Carbonyl Group Flashcards
(30 cards)
What is the functional group of carboxylic acids?
RCOOH
What is the pH of carboxylic acids?
3-6 so very weak acids
Why are carboxylic acids weak?
The H+ ions only partially disassociate.
How can carboxylic acids be chemically tested?
Add sodium carbonate solution and it will effervesce- bubble into limewater and it will turn cloudy if the gas was CO2.
Why do carboxylic acids have high boiling points?
They form hydrogen bonds.
What is the functional group of esters?
R’COOR
How are esters produced?
By reacting carboxylic acids with alcohols with a H+ concentrated H2SO4 catalyst.
How can esters be separated from their production mixture?
They are more volatile so can be distilled off.
What is produced when propane-1,2,3-triol (glycerol) when it is reacted with long chain carboxylic acids?
Vegetable and animal fats
How is biodiesel produced?
By reacting a triglyceride (Vegetable oil/animal fat) with an alcohol in the presence of an alkaline catalyst.
How is soap produced?
Hydrolyse triglycerides to produce soap and glycerol.
How does soap work?
It creates a micelle in which the dirt is isolated since the soap will have a hydrophobic tail and hydrophilic head.
What is biodiesel?
A mixture of methyl esters from long chain fatty acids (triglycerides)
What catalyst is used in the production of biodiesel?
Sodium Hydroxide
Why is an acid catalyst in the hydrolysis of esters undesirable?
It is a reversible reaction so products cannot be obtained in a full yield.
Why is a base catalysed hydrolysis reaction better with esters?
The base will react with the acid produced to produce a salt which makes the reaction non-reversible.
Why can weak nucleophiles react with acyls? (especially acid chlorides)
The carbon is attached to two electronegative species so has a greater 𝛅+ charge meaning it is more attractive to nucleophiles. Acid chloride especially because the chloride is a good leaving group.
Why do the electrons from the C=O moves and not the C-Cl?
The C=O is weaker since one of the pairs can move and the other will still be intact.
How is aspirin produced?
2-hydroxybenzoic acid is reacted with ethnic anhydride so it can be acylated.
What are the advantages of acid anhydride over acid chloride in the production of aspirin?
Cheaper
Safer- less corrosive and reacts slower with water
Doesn’t produce dangerous fumes of HCl
What is the disadvantage of using Acid anhydride over acid chloride in the production of aspirin?
Water is used in acid anhydride but this water could react with 2-hydroxybenzoic acid (but carboxylic acids aren’t as readily reactive)
How are acid chlorides produced?
by reacting a carboxylic acid with PCl5
How are acid anhydrides produced?
By reacting (2) carboxylic acid with P4O10
Why must the reaction of cyanide and aldehydes/keytones be in solution?
So that the H+ ions can attached to the -ve oxygen group
