ochem reactions

combustion

WHO: alkanes, alkenes, alcohols

WHAT: burn in excess oxygen, carbon dioxide and water formed as products (CO+H2O or just C is oxygen supply is limited)

NEEDS: excess oxygen

catalytic cracking

WHO: alkanes

WHAT: break down large molecules into smaller molecules, can form alkanes alkenes even hydrogen

NEEDS: catalyst (silicon dioxide or aluminium oxide) and high temperatures around 600C

substitution (with halogen)

WHO: alkanes

WHAT: reacts with halogens (Cl2/Br2 etc)

NEEDS: presence of ultraviolet light

ADDITION of Halogen

NEEDS: bromine/chlorine dissolved in CCl4 in the dark, room temperature

forms alkane btw (?)

TEST for C=C

to a test tube containing ___, add bromine dissolved in CCl 4 in the dark. If c=c bond present, orange-red solution is decolourised

ADDITION of steam

WHAT: react with H2O to form alcohol

NEEDS: Lab: Concentrated H2SO4 at room temeprature, add H2O and warm

Industrial: 300C celcius, 60 bar pressure, concentrated H3PO4

ADDITION of hydrogen

WHAT; forms alkanes alkenes even

NEEDS: hydrogen gas, platinum catalyst

ELIMINATION

WHO: Alchohol

WHAT: forms alkenes + steam

NEEDS: excess concentrated sulfuric acid at 170 degrees celcius

OXIDATION

WHO: Alcohol

WHAT: oxidised to carboxylic acid

NEEDS: Acidified KMnO4 and Heat!

!!! tertiary alcohols resistant to oxidation (no colour change), secondary alcohol forms ketone

CONDENSATION

WHO: alcohol + carboxylic acid

WHAT: reversible reaction to form ester + water

NEEDS: concentrated sulfuric acid as catalyst, heated under reflux conditions

HYDROLYSIS of esters

reversible to form carboxylic acid and alcohol

fermentation of ethanol

NEEDS: Yeast (catalyst), absence of air, temperature below 37C, produces dilute ethanol solution FROM fermenting suugars/starch (C6H12O6) (aq)