alcohols Flashcards
description of an aldehyde
functional group CHO
carbonyl bonded to at least one H atom
name ends in …al
description of a ketone
functional group is CO
carbonyl bonded to two C atoms
name ends in ….one
description of a carboxylic acid
functional group is COOH
carbonyl bonded to an OH group
name ends in …oic acid
alcohol classification
primary alcohol- C bonded to OH is bonded to one other C
secondary alcohol - C bonded to OH is bonded to two other C
tertiary alcohol - C bonded to OH is bonded to three other C
observation for alcohol oxidation
orange to green
acidified K2Cr2O7 is used as an oxidising agent
primary alcohol to aldehyde
reagent - acidified K2Cr2O7
conditions - heat under distillation
CH3CH2OH + [O] -> CH3CHO + H2O
aldehyde to carboxylic acid
reagent - acidified K2Cr2O7
conditions - heat under reflux
CH3CHO + [O] -> CH3COOH
primary alcohol to carboxylic acid
reagent - acidified K2Cr2O7
conditions - heat under reflux, excess oxidising agent
CH3CH2OH + 2[O] -> CH3COOH + H2O
oxidation of secondary alcohols
reagent - acidified K2Cr2O7
conditions - heat under reflux/distillation
CH3CH(OH)CH3 + [O]-> CH3COCH3 + H2O
features of a condenser
open at both ends
cold water flows around outside
purpose of a condenser
cools hot vapour and condenses to liquid
purpose of anti bumping granules
prevent the formation of large bubbles
why is reflux used to oxidise a primary alcohol to a carboxylic acid
reflux doesnt allow any reactant vapour to escape
model answer
describe when a reaction mixture is refluxed
-ethanol and acidified potassium dichromate (vI) are heated to boiling point for a prolonged time
-ethanal vapour is formed which escapes from the liquid mixture and is then condensed back into liquid and returned to the reaction mixture
-any ethanol and ethanal that initially evaporates can then be oxidised
what happens to an aldehyde as it is produced during distillation
the aldehyde forms as a vapour and escapes from the reaction mixture into the condenser