C10 - Organic Reactions

• Organic chemistry

  A specific type of chemistry looking into molecules that contain carbon
• Molecules containing carbon

  • Esters
  • Alcohols
  • Alkenes
• Alkenes

  • They have double bonds
  • They are more reactive than alkanes because the double bond means they are not saturated
• Reaction of alkenes with bromine

  1. Bromine adds to the double bond

  2. Bromoethane is colourless, unlike orange bromine
• Reaction of alkenes with hydrogen

  Converts alkene to alkane
• Alcohols


  Organic compounds with the functional group OH
• Carboxylic acids


  Organic compounds with the functional group COOH
• Esters


  Organic compounds with the functional group COO-R
• Alcohols

  • They are highly combustible
  • They can be used to make strong alkalis
• Oxidation of alcohols

  Alcohols are oxidised to carboxylic acids
• Weak acids

  Carboxylic acids do not fully dissociate in water to produce H+ ions
• Reaction of carboxylic acids with metal carbonates

  Forms a salt, water and carbon dioxide
• Esters


  They have distinctive sweet smells
• Ester formation

  Reaction of an alcohol and a carboxylic acid to form an ester and water
• Ester naming

  Alcohol name with -yl ending + carboxylic acid name with -oate ending
• Carboxylic acids are weak acids that ionize partially in solution, forming hydrogen ions (H+).
• Alcohols can be oxidized to carboxylic acids using chromic acid or potassium dichromate(VI) as the oxidizing agent, with the addition of sulfuric acid as a catalyst.
• Condensation Polymers


  A second type of polymer formed from a condensation reaction
• Condensation polymerisation

  1. Requires reagents with correct functional groups at both ends of the molecule

  2. For polyester, need a diol and a diacid
• To make different sorts of polyester, you simply change the R group
• Techniques for making ethanol

  • Fermentation
  • Hydration of ethane
• Fermentation

  Sugar and yeast (anaerobic respiration) produces ethanol
• Hydration of ethene

  Ethene reacted with steam at a high temp and pressure
• Fermentation

  • Uses plants so is renewable, carbon neutral. Needs low temp 37°C
• Hydration of ethene

  • Fast, produces ethanol in large quantities
• Fermentation

  • Slow, relies on crops
• Hydration of ethene

  • Ethene from crude oil is non renewable. Lots of energy required
• When dissolved in water, carboxylic acids act as weak acids as they partially dissociate
• Alcohol and a carboxylic acid reaction

  Form an ester, requires a strong acid catalyst
• Condensation polymer


  Formed from monomers with functional groups at both ends, releases small molecules
• Ester

  Chemicals with the functional group R-COO-R'
• How to make a polyester

  Diol (OH functional group on both sides of molecule) and diacid (COOH functional group on both sides of molecule) needed.