Alcohols Flashcards
Structural formulas for each carbonyl compound
Aldehyde- CHO
Ketone- CO
Carboxylic Acid- COOH
Eli action of alcohols
Reaction: Dehydration
Mechanism: elimination
Conditions: Hot conc, H2SO4
Observation for alcohol observation
Orange to Green
Primary alcohol —> Aldehyde
Reagent: K2Cr2O7
Conditions: Acidified potassium dichromate, under distillation
CH3CH2OH + [O] —> CH3CHO + H2O
Aldehyde —> Carboxylic acid
Reagent: K2Cr2O7
Conditions: Acidified with conc H2SO4, heat under reflux
CH3CHO +[o] —> CH3COOH
Primary alcohol —> Carboxylic acid
Reagent: K2Cr2O7
Conditions —> Acidified, heat under reflux
CH3CH2OH + 2[O]—> CH3COOH + H2O
Oxidation of secondary alcohols
Reagents: K2Cr2O7
Conditions: acidified, heat under distillation or reflux
CH3CH(OH)CH3 + [O] —> CH3COCH3 + H2O
Oxidation Equipment:
Features of condenser: Open at both ends, cold water flows around the outside
Purpose: Cool hot vapour and condense it into a liquid
Antibumping granules- Prevent the formation of large bubbles.
Reflux
Open top prevents pressure build up- vapour moves into the condenser and is cooled back to a liquid and falls back into the reaction mixture to oxidise
Why is reflux used to oxidise a primary alcohol to a Carboxylic acid
To prevent any vapour from escaping the reaction mixture
Describe what happens when a reaction mixture is refluxed
Heat the mixture to a boiling point, ethanol is oxidised to ethanal, ethanal is vaporised and escapes from the mixture, reflux allows the vapour to cool down and fall back into the mixture, so the ethanol is further oxidised to ethanoic acid.
Distillation
Thermometer in the top, water out water in, open end to prevent built up pressure. Collect the distillate
Test for Carboxylic acids
`Na2CO3, produces effervescence
CO32- + 2H+ —> CO2 + H2O
