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Chemical resistance of common types of gloves to various
compounds
Glove type
Compound

Neoprene

Nitrile

Latex

Acetone
Chloroform
Dichloromethane
Diethyl ether
Ethanol
Ethyl acetate
Hexane
Methanol
Nitric acid (conc.)
Sodium hydroxide
Sulfuric acid (conc.)
Toluene

good
good
fair
very good

very good
good
excellent
very good
good
very good
good
fair

fair
poor
poor
good
excellent
poor
excellent
fair
poor
excellent
poor
fair

good
poor
poor
poor
excellent
fair
poor
fair

poor
excellent
poor
poor

Common organic solvents
Name

Boiling
Density
Dielectric Miscible
point (°C) (g · mlϪ1) constant with H2O

Acetone (2-propanone)
Dichloromethane
Diethyl ether
Ethanol (95% aq. azeotrope)
Ethanol (anhydrous)
Ethyl acetate
Hexane
Methanol
Pentane
2-Propanol (Isopropyl alcohol)
Toluene

56.5
40
35
78
78.5

77
69
65
36
82.5
111

0.792
1.326
0.713
0.816
0.789
0.902
0.660
0.792
0.626
0.785
0.866

21
9.1
4.3
27
25
6.0
1.9
33
1.8
18
2.4


yes
no
no
yes
yes
slightly
no
yes
no
yes
no

Selected data on common acid and base solutions
Compound

Molarity

Density
(g · mlϪ1)

% by weight

Acetic acid (glacial)
Ammonia (concentrated)
Hydrobromic acid (concentrated)
Hydrochloric acid (concentrated)
Nitric acid (concentrated)
Phosphoric acid (concentrated)
Sodium hydroxide

Sulfuric acid (concentrated)

17
15.3
8.9
12
16
14.7
6
18

1.05
0.90
1.49
1.18
1.42
1.70
1.22
1.84

100
28.4
48
37
71
85
20
95–98



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Quick reference for other important tables
Page
13

C DEPT signals (22.8)
C chemical shifts (22.1)
Common GC stationary phases (19.1)
Drying agents (12.1)
Filter paper types (10.1)
1
H chemical shifts (21.2)
1
H coupling constants (21.6)
NMR Solvents, deuterated (21.1)
Recrystallization solvents (15.1)
TLC solvent polarities (17.1)
13

392
377
261
133
104
329
351
320
185
232


2.0 mL

1.5 mL

1.0 mL

Quick reference for other important figures
Page

Distillation
fractional (13.17)
simple (13.7)
short-path (13.8)
standard taper microscale (13.10)
Williamson microscale (13.13)
Extraction
microscale (11.8, 11.10)
miniscale (11.5)
Filtration, vacuum
microscale (10.7)
miniscale (10.6)
Glassware
standard taper miniscale (4.4)
standard taper microscale (4.6)
Williamson microscale (4.8)

160
149
152

153
156

0.5 mL

128, 130
123–124
111
110
33
35
36

0.1 mL

Quick reference for sections on sources of
confusion
Page

Computational chemistry
Distillation
Drying organic liquids
Extraction
Filtration
Gas chromatography (GC)
IR spectroscopy
Liquid chromatography (LC)
Melting points
Mass spectrometry (MS)
1

H NMR spectroscopy
Recrystallization
Thin-layer chromatography (TLC)
UV/VIS spectroscopy

cm

1

2

3

4

82
172
140
131
112
268
307
251
181
424
352
195
233
438


5

6

7

8

9

10

11

12

13

14

15


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Techniques
in Organic Chemistry


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Publisher: Clancy Marshall
Sponsoring Editor: Kathryn Treadway
Assistant Editor: Tony Petrites
Editorial Assistant: Kristina Treadway
Director of Marketing: John Britch
Media and Supplements Editor: Dave Quinn
Project Editor: Leigh Renhard
Production Manager: Julia DeRosa
Design Manager: Blake Logan
Cover Designer: Michael Jung
Text Designer: Marcia Cohen
Illustration Coordinator: Bill Page
Illustrations: Fine Line Illustrations, Network Graphics
Composition: MPS Limited, A Macmillan Company
Printing and Binding: Quebecor Dubuque

Library of Congress Control Number: 2009934363
ISBN-13: 978-1-4292-1956-3
ISBN-10: 1-4292-1956-4
© 2010 by W. H. Freeman and Company
All rights reserved
Printed in the United States of America
First printing
W. H. Freeman and Company

41 Madison Avenue, New York, NY 10010
Houndmills, Basingstoke, RG21 6XS, England
www.whfreeman.com


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Techniques
in Organic Chemistry
Miniscale, Standard Taper Microscale,
and Williamson Microscale

Third Edition

JERRY R. MOHRIG
Carleton College

CHRISTINA NORING HAMMOND
Vassar College

PAUL F. SCHATZ
University of Wisconsin, Madison

W. H. Freeman and Company
New York



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Contents
Preface

xiii

PART 1 INTRODUCTION TO THE ORGANIC LABORATORY

1

ESSAY— The Role of the Laboratory

1

Safety in the Laboratory

3

1.1
1.2
1.3
1.4
1.5
1.6

2


Protecting the Environment
2.1
2.2
2.3
2.4

3

Causes of Laboratory Accidents / 3
Safety Features in the Laboratory / 5
Preventing Accidents / 6
What to Do if an Accident Occurs / 9
Chemical Toxicology / 10
Where to Find Chemical Safety Information / 11

Green Chemistry / 14
How Can a Laboratory Procedure Be Made Greener? / 15
Fewer Reaction By-Products / 18
Handling Laboratory Waste / 20

Laboratory Notebooks and Prelaboratory Information
3.1
3.2
3.3

14

21

The Laboratory Notebook / 21

Calculation of the Percent Yield / 24
Sources of Prelaboratory Information / 25

PART 2 CARRYING OUT CHEMICAL REACTIONS

4

ESSAY— Learning to Do Organic Chemistry

29

Laboratory Glassware

31

4.1
4.2
4.3
4.4

Desk Equipment / 31
Standard Taper Miniscale Glassware / 31
Microscale Glassware / 34
Cleaning and Drying Laboratory Glassware / 37


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viii


5

Contents

Measurements and Transferring Reagents
5.1
5.2
5.3
5.4

6

7

8.4
8.5

9

9.5

67

Picturing Molecules on the Computer / 68
Molecular Mechanics Method / 69
Quantum Mechanics Methods: Ab Initio, Semiempirical,
and DFT Methods / 75
Which Computational Method Is Best? / 81
Sources of Confusion / 82


Designing a Chemical Reaction
9.1
9.2
9.3
9.4

58

Refluxing a Reaction Mixture / 59
Anhydrous Reaction Conditions / 61
Addition of Reagents During a Reaction / 62
Removal of Noxious Vapors / 63

Computational Chemistry
8.1
8.2
8.3

49

Preventing Bumping of Liquids / 50
Heating Devices / 51
Cooling Methods / 57
Laboratory Jacks / 58

Assembling a Reaction Apparatus
7.1
7.2
7.3
7.4


8

Using Electronic Balances / 38
Transferring Solids to a Reaction Vessel / 40
Measuring Volume and Transferring Liquids / 42
Measuring Temperature / 47

Heating and Cooling Methods
6.1
6.2
6.3
6.4

38

85

Importance of the Library / 86
Modifying the Scale of a Reaction and Carrying It Out / 86
Case Study: Synthesis of a Solvatochromic Dye / 90
Case Study: Oxidation of a Secondary Alcohol to a Ketone
Using NaOCl Bleach / 92
The Literature of Organic Chemistry / 93

PART 3 SEPARATION AND PURIFICATION TECHNIQUES
10

ESSAY— Intermolecular Forces in Organic Chemistry
Filtration

10.1
10.2
10.3
10.4
10.5
10.6

Filtering Media / 104
Miniscale Gravity Filtration / 106
Microscale Gravity Filtration / 108
Vacuum Filtration / 109
Other Liquid-Solid and Liquid-Liquid Separation Techniques / 112
Sources of Confusion / 112

99
104


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ix

Contents

11

Extraction
11.1
11.2
11.3

11.4
11.5

113

Understanding How Extraction Works / 114
Practical Advice on Extractions / 118
Miniscale Extractions / 122
Summary of the Miniscale Extraction Procedure / 124
Microscale Extractions / 125
11.5A EQUIPMENT AND TECHNIQUES COMMON TO MICROSCALE EXTRACTIONS / 125
11.5B MICROSCALE EXTRACTIONS WITH AN ORGANIC PHASE LESS DENSE THAN WATER / 127
11.5C MICROSCALE EXTRACTIONS WITH AN ORGANIC PHASE DENSER THAN WATER / 130

11.6

12

Drying Organic Liquids and Recovering Reaction Products
12.1
12.2
12.3
12.4

13

Sources of Confusion in Extractions / 131

Drying Agents / 133
Methods for Separating Drying Agents from Organic Liquids / 135

Recovery of an Organic Product from a Dried Extraction Solution / 137
Sources of Confusion in Drying Liquids / 140

Boiling Points and Distillation
13.1
13.2
13.3

132

141

Determination of Boiling Points / 142
Distillation and Separation of Mixtures / 145
Simple Distillation / 149
13.3A MINISCALE DISTILLATION / 149
13.3B MINISCALE SHORT-PATH DISTILLATION / 152
13.3C MICROSCALE DISTILLATION USING STANDARD TAPER 14/10 APPARATUS / 153
13.3D MICROSCALE DISTILLATION USING WILLIAMSON APPARATUS / 156

13.4
13.5
13.6
13.7
13.8

14

Melting Points and Melting Ranges
14.1

14.2
14.3
14.4
14.5
14.6

15

Fractional Distillation / 157
Azeotropic Distillation / 162
Steam Distillation / 164
Vacuum Distillation / 166
Sources of Confusion / 172

Melting-Point Theory / 175
Apparatus for Determining Melting Ranges / 176
Determining Melting Ranges / 178
Summary of Mel-Temp Melting-Point Determinations / 180
Using Melting Points to Identify Compounds / 180
Sources of Confusion / 181

Recrystallization
15.1
15.2
15.3
15.4
15.5
15.6

174


Introduction to Recrystallization / 183
Carrying Out Successful Recrystallizations / 186
How to Select a Recrystallization Solvent / 188
Miniscale Procedure for Recrystallizing a Solid / 189
Summary of the Miniscale Recrystallization Procedure / 193
Microscale Recrystallization / 193

183


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x

Contents

15.7
15.8

16

Summary of Microscale Recrystallization Procedure / 195
Sources of Confusion / 195

Specialized Techniques

197

Sublimation / 198

16.1 Assembling the Apparatus for a Sublimation / 198
16.2 Carrying Out a Sublimation / 199
Refractometry / 200
16.3 The Refractometer / 201
16.4 Determining a Refractive Index / 202
Optical Activity and Enantiomeric Analysis / 203
16.5 Mixtures of Optical Isomers: Separation/Resolution / 203
16.6 Polarimetric Techniques / 207
16.7 Analyzing Polarimetric Readings / 209
16.8 Modern Methods of Enantiomeric Analysis / 211
Inert Atmosphere Reaction Conditions / 212
16.9 Reaction Apparatus / 212
16.10 Transfer of Reagents Using Syringe Techniques / 216

PART 4 CHROMATOGRAPHY
17

ESSAY— Modern Chromatographic Separations
Thin-Layer Chromatography
17.1
17.2
17.3
17.4
17.5
17.6
17.7
17.8
17.9

18


Plates for Thin-Layer Chromatography / 222
Sample Application / 223
Development of a TLC Plate / 226
Visualization Techniques / 227
Analysis of a Thin-Layer Chromatogram / 229
Summary of TLC Procedure / 230
How to Choose a Developing Solvent When None Is Specified / 231
Using TLC Analysis in Synthetic Organic Chemistry / 233
Sources of Confusion / 233

Liquid Chromatography
18.1
18.2
18.3
18.4
18.5

235

Adsorbents / 236
Elution Solvents / 238
Determining the Column Size / 239
Miniscale Liquid Chromatography / 240
Microscale Liquid Chromatography / 244
18.5A PREPARATION AND ELUTION
18.5B PREPARATION AND ELUTION

18.6
18.7

18.8
18.9

219
221

OF A
OF A

MICROSCALE COLUMN / 245
WILLIAMSON MICROSCALE COLUMN / 246

Summary of Column Chromatography Procedures / 248
Flash Chromatography / 248
Sources of Confusion / 251
High-Performance Liquid Chromatography / 253


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xi

Contents

19

Gas Chromatography
19.1
19.2
19.3

19.4
19.5
19.6
19.7
19.8

256

Instrumentation for GC / 258
Types of Columns and Liquid Stationary Phases / 259
Detectors / 261
Recorders and Data Stations / 263
Practical GC Operating Procedures / 265
Sources of Confusion / 268
Identification of Components Shown on a Chromatogram / 269
Quantitative Analysis / 270

PART 5 SPECTROSCOPIC METHODS
20

ESSAY— The Spectroscopic Revolution
Infrared Spectroscopy
20.1
20.2
20.3
20.4
20.5
20.6
20.7
20.8

20.9
20.10

21

22

IR Spectra / 277
Molecular Vibrations / 277
IR Instrumentation / 282
Operating an FTIR Spectrometer / 284
Sample Preparation for Transmittance IR Spectra / 285
Sample Preparation for Attenuated Total Reflectance (ATR) Spectra / 290
Interpreting IR Spectra / 291
Procedure for Interpreting an IR Spectrum / 303
Case Study / 306
Sources of Confusion / 307

Nuclear Magnetic Resonance Spectroscopy
21.1
21.2
21.3
21.4
21.5
21.6
21.7
21.8
21.9
21.10
21.11

21.12
13

315

NMR Instrumentation / 317
Preparing Samples for NMR Analysis / 319
Summary of Steps for Preparing an NMR Sample / 324
Interpreting 1H NMR Spectra / 324
How Many Types of Protons Are Present? / 324
Counting Protons (Integration) / 325
Chemical Shift / 326
Quantitative Estimation of Chemical Shifts / 332
Spin-Spin Coupling (Splitting) / 342
Sources of Confusion / 352
Two Case Studies / 358
Advanced Topics in 1H NMR / 365

C and Two-Dimensional NMR Spectroscopy

22.1
22.2
22.3
22.4

275
277

13


C NMR Spectra / 371
C Chemical Shifts / 376
Quantitative Estimation of 13C Chemical Shifts / 380
Determining Numbers of Protons on Carbon Atoms / 391

13

371


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xii

Contents

22.5
22.6

23

Mass Spectrometry
23.1
23.2
23.3
23.4
23.5
23.6
23.7


24

Index

405

Mass Spectrometers / 406
Mass Spectra and the Molecular Ion / 410
High-Resolution Mass Spectrometry / 413
Mass Spectral Libraries / 415
Fragmentation of the Molecule / 417
Case Study / 422
Sources of Confusion / 424

Ultraviolet and Visible Spectroscopy
24.1
24.2
24.3
24.4

25

Case Study / 393
Two-Dimensional Correlated Spectroscopy (2D COSY) / 396

428

UV/VIS Spectra and Electronic Excitation / 429
UV/VIS Instrumentation / 434
Preparing Samples and Operating the Spectrometer / 435

Sources of Confusion / 438

Integrated Spectroscopy Problems

439
449


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Preface
The major focus of the Third Edition of Techniques in Organic Chemistry is the same
as the focus of the earlier editions: the fundamental techniques that students encounter in the organic chemistry laboratory. However, we have also expanded our
emphasis on the areas that students need to develop their skills in the critical interpretation of their experimental data and to successfully carry out guided-inquiry
experiments.
Organic chemistry is an experimental science, and students learn its process in
the laboratory. Our primary goal should be to teach students how to carry out welldesigned experiments and draw reasonable conclusions from their results—a
process at the heart of science. We should work to find opportunities that engage
students in addressing questions whose answers come from their experiments, in an
environment where they can succeed. These opportunities should be designed to
catch students’ interest, transporting them from passive spectators to active participants. A well-written and comprehensive textbook on the techniques of experimental organic chemistry is an important asset in reaching these goals.

Changes in the Third Edition
The Third Edition of Techniques in Organic Chemistry includes a number of new features. Entirely new sections have been added on planning a chemical reaction, computational chemistry, and 13C nuclear magnetic resonance spectroscopy. A new
chapter on UV-visible spectroscopy has been added. Many sections concerning basic
techniques have been brought up to date and reorganized to better meet the practical needs of students as they encounter laboratory work.
A short essay introduces each of the five major parts of the Third Edition, on topics from the role of the laboratory to the spectroscopic revolution. Perhaps most important, the essay Intermolecular Forces in Organic Chemistry provides the basis for
subsequent discussions on organic separation and purification techniques.
Many important features of earlier editions have been retained in the Third
Edition. Subsections on sources of confusion again walk students through the pitfalls that could easily discourage them if they did not have this practical support.

For easy reference, commonly used data on solvents and acids and bases, as well as
quick references to frequently used techniques, are located inside the front cover.
Data tables for IR and NMR spectroscopy appear inside the back cover and on the
back foldout. We believe that these features will assist active learning as students
encounter the need for this information during their laboratory work.

Who Should Use This Book?
The book is intended to serve as a laboratory textbook of experimental techniques
for all students of organic chemistry. It can be used in conjunction with any lab experiments to provide the background and skills necessary for mastering the organic


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xiv

Preface

chemistry laboratory. The book is written to provide effective support for guidedinquiry and design-based experiments and projects. It can also serve as a useful reference for laboratory practitioners and instructors.

Flexibility
Techniques in Organic Chemistry offers a great deal of flexibility. It can be used in any
organic laboratory with any glassware. The basic techniques for using standard taper
miniscale glassware as well as 14/10 standard taper microscale and Williamson microscale glassware are all covered. The miniscale glassware that is described is
appropriate with virtually any 14/20 or 19/22 standard taper glassware kit.

Modern Instrumentation
Modern instrumental methods play a crucial role in supporting guided-inquiry experiments, which provide the active learning opportunities many instructors seek for
their students. We feature instrumental methods that offer quick, reliable, quantitative data. NMR spectroscopy and gas chromatography are particularly important.
Our emphasis is on how to acquire good data and how to read spectra efficiently and
with real understanding. Chapters on 1H and 13C NMR, IR, and mass spectrometry

stress the practical interpretation of spectra and how they can be used to answer
questions posed in an experimental context. They describe how to deal with real laboratory samples and include case studies of analyzed spectra.

Organization
The book is divided into five parts:
•
•
•

•
•

Part 1 has chapters on safety, green chemistry, and the lab notebook.
Part 2 discusses glassware, measurements, heating methods, computational
chemistry, and planning a chemical reaction.
Part 3 introduces filtration, extraction, drying organic liquids, distillation, melting
points, recrystallization, and a chapter on specialized techniques—sublimation,
refractometry, measurement of optical activity, and inert atmosphere techniques.
Part 4 presents the three chromatographic techniques widely used in the organic
laboratory—thin-layer, liquid, and gas chromatography.
Part 5 discusses IR, 1H and 13C NMR, MS, and UV-visible spectra in some detail.

Traditional organic qualitative analysis is available on our Web site:
www.whfreeman.com/mohrig.

Modern Projects and Experiments in Organic Chemistry
The accompanying laboratory manual, Modern Projects and Experiments in Organic
Chemistry, comes in two complete versions:
•
•


Modern Projects and Experiments in Organic Chemistry: Miniscale and Standard Taper
Microscale (ISBN 0-7167-9779-8)
Modern Projects and Experiments in Organic Chemistry: Miniscale and Williamson
Microscale (ISBN 0-7167-3921-6)


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xv

Preface

Modern Projects and Experiments is a combination of inquiry-based and traditional experiments, plus multiweek inquiry-based projects. It is designed to provide quality
content, student accessibility, and instructor flexibility. This laboratory manual introduces students to the way the contemporary organic lab actually functions and allows them to experience the process of science.

Custom Publishing
All experiments and projects are available through LabPartner for Chemistry,
Freeman Custom Publishing’s newest offering. LabPartner provides instructors with
a diverse database of experiments, selected from the extensive array published by
W. H. Freeman and Hayden-McNeil Publishing. Instructors can use LabPartner to
create their own customized lab manual by selecting specific experiments from
Modern Projects and Experiments, adding experiments from other WHF or H-M titles,
and incorporating their own original material so that the manual is organized to suit
their course. Visit to learn more.

ACKNOWLEDGMENTS
We have benefited greatly from the insights and thoughtful critiques of the reviewers for this edition:
Scott Allen, University of Tampa
Bal Barot, Lake Michigan College

Peter T. Bell, Tarleton State University
Haishi Cao, University of Nebraska, Kearney
J. Derek Elgin, Coastal Carolina University
George Griffin, Bunker Hill Community College
Jason A. Morrill, William Jewel College
Judith Moroz, Bradley University
Kimberly A. O. Pacheco, University of Northern Colorado
David Schedler, Birmingham Southern College
Levi Simpson, University of Texas, Southwestern Medical Center
Patricia Somers, Colorado State University
Bernhard Vogler, University of Alabama, Huntsville
Denyce K. Wicht, Suffolk University
Kurt Wiegel, University of Wisconsin, Eau Claire
Jane E. Wissinger, University of Minnesota
Linfeng Xie, University of Wisconsin, Oshkosh
We especially thank Jane Wissinger and George Griffin, who provided many
helpful suggestions regarding specific techniques for this edition, as well as thoughtful critiques of the entire book.
We wish to thank Kathryn Treadwell, our editor at W. H. Freeman and Company,
for her direction in planning this revision, arranging for such an outstanding group
of reviewers, and overseeing most of the manuscript preparation. We also thank
Kristina Treadwell, our editor during the last stages of publication, Leigh Renhard,
Project Editor, for her proficient direction of the production stages, and Penny Hull


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xvi

Preface


for her skillful copy editing. We express heartfelt thanks for the patience and support
of our spouses, Adrienne Mohrig, Bill Hammond, and Ellie Schatz, during the writing of this book.
We hope that teachers and students of organic chemistry find our approach to
laboratory techniques effective, and we would be pleased to hear from those who use
our book. Please write to us in care of the Chemistry Acquisitions Editor at W. H.
Freeman and Company, 41 Madison Avenue, New York, NY 10010, or e-mail us at



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PART

3
1
Introduction to the
Organic Laboratory
Essay — The Role of the Laboratory
Organic chemistry is an experimental science, and the laboratory is where you learn
about “how we know what we know about it.” The laboratory deals with the
processes of scientific inquiry that organic chemists use. It demonstrates the experimental basis of what your textbook presents as fact. The primary goal of the laboratory is to help you understand how organic chemistry is done by actually doing it.
Learning how to obtain and interpret experimental results and draw reasonable conclusions from them is at the heart of doing science. Your laboratory work will give
you the opportunity to exercise your critical thinking abilities, to join in the process
of science—to observe, to think, and to act.
To learn to do experimental organic chemistry, you need to master an array of techniques for carrying out and interpreting chemical reactions, separating products from
their reaction mixtures, purifying products, and analyzing the results. Techniques in
Organic Chemistry is designed to provide you with a sound fundamental understanding of the techniques that organic chemists use and the chemical principles they are
based on. Mastering these techniques involves attention to detail and careful observations that will enable you to obtain accurate results and reach reasonable conclusions
in your investigations of chemical phenomena.
While you are in the laboratory, you will have a variety of experiences—from learning basic techniques to running chemical reactions. Interpretation of your experimental results will involve consideration of the relationship between theory and

experiment and provide reinforcement of what you are learning in the classroom. You
may have the opportunity to do guided-inquiry experiments that ask you to answer a
question or solve a problem by drawing conclusions from your experiments. You may
also have the opportunity to synthesize an interesting organic compound by adapting
a generic experimental procedure from the chemical literature.

1


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2

Part 1

•

Introduction to the Organic Laboratory

Science is often done by teams of people working together on problems, and your
experiments may involve teamwork with other students in your lab section. Some of
your lab work may involve multiweek related experiments, which have a flexibility
that may allow you to repeat a reaction procedure successfully if it didn’t work well
the first time. In fact, virtually all experimental results that are reported in chemical
journals have been repeated many times before they are published.
Part of learning how to do organic chemistry in the laboratory includes learning how to do it safely. Technique 1 discusses laboratory safety and safe handling
practices for the chemicals you will use. We urge you to read it carefully before you
begin laboratory work.



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TECHNIQUE

1

SAFETY IN THE LABORATORY
As you begin your study of experimental organic chemistry, you
need a basic understanding of safety principles for handling chemicals and equipment in the laboratory. Consider this chapter to be
required reading before you perform any experiments.
The organic chemistry laboratory is a place where accidents can
and do occur and where safety is everyone’s business. While working in the laboratory, you are protected by the instructions in an
experiment and by the laboratory itself, which is designed to safeguard you from most routine hazards. However, neither the experimental directions nor the laboratory facilities can protect you from
the worst hazard—your own or your neighbors’ carelessness.
In addition to knowledge of basic laboratory safety, you need to
learn how to work safely with organic chemicals. Many organic
compounds are flammable or toxic. Some can be absorbed through
the skin; others are volatile and vaporize easily into the air in the
laboratory. Despite the hazards, organic compounds can be handled
with a minimum of risk if you are adequately informed about the
hazards and necessary safe handling procedures and if you use common sense while you are in the laboratory.
At the first meeting of your lab class, local safety issues will be
discussed—the chemistry department’s policies on safety goggles
and protective gloves, the location of safety showers and eye wash
stations, and the procedures to be followed in emergency situations.
The information in this chapter is intended to complement your
instructor’s safety rules and instructions.

1.1

Causes of Laboratory Accidents

Laboratory accidents are of three general types: accidents involving
fires and explosions, accidents producing cuts or burns, and accidents
occurring from inhalation, absorption through the skin, or ingestion
of toxic materials.

Fires and Explosions

Fire is the chemical union of a fuel with an oxidizing agent, usually
molecular oxygen, and is accompanied by the evolution of heat
and flame. Most fires involve ordinary combustible materials—
hydrocarbons or their derivatives. Such fires are extinguished by removing oxygen or the combustible material or by decreasing the
heat of the fire. Fires are prevented by keeping flammable materials
away from a flame source or from oxygen (obviously, the former is
easier).
Four sources of ignition are present in the organic laboratory:
open flames, hot surfaces such as hot plates or heating mantles, faulty
electrical equipment, and chemicals. The most obvious way to prevent
a fire is to prevent ignition.

3


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4

Part 1

•


Introduction to the Organic Laboratory

AT

HE
EAT

H

R

STI

FIGURE 1.1
Heating devices.

Ceramic heating mantle

R

STI

Hot plate/stirrer

Open flames. Open-flame ignition of organic vapors or liquids is
easily prevented: Never bring a lighted Bunsen burner or a match
near a low-boiling-point flammable liquid. Furthermore, because
vapors from organic liquids can travel over long distances at bench
or floor level (they are heavier than air), an open flame within 10 ft
of diethyl ether, pentane, or other low-boiling organic solvents is an

unsafe practice. In fact, the use of a Bunsen burner or any other
flame in an organic laboratory should be a rare occurrence and done
only with the permission of your instructor.
Hot surfaces. A hot surface, such as a hot plate or heating mantle,
presents a trickier problem (Figure 1.1). An organic solvent spilled
or heated recklessly on a hot plate surface may burst into flames.
The thermostat on most hot plates is not sealed and can spark when
it cycles on and off. The spark can ignite flammable vapors from an
open container such as a beaker. Remove any hot heating mantle or
hot plate from the vicinity before pouring a volatile organic liquid
because the vapors from the solvent can be ignited by the hot surface of a hot plate or a heating mantle.
Faulty electrical equipment. Do not use appliances with frayed or
damaged electrical cords as their use could lead to an electrical fire.
Chemical fires. Chemical reactions sometimes produce enough heat
to cause a fire and explosion. For example, in the reaction of metallic
sodium with water, the hydrogen gas that forms in the reaction can
explode and ignite a volatile solvent that happens to be nearby.

Cuts and Injuries

FIGURE 1.2
Breaking a glass rod
properly.

Cuts and mechanical injuries are hazards anywhere, including the
laboratory.
Breaking glass rods or tubing. When you purposely break a glass
rod or a glass tube, do it correctly. Score (scratch) a small line on one
side of the tube with a file. Wet the scored line with a drop of water.
Then, holding the tube on both sides with a paper towel and with

the scored part away from you, quickly snap it by pulling the ends
toward you (Figure 1.2).


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Safety in the Laboratory

5

Inserting glass into stoppers. Insert thermometers or glass tubes
into corks, rubber stoppers, and thermometer adapters carefully
and correctly. First, lubricate the end of the glass tube with a drop
of water or glycerol. Then, while holding the tube with a towel
close to the lubricated end, insert it slowly by firmly rotating it into
the stopper. Never hold the thermometer by the end away from the
stopper—it may break and the shattered end may be driven into
your hand.
Chipped glassware. Check the rims of beakers, flasks, and other
glassware for chips. Discard any piece of glassware that is chipped
because you could be cut very easily by the sharp edge.

Inhalation, Ingestion,
and Skin Absorption

Inhalation. The hoods in the laboratory protect you from inhalation
of noxious fumes, toxic vapors, or dust from finely powdered materials. A hood is an enclosed space with a continuous flow of air

that sweeps over the bench top, removing vapors or fumes from
the area.
Because many compounds used in the organic laboratory are at
least potentially dangerous, the best practice is to run every experiment in a hood, if possible. Your instructor will tell you when an experiment must be carried out in a hood. Make sure that the hood is
turned on before you use it. Position the sash for the optimal airflow through the hood. If the optimum sash position is not indicated
on the hoods in your laboratory, consult your instructor about how
far to open the sash.
Ingestion. Ingestion of chemicals by mouth is easily prevented. Never
taste any substance or pipet any liquid by mouth. Wash your hands
with soap and water before you leave the laboratory. No food or drink
of any sort should be brought into a laboratory or eaten there.
Absorption through the skin. Many organic compounds are absorbed
through the skin. Wear the appropriate gloves while handling reagents
and reaction mixtures. If you spill any substance on your skin, notify
your instructor immediately, and wash the affected area thoroughly
with water for 10–15 min.

1.2

Safety Features in the Laboratory
Organic laboratories contain many safety features for the protection and comfort of the people who work in them. It is unlikely
that you will have to use the safety features in your lab, but in the
event that you do, you must know what and where they are and
how they operate.

Fire Extinguishers

Colleges and universities all have standard policies regarding the
handling of fires. Your instructor will inform you whether evacuation of the lab or the use of a fire extinguisher takes priority at



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Part 1

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Introduction to the Organic Laboratory

your institution. Learn where the exits from your laboratory are
located.
Fire extinguishers are strategically located in your laboratory.
There may be several types, and your instructor may demonstrate
their use. Your lab is probably equipped with either class BC or
class ABC dry chemical fire extinguishers suitable for solvent or
electrical fires.

Fire Blankets

Fire blankets are used for one thing and one thing only—to smother
a fire involving a person’s clothing. Fire blankets are available in
most labs.

Safety Showers

Safety showers are for acid burns and other spills of corrosive, irritating, or toxic chemicals on the skin or clothing. If a safety shower
is nearby, it can also be used when a person’s clothing or hair is
ablaze. The typical safety shower dumps a huge volume of water in

a short period of time and thus is effective for both fire and acid
spills, when speed is of the essence. Do not use the safety shower
routinely, but do not hesitate to use it in an emergency.

Eye Wash Stations

You should always wear safety goggles while working in a laboratory, but if you accidentally splash something in your eyes, immediately use the eye wash station to rinse them with copious quantities
of slightly warm water for 10–15 min. Learn the location of the eye
wash stations in your laboratory and examine the instructions on
them during the first (check-in) lab session.

First Aid Kits

Your laboratory or a nearby stockroom may contain a basic first aid
kit consisting of such items as adhesive bandages, sterile pads, and
adhesive tape for treating a small cut or burn. All injuries, no matter
how slight, should be reported to your instructor immediately.
Your instructor will indicate the location of the first aid station and
instruct you in its use.

1.3

Preventing Accidents
Accidents can largely be prevented by common sense and knowledge
of simple safety rules.

Personal Safety

1.


2.

Think about what you are doing while you are in the laboratory.
Read the experiment before the laboratory session starts and
perform laboratory operations with careful forethought.
It is a law in many states and common sense in the remainder to
wear safety glasses or goggles at all times in the laboratory.
Your institution may have a policy regarding wearing contact
lenses in the laboratory; learn what it is and follow it. Wear
clothing that covers and protects your body. Shorts, tank tops,
and sandals (or bare feet) are not suitable attire for the lab.
Avoid loose clothing and loose long hair, which are fire hazards
or could become entangled in an apparatus. Laboratory aprons
or lab coats may be required by your instructor. Always wash


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7

Safety in the Laboratory

3.
4.

5.
6.


Precautions When
Handling Reagents

your hands with soap and water at the end of the laboratory
period.
Never eat, chew gum, drink beverages, or apply cosmetics in
the lab.
Be aware of what your neighbors are doing. Many accidents
and injuries in the laboratory are caused by other people. Often
the person hurt worst in an accident is the one standing next to
the place where the accident occurred. Make yourself aware of the
procedures that should be followed in case of any accident. [See
Technique 1.4].
Never work alone in the laboratory. Being alone in a situation
in which you may be helpless can be life threatening.
Women who are pregnant or who become pregnant should discuss with the appropriate medical professionals the advisability
of working in the organic chemistry laboratory.

Never taste, ingest, or sniff directly any chemical. Always use the
hood when working with volatile, toxic, or noxious materials.
Handle all chemicals carefully, and remember that many chemicals
can enter the body through the skin and eyes, as well as through the
mouth and lungs.
Protective attire. Wear a lab coat or apron when working with hazardous chemicals. Cotton is the preferred fabric because synthetic
fabrics could melt in a fire or undergo a reaction that causes the fabric
to adhere to the skin and cause a severe burn.
Disposable gloves. Disposable gloves are available in all laboratories. Wear gloves to prevent chemicals from coming into contact
with your skin unnecessarily. Table 1.1 lists a few common chemicals


T A B L E

1 . 1

Chemical resistance of common types of gloves
to various compounds
GLOVE TYPE

Compound

Neoprene

Nitrile

Latex

Acetone
Chloroform
Dichloromethane
Diethyl ether
Ethanol
Ethyl acetate
Hexane
Methanol
Nitric acid (conc.)
Sodium hydroxide
Sulfuric acid (conc.)
Toluene

good

good
fair
very good
very good
good
excellent
very good
good
very good
good
fair

fair
poor
poor
good
excellent
poor
excellent
fair
poor
excellent
poor
fair

good
poor
poor
poor
excellent

fair
poor
fair
poor
excellent
poor
poor

The information in this table was compiled from the Web site orm.
umd.edu/CampusInfo/Departments/EnvirSafety/Is/gloves.html and from
“Chemical Resistance and Barrier Guide for Nitrile and Natural Rubber Latex
Gloves,” Safeskin Corporation, San Diego, CA, 1996.