Laboratory experiments using microwave heating

230 Pages·2013·13.312 MB·English

by  Nicholas E. Leadbeater, Cynthia B. McGowan

GENERAL CHEMISTRY
Laboratory
Experiments
USING
MICROWAVE HEATING
Allowing many chemical reactions to be completed within minutes, microwave
heating has revolutionized preparative chemistry. As a result, this technology has been
widely adopted in both academic and industrial laboratories. Integrating microwave-
assisted chemistry into undergraduate laboratory courses enables students to perform
a broader range of reactions in the allotted lab period. As a result, they can be
introduced to chemistry that would otherwise have been inaccessible due to time
constraints (for example, the need for an overnight reflux).

Laboratory Experiments Using Microwave Heating provides 22 experiments encompassing
organic, inorganic, and analytical chemistry performed using microwave heating
as a tool, making them fast and easy to accomplish in a laboratory period. Utilizing
the time-saving experiments described in this book also permits students to repeat
experiments if necessary or attempt additional self-designed experiments during
the lab course.

A number of the chemical transformations use water as a solvent in lieu of classical
organic solvents. This contributes to greener, more sustainable teaching strategies
for faculty and students, while maintaining high reaction yields. All the experiments
have been tested and verified in laboratory classes, and many were even developed
by students. Each chapter includes an introduction to the experiment and two
protocols—one for use with a smaller monomode microwave unit employing a single
reaction vessel and one for use with a larger multimode microwave unit employing
a carousel of reaction vessels.
K12632
ISBN: 978-1-4398-5609-3
90000
9 781439 856093
12282_Front/Back.indd 2 3/21/13 10:22 AM
Laboratory
Experiments
USING
MICROWAVE HEATING
n E. C B.
iCholas ynthia
l M G
EadBEatEr C owan
Boca Raton London New York
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Version Date: 20130311
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Contents
Preface................................................................................................................xiii
About the Authors ...............................................................................................xv
Introduction: Using Microwave Heating in Chemistry: The Basics ...................1
Introduction ...............................................................................1
Physical Chemistry Concepts ....................................................2
Equipment ..................................................................................3
Microwave Heating in Preparative Chemistry ..........................5
Use of Water as a Solvent ..........................................................6
Performing a Reaction Using Microwave Heating ....................6
Safety .........................................................................................9
Experimental Protocols .............................................................9
Experiment 1 Diels–Alder Cycloaddition Reaction .......................................11
Introduction .............................................................................11
Procedure for Use in a Monomode Microwave Unit ...............13
Synthesis of 3a,4,9,9a-Tetrahydro-4-(Hydroxymethyl)-
4,9[1′,2′]-Benzeno-1H-Benz[f]Isoindole-1,3(2H)-Dione .....13
Perform the Reaction ...........................................................13
Isolate the Product ...............................................................14
Characterize the Product .....................................................14
Procedure for Use in a Multimode Microwave Unit ...............15
Synthesis of 3a,4,9,9a-Tetrahydro-4-(Hydroxymethyl)-
4,9[1′,2′]-Benzeno-1H-Benz[f]Isoindole-1,3(2H)-Dione .....15
Perform the Reaction ...........................................................15
Isolate the Product ...............................................................16
Characterize the Product .....................................................16
Questions .................................................................................17
Experiment 2 Second-Order Elimination Reaction: Preparation of
Heptene from 2-Bromoheptane ...............................................19
Introduction .............................................................................19
Procedure for Use in a Monomode Microwave Unit ...............21
Perform the Reaction ...........................................................21
A. Sodium Methoxide .....................................................21
B. Potassium tert-Butoxide .............................................22
Isolate the Product (A or B) .................................................22
Analyze the Product (A or B) ..............................................23
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iv Contents
Procedure for Use in a Multimode Microwave Unit ...............24
Perform the Reaction ...........................................................24
A. Sodium Methoxide .....................................................24
B. Potassium tert-Butoxide .............................................25
Isolate the Product (A or B) .................................................25
Analyze the Product (A or B) ..............................................26
Questions .................................................................................27
Experiment 3 An Addition–Elimination Sequence: Preparation of a
Bromoalkene ............................................................................29
Introduction .............................................................................29
Procedure for Use in a Monomode Microwave Unit ...............31
Preparation of β-Bromo-p-Methoxystyrene
(1-[(E)-2-Bromoethenyl]-4-Methoxybenzene) .....................31
Perform the Reaction ...........................................................31
Isolate the Product ...............................................................32
Purification of the Product if the TLC Shows
Unreacted Starting Material ................................................33
Characterize the Product .....................................................34
Procedure for Use in a Multimode Microwave Unit ...............35
Preparation of β-Bromo-p-Methoxystyrene
(1-[(E)-2-Bromoethenyl]-4-Methoxybenzene) .....................35
Perform the Reaction ...........................................................35
Isolate the Product ...............................................................36
Purification of the Product if the TLC Shows
Unreacted Starting Material ................................................37
Characterize the Product .....................................................38
Questions .................................................................................39
Experiment 4 Fischer Esterification: Preparation of
Ethyl-4-Aminobenzoate (Benzocaine) ....................................41
Introduction .............................................................................41
Procedure for Use in a Monomode Microwave Unit ...............43
Perform the Reaction ...........................................................43
Isolate the Product ...............................................................44
Characterize the Product .....................................................44
Procedure for Use in a Multimode Microwave Unit ...............45
Perform the Reaction ...........................................................45
Isolate the Product ...............................................................46
Characterize the Product .....................................................47
Questions .................................................................................48
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Contents v
Experiment 5 Transesterification Reaction: Preparation of Biodiesel ...........49
Introduction .............................................................................49
Procedure for Use in a Monomode Microwave Unit ...............53
Preparation of Biodiesel Using Acid Catalysis ....................53
Perform the Reaction ...........................................................53
Determine the Extent of Reaction Using Thin-Layer
Chromatography ..................................................................54
Quantify the Extent of Reaction Using NMR Spectroscopy ...54
Procedure for Use in a Multimode Microwave Unit ...............55
Preparation of Biodiesel Using Acid Catalysis ....................55
Perform the Reaction ...........................................................55
Determine the Extent of Reaction Using Thin-Layer
Chromatography ..................................................................56
Quantify the Extent of Reaction Using NMR Spectroscopy ...56
Procedure for Use in a Monomode Microwave Unit ...............57
Preparation of Biodiesel Using Base Catalysis ....................57
Perform the Reaction ...........................................................57
Determine the Extent of Reaction Using Thin-Layer
Chromatography ..................................................................58
Quantify the Extent of Reaction Using NMR Spectroscopy ...58
Procedure for Use in a Multimode Microwave Unit ...............59
Preparation of Biodiesel Using Base Catalysis ....................59
Perform the Reaction ...........................................................59
Determine the Extent of Reaction Using Thin-Layer
Chromatography ..................................................................60
Quantify the Extent of Reaction Using NMR Spectroscopy ...60
Questions .................................................................................62
Experiment 6 Knoevenagel Condensation Reaction: Preparation of
3-Acetylcoumarin ....................................................................63
Introduction .............................................................................63
Procedure for Use in a Monomode Microwave Unit ...............66
Perform the Reaction ...........................................................66
Isolate the Product ...............................................................66
Characterize the Product .....................................................67
Procedure for Use in a Multimode Microwave Unit ...............68
Perform the Reaction ...........................................................68
Isolate the Product ...............................................................69
Characterize the Product .....................................................69
Questions .................................................................................70
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vi Contents
Experiment 7 The Perkin Reaction: Condensation of an Aromatic
Aldehyde with Rhodanine .......................................................71
Introduction .............................................................................71
Procedure for Use in a Monomode Microwave Unit ...............73
Reaction of Rhodanine with 2-Chlorobenzaldehyde ..........73
Perform the Reaction ...........................................................73
Isolate the Product ...............................................................74
Characterize the Product .....................................................74
Procedure for Use in a Multimode Microwave Unit ...............75
Reaction of Rhodanine with 2-Chlorobenzaldehyde ..........75
Perform the Reaction ...........................................................75
Isolate the Product ...............................................................76
Characterize the Product .....................................................76
Questions .................................................................................77
Experiment 8 Williamson Ether Synthesis: Preparation of Allyl Phenyl
Ether .........................................................................................79
Introduction .............................................................................79
Procedure for Use in a Monomode Microwave Unit ...............81
Perform the Reaction ...........................................................81
Isolate the Product ...............................................................81
Characterize the Product .....................................................84
Procedure for Use in a Multimode Microwave Unit ...............85
Perform the Reaction ...........................................................85
Isolate the Product ...............................................................86
Characterize the Product .....................................................88
Questions .................................................................................89
Experiment 9 Claisen Rearrangement: Preparation of 2-Allyl Phenol
from Allyl Phenyl Ether ..............................................................91
Introduction .............................................................................91
Procedure for Use in a Monomode Microwave Unit ...............93
Perform the Reaction ...........................................................93
Isolate the Product ...............................................................93
Characterize the Product .....................................................95
Procedure for Use in a Multimode Microwave Unit ...............96
Perform the Reaction ...........................................................96
Isolate the Product ...............................................................96
Characterize the Product .....................................................99
Questions ...............................................................................100
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Contents vii
Experiment 10 Hydration of an Alkyne: Preparation of Acetophenone
from Phenylacetylene..............................................................101
Introduction ............................................................................101
Procedure for Use in a Monomode Microwave Unit .............103
Perform the Reaction .........................................................103
Isolate the Product .............................................................104
Product Analysis ................................................................104
Procedure for Use in a Multimode Microwave Unit .............105
Perform the Reaction .........................................................105
Isolate the Product .............................................................106
Product Analysis ................................................................106
Questions ...............................................................................107
Experiment 11 Oxidation of a Secondary Alcohol: Preparation of a Ketone ...109
Introduction ...........................................................................109
Procedure for Use in a Monomode Microwave Unit ..............112
Perform the Reaction ..........................................................113
Isolate the Product ..............................................................113
Characterize the Product ....................................................114
Procedure for Use in a Multimode Microwave Unit ..............115
Perform the Reaction ..........................................................116
Isolate the Product ..............................................................116
Characterize the Product ....................................................117
Questions ................................................................................118
Experiment 12 Suzuki Coupling Reaction: Preparation of a Biaryl ...............119
Introduction ............................................................................119
Procedure for Use in a Monomode Microwave Unit .............121
Preparation of 4-Acetylbiphenyl ........................................121
Perform the Reaction .........................................................121
Isolate the Product .............................................................122
Characterize the Product ...................................................124
Procedure for Use in a Multimode Microwave Unit .............125
Preparation of 4-Acetylbiphenyl ........................................125
Perform the Reaction .........................................................125
Isolate the Product .............................................................126
Characterize the Product ...................................................128
Questions ...............................................................................129
Experiment 13 Heck Reaction: Preparation of Substituted Cinnamic Acids ....131
Introduction ............................................................................131
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viii Contents
Procedure for Use in a Monomode Microwave Unit .............133
Preparation of 4-Methoxycinnamic Acid
(2E-3-(4-Methoxyphenyl)-2-Propenoic Acid)....................133
Perform the Reaction .........................................................133
Isolate the Product .............................................................134
Characterize the Product ...................................................134
Procedure for Use in a Multimode Microwave Unit .............135
Preparation of 4-Methoxycinnamic Acid
(2E-3-(4-Methoxyphenyl)-2-Propenoic Acid)....................135
Perform the Reaction .........................................................135
Isolate the Product .............................................................136
Characterize the Product ...................................................136
Procedure for Use in a Monomode Microwave Unit .............137
Synthesis of 4-Acetylcinnamic Acid
(2E-3-(4-Acetylphenyl)-2-Propenoic Acid) .......................137
Perform the Reaction .........................................................137
Isolate the Product .............................................................138
Characterize the Product ...................................................138
Procedure for Use in a Multimode Microwave Unit .............139
Synthesis of 4-Acetylcinnamic Acid
(2E-3-(4-Acetylphenyl)-2-Propenoic Acid) .......................139
Perform the Reaction .........................................................139
Isolate the Product .............................................................140
Characterize the Product ...................................................140
Questions ................................................................................141
Experiment 14 Preparation of an Aryl Nitrile: Application of a
Copper-Catalyzed Cyanation Reaction ..................................143
Introduction ............................................................................143
Procedure for Use in a Monomode Microwave Unit .............145
Preparation of 1-Cyanonaphthalene ..................................145
Perform the Reaction .........................................................145
Isolate the Product .............................................................146
Characterize the Product ....................................................147
Procedure for Use in a Multimode Microwave Unit .............148
Preparation of 1-Cyanonaphthalene ..................................148
Perform the Reaction .........................................................148
Isolate the Product .............................................................149
Characterize the Product ...................................................150
Questions ...............................................................................151
Experiment 15 Alkene Metathesis: Preparation of a
Substituted Cyclopentene........................................................153
Introduction ...........................................................................153
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Contents ix
Procedure for Use in a Monomode Microwave Unit .............156
Preparation of Diethyl Cyclopent-3-Ene-1,1-Dicarboxylate ...156
Perform the Reaction .........................................................156
Isolate the Product .............................................................157
Characterize the Product ...................................................157
Procedure for Use in a Multimode Microwave Unit .............158
Preparation of Diethyl Cyclopent-3-Ene-1,1-Dicarboxylate ...158
Perform the Reaction .........................................................158
Isolate the Product .............................................................159
Characterize the Product ...................................................159
Questions ...............................................................................160
Experiment 16 Click Reaction: Preparation of a Triazole ..............................161
Introduction ............................................................................161
Procedure for Use in a Monomode Microwave Unit .............164
Preparation of 1-Phenyl-2-(4-Phenyl-[1,2,3]Triazol-1-yl)-
Ethanone ............................................................................164
Perform the Reaction .........................................................164
Isolate the Product .............................................................165
Characterize the Product ...................................................165
Procedure for Use in a Multimode Microwave Unit .............166
Preparation of 1-Phenyl-2-(4-Phenyl-[1,2,3]Triazol-1-yl)-
Ethanone ............................................................................166
Perform the Reaction .........................................................166
Isolate the Product .............................................................167
Characterize the Product ...................................................167
Questions ...............................................................................168
Experiment 17 Coordination Chemistry: Preparation of Cisplatin ................169
Introduction ...........................................................................169
Procedure for Use in a Monomode Microwave Unit ..............171
Preparation of cis-Diamminedichloroplatinum(II)
(Cisplatin) ............................................................................171
Perform the Reaction ..........................................................171
Isolate the Product ..............................................................171
Characterize the Product ...................................................172
Procedure for Use in a Multimode Microwave Unit ..............173
Preparation of cis-Diamminedichloroplatinum(II)
(Cisplatin) ............................................................................173
Perform the Reaction ..........................................................173
Isolate the Product ..............................................................174
Characterize the Product ....................................................174
Questions ................................................................................175
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