3)3CBr is 2-bromo-2-methylpropane: the longest chain has three carbons, and both the Br and the CH3 branch are on carbon 2
• BrCH2CH2Cl is 1-bromo-2-chloroethane: bromo comes before chloro alphabetically, and the lowest numbers are 1 and 2 either way, so the first-cited substituent (bromo) gets the lower numberWorked example: name CH3CHClCH2CH3. The chain has four carbons (butane). Numbering from the left puts Cl on carbon 2; from the right it would be carbon 3. So the name is 2-chlorobutane.When writing names, use commas between numbers and hyphens between numbers and letters.
1. Find the longest carbon chain; this gives the stem name (e.g. propane).
2. Number the chain from the end that gives the substituents the lowest numbers.
3. Put the position number in front of each prefix, e.g. 2-bromo.
4. If there are two or more of the same halogen, use di-, tri- or tetra- and give every position, e.g. 1,2-dichloro.
5. List different substituents (including alkyl groups such as methyl) in alphabetical order, ignoring di- and tri-.Examples:
• CH3CH2CH2Cl is 1-chloropropane
• CH3CHBrCH3 is 2-bromopropane
• CHCl3 is trichloromethane
• (CH3)3CBr is 2-bromo-2-methylpropane: the longest chain has three carbons, and both the Br and the CH3 branch are on carbon 2
• BrCH2CH2Cl is 1-bromo-2-chloroethane: bromo comes before chloro alphabetically, and the lowest numbers are 1 and 2 either way, so the first-cited substituent (bromo) gets the lower numberWorked example: name CH3CHClCH2CH3. The chain has four carbons (butane). Numbering from the left puts Cl on carbon 2; from the right it would be carbon 3. So the name is 2-chlorobutane.When writing names, use commas between numbers and hyphens between numbers and letters.