3.3.9 Carboxylic acids and derivatives Flashcards
Carboxylic acid function group and what it can be broken into
Carboxyl - COOH
carbonyl - C=O
hydroxyl - OH
Are carboxylic acids weak or strong
Weak
Carboxylic acids are weak acids whag does this mean
They partially dissociate to form a H+ ion and a carboxylate ion
Carboxylate ion
and give ezamples
O
||
R - C
\
O-
O
|| H7C3 ---- C
\
O- butanoate ion
Where does equibrum lie when Carboxylic acid disassociates
Lies to
The left as it dissociates poorly
Carboxylic acid + metal carbonate -> …
Salt + CO2 + water
carboxylic acid + metal s
eg methanoic acid + sodium
salt + hydrogen gas
sodium methanoate and h2
carboxylic acids react with metal oxides and hydroxides to form
salt + water
How to form esters (2 ways)
- Reacting Alcohol + Carboxylic acid and sulfuric acid catalyst
- alcohol + acid anhydrid
Ester functional group
O
||
C
\
O
ester general fomula
R1COOR2
R2 starts w a carbon atom
Equation for reacting Carboxylic acid with alcohol and cond
Carboxylic acid + alcohol -> ester + water
- strong acid catalyst like hcl or h2so4
- heat
Acid anhydride and alcohol equation
Acid anhydride + alcohol -> ester + Carboxylic acid
2 part process in naming esters
1) name alkyl group eg ethyl methyl
2) name part of ester formed from Carboxylic acid instead of using -oic acid we use - oate
Eg propanoate
4 Uses of esters and explain the property of esters that gives them thus ability
Eg fragrances
and food flavouring cus they’re sweet smelling,soluble in ethanol,volatile,dont react w h2o and non toxic
- solvents bc they’re polarso will dissolve readily in other polar compounds
- plasticisers - make plastics more flexible during polymerisation process they can leach out of the plastic over time
2 methods of ester hydrolysis
Acid hydrolysis
Base hydrolysis
Describe method of acid hydrolysis
Dilute hydrochloric acid
heat Under reflux splitting up ester into alcohol and Carboxylic acid
reaction is reversible
Describe method of base hydrolysis
saponification
Base - excess dilute NaOH heat under reflux spitting up ester into carboxylate salt and an alcohol
reaction not reversible
when we react glycerol and fatty acids we produce…
an ester which makes fats and oils
glycerol IUPAC name
propan - 1,2,3 - triol
2 kinds of fatty acid and explain them
saturated - single c-c bonds
unsaturated - double c=c bonds
unsaturated fatty acids with more double bonds are called…
polyunsaturated fatty acids
an oil and fats are an example of an …
ester
ester link
O
ll
O - C
what kind of hydrocarbon chains does vegetable oil have and what does this mean
unsaturated hydrocarbon chains
so theyre not straight and cannot pack closely together due to lower vdw forces
lower mp and liquids @ room temp
what kind of hydrocarbon chains do animal fats have and what does this mean
saturated hydrocarbon chains
staight and more unifrom
higher vdw
solid at room temp
animal fats and vegetable oils can be hydrolysed by heating them with _____ ______
the product is ______
animal fats and vegetable oils can be hydrolysed by heating them with sodium hydroxide
the product is soap
what can vegetable oils be converted into and how
biodiesel
by reacting oils w methanol and potassium hydroxide catalyst
oil plus methanol makes …
makes gylcerol and methyl ester in presense of KOH catalsyt
why is thanol suitable solvent for heating cocunut oil w koh give saftey prec and justificartion
dissolves both oil and koh
use water bath to heat
prevemt fire/ ethanol is flammable
biodisel is a mixture of
methyl ester of long chain carboxylic acids
biodisel is produced by
reacting vegetable oils with methanol in the presense of strong alkali catalyst
acyl chloride functional group
O
//
C
\
Cl
acyl chloride general formula
RCOCl
ethanoyl chloride + water –> …
ethanooic acid + HCl
structure of biodiesel
https://www.physicsandmathstutor.com/pdf-pages/?pdf=https%3A%2F%2Fpmt.physicsandmathstutor.com%2Fdownload%2FChemistry%2FA-level%2FTopic-Qs%2FAQA%2FOrganic-II%2F3.09-Carboxylic-Acids-and-Derivatives%2FSet-I%2FCarboxylic%20Acids%20and%20Derivatives%20MS.pdf
explain how co2 causes global warming (2)
C=O Bonds in CO2 absorb infrared radiation
IR radiation emitted by the earth does not escape (from the
atmosphere)
A compound has reacted w water and produced a carboxylic acid and hcl gas white steamy fumes
Is it a acyl chloride or acid anhydride
Acyl chloride as when they react with water they produce hcl white steamy fumes
outline the method used for recrystallisation (5)
Dissolve the product in the minimum volume of hot solvent
Allow the solution to cool and allow crystals to form.
Filter off the pure product under reduced pressure / using a Buchner
funnel and side arm flask
Test for carboxylic acid
React w carbonate - will produce co2 so effervescence or fizzing
