Carboxylic Acids and Derivatives: Acylation - Acyl Chlorides

Question 1

What functional group do acyl chlorides have?

Answer 1

• RC(=O)Cl

Question 2

What is the general formula for acyl chlorides?

Answer 2

• CnH(2n-1)OCl

Question 3

What is the suffix for acyl chlorides?

Answer 3

• -oyl chloride

Question 4

How do you name acyl chlorides?

Answer 4

• Like with carboxylic acids, start numbering carbons from the end - where the functional group is

Question 5

Which substances do acyl chlorides react with? (Not exclusive to these substances, just the ones you need to know)

Answer 5

• Water
• Alcohols
• Ammonia
• Primary amines

Question 6

What is the general word equation for the reaction between acyl chlorides and water?

Answer 6

• Acyl chloride + water → carboxylic acid + hydrogen chloride gas

Question 7

What is the general word equation for the reaction between acyl chlorides and alcohols?

Answer 7

• Acyl chloride + alcohols → ester + hydrogen chloride gas

Question 8

What is the general word equation for the reaction between acyl chlorides and ammonia?

Answer 8

• Acyl chloride + ammonia → amide + hydrogen chloride gas

Question 9

What is the functional group of an amide?

Answer 9

• RC(=O)NH2

Question 10

What is the general word equation for the reaction between acyl chlorides and primary amines?

Answer 10

• Acyl chloride + primary amine → N-substituted amide + hydrogen chloride

Question 11

What are N-substituted amides?

Answer 11

• Have at least one alkyl or aryl group bonded to the nitrogen, instead of hydrogen atoms

Question 12

How do you name N-substituted amides?

Answer 12

• E.g N-methylethanamide CH3C(=O)NHCH3
• N-methyl - methyl (CH3) is bonded to nitrogen
• Eth(an-) - 2 carbons in acyl group
• Acyl group - RC(=O)

Question 13

Which substance is always formed in reaction between acyl chlorides and water/alcohols/ammonia/amides/primary amines?

Answer 13

• Hydrogen chloride gas

Question 14

What type of mechanism occurs during reaction between acyl chlorides and water/alcohols/ammonia/amides/primary amines?

Answer 14

• Nucleophilic addition-elimination

Question 15

What are the main steps of the nucleophilic addition-elimination mechanism?

Answer 15

• The nucleophile adds onto the acyl chloride, displacing a Cl ion
• The hydrogen leaves to create an acyl chloride derivative (hydrogen chloride)

Question 16

Why do nucleophiles attack carbon in acyl chlorides?

Answer 16

• In acyl chlorides, both the chlorine and oxygen atoms are more electronegative than carbon, giving carbon a δ+ charge
• So, easily attacked by nucleophiles

Question 17

Describe the steps of a nucleophilic addition-elimination reaction between acyl chlorides and nucleophiles

Answer 17

• The nucleophile attacks the δ+ carbon on the acyl chloride
• A pair of electrons is transferred from the C=O bond to the oxygen
• The oxygen has a lone pair and a negative charge. The oxygen reforms the C=O bond and the chlorine is displaced
• This leaves a positively charged nucleophile ion and a negatively charged chloride ion
• A pair of electrons from a hydrogen is transferred from the Nu-H bond to the nucleophile
• This leaves an acyl derivative

Question 18

Outline a mechanism for the reaction between ethanoyl chloride with water

Answer 18

• Sorry I don’t have Brainscape Pro so I can’t put a picture here…

Question 19

Outline a mechanism for the reaction between ethanoyl chloride with methanol

Answer 19

• Sorry I don’t have Brainscape Pro so I can’t put a picture here…

Question 20

Outline a mechanism for the reaction between ethanoyl chloride with ammonia

Answer 20

• Sorry I don’t have Brainscape Pro so I can’t put a picture here…

Question 21

Outline a mechanism for the reaction between ethanoyl chloride with methylamine

Answer 21

• Sorry I don’t have Brainscape Pro so I can’t put a picture here…