carbonyl compounds Flashcards

1
Q

What is a carbonyl compound?

A

A compound which contains the functional group C=O

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2
Q

Why can carbonyl compounds react with nucleophiles?

A

C=O bonds in carbonyl compounds are polar as O is more electronegative than C. Therefore carbonyl compounds can eat with nucleophiles via nucleophilic addition.

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3
Q

What is NaBH4?

A

NaBH4 is a reducing agent (electron donor) for ketones and aldehydes.

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4
Q

What happens when an aldehyde reacts with NaBH4?

A

Aldehyde + 2[H] –> Primary alcohol

The reverse of an oxidation reaction from a primary alcohol to aldehyde.

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5
Q

What happens when NaBH4 reacts with a ketone?

A

Ketone + 2[H] –> Secondary alcohol

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6
Q

What else can act as a nucleophile, similar to NaBH4?

A

HCN

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7
Q

What is able to detect the C=O group found in aldehydes and ketones? What shows a positive test?

A

2,4 dinitrophenylhydrazine, 2,4 DNP or 2,4 DNPH can detect a C=O bond
In the presence of a C=O bond it will produce a yellow/orange precipitate
2,4 DNP is usually dissolved in methanol and H2SO4 to produce brady’s reagent

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8
Q

How can you distinguish between an aldehyde and ketone?

A

Using tollens reagent [a solution of AgNO3 + NH3], in the presence of an aldehyde it will produced a silver mirror as the silver ions are reduced to silver as the aldehyde is oxidised to a carboxylic acid.

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9
Q

Are carboxylic acids soluble, why and what does it depend on?

A

Carboxylic acids are polar and can form H-bonds with H2O therefore are soluble.

Solubility will decrease as the number of C atoms increase as the C- chain will have a stronger overall effect.

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10
Q

What type of reactions can carboxylic acids take part in?

A

Redox reactions with metals and neutralisation reactions with bases.

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11
Q

What is a carboxylate ion and how do you name them?

A

A carboxylate ion is a salt formed from a carboxylic acid and it named by replacing the -ic acid to ate. E.g Carboxylate.

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12
Q

Carboxylic acids + Metals -> ?

How can you identify this reaction is taking place?

A

Carboxylic salt + H2

*Effervescence and metal will disappear

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13
Q

Carboxylic acids + metal oxides ->?

A

Carboxylate salt + H2O

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14
Q

Carboxylic acids + Alkalis ->?

A

Carboxylate salt + Water

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15
Q

Carboxylic acid + carbonate -> ?

A

Carboxylate salt, CO2 and H2O

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16
Q

How can you identify a -COOH group?

A

Carboxylic acids are the only organic compound that are sufficiently acidic enough to react with carbonates such as Na2CO3

17
Q

What is a carboxylic acid derivative? What are some examples?

A

A compound that can be hydrolysed to form a parent carboxylic acid and will have an acetyl group.
R-C=O-
Esters, acyl chlorides , acid anhydrides

18
Q

What is an ester?

A

Named after carboxylic parent -oate
Whatever is attached to the C=O-O is the -oate part
The alkyl chain attached is the -yl

19
Q

What is an acyl chloride?

A

Named after carboxylic acid parent with -oyl chloride

Functional group C=O-Cl

20
Q

What is an acid anyhride?

A

Formed from the removal of a H2O from a carboxylic acid to form two carboxylic acids
Suffix -Anhydride

21
Q

What is esterification? What conditions are required?

A

The reaction of an alcohol and carboxylic acid to produce an ester.
Warmed + Concentrated H2SO4

22
Q

Draw out the reaction between ethanoic acid and ethanol

A

:D

23
Q

How do acyl-chlorides from? What are some properties of Acyl chlorides?

A

Parent carboxylic acid will react with thionyl chloride (SOCl2)

Very reactive, can convert into esters and amides with good yields and can react with nucleophiles

24
Q

Acyl chloride + Alcohol?

A

Ester!

25
Q

Acyl chloride + Phenol?

A

Ester !

26
Q

Acyl chloride + Ammonia?

A

Amides + NH4Cl

NH2 will replaced the CL-

27
Q

How can esters be hydrolysed?

A

By an aqueous acid or alkali

Acid hydrolysis is the reverse of esterification, ester -> carboxylic acid and alchohol

Alkaline hydrolysis is irreversible, heated under reflux with OH- ions -> salt ion and alchohol