Derivatives Of Carboxylic Acids

Question 1

Esters Functional Group

Answer 1

-COO-

Question 2

How are esters formed?

Answer 2

condensation reaction between alcohol and a carboxylic acid

elimination reaction between alcohol and acyl chloride

Question 3

What are ester reactions based around

Answer 3

polar ester link
as it can be hydrolysed

Question 4

Physical properties esters

Answer 4

neutral liquids
pleasant, fruity odour

Question 5

Ester Solubility in Water

Answer 5

-very small molecules soluble but decreases as length chain increases
-polar carbonyl group on ester can form H bonds in water
-As non-polar hydrocarbon chain increase in size - ester molecule can no longer form H bonds effectively

Question 6

Ester Boiling Point

Answer 6

bonding mostly VdW with some p d-d between C=O
-higher bp than alkane due to pd-d
-lower than carboxylic acid as they have H bonds

Length of ester incr bp incr
-increased no. electrons causes more vdw between molecules

Question 7

Formations Of Esters

Answer 7

Alcohol and Carboxylic Acid

Alcohol and Acyl Chloride

Question 8

Alcohol and Carboxylic Acid

Answer 8

OH acid and H of OH on alcohol form water

Conc. Sulfuric Acid added to remove water and promote formation
-mixture heated and distilled -ester collected

Question 9

Alcohol and Acyl Chloride

Answer 9

Cl of acyl chloride react with H from OH in Alc to form HCl

produces higher yield of ester as gaseous HCl removed from equilibrium- promote formation

Question 10

Preparation Of An Ester

Answer 10

-place mixture of alcohol and conc H2SO4 in a pear shaped/round bottom flask

• add a mixture of alcohol and Carboxylic acid slowly from a dropping funnel

-swirl the mixture

• add anti-bump granules and arrange apparatus for distillation
• heat the mixture gently and collect distillate around 2°C either side of BP

-place separating funnel and wash with NaCO3 solution to remove acidic impurities

-remove lower aqueous layer and add anhydrous Calcium Chloride
to upper organic layer

-filter or decant to remove Calcium Chloride

-Redustill, collecting distillate 1°C on either side of BP

Question 11

Why is mixture not heated under reflux in prep of ester

Answer 11

Ester will have lowest bp of organic substances in mixture
- no H bonds

Question 12

How is Acyl Chloride Produced

Answer 12

Carboxylic Acid reacts w/PCl5
OH sub by Cl

Question 13

Properties Acyl Chlorides

Answer 13

All highly reactive
React w/ alcohols to form esters
React w/water to produce CA and HCl gas

Question 14

Acyl Chloride With Water

Answer 14

CH3COCl + H2O -> CH3COOH + HCl

•Hydrolysis Reaction
•Fizzes and Misty Fumes
•Ethanoyl Chloride is colourless, corrosive liquid - fumes in contact with moist air as HCl released