alcohols 3.3.5 in papers 2 + 3

pottasium dichromate (VI) Kr2Cr2O7

aldhydes or carboxcylic acids

ketones

This is because there is no hydrogen atom bonded to the carbon with the -OH group

• [Ag(NH3)2]+ • if an aldhyde is present a silver mirror will form and carboxcylic acid will form • if a ketone is present there will be no visible change

• Cu2+ • if aldhyde present, colour changes from blue to red and carboxylic acid is formed • if ketone present theres no reaction/visible change

• sodium carbonate • will start to fizz and carbon dioxide will form

• acid catalysed elimination reaction • Alkenes produced by this method can be used to produce addition polymers without using monomers derived from crude oil. • Concentrated sulfuric or phosphoric acids needed for this to happen

• yeast • no air • temp: 30-40 • The optimum temperature for fermentation is around 38oC • At lower temperatures the reaction is too slow. • At higher temperatures the yeast dies and the enzymes denature. • Fermentation is done in an absence of air because the presence of air can cause extra reactions to occur. It oxidises the ethanol produced to ethanoic acid

• sugar is a renewable resource • production uses low level technology / cheap equipment

• batch process which is slow and gives high production costs • ethanol made is not pure and needs purifying by fractional distillation • depletes land used for growing food crops

• high temperature 300 °C • high pressure 70 atm • strong acidic catalyst of conc H3PO4 • reagent: ETHENE - from cracking of fractions from distilled crude oil • this is a hydration reaction using an acid catalyst

• • faster reaction • purer product • continuous process (which means cheaper manpower)

• high technology equipment needed (expensive initial costs) • ethene is non-renewable resource (will become more expensive when raw materials run out) • high energy costs for pumping to produce high pressures

a fuel produced from plants

an activity that has no net annual carbon (greenhouse gas) emissions to the atmosphere

• It can be argued that ethanol produced from this method is classed as carbon–neutral because any carbon dioxide given off when the biofuel is burnt would have been extracted from the air by photosynthesis when the plant grew. • There would be no net CO2 emission into the atmosphere 6 CO2 + 6 H2O -> C6H12O6 + 6 O2 C6H12O6 -> 2 CH3CH2OH + 2 CO2 2 CH3CH2OH + 6O2 -> 4 CO2 + 6 H2O • Overall for every 6 molecules of CO2 absorbed, 6 molecules of CO2 are emitted. There is no net contribution of CO2 to the atmosphere.

• This does not take into account any energy needed to irrigate plants, fractionally distillation the ethanol from the reaction mixture or process the fuel. • If the energy for these processes comes from fossil fuels then the ethanol produced is not carbon neutral.

compounds with similar boiling points