Carbonyl compounds Flashcards
What is a carbonyl group?
A carbon-oxygen double bond
What compounds is a cabonyl group found in?
Aldehyde and ketones
What is the relative charge o the carbon of a carbonyl group?
+
What feature of a carbonyl group makes it susceptible to attack from nucleophiles?
The polarity of the double bond.
What are the typical reactions of carbonyl compounds?
Nucleophilic addition
What happens ina nucleophilic addition reaction?
The nucleophile adds onto the C^d+ and a hydrogen adds on to the O^d-
What are the products called when the nucleophile was a cyanide ion?
Hydroxynitriles.
What can aldehydes be oxidised into and what is the oxidising agent?
Carboxylic acids, acidified potassium dichromate
What can aldehydes be reduced into and what is the reducing agent?
Primary alcohols, Sodium tetrehydridoborate(III) NaBH4
What can ketones be reduced to?
Secondary alcohols.
What happens when an aldehyde is warmed with Tollen’s reagent?
Ag+ is reduced to Ag
What happens when an aldehyde is is warmed with Fehling’s solution?
The Cu2+ ions are reduced to Cu+
What is the general formula of a carboxylic acid?
R-COOH
What is the general formula of an ester?
R-COO-R
How do you name an ester?
The name of the second R group is placed first and then the first R group with -oate on the end.
Why is the carbonyl group in carboxylic acids more polar than the carbonyl group in aldehydes and ketones?
Due to the second oxygen atom bonded to it.
What is the name for the ion produced if the H^d+ is lost from a carboxylic acid and what happens to the charge?
A carboxylate ion, the negative charge is spread over three atoms.
Why is a carboxylate ion stable?
Due to the delocalised electrons
What is produced when ethanoic acid reacts with sodium hydrogencarbonate?
Sodium ethanoate, CO2 and H2O
How are esters produced and what is the name of the reaction?
Carboxylic acids reacting with alcohols with a strong acid catalyst (H2SO4).
What is acid hydrolysis of an ester?
Ester + H2O –> Carboxylic acid + alcohol
What happens when a base is used to catalyse the hydrolysis of an ester instead of an acid?
the salt of the acid is formed so equlibrium is not reached and more product is formed.
Name 4 common uses of esters?
- Solvents,
- Plasticisers,
- Perfumes,
- Food flavourings.
What is produced when a triglyceride is reacted with NaOH?
Glycerol and a mixture of sodium salts of the acids that form part of the ester.
How is biodiesel produced?
Triglyceride + KOH
What is acylation?
The substitution of the acyl group R-CO-R into another molecule.
Name 4 acid derivatives that contain an acyl group.
Ester, acyl chloride, acid anhydride and amine.
What is ab addition-elimination reaction?
Nucleophile attacks the C^d+ atom, followed by the loss of Z- (the leaving group. R-CO-Z
What is the speed of an addition-elimination reaction governed by? 3 things.
- the size of the charge on the carbonyl carbon which depends on the electron attracting power of Z,
- How easily Z is lost.
- How good the nucleophile is.
Name 4 typical nucleophiles.
Primary amine
Ammonia
Alcohol
Water
Why would you use propanoyl chloride instead of propanoic acid when preparing methyl-propanoate from methanol?
Its faster as Cl- dissociates more readily.
Why would you use propanoic acid rather than propanoyl chloride when preparing methyl-propanoate from methanol?
Propanoyl chloride would produce HCl which is toxic, corrosive and harmful to the environment.
