Intro to organic chem

• Hydrocarbon


  Compound consisting of hydrogen and carbon only
• Molecular formula


  Formula which shows the actual number of each type of atom
• Unsaturated


  Contains a C=C double bond
• Saturated


  Contain single carbon-carbon bonds only
• General formula


  Algebraic formula for a homologous series e.g. CnH2n
• Empirical formula


  Shows the simplest whole number ratio of atoms of each element in the compound
• Displayed formula


  Shows all the covalent bonds and atoms present in a molecule
• Drawing organic compounds


  • Add the hydrogen atoms so that each carbon has 4 bonds
• Shape around carbon atom in saturated hydrocarbons

  • Tetrahedral
  • Bond angle 109.5o
• Skeletal formula


  Simplified organic formula, shown by removing hydrogen atoms from alkyl chains, leaving just a carbon skeleton and associated functional groups
• Structural formula


  Minimal detail that shows the arrangement of atoms in a molecule
• Functional group


  Atom or group of atoms which when present in different molecules causes them to have similar chemical properties
• Homologous series


  • Families of organic compounds with the same functional group and same general formula
  • They show a gradual change in physical properties (e.g. boiling point)
  • Each member differs by CH2 from the last
  • Have same chemical properties
• Homologous series


  • Alkane
  • Alkenes
  • Alcohols
  • Halogenoalkanes
  • Aldehydes
  • Ketones
  • Carboxylic acids
  • Esters
• Naming rules for carbon chains

  • Count the longest carbon chain and name appropriately
  • Find any branched chains and count how many carbons they contain
  • Add the appropriate prefix for each branch chain
• Naming functional groups


  • The position of the functional group on the carbon chain is given by a number – counting from the end of the molecule that gives the functional group the lowest number
  • For aldehydes, carboxylic acids & nitriles, the functional group is always on carbon 1
  • Words are separated by numbers with dashes
  • Numbers are separated by commas
  • If there is more than one functional group or side chain, the groups are listed in alphabetical order (ignoring any di, tri)
• Naming suffixes


  • If the suffix starts with a vowel- remove the –e from the stem alkane name
  • If the suffix starts with a consonant or there are two or more of a functional group meaning di, or tri needs to be used then do not remove the the –e from the stem alkane name
  • The functional groups take precedence over branched chains in giving the lowest number
• Naming examples


  • 3-bromo-1-fluoropentane
  • 2,2-dichloro-1-fluorobutane
  • 2,3-dibromopentane
  • trichloromethane
• Naming multiple functional groups


  • Where there are two or more of the same groups, di-, tri- ,tetra-, penta- or hexa- are used
  • The functional group with the highest priority takes the suffix, with all others taking the prefix form
  • Double and triple C-C bonds only take suffix form
• Naming examples with multiple functional groups

  • 2-bromobut-3-en-1-ol
  • E-but-2-enoic acid
  • 2,3-dichloro-1-fluoro-3-methylpentane
  • 5,5-dibromo-4-iodo-3-methylpent-1-ene
  • E-3,6-dichlorohex-4-en-1-ol
• Aldehydes


  • Name ends in -al
  • C=O bond is always on the first carbon of the chain
• Aldehyde examples


  • ethanal
• Ketones


  • Name ends in -one
  • If 5C's or more in a chain then need a number to show the position of the double bond
• Ketone examples


  • propanone
  • pentan-2-one
• Carboxylic acids


  • Name ends in -oic acid
  • No number is necessary for the acid group as it must always be at the end of the chain
  • Numbering always starts from the carboxylic acid end
• Carboxylic acid examples


  • propanoic acid
  • ethanedioic acid
• Naming multiple carboxylic/aldehyde groups

  • If two carboxylic acid groups then it is called a -dioic acid
  • If two aldehyde groups then di is put before -al and an e is added to the stem
• Examples with multiple carboxylic/aldehyde groups

  • pentane-2,4-dione
  • pentanedial
• Aldehydes


  An aldehyde's name ends in -al, it always has the C=O bond on the first carbon of the chain so it does not need an extra number
• Ketones


  Ketones end in -one, when ketones have 5C's or more in a chain then it needs a number to show the position of the double bond
• Carboxylic acids


  These have the ending -oic acid but no number is necessary for the acid group as it must always be at the end of the chain. The numbering always starts from the carboxylic acid end
• Dioic acids


  If there are carboxylic acid groups on both ends of the chain then it is called a -dioic acid
• Diketones


  If two ketone groups then di is put before -one and an e is added to the stem
• Dialdehydes


  If two aldehyde groups then di is put before -al and an e is added to the stem
• Hydroxy aldehydes


  Aldehydes have a higher priority than alcohol so the -OH group uses the hydroxy prefix
• Hydroxy carboxylic acids


  The -OH group uses the hydroxy prefix
• Homolytic fission


  The bond has broken in a process called homolytic fission, each atom gets one electron from the covalent bond
• Free radicals


  A free radical is a reactive species which possess an unpaired electron
• Heterolytic fission


  Heterolytic fission produces ions, one atom gets both electrons from the covalent bond
• Curly arrows


  We use curly arrows in mechanisms to show the movement of an electron pair showing either breaking or formation of a covalent bond