Chemistry - Alcohols and Carbolic Acids

• what are the uses of alcohols

  disinfectants / cleaning products

  alcoholic drinks

  perfume

  feul

  antiseptics
• what are the two routes of alcohols

  fermentation

  hydration of ethene
• describe how alcohol is made through hydration of ethene

  ethene ( obtained by cracking hydrocarbons ) react with steam to produce ethanol

  CH2=CH2 (g) + H2O ( reversible reaction ) CH3CH2OH (g) -45kg mol-1

  temperature - 300 degrees

  pressure - 60-70 atm

  catalyst - phosphoric acid
• what are the strengths and weaknesses of the hydration of ethene

  strength

  no waste products

  cheap

  continuous

  weakness

  crude oil

  non-renewable

  dangerous
• describe fermentation to create alcohol

  sugars are converted into ethanol

  disolved sugar ( sugar cane ) in water and added yeast while warming up

  yeast acts a catalyst

  C6H2O6 - 2C2H5OH + 2CO2

  used for alcoholic drinks
• what are the pros and cons to fermentation

  pros

  renewable

  cons

  carbon dioxide release

  batch process

  slow
• what are biofuels

  fuels made from living organism

  bioethanol - fermentation

  biodiesal - oils and fats in seed
• what are the advantages of biofeuls

  renewable - growth of plants and use of animal waste products

  Greenhouse gases - carbon dioxide given out is taken back in woht the plants needing to grow for the fuel

  economic and political security - less dependant on countries with fossil fuels
• what are the disadvantages of biofuels

  land use - produce plant not for food / wildlife and habitats

  use of resources - water and fertiliser needed / strain local supply and pollute water

  carbon neutrality - with transport of materials and products / building and running a factory - not really carbon neutral

  costly - lost of equipment
• What is a primary alcohol?

  When the carbon with the OH group attached is also attached to one another carbon
• what is a secondary alcohol?

  When the carbon with the OH group is attached to 2 other carbons
• What is a tertiary alcohol?

  When the carbon with the group is attached to 3 other carbons
• Define dehydration

  An elimination reaction in which water is removed from a saturated molecule to make an unsaturated molecule
• What are the products for the dehydration of alcohol and the conditions required?

  An Alkene

  In the presence of an acid catalyst

  Concentrated sulphuric acid or phosphoric acid

  or pumice stone

  heated under reflux with catalyst for 40 minutes
• Define reflux

  Continuous evaporation and condensation to ensure reaction is complete
• Define oxidation

  The addition of oxygen and removal of hydrogen
• What will it oxidation agent and reduction agent have?

  Oxidation agent - lots of oxygen

  Reduction agent - lots of hydrogen
• What does the partial oxidation of alcohol create?

  aldehydes

  Requires acidified potassium dichromate ( K2Cr2O7)

  Colour change - orange to green
• What does the full oxidation of alcohol create?

  Carboxylic acid

  Acidified potassium dichromate ( K2Cr2O7 )

  Colour change - orange to green
• What are the rules of the oxidation of alcohol?

  Partial oxidation is done through distillation

  Full oxidation is done through reflux

  Only primary alcohols make aldehydes as the functional group is on the end

  Secondary alcohols make ketones - end of molecule

  Tertiary alcohol will not oxidise

  Carboxylic acids are created from further oxidation of aldehydes
• how can you identify a carboxylic acid?

  has a COOH group ( double bonded to a oxygen and single bonded to OH)
• why can't hydrocarbon chains longer than 5 carbons soluble in water

  they become non-polar

  only undergo van der waales intereactions and no hydrogen bonding
• what can carboxylic acids form

  dimers
• are carboxylic acids soluble in water

  yes with 4 carbon chains or under
• what does the partial oxidation of carboxylic acid make ?

  salt with a -thanonate ion
• how can an ester be identifiable

  middle of compound

  carbon is double bonded to an oxygen and single bonded to another oxygen
• what does a carboxylic acid and alcohol make

  ester and water

  requires a concentrated sulfuric acid catalyst

  name - acid then carboxylic acid ( ethyl ethanoate )

  ends in -oate
• what are the properties of esters

  volatile - easy to change state - liquid to gas

  flammable - make dangerous

  solubility - doesn't mix well with water but mixes well with alcohols and organic solvents

  pleasant smell - sweet or fruity
• what are the uses of esters

  perfumes

  flavourings

  ointments

  paint , ink , glue and nail varnish remover