Amines

• Draw the structure of ammonia

  0 Carbons

  
• Draw the structure of a primary amine

  1 carbon

  
• Draw the structure of a Secondary amine

  2 carbons

  
• Draw the structure of a tertiary amine

  3 carbons

  
• Draw the structure of a Quaternary amine

  4 carbons

  
• How do you name amines

  -amine

  Amino-
• Why are amines so reactive

  • The lone pair of electrons on the NITROGEN
  • due to the POLAR N-H bond
• What shapes are amines around the N

  • Trigonal pyramidal
  • 107 degrees due to LONE PAIR ON N
• What kind of intermolecular forces do amines have

  • Hydrogen bonding
  • Due to a polar N-H bond lone pair of electrons on N atom
• Do amines have intermolecular forces which are stronger than or weaker than alcohols

  • WEAKER
  • As N has a LOWER electronegativity than O
  • Which means it has weaker hydrogen bonding
• What state are amines at 298K

  • Short chains are GASES
  • longer chains are VOLATILE LIQUIDS
• What do amines smell like

  Fishy smells
• Which primary amines are soluble in water/alcohol

  • Up to FOUR carbon atoms long
  • Because they can hydrogen bond to water molecules
  • After this, the non-polarity of the hydrocarbon chain makes them INSOLUBLE
• What kinds of solvents are most other amines soluble in

  Less or NON-POLAR solvents
• How soluble is phenylamine

  • Not very soluble
  • Due to the non-polarity of the benzene ring
  • C6H6 can NOT form hydrogen bonds
• How can and when do amines act as bases

  when they bond to a H+
• How can/when do amines act as NUCLEOPHILES

  • When they bond with an electron-deficient C atom
  • Donates a lone pair from N
• Draw a mechanism for the basic action of an amine with water

  ..

  
• What is the product from the basic action of an AMINE with WATER

  • Ammonium ion
  • Which forms a salt with an ANION
• Is an ammonium ion soluble in water

  • YES
  • Because its attracted to the polar water molecule
• How can you regenerate the soluble amine from the AMMONIUM SALT

  • Add a strong base such as NaOH
  • Because it REMOVES the H+ from the ammonium ion
• In order to be the STRONGEST base, what must a particular amine have

  • The GREATEST electron density around the N atom
  • Because it makes it a better electron pair donor (attracts protons more_
• What does positive/negative inductive effect mean

  • POSITIVE inductive effect = DONATE electrons. INCREASE density around N
  • Negative inductive effect = REMOVE electrons. DECREASES density around N
• What effect do alkyl groups have (on electron density and base strength)

  • POSITIVE inductive effect
  • INCREASES electron density around N
  • STRONGER base
• What effect do aryl groups have (on electron density and base strength)

  • NEGATIVE inductive effect
  • DECREASES electron density around N
  • WEAKER BASE
• Why are TERTIARY amines never good bases

  • They are INSOLUBLE in WATER
• Which amines are the strongest bases (strongest first)

  SECONDARY amine -> PRIMARY amine -> NH3 -> Phenylamine (weakest)
• Draw a mechanism for the nucleophillic substitution of NH3 with RCH2Br to form PRIMARY amines

  primary amines

  
• How can primary amines then form 2/3/4 ammonium ions

  • Multiple substitutions
  • Primary amine is a nucleophile that attacks the original haloalkane
• What are the problems with the method of multiple substitutions

  Not efficient as it has a low yield of primary amines due to multiple substitutions
• How could you maximise the yield of the primary amine

  Use EXCESS AMMONIA
• What type of mechanism is the reaction of a haloalkane with a CYANIDE ION

  Nucleophillic substitution
• What conditions does the nucleophillic substitution of a haloalkane with cyanide ion require

  • Ethanol as a solvent
  • A nitrite is formed
• How do you get from a nitrile to a PRIMARY AMINE

  • Reduction using NICKEL
  • HYDROGEN as a catalyst
• Why is reduction using nickle a purer method

  Only the PRIMARY amine can be formed
• What conditions are needed to form nitrobenzene from benzene

  • CONCENTRATED H2SO4 and HNO3 to form NO2 + ion for electrophilic attack
• How do you form an ammonium chloride salt from nitrobenzene

  • Reduce the nitrile using tin/Hcl
  • Because this forms an ammonium salt with Cl- ions
  • Room temperature
• Equation for the reaction of nitrobenzene -> phenylamine

  C6H5NO2 + 6[H] -> C6H5NH2 + 2H2O
• What mechanism is used for forming amides from acyl chlorides and amines

  Nucleophillic addition/elimination
• Draw a mechanism for the reaction of ethanoyl chloride with ethanamine

  .