PC2M6

• Addition reactions


  Occur when two reactants combine to create a single new product without any leftover atoms
• Elimination reactions


  Happen when a single organic reactant divides into two products, frequently resulting in the creation of a small molecule like H2O or HCl
• Substitution reactions


  Occur when two reactants exchange parts to give two new products
• Rearrangement reactions


  Occur when a single organic reactant undergoes a reorganization of bonds and atoms to yield a single isomeric product
• Reaction mechanism


  • Overall description of how a reaction occurs.
  • Describes what takes place at each stage of a chemical transformation.
  • explains the order of bond-making and bond-breaking
• REACTION MECHANISM - Bond breaking


  Symmetrical cleavage is said to be homolytic, and the unsymmetrical cleavage is said to be heterolytic
• Radical reactions


  • Involve symmetrical bond-breaking and bond-making
  • Involves a neutral chemical species that contains an odd number of electrons and thus has a single, unpaired electron in one of its orbitals
• Polar reactions


  • Processes that involve unsymmetrical bond breaking and making
  • involve species that have an even number of electrons and thus have only electron pairs in their orbitals
• Nucleophile


  Nucleus-loving, (-) polarized, electron-rich, donates electrons
• Electrophile


  Electron-loving, (+) polarized, electron-poor, accepts electrons
• Ampiphile


  May act as either nucleophile or electrophile depending on the corresponding compound it is made to react
• Neutral nucleophiles


  • Ammonia, water, amines, carboxylic acid, thiols, alcohol
• Charged nucleophiles


  • Hydroxide ion, chloride, fluoride, iodide, bromide ions, CN-
• Electrophiles


  • Carbonyl compounds, halides, hydrocarbons, carbocation
• Nucleophilic substitution reaction

  Electrophiles leave the molecule and are replaced by nucleophiles
• SN2 (Substitution nucleophilic bimolecular)


  2 compounds reacting with resulting to 2 products
• SN1 (Substitution nucleophilic unimolecular)


  1 compound reacting to reagent producing 1 product
• SN1 mechanism

  • Slow ionization of the substrate as the rate-determining step.
  • rapid reaction between the intermediate carbocation and the nucleophile
• Addition reaction


  • Most common organic reaction of unsaturated hydrocarbons and carbonyl groups.
  • pi bonds are broken to form new sigma bonds.
  • reactants have double/ triple bonds.
  • products are all in single bonds
• Addition reactions


  • Addition of hydrogen to form alkanes, addition of halides to form alkyl halides

  
• Elimination reaction


  • The reactants consist of single bondsand the resulting product will include a double bond.
  • Byproducts like salt and water may or may not be explicitly stated in the reaction.
  • This process is the reverse of an addition reaction.
• Rearrangement reactions


  • Rearrangement of functional groups or hydrogen atoms.
  • sometimes involved in other types of reactions
• Acid-base reactions


  Another classification of organic reactions
• KINDS OF ORGANIC REACTIONS

  • ADDITION REACTIONS
  • ELIMINATION REACTIONS
  • SUBSTITUTION REACTIONS
  • REARRANGEMENT REACTIONS
• NUCLEOPHILE

  • Neutral Nu
  • Charged Nu
• SUBSTITUTION REACTION

  Most typical: nucleophilic substitution

  Terms:

  • nucleophile: electron- rich substance; donates electron; acts as Lewis base
  • electrophile: electron-poor substance; accepts electron; acts as Lewis acid
• ORGANIC REACTIONS

  • another classification of reactions are the acid/base reactions

  2 MAIN THEORIES

  • Lewis theory (L- electron)
  • BROnsted- Lowry (BRO -proton)
• SN2 MECHANISM

  • one- step process with no intermediate
  • bond-breaking is simultaneous with the bond formation