Basic IUPAC Organic Nomenclature

Acyl Halides or Acid Halides

Nomenclature	Formula	3D structure
Functional class name = acyl or acid halide Substituent suffix = -oyl halide

• Acyl or acid halides are derivatives of carboxylic acids.
• The root name is based on the longest chain including the carbonyl group of the acyl group.
  
• Since the acyl group is at the end of the chain, the C=O carbon must be C1.
• The acyl halide suffix is appended after the hydrocarbon suffix minus the "e" : e.g.  -ane + -oyl halide = -anoyl halide etc.
• The most common halide encountered is the chloride, hence acyl or acid chlorides, e.g. ethanoyl chloride

Functional group is an acyl halide therefore suffix = -oyl chloride Hydrocarbon structure is an alkane therefore -an- The longest continuous chain is C2 therefore root = eth ethanoyl chloride	CH3C(=O)Cl
Functional group is an acyl halide therefore suffix = -oyl chloride Hydrocarbon structure is an alkane therefore -an- The longest continuous chain is C4 therefore root = but butanoyl chloride	CH3CH2CH2C(=O)Cl
Functional group is an acyl halide therefore suffix = -oyl chloride Hydrocarbon structure is an alkane therefore -an- The longest continuous chain is C3 therefore root = prop The branch is a C1 alkyl group i.e. a methyl group The functional groups requires numbering from the right as drawn, the substituent locant is 2- 2-methylpropanoyl chloride	(CH3)2CHC(=O)Cl

©Dr. Ian Hunt, Department of Chemistry