Question 1a

Marks: 2

a)

A student is asked to prepare a sample of propyl propanoate using propanal.

Suggest a reaction scheme, using displayed formulae, that the student could use to prepare their sample of propyl propanoate.

Conditions and reagents are not required.

[2]

Key Concepts

Organic Synthesis
Carboxylic acids & esters

Question 1b

Marks: 1

b)

Use your answer from part (a) to help answer this question.

One of the intermediates in the reaction scheme, from part (a), has a molecular mass of 74.0 g mol^-1.

Give the reagents and conditions required to form this intermediate.

[1]

Key Concepts

Organic Synthesis
Oxidation of primary alcohols

Question 1c

Marks: 2

c)

Propanal and the other intermediate (M_r = 60.0) in the reaction scheme, from part (a), are to be separated by distillation.

Explain which chemical will distil first.

[2]

Key Concepts

Distillation & reflux

Question 1d

Marks: 4

d)

Use your answer from part (a) to help answer this question.

Consider the intermediate in the reaction scheme, from part(a), which has a molecular mass of 60.0 g mol^-1.

i)

Give the reagents and conditions required to form this intermediate.

[3]

ii)

Describe how you could prove that this intermediate has been formed without reversing the reaction using section 26 of the data booklet.

[1]

Key Concepts

Reduction Reactions
Organic Synthesis
How IR spectroscopy works

Question 2a

Marks: 2

a)

The following three step synthesis route was carried out:

A $\overset{i) H_{2} {SO}_{4} ii) H_{2} O}{\to}$ B $\overset{K_{2} {Cr}_{2} O_{7} + H_{2} {SO}_{4}}{\to}$ C $\overset{H_{2} {SO}_{4}}{\to}$ D

Reactant A is a hydrocarbon containing 85.71% carbon and shows 4 peaks in a ¹H NMR spectrum. Deduce the identity of A.

[2]

Key Concepts

Structure Identification Problems
Organic Synthesis

Question 2b

Marks: 2

b)

Intermediate B shows a fragment at m/z 43 in the mass spectrum and has a molecular ion at m/z 74.

Deduce the identity of B, giving a reason.

[2]

Key Concepts

Structure Identification Problems
Organic Synthesis

Question 2c

Marks: 2

c)

The question is about intermediate C in the synthesis.

i)

Suggest an identity for intermediate C.

[1]

ii)

State the reaction conditions for the conversion of B to C.

[1]

Key Concepts

Structure Identification Problems
Organic Synthesis

Question 2d

Marks: 2

d)

Deduce the identify of the reaction product, D, and give one piece of spectral data that would support your answer.

[2]

Key Concepts

Structure Identification Problems
Organic Synthesis

Question 3a

Marks: 2

a)

Benzene and cyclohexene are two hydrocarbons that are able to react with bromine. State the type of reactions in each case.

[2]

Key Concepts

Organic Synthesis
Reactions of benzene
Halogenation of alkenes

Question 3b

Marks: 2

b)

Benzene can be converted into nitrobenzene in a one step reaction. State the names of the reagents needed for the reaction and the formula of the electrophile in the reaction.

[2]

Key Concepts

Organic Synthesis

Question 3c

Marks: 4

c)

Outline the mechanism of the reaction between benzene and the electrophile in part c)

[4]

Key Concepts

Organic Synthesis

Question 3d

Marks: 3

d)

Aniline is useful precursor for making synthetic dyes. It can be made from nitrobenzene in a two step synthesis. Give the reagents and conditions for the reaction.

[3]

Key Concepts

Organic Synthesis

Question 4a

Marks: 2

a)

For the reaction profile outlined in the reaction profile below, state the mechanism or type of reaction for steps 1 and 2.

Propane

\overset{Step 1}{\to}

1-bromopropane

\overset{Step 2}{\to}

Compound X

\overset{Step 3}{\to}

Propanal

Step 1 ...............................................................

Step 2 ...............................................................

[2]

Key Concepts

Organic Synthesis
Nucleophilic Substitution Reactions
Halogenation of alkanes

Question 4b

Marks: 3

b)

Outline the mechanism for step 2.

[3]

Key Concepts

Nucleophilic Substitution Reactions
SN2 Mechanism
Organic Synthesis

Question 4c

Marks: 3

c)

Compound X can be oxidised by the reaction with acidified potassium dichromate to give propanal. Compound X will oxidise to propanoic acid if allowed to fully oxidise. Explain how full oxidation can be prevented.

[3]

Key Concepts

Organic Synthesis
Distillation & reflux

Question 4d

Marks: 4

d)

State the following for step 1.

Reagents and conditions ..........................................

Mechanism ..........................................

[4]

Key Concepts

Organic Synthesis
Halogenation of alkanes

DP IB Chemistry: HL

Topic Questions

20.2 Synthetic Routes

Question 1a

Key Concepts

Question 1b

Key Concepts

Question 1c

Key Concepts

Question 1d

Key Concepts

Question 2a

Key Concepts

Question 2b

Key Concepts

Question 2c

Key Concepts

Question 2d

Key Concepts

Question 3a

Key Concepts

Question 3b

Key Concepts

Question 3c

Key Concepts

Question 3d

Key Concepts

Question 4a

Key Concepts

Question 4b

Key Concepts

Question 4c

Key Concepts

Question 4d

Key Concepts

Resources

Members

Company

Quick Links