Acyl Chlorides and Acid Anhydrides

• All carboxylic acid derivatives contain a carbonyl group. When the carbonyl group is derived from a carboxylic acid, it is called an acyl group
• Acyl chloride - chlorine next to a carbonyl group - R-COCl general formula
• carboxylic acid + sulfurous dichloride --> acyl chloride + sulfur dioxide + hydrogen chloride

  CH3COOH + SOCl2 --> CH3COCl + SO2 + HCl
• naming acyl chlorides

  length of carbon chain -oyl chloride

  E.g. ethanoyl chloride

  butanoyl chloride
• Acid anhydrides naming

  carbon chain -anoic anhydride

  e.g ethanoic anhydride

  propanoic anhydride
• Acid anhydrides are molecules with two carbonyl groups bonded to the same oxygen atoms. General formula - RCOOCOR

  
• carboxylic acids are dehydrated to form acid anhydrides
• Both acyl chlorides and acid anhydrides react with water to form carboxylic acids. Hydration of acyl chlorides is violent