Alcohols Flashcards
How are alcohols classed?
Primary, secondary or tertiary
How are alcohols with 2+ OH groups named?
E.g. ethane-1,2-diol
Why are the boiling points of alcohols higher than alkanes?
Alcohols have stronger hydrogen bonding between molecules
Volatility definition
Ease of boiling (alcohols have low volatility)
Why are alcohols soluble in water?
Can form hydrogen bonds with water molecules
What influences the solubility of alcohols?
Length of the hydrocarbon chain (longer chain decreases influence of the OH group so solubility decreases)
What is the conversion, reagents and conditions of the dehydration/elimination of alcohols?
Conversion: Alcohol –> alkene
Reagents: Acid catalyst
Conditions: Heat under reflux
What is the conversion, reagents and conditions of the substitution of alcohols?
Conversion: Alcohol –> haloalkane (+H2O)
Reagents: NaX + H2SO4
Conditions: Heat under reflux
What is the structural formula of an aldehyde and how are they named?
CHO, ending changes to -al
What is the structural formula of a ketone and how are they named?
COC, ending changes to -one
What is the structural formula of a carboxylic acid and how are they named?
COOH, ending changes to -oic acid
What colour change occurs during an oxidation of alcohols reaction?
Orange to green
What is the conversion, reagents and conditions for the oxidation of primary alcohols by distillation?
Conversion: 1° alcohol –> aldehyde
Reagents: K2Cr2O7 and H2SO4
Conditions: Distillation
What is the conversion, reagents and conditions for the oxidation of primary alcohols by heating under reflux?
Conversion: 1° alcohol –> carboxylic acid
Reagents: K2Cr2O7 and H2SO4
Conditions: Heat under reflux
How is the oxidising agent represented in equations?
[O]
How many moles of H2O are made when the alcohol has more than one OH group?
2 OH groups in the alcohol = 2 moles of H2O made
What happens to the amount of oxidising agent when a carboxylic acid is formed during an oxidation of alcohols reaction?
1[O] –> 2[O] because 1 extra oxygen is added
What is the conversion, reagents and conditions for the oxidation of secondary alcohols by heating under reflux?
Conversion: 2° alcohol –> ketone
Reagents: K2Cr2O7 and H2SO4
Conditions: Heat under reflux (or distillation)
Why does nothing happen when potassium dichromate (K2Cr2O7) is added to tertiary alcohols?
They are resistant to oxidation
What is the structural formula for an ester and how are they named?
COOC, alcohol ending changes to -yl and acid ending changes to -oate
E.g ethanol + ethanoic acid –> ethyl ethanoate
What is the conversion, reagents and conditions for esterification?
Conversion: Carboxylic acid + alcohol –> ester (+H20)
Reagents: Conc. H2SO4 catalyst
Conditions: Heat under reflux
What can esters be hydrolysed by?
Acids or alkalis
What is ACID hydrolysis the reverse of?
Esterification
What is the conversion, reagents and conditions of acid hydrolysis?
Conversion: Ester –> carboxylic acid + alcohol
Reagents: Acid catalyst and H2O
Conditions: Heat under reflux
What is the conversion, reagents and conditions of alkali hydrolysis?
Conversion: Ester –> CARBOXYLATE SALT + alcohol
Reagents: NaOH/KOH
Conditions: Heat under reflux
What is the procedure (5 steps) of the purification of an organic liquid?
- Separate organic layer using a separating funnel to run off the aqueous layer
- Wash with Na2CO3(aq) to neutralise any acid catalyst
- Wash with water and run off aqueous layer, keeping organic layer
- Dry organic layer using anhydrous drying agent (CaCl2), add until liquid goes CLEAR
- Distil and collect at the boiling point of the product
