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Chem Factsheet April 2003

Number 52

Reactions of Functional Groups - A Summary To succeed in this topic you need to: • Be able to recall and write out the functional groups represented in this Factsheet; • Have a thorough knowledge of the organic reactions and their conditions (described in the Organic Chemistry Factsheets to date 27, 31, 32, 33, 34 and 39); • Recognise the summarised versions of the equations in this Factsheet and be able to write them out in full under exam conditions.

Reactions of alkenes

After working through this Factsheet you will: • Have revised the organic chemistry reactions that candidates are required to learn for AS and A2 Chemistry modules. • Have a reference paper as you start to work through questions on organic pathways and synthesis.

Diol

CO2 + H2O Alkane H2 electrophilic heat, addition Ni catalyst

Di-halogenoalkane halogen

hydrogen halide

electrophilic addition

Halogenoalkane electrophilic addition

oxidation electrophilic addition

Reactions of alcohols bromo-alkane nucleophilic substitution chloro-alkane

These spider diagrams represent the reactions in a summarised version, in a visual fashion that suits many learners. They should be used in conjunction with Factsheets 27, 31, 32, 33, 34 and 39, which show the reactions in a more detailed format.

NaBr(s) + H2SO 4(conc.) to make HBr

nucleophilic substitution

A good way of using this Factsheet to revise effectively would be as follows: 1. Pick a group to revise (e.g. alkanes). 2. Pick a member of that group at random (e.g. propane). 3. Use the spider diagram to help you write out balanced chemical reactions, with conditions, for the organic chemical you have chosen.

iodo-alkane nucleophilic substitution

P(s) + I2(s) to make PI 3

dry PCl5

halogenation

Propane and oxygen (combustion) C3H8 + 5O2

heat

Alcohol

3CO2 + 4H2O dehydration

Propane and chlorine (free radical substitution) C3H8 + Cl2

uv light

C3H7Cl + HCl

conc. H2SO4

In an exam, candidates are required to apply their knowledge of organic reactions to a wide variety of compounds, so the more of these you do, the better!

Carbon Dioxide + Water

heat to 170 o C

oxidation primary alcohols

Cr2O72−(aq)

O2 heat

halogen

Alkanes UV Light

Cr2O72−(aq)

aldehyde Halogeno alkane

further oxidation Cr2O72−(aq)

free radical substitution

H+(aq)

carboxylic acid

1

secondary alcohols

H+(aq)

alkene

Reactions of alkanes

combustion

heat

Alkenes

alkaline KMnO4(aq)

This Factsheet is designed to be used as a revision aid as candidates set about the sometimes daunting task of learning all of the organic reactions required by the A2 Chemistry course.

(e.g.)

O2

H+(aq)

ketone

Chem Factsheet

Reactions of Functional Groups - A Summary Ester Reactions

Fig. 3 Halogenoalkane reactions Alcohol

Nitrile nucleophilic substitution

KCN in water/ethanol

Carboxylic acid + Alcohol

nucleophilic substitution

NaOH(aq)

heat under reflux

heat under reflux

Carboxylic acid + Alcohol

H 2O

Ester acid conditions

alkaline conditions

Halogenoalkane KOH in ethanol

NH3 in ethanol

H 2O

heat under reflux

heat

Amines

Acyl Chloride Reactions

Alkene nucleophilic elimination

nucleophilic substitution

Grignard Reagents

Carboxylic acid

Ester

nucleophilic substitution

nucleophilic substitution H 2O

Preparation

alcohol

Mg turnings

Grignard Reagent "R-MgHal"

Halogenoalkane Dry ether solvent Boil under reflux

Acyl Chloride

addition

primary amine

Reactions Primary Alcohol

N-substituted Amide

nucleophilic addition / hydrolysis

nucleophilic substitution

ketone + H2O(l)

H+(aq)

nucleophilic addition / hydrolysis

nucleophilic addition / hydrolysis

nucleophilic addition / hydrolysis

2,4-DNP Derivative nucleophilic addition then elimination

Polyester nucleophilic substitution / polymerisation

boil under reflux conc. H2SO4 Na2CO3 or NaHCO 3

Diacid + H+(aq) Diol

Carboxylic Acid aqueous

Sodium Salt + CO2 + H2O neutralisation

reduction LiAlH4 then H+(aq) LiAlH4 in dry ether

dry

HCN

PCl5

Acyl Chloride nucleophilic substitution

2

reduction LiAlH4 in ether

silver nitrate in ammonia warm solution

Fehlings solution

H2SO4

Positive Silver Mirror Test redox

Alcohol alcohol

Primary Alcohol

NaBH4 in ethanol

Aldehydes 2,4-DNP in ethanol

Carboxylic Acid Reactions

nucleophilic substitution

reduction

nucleophilic addition trace of KOH

Tertiary Alcohol

Primary Alcohol

Hydroxy-nitrile compound

H+(aq)

Carboxylic Acid

Ester

nucleophilic substitution

Reactions of Aldehydes

aldehyde (not methanal) + H2O(l)

Grignard Reagent "R-MgHal" CO2 (g) + H2O(l)

Secondary Alcohol

H+(aq)

H 2O

Amide

nucleophilic substitution

methanal, CH2=O(g) then use + H2O(l) dilute acid for hydrolysis

Alkane

NH3

warm

Positive Fehlings Test redox

Chem Factsheet

Reactions of Functional Groups - A Summary Reactions of Aldehydes

Reactions of Amino Acids Secondary Alcohol

Hydroxy-nitrile compound

reduction

HCN

reduction

NaBH4 in ethanol

alkali

Amino Acids

neutralisation

Secondary Alcohol

nucleophilic addition trace of KOH

acid

Salt

Salt neutralisation

Reactions of Phenol

LiAlH4 in ether

2,4,6tribromophenol

Phenate ion

Ketones

neutralisation

electrophilic substitution -

OH (aq)

2,4-DNP in H2SO4

Br 2(aq)

Phenol

2,4-DNP Derivative

acyl chloride, in NaOH(aq)

nucleophilic addition then elimination

Ester

Reactions of Amines

nucleophilic substitution

Salts

Substituted Amides

nucleophilic addition / neutralisation

nucleophilic substitution

Reactions of Benzene Bromobenzene

acid

electrophilic substitution

acyl chloride

Amines

Br2

primary amines + acyl chlorides if monomers contain 2 amine groups and 2 acyl chloride groups

Benzene 50o C conc H2SO4

Polyamides nucleophilic substitution polymerisation

hydrolysis

alkali

acid

Nitriles

heat under reflux

heat under reflux

Br2

Nitrobenzene

Alkylbenzene electrophilic substitution

Sn, conc. HCL, NaOH

Carboxylic acid

Fe cat. dry HNO3

electrophilic substitution

Reactions of Nitrites Carboxylic acid salt

Fe cat. dry

KMnO 4

in alkali heat under reflux

hydrolysis

Phenylamine

LiAlH4 in ether

reduction

Benzocarboxylic acid oxidation

HNO2 + HCl

Amine reduction

Benzenediazonium ions

Reactions of Amides

Nitrile dehydration

P4 O10 warm

Amides

Br2(l) + NaOH(aq) warm

Amine + CO2

Acknowledgements: This Factsheet was researched and written by Kieron Heath Curriculum Press, Unit 305B, The Big Peg, 120 Vyse Street, Birmingham, B18 6NF ChemistryFactsheets may be copied free of charge by teaching staff or students, provided that their school is a registered subscriber. No part of these Factsheets may be reproduced, stored in a retrieval system, or transmitted, in any other form or by any other means, without the prior permission of the publisher. ISSN 1351-5136

hydrolysis

3