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GREEN CHEMISTRY ANDENGINEERING
GREEN CHEMISTRY ANDENGINEERING
A Practical Design Approach
CONCEPCION JIMENEZ-GONZALEZ
DAVID J. C. CONSTABLE
Copyright � 2011 by John Wiley & Sons, Inc. All rights reserved.
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Library of Congress Cataloging-in-Publication Data:
Jim�enez-Gonz�alez, Concepcion Conchita.
Green chemistry and engineering : a practical design approach / Concepcion Conchita
Jim�enez-Gonz�alez, David J. C. Constable.
p. cm.
Includes index.
ISBN 978-0-470-17087-8 (cloth)
1. Environmental chemistry–Industrial applications. 2. Sustainable engineering. I.
Constable, David J. C., 1958- II. Title.
TP155.2.E58J56 2010
660–dc22
2010003431
Printed in Singapore
10 9 8 7 6 5 4 3 2 1
CONTENTS
PREFACE xi
PART I GREEEN CHEMISTRY AND GREEN ENGINEERING IN
THE MOVEMENT TOWARD SUSTAINABILITY 1
1 Green Chemistry and Engineering in the Context of Sustainability 3
1.1 Why Green Chemistry? 3
1.2 Green Chemistry, Green Engineering, and Sustainability 6
1.3 Until Death Do Us Part: A Marriage of Disciplines 13
Problems 15
References 15
2 Green Chemistry and Green Engineering Principles 17
2.1 Green Chemistry Principles 17
2.2 Twelve More Green Chemistry Principles 26
2.3 Twelve Principles of Green Engineering 28
2.4 The San Destin Declaration: Principles of Green Engineering 31
2.5 Simplifying the Principles 34
Problems 38
References 39
3 Starting with the Basics: Integrating Environment, Health,
and Safety 41
3.1 Environmental Issues of Importance 42
3.2 Health Issues of Importance 54
v
3.3 Safety Issues of Importance 62
3.4 Hazard and Risk 68
3.5 Integrated Perspective on Environment, Health, and Safety 70
Problems 70
References 73
4 How Do We Know It’s Green? A Metrics Primer 77
4.1 General Considerations About Green Chemistry and Engineering
Metrics 77
4.2 Chemistry Metrics 79
4.3 Process Metrics 89
4.4 Cost Implications and Green Chemistry Metrics 101
4.5 A Final Word on Green Metrics 101
Problems 102
References 103
PART II THE BEGINNING: DESIGNING GREENER, SAFER
CHEMICAL SYNTHESES 107
5 Route and Chemistry Selection 109
5.1 The Challenge of Synthetic Chemistry 109
5.2 Making Molecules 110
5.3 Using Different Chemistries 119
5.4 Route Strategy 122
5.5 Protection–Deprotection 124
5.6 Going from a Route to a Process 126
Problems 127
References 130
6 Material Selection: Solvents, Catalysts, and Reagents 133
6.1 Solvents and Solvent Selection Strategies 133
6.2 Catalysts and Catalyst Selection Strategies 154
6.3 Other Reagents 168
Problems 168
References 173
7 Reaction Conditions and Green Chemistry 175
7.1 Stoichiometry 176
7.2 Design of Experiments 178
7.3 Temperature 180
7.4 Solvent Use 182
7.5 Solvents and Energy Use 184
7.6 Reaction and Processing Time 187
7.7 Order and Rate of Reagent Addition 188
7.8 Mixing 189
vi CONTENTS
Appendix 7.1: Common Practices in Batch Chemical Processing and Their
Green Chemistry Impacts 191
Problems 196
References 200
8 Bioprocesses 203
8.1 How Biotechnology Has Been Used 203
8.2 Are Bioprocesses Green? 204
8.3 What Is Involved in Bioprocessing 205
8.4 Examples of Products Obtained from Bioprocessing 216
Problems 226
References 232
PART III FROM THE FLASK TO THE PLANT: DESIGNING GREENER,
SAFER, MORE SUSTAINABLE MANUFACTURING
PROCESSES 233
9 Mass and Energy Balances 235
9.1 Why We Need Mass Balances, Energy Balances, and Process
Flow Diagrams 236
9.2 Types of Processes 237
9.3 Process Flow Diagams 238
9.4 Mass Balances 241
9.5 Energy Balances 250
9.6 Measuring Greenness of a Process Through Energy and Mass
Balances 261
Problems 265
References 272
10 The Scale-up Effect 273
10.1 The Scale-up Problem 273
10.2 Factors Affecting Scale-up 276
10.3 Scale-up Tools 283
10.4 Numbering-up vs. Scaling-up 289
Problems 290
References 293
11 Reactors and Separations 295
11.1 Reactors and Separations in Green Engineering 296
11.2 Reactors 296
11.3 Separations and Other Unit Operations 307
11.4 Batch vs. Continuous Processes 321
11.5 Does Size Matter? 323
Problems 323
References 327
CONTENTS vii
12 Process Synthesis 331
12.1 Process Synthesis Background 331
12.2 Process Synthesis Approaches and Green Engineering 333
12.3 Evolutionary Techniques 334
12.4 Heuristics Methods 343
12.5 Hierarchical Decomposition 346
12.6 Superstructure and Multiobjective Optimization 349
12.7 Synthesis of Subsystems 354
Problems 355
References 359
13 Mass and Energy Integration 363
13.1 Process Integration: Synthesis, Analysis,
and Optimization 363
13.2 Energy Integration 365
13.3 Mass Integration 373
Problems 381
References 388
14 Inherent Safety 391
14.1 Inherent Safety vs. Traditional Process Safety 391
14.2 Inherent Safety and Inherently Safer Design 394
14.3 Inherent Safety in Route Strategy and Process Design 398
14.4 Conclusions on Inherent Safety 406
Problems 406
References 411
15 Process Intensification 413
15.1 Process Intensification Background 413
15.2 Process Intensification Technologies 416
15.3 Process Intensification Techniques 435
15.4 Perspectives on Process Intensification 437
Problems 437
References 442
PART IV EXPANDING THE BOUNDARIES 447
16 Life Cycle Inventory and Assessment Concepts 449
16.1 Life Cycle Inventory and Assessment Background 450
16.2 LCI/A Methodology 452
16.3 Interpretation: Making Decisions with LCI/A 473
16.4 Streamlined Life Cycle Assessment 481
Problems 484
References 488
viii CONTENTS
17 Impacts of Materials and Procurement 493
17.1 Life Cycle Management 493
17.2 Where Chemical Trees and Supply Chains Come From 495
17.3 Green (Sustainable) Procurement 500
17.4 Transportation Impacts 511
Problems 515
References 517
18 Impacts of Energy Requirements 519
18.1 Where Energy Comes From 519
18.2 Environmental Life Cycle Emissions and Impacts
of Energy Generation 525
18.3 From Emissions to Impacts 537
18.4 Energy Requirements for Waste Treatment 540
Problems 540
References 542
19 Impacts of Waste and Waste Treatment 545
19.1 Environmental Fate and Effects Data 546
19.2 Environmental Fate Information: Physical Properties 550
19.3 Environmental Fate Information: Transformation and Depletion
Mechanisms 557
19.4 Environmental Effects Information 559
19.5 Environmental Risk Assessment 562
19.6 Environmental Life Cycle Impacts of Waste Treatment 565
Problems 574
References 576
20 Total Cost Assessment 579
20.1 Total Cost Assessment Background 579
20.2 Importance of Total Cost Assessment 580
20.3 Relationship Between Life Cycle Inventory/Assessment and Total
Cost Assessment 582
20.4 Timing of a Total Cost Assessment 583
20.5 Total Cost Assessment Methodology 583
20.6 Total Cost Assessment in a Green Chemistry Context 589
Problems 594
References 597
PART V WHAT LIES AHEAD 599
21 Emerging Materials 601
21.1 Emerging Materials Development 601
21.2 Nanomaterials 602
CONTENTS ix
21.3 Bioplastics and Biopolymers 605
21.4 About New Green Materials 609
Problems 609
References 611
22 Renewable Resources 613
22.1 Why We Need Renewable Resources 613
22.2 Renewable Materials 616
22.3 The Biorefinery 621
22.4 Renewable Energy 625
Problems 630
References 632
23 Evaluating Technologies 635
23.1 Why We Need to Evaluate Technologies and Processes
Comprehensively 635
23.2 Comparing Technologies and Processes 636
23.3 One Way to Compare Technologies 637
23.4 Trade-Offs 644
23.5 Advantages and Limitations of Comparing Technologies 645
Problems 646
References 649
24 Industrial Ecology 651
24.1 Industrial Ecology Background 652
24.2 Principles and Concepts of Industrial Ecology and Design 655
24.3 Industrial Ecology and Design 657
24.4 Industrial Ecology in Practice 663
Problems 665
References 666
25 Tying It All Together: Is Sustainability Possible? 669
25.1 Can Green Chemistry and Green Engineering Enable Sustainability? 670
25.2 Sustainability: Culture and Policy 671
25.3 Influencing Sustainability 672
25.4 Moving to Action 674
Problems 674
References 675
INDEX 677
x CONTENTS
PREFACE
In the last decade, interest in and understanding of green chemistry and green engineering
have increased steadily beyond academia and into the business world. Industries within
different sectors of the economy have made concerted efforts to embed these concepts in
their operations. Given our experience with green chemistry and green engineering in the
pharmaceutical industry, we were initially approached by the publishers to edit a book on
green chemistry in the pharmaceutical industry. This was a worthy proposal, but we felt
that we had a greater opportunity and worthier endeavor to produce a book that would
attempt to fully integrate green chemistry and green engineering into the academic
curricula and that at the same time could serve as a practical reference to chemists and
engineers in the workplace.
Green chemistry and green engineering are still relatively new areas that have not been
completely ingrained in traditional chemistry and engineering curricula, but classes and
even majors in these topics are becoming increasingly common. However, most classes in
green chemistry are taught from an environmental chemistry perspective or a synthetic
organic chemistry perspective, with neither approach addressing issues ofmanufacturing or
manufacturability of products. Green engineering classes, on the other hand, tend to
emphasize issues related to manufacturing, but do not treat reaction and process chemistry
sufficiently, so these disciplines still seem to be disconnected. This lack of integration
between chemistry, engineering, and other key disciplines has been one of the main
challenges that we have had within the industrial workplace and in previous academic
experiences.
As a consequence of these experiences, we decided to write this book to bridge the great
divide between bench chemistry, process design, engineering, environment, health, safety,
and life cycle considerations. We felt that a systems-oriented and integrated approach was
needed to evolvegreen chemistry and green engineering as disciplines in the broader context
of sustainability. To achieve this, we have organized the book in five main sections.
xi
. Part I. Green Chemistry and Green Engineering in the Movement Toward Sustain-
ability. Chapters 1 to 4 set the broader context of sustainability, highlighting the key
role that green chemistry and green engineering have in moving society toward the
adoption of more sustainable practices in providing key items of commerce.
. Part II. The Beginning: Designing Greener, Safer Chemical Synthesis. Chapters 5 to 8
address the key components of chemistry that will contribute to the achievement of
more sustainable chemical reactions and reaction pathways. They also provide an
approach to materials selection that promotes the overall greenness of a chemical
synthesis without diminishing the efficiency of the chemistry or associated chemical
process.
. Part III. From the Flask to the Plant: Designing Greener, Safer, More Sustainable
Manufacturing Processes. Chapters 9 to 15 provide those key engineering concepts
that support the design of greener, more sustainable chemical processes.
. Part IV. Expanding the Boundaries: Looking Beyond Our Processes. Chapters 16 to
20 introduce a life cycle thinking perspective by providing background and context
for placing a particular chemical process in the broader chemical enterprise,
including its impacts from raw materials extraction to recycle/reuse or end-of-life
considerations.
. Part V. What Lies Ahead: Beyond the Chemical Processing Technology of Today or
Delivering Tomorrow’s ProductsMore Sustainably. Finally, Chapters 21 to 25 provide
some indication of trends in chemical processing that may lead us toward more
sustainable practices.
To help provide a practical approach, we have included examples and exercises that will
help the student or practitioner to understand these concepts as applied to the industrial
setting and to use the material in direct and indirect applications. The exercises are intended
tomake the book suitable for both self-study or as a textbook, andmost exercises are derived
from our professional experiences.
The book is an outgrowth of our experience in applied and fundamental research,
consulting, teaching, and corporatework on the areas of green chemistry, green engineering,
and sustainability. It is intended primarily for graduate and senior-level courses in chemistry
and chemical engineering, although we believe that chemists and engineers working in
manufacturing, research, and development, especially in the fine-chemical and pharmaceu-
tical areas, will find the book to be a useful reference for process design and reengineering.
Our aim is to provide a balance between academic needs andpractical industrial applications
of an integrated approach to green chemistry and green engineering in the context of
sustainability.
Acknowledgments
We thank all our colleagues who have contributed directly or indirectly to our journey
toward sustainability, and whose ideas and collaborations throughout the years have
contributed to our own experience in the areas of green chemistry and green engineering.
We also express our gratitude to GlaxoSmithKline, in general, and to James R. Hagan, in
particular, for their support and encouragement.
xii PREFACE
We also give special thanks to Rafiqul Gani and Ana Carvalho from the Computer
Aided Process-Product Engineering Center, Department of Chemical and Biochemical
Engineering at the Technical University of Denmark, for their comments, reviews, and
contributions to Chapter 12; toMariana Pierobon and BASF for their helpful comments and
for allowing us to use one of BASF’s eco-efficiency assessments as an example in the life
cycle chapters; to Sara Conradt for allowing us to use a sample of her masters thesis as an
example of LCA outputs; and to Tom Roper and John Hayler at GSK for their feedback on
green chemistry throughout the years. Finally, we want to thank Chemical Engineering
magazine, the American Chemical Society, Springer Science and BusinessMedia, Elsevier,
John Wiley & Sons, the Royal Society of Chemistry, and Wiley-VCH for permission to
reproduce some printed material.
CONCEPCION JIM�ENEZ-GONZ�ALEZ
DAVID J. C. CONSTABLE
December 2009
PREFACE xiii
PART I
GREEN CHEMISTRY AND GREENENGINEERING IN THE MOVEMENTTOWARD SUSTAINABILITY
1
1GREEN CHEMISTRY AND ENGINEERINGIN THE CONTEXT OF SUSTAINABILITY
What This Chapter Is About Green chemistry andgreen engineering need to be seen as an
integral part of thewider context of sustainability. In this chapterwe explore green chemistry
and green engineering as tools to drive sustainability from a triple-bottom-line perspective
with influences on the social and economic aspects of sustainability.
Learning Objectives At the end of this chapter, the student will be able to:
. Understand the need for the development of greener chemistries and chemical
processes.
. Identify sustainability principles and associate standard chemical processes with the
three areas of sustainability: social, economic, and environmental.
. Identify green chemistry and green engineering as part of the tools used to drive
sustainability through innovation.
. Understand the need for an integrated approach to green chemistry and engineering.
1.1 WHY GREEN CHEMISTRY?
AþB!C ð1:1Þ
Reactant A plus reactant B gives product C. No by-products, no waste, at ambient
temperature, no need for separation. Is it really that easy?
Green Chemistry and Engineering: A Practical Design Approach, By Concepcion Jim�enez-Gonz�alez andDavid J. C. ConstableCopyright � 2011 John Wiley & Sons, Inc.
3
If industrial chemical reactions were that straightforward, chemists and engineers would
have significantlymore time on their hands and significantly less excitement and fewer long
hours atwork.Chemists knowthat this hypothetical reaction isnot the case in real life, as they
have less-than-perfect chemical conversions, competing reactions to avoid, hazardous
materials to manage, impurities in raw materials, and the final product to reduce. Engineers
know that in addition to conquering chemistry, there are by-products to separate, waste to
treat, energy transfer to optimize, solvent to purify and recover, and hazardous reaction
conditions to control. At the end of this first reality check, we see that our initial reaction is a
much more complicated network of inputs and outputs, something that looks more like
Figure 1.1.
Green chemistry and green engineering are, in a very simplified way, the tools and
principles that we use to ensure that our processes and chemical reactions aremore efficient,
safer, cleaner, and produce less waste by design. In other words, green chemistry and green
engineering assist us infirst thinking about and thendesigning synthetic routes andprocesses
that are more similar to the hypothetical reaction depicted in equation (1.1) than to the more
accurate reflection of current reality shown in, Figure 1.1.
What are the drivers in the search for greener chemistries and processes? Engineers and
scientists have in their capable hands the possibility of transforming the world by
modifying the materials and the processes that we use every day to manufacture the
products we buy and the way we conduct business. However, innovation and progress
need to be set in the context of their implications beyond the laboratory or the
manufacturing plant. With the ability to effect change comes the responsibility to ensure
that the new materials, processes, and designs have a minimum (or positive) overall
environmental impact. In addition, common sense suggests that there is a strong business
case for green chemistry and engineering: linked primarily to higher efficiencies, better
utilization of resources, use of less hazardous chemicals, lower waste treatment costs, and
fewer accidents.
Need to control exposure, separate,
recovery, not in salable product Energy expenditure, potential for safety issues
A Bsolvent, heat
C D+
Need separations train to purify product
+catalyst
+
Loss ofExpensive,
heavy metals?
A D+ E
Creation of competing reactionsreactant
nonvaluable by-products = waste + Need for separation and
disposal. Toxic?
FIGURE 1.1 Simplified vision of some of the challenges and realities of designing a chemical
synthesis and process.
4 GREEN CHEMISTRYAND ENGINEERING IN THE CONTEXT OF SUSTAINABILITY
Example 1.1 Potassium hydroxide is manufactured by electrolysis of aqueous potassium
chloride brine,1 as illustrated by the following net reaction:
2KClþ 2H2O! 2KOHþCl2 þH2
How is this simple inorganic reaction different from themore complex challenges of the real
world? Identify some of the green chemistry/green engineering challenges.
Solution The electrolysis reaction can be carried out in diaphragm,membrane, ormercury
cell processes. The complexity of the reactions depend on the process that is used. Let’s
explore the mercury cell process, which has, historically, been the most commonly used
method to produce chlorine.1,2 In this case, potassium chloride is converted to a mercury
amalgam in a mercury cell evolving chlorine gas. The depleted brine is recycled to dissolve
the input KCl. The mercury amalgam passes from the mercury cell to the denuder. In the
denuder, fresh water is added for the reaction and as a solvent for the KOH. Hydrogen gas is
evolved from the reaction and mercury is recycled to the electrolysis cell:
Mercury cell : KClpotassium
chloride
þ Hgmercury
! K� Hgpotassium
mercury
amalgam
þ 0:5Cl2chlorine
Denuder : K� Hgpotassium
mercury
amalgam
þ H2Owater
! KOHpotassium
hydroxide
þ 0:5H2hydrogen
þ Hgmercury
Our simple net reaction has become a bit more complex, but it does not end there.We’ve
not talked about a key input— energy. Electricity is required to drive the reaction forward;
it represents themajor part of the energy requirement for these types of reactions, and there is
a need to optimize it.As amatter of fact, as of 2006 the chlor-alkali sectorwas the largest user
of electricity in the chemical industry.2
But energy is not the only thing that we need toworry about. In addition to energy inputs,
there is a need to eliminate impurities. To do that, the brine can be treated with potassium
carbonate3 to precipitatemagnesiumandheavymetals, andbariumcarbonate is oftenused to
precipitate sulfates.4Also, hydrochloric acid needs to be added, as an acidic pH is required to
drive the reaction to produce the desired chlorine gas, which can then be recovered from the
solution, as shown in the following equilibrium reaction:
Hþ þOCl� þHCl > H2OþCl2
Besides using a large quantity of electricity,we have toworry about potential emissions from
the reaction.Mercury is present in the reaction cell and the purged brine.Mercury emissions
from the cell and the brine have long been a target for significant reduction. The purged brine
is typically treatedwith sodiumhydrosulfide to precipitatemercury sulfide, and themercury-
containing solid wastes need to be sent for mercury recovery. Other emission concerns
includemanagement of the environmental, health, and safety (EHS) challenges related to the
gases in the reactions.Both the chlorine andhydrogengas streamsmust be processed further.
Chlorine is cooledandscrubbedwith sulfuric acid to removewater, followedbycompression
and refrigeration. The hydrogen gas is cooled to remove water, impurities, and mercury,
WHY GREEN CHEMISTRY? 5
followed by further cooling or treatment with activated carbon for more complete mercury
removal.5 In addition, hydrogen is often burned as fuel at chlor-alkali plants.
The membrane process was introduced in the 1970s and it is more energy efficient and
more environmentally sustainable, which is making it the technology of choice. However, a
typicalmercury-basedplant can containup to100cells andhas an economic life spanof 40 to
60 years. A long phase-out is required to convert an existing mercury plant. For example, as
of 2005, 48% of the European chlor-alkali capacity was mercury cell–based.2
Additional Point to Ponder Chemistries and processes described in most textbooks
normally don’t give you all the information you need to consider the mass and energy
inputs and outputs associatedwith a given reaction. In reality youwon’t always have the data
you need and will have to use estimations to generate data, run experiments, perhaps use
“nearest neighbor” approaches and/or make assumptions based on your experience.
Sometimes, you will just have to use “simple” common sense.
1.2 GREEN CHEMISTRY, GREEN ENGINEERING, AND SUSTAINABILITY
The modern understanding of sustainability began with the United Nations World Com-
missiononEnvironment andDevelopment’s reportOurCommonFuture,6 alsoknownas the
Brundtland Report. The Brundtland Commission described sustainable development as
“development thatmeets the needs of the present without compromising the ability of future
generations tomeet their own needs.”What does this actually mean? This definition doesn’t
give us many clues or supply much practical guidance as to how to implement sustainable
development or move toward more sustainable activities, but it does provide us with a
powerful aspiration. It has been up to society collectively and up to us as individuals to
develop guidance and tools that will help us to design systems and processes that have the
potential to achieve the type of development described in the definition.
The first thing to remember is that sustainability or sustainable development is a complex
concept with which many people are still attempting to come to terms. In 1998, John
Elkington, one of the early innovators of sustainable development, coined the phrase triple
bottom line.7 Elkington did this in an attempt to make sustainable development more
understandable and palatable to business people, to encourage them to see it as a logical
extension of the traditional business focus on economic performance. By using this term,
Elkington was trying to highlight the need to consider the intricate nterrelationships among
environmental, social, and economic aspects of human society and the world. In a way,
sustainability can be seen as a very delicate balancing act among these three factors, and not
always with a strong one-to-one relationship. Table 1.1 provides a summary of several
approaches to sustainable development principles. It should be noted that the Carnoules
statement includes an organizational principle framework, in addition to the overarching
social aspects widely recognized to be an integral part of sustainability. This organizational
principle is usefulwhen relating the operational aspects of sustainabilitywithin the sphere of
controls defined by company culture and policy.
When talking about sustainability, one cannot focus on only a single aspect, as this
necessarily limits and biases one’s view. For a system to be sustainable, there is the need to
balance, insofar as possible, social, economic, and environmental aspects, ideally having
each area “in theblack,” that is,with no single aspect optimized to thedetriment of the others.
6 GREEN CHEMISTRYAND ENGINEERING IN THE CONTEXT OF SUSTAINABILITY
TABLE 1.1 Summary of Several Approaches to Sustainable Development Principles
Alcoa8International Chamber
of Commerce9 Chemical Associations10 Carnoules Statement11 Hanover Principles12 Natural Step13 UN Global Compact14
Supporting the
growth of
customer
businesses.
Standing among the
industrial
companies in the
first quintile of
return on capital
among S&P
Industrials Index
companies.
Elimination of all
injuries and
work-related
illnesses and the
elimination of
waste.
Integration of
EHS with
manufacturing.
Products designed for
the environment.
EHS as a core value.
An incident-free
workplace (an
incident is any
unpredicted event
with the capacity to
harm human
health, the
environmental, or
physical property).
Corporate priority: To
recognize environmental
management as among the
highest corporate priorities
and as a key determinant to
sustainable development;
to establish policies,
programs, and practices
for conducting operations
in an environmentally
sound manner.
Integrated management:
To integrate these policies,
programs, and practices
fully into each business as
an essential element of
management in all its
functions.
Process of improvement:
To continue to improve
corporate policies,
programs, and
environmental
performance, taking
into account technical
developments, scientific
understanding, consumer
needs, and community
expectations, with legal
regulations as a starting
point; and to apply the same
environmental criteria
internationally.
Responsible Care
Policy:Wewill have a health,
safety, and Environmental
(HS&E) policy that will
reflect our commitment and
be an integral part of our
overall business policy.
Employee involvement: We
recognize that the
involvement and
commitment of our
employees and associates
will be essential to the
achievement of our
objectives. We will adopt
communication and
training programs aimed at
achieving that involvement
and commitment.
Experience sharing: In
addition to ensuring that
our activities meet the
relevant statutory
obligations, we will share
experience with our
industry colleagues and
seek to learn from and
incorporate best practice
into our own activities.
Legislators and regulators:
We will seek to work in
cooperationwith legislators
and regulators.
Environmental Principles
Protect ecosystems’ functions
and evolution.
Enhance (genetic, species,
and ecosystem)
biodiversity.
Reduce anthropogenic
resource throughput and
degradation of land and sea.
Minimize the burden for
the environment: Improve
resource productivity
(mass, energy, land).
Minimize the impacts on
health and environment:
minimize the outputs of
known (eco)toxics.
Minimize damage for the
economy: reduce costs
related to environmental
degradation (damage costs,
compliance costs,
administrative costs,
avoidance costs, etc.).
Social Principles
Social cohesion and social
security.
Insist on rights of
humanity and nature to
coexist in a healthy,
supportive, diverse,
and sustainable
condition.
Recognize
interdependence. The
elements of human
design interact with
and depend on the
natural world, with
broad and diverse
implications at every
scale. Expand design
considerations to
recognize even distant
effects.
Respect relationships
between spirit and
matter. Consider all
aspects of human
settlement, including
community, dwelling,
industry, and trade in
terms of existing and
evolving connections
between spiritual and
material
consciousness.
System condition 1:
Substances from the
Earth’s crust must not
increase in nature
systematically. In a
sustainable society,
natural resources
should not be extracted
at a faster pace than
their re-deposit into the
ground.
System condition 2:
Substances produced
by society must not
increase in nature
systematically.
In a sustainable society,
man-made substances
should not be produced
at a faster pace than
they can be naturally
degraded or
re-deposited into
the ground.
System condition 3: The
physical basis for the
productivity and
diversity of naturemust
not be diminished
systematically.
To support and respect the
protection of
internationally
proclaimed human
rights.
To avoid complicity in
human rights abuses.
To uphold freedom of
association and the
effective recognition of
the right to collective
bargaining.
To eliminate all forms of
forced and compulsory
labor.
To effectively abolish
child labor.
To eliminate
discrimination with
respect to employment
and occupation.
To support a
precautionary
approach to
environmental
challenges.
To promote greater
environmental
responsibility.
(continued )
7
TABLE 1.1 (Continued )
Alcoa8International Chamber
of Commerce9 Chemical Associations10 Carnoules Statement11 Hanover Principles12 Natural Step13 UN Global Compact14
Increased
transparency and
closer
collaboration in
community-based
EHS initiatives.
Employee education: To
educate, train, and motivate
employees to conduct their
activities in an
environmentally
responsible manner.
Prior assessment: To assess
environmental impacts
before starting a new
activity or project and
before decommissioning a
facility or leaving a site.
Products and services: To
develop and provide
products or services that
have no undue
environmental impact and
are safe in their intended
use, that are efficient in
their consumption of
energy and natural
resources, and that can be
recycled, reused, or
disposed of safely.
Customer advice: To advise
and, where relevant,
educate customers,
distributors, and the public
in the safe use,
transportation, storage, and
disposal of products
provided; and to apply
similar considerations to
the provision of services.
Process safety:Wewill assess
and manage the risks
associated with our
processes.
Product stewardship:Wewill
assess the risks associated
with our products and seek
to ensure that these risks are
properly managed
throughout the supply chain
through stewardship
programs involving our
customers, suppliers, and
distributors.
Resource conservation: We
will work to conserve
resources and reduce waste
in all our activities.
Stakeholder engagement:We
will monitor our HS&E
performance and report
progress to stakeholders;
we will listen to the
appropriate communities
and engage them in
dialogue about our
activities and our products.
Access to education.
Identity and self-realization.
Security.
Equitable access to food,
drinking water, and natural
resources.
Healthy and secure shelter.
Readjusted demand for
resource consumption, and
the environmental impact
of household consumption.
Secure environmental quality
for the health of human
beings.
Economic Principles
Sufficient supply and goods
and services
Efficient wealth creation
Economic system’s evolution
and competitiveness
Enhance the distributional
justice (equity principle)
Efforts (paid and unpaid)
should be devoted fairly to
generate sustainable
incomes.
Provide opportunities for paid
labor to all willing and able
to work.
Increase knowledge intensity.
Refocus innovation and adapt
its speed to societal
demands.
Accept responsibility for
the consequences of
design decisions on
human well-being, the
health of natural
systems, and their right
to coexist.
Create safe objects of
long-term value. Do
not burden future
generations with
requirements for
maintenance or
vigilant administration
of potential danger due
to the careless creation
of products, processes,
or standards.
Eliminate the concept of
waste. Evaluate and
optimize the full life
cycle of products and
processes to approach
the state of natural
systems in which there
is no waste.
Rely on natural energy
flows. Human designs
should, like the living
world, derive their
creative forces from
perpetual solar income.
Incorporate this energy
efficiently and safely
for responsible use.
In a sustainable society,
nature’s productivity
should not be
diminished in either
quality or quantity, nor
should more be
harvested than can be
recreated.
System condition 4:
We must be fair and
efficient in meeting
basic human needs.
In a sustainable society,
basic human needs
must be met with the
most resource-efficient
methods possible,
including the just
distribution of
resources.
To encourage the
development and
diffusion of
environmentally
friendly technologies.
8
Facilities and operations: To
develop, design, and
operate facilities and
conduct activities taking
into consideration the
efficient use of energy and
materials, the sustainable
use of renewable resources,
theminimization of adverse
environmental impact and
waste generation, and the
safe and responsible
disposal of residual wastes.
Research: To conduct or
support research on the
environmental impacts of
raw materials, products,
processes, emissions, and
wastes associated with the
enterprise and on the means
of minimizing such adverse
impacts.
Precautionary approach: To
modify the manufacture,
marketing, or use of
products or services or the
conduct of activities,
consistent with scientific
and technical
understanding, to prevent
serious or irreversible
environmental degradation.
Management systems: We
will maintain documented
management systems
which are consistent with
the principles of
responsible care and which
will be subject to a formal
verification procedure.
Past, present, and future:
Our responsible care
management systems will
address the impact of both
current and past activities.
Social Principles
Ethical trade: to ensure that
all business, wherever
companies trade, is
conducted to the highest
global ethical standards.
Public understanding: to play
their part in helping people
understand and appreciate
relevant science and
technology.
Part of the community: to play
an active role in their
communities by interacting
with schools, local
government, and other
bodies.
Organizational Principles
Ensure structural change to
reflect the need for societal
development.
Improve societal interchange,
communication, and
intercultural learning.
Protect cultural diversity
Achieve distributional
fairness and justice, equity
and sufficiency.
Develop anticipatory
capacities for the
democratic process.
Understand the limitation
of design. No human
creation lasts forever
and design does not
solve all problems.
Those who create and
plan should practice
humility in the face of
nature. Treat nature as
a model and mentor,
not as an
inconvenience to be
evaded or controlled.
Seek constant
improvement by the
sharing of knowledge.
Encourage direct and
open communication
among colleagues,
patrons,
manufacturers, and
users to link long-term
sustainable
considerations with
ethical responsibility,
and reestablish the
integral relationship
between natural
processes and human
activity.
(continued )
9
TABLE 1.1 (Continued )
Alcoa8International Chamber
of Commerce9 Chemical Associations10 Carnoules Statement11 Hanover Principles12 Natural Step13 UN Global Compact14
Contractors and suppliers: To
promote the adoption of
these principles by
contractors acting on behalf
of the enterprise,
encouraging and, where
appropriate, requiring
improvements in their
practices to make them
consistent with those of the
enterprise; and to
encourage the wider
adoption of these principles
by suppliers.
Emergency preparedness: To
develop and maintain,
where significant hazards
exist, emergency
preparedness plans in
conjunction with the
emergency services,
relevant authorities, and the
local community,
recognizing potential
transboundary impacts.
Transfer of technology: To
contribute to the transfer of
environmentally sound
technology and
management methods
throughout the industrial
and public sectors.
Employability: to ensure that
all employees have access to
training and development
opportunities to enable
them to fulfill their role in
the organization and to keep
them up to date with the
labor market.
Equality of treatment and
opportunity: to ensure that
all employees are free from
discrimination and have the
opportunity to develop their
careers and themselves,
subject only to business
needs and personal ability.
Participation: to ensure that
all employees have access to
the information needed for
them to do their job, be
consulted about matters that
affect them, and have the
opportunity to participate, to
the appropriate level, in the
management of their company.
Balance between work and life:
to provide all employees with
the opportunity to balance the
requirements of their work and
their life outside work so as to
enhance work effectiveness
and personal well-being.
10
Contributing to the common
effort: To contribute to the
development of public
policy and to business,
governmental and
intergovernmental
programs, and educational
initiatives that will enhance
environmental awareness
and protection.
Openness to concerns: To
foster openness and
dialogue with employees
and the public, anticipating
and responding to their
concerns about the
potential hazards and
impacts of operations,
products, wastes, or
services, including those of
transboundary or global
significance.
Compliance and reporting:
To measure environmental
performance; to conduct
regular environmental
audits and assessments of
compliance with company
requirements, legal
requirements, and these
principles; and periodically
to provide appropriate
information to the board of
directors, shareholders,
employees, the authorities
and the public.
Economic Principles
Sustainable profitability:
generating profits to satisfy
shareholders’ expectations
and to invest in the future
through R&D, capital
expenditure, and employee
development.
Competitiveness: achieving
long-term competitiveness
through the spread of
international best practice,
in a climate of fair
competition
Innovation: continuing to
research, develop, and
market innovative products
that help improve economic
well-being and quality of
life.
Wealth generation:
generating wealth, thereby
sustaining employment,
improving the UK’s trade
balance, and contributing to
government revenue to fund
public expenditure.
Economic growth: continuing
their key role in supporting
sustained UK economic
growth throughout the entire
manufacturing supply chain.
Resource efficiency: making the
most efficient use of resources,
whether they be land,water, raw
materials, or energy.
11
One of the most puzzling, challenging, and exciting characteristics in the study of
sustainability is the inherent complexity of the concept. There are synergies, trade-offs,
a variety of shared values of what constitutes a sustainable practice, and so on. Figure 1.2
displays those interrelations graphically.
Green chemistry and green engineering represent some of the many concepts, tools,
and disciplines that come into play in helping to move society toward more sustainable
practices. They do this by focusing scientists and engineers on how to design more
environmentally friendly, more efficient, and inherently safer chemistries and manufactur-
ing processes. However, some might suggest that when talking about green chemistry and
green engineering in the context of sustainable development, we can honestly say simply
that the primary focus area is what has come to be known as environmental sustainability.
Is this really true? Whereas green chemistry and green engineering may be seen as being
related primarily to the environmental aspects of sustainability, they also have strong ties
to the eco-environmental (or eco-efficiency) sub-area of sustainability by virtue of the fact
that they include resource conservation and efficiency. By the same token, green chemistry
and green engineering are related to the social aspects of sustainability because
they promote the design of manufacturing processes that are inherently safer, thereby
ensuring that workers and residential neighborhoods close to manufacturing sites are
protected.
Example 1.2 Explain how reaction (1.1) relates to the three aspects of sustainability.
Solution Several of the issues related to green chemistry and green engineering were
highlighted in the solution to Example 1.1. Table 1.2 provides examples of how they relate to
the three aspects of sustainability.
Sustainability
Vision
Social - Internal/
Organizational
Eco
no
mic
Environmental
Socioeconomic Organizational - Societal
SocioenvironmentalEcoenvironmental
So
cia
l -
Exte
rnal
FIGURE 1.2 Spheres of action of sustainability.
12 GREEN CHEMISTRYAND ENGINEERING IN THE CONTEXT OF SUSTAINABILITY
Additional Point to Ponder Most textbook examples and problems have only one correct
answer, althoughmany examples have several possible answers. In real-worldmanufacturing
processes, it is common to have difficulties in defining what the true problem is—and when
this is defined, several “not-quite-optimal” answers may be found. When this happens, a
decision must be made that accounts for or balances all the important factors and, hopefully,
leads to the optimal or “best” answer.
1.3 UNTIL DEATH DO US PART: A MARRIAGE OF DISCIPLINES
What does it mean to have an integrated perspective between green chemistry and green
engineering? Just imagine the following not-so-hypothetical scenario. A chemist works at a
large company and after years of hardwork discovers a novel synthesis to produce a valuable
material. At this point, hundreds of engineering questions are formulated and need to be
addressed, such as:
. What is the best design for the reactor? Which material?
. Does the reaction need to be heated? Cooled? How fast are heating and cooling
transferred?
. What types of separation processes are needed?
. How could the desired purity be achieved?
. How fast is the reaction? Is there a risk of an exothermic runaway?
. What can possibly go wrong? How can we prepare for problems?
TABLE 1.2 Issues Related to Sustainability
Environmental Social Economic
Mercury emissions from a cell
and in the purged brine
Worker safety issues related to
chlorine and hydrogen
management
Jobs and wealth created by a
potassium chloride plant
Energy consumption Safety and well-being of
communities adjacent to
manufacturing plant
Economic resources needed to
operate the plant in a safe
and efficient manner
Water consumption
Emissions released during
energy production
Potential for process
accidents, incidents, and
lost-time injuries
Investment that will be
necessary to replace
mercury cells for an
alternative technology
Fugitive chlorine emissions
Waste management of
carbonate precipitates
Issues related to safely
transporting chlorine
Supply chain implications for
other products that utilize
KCl or chlorine
Environmental impacts
resulting from mercury
mining
Working conditions in
mercury mines to extract
the metal
UNTIL DEATH DO US PART: A MARRIAGE OF DISCIPLINES 13
. Are there inherent hazards in the materials?
. Are there any incompatibilities with materials?
. How much waste is produced? How toxic is it? Can it be avoided?
. Where should the reactants be procured? Is it more efficient to make them or to buy
them?
. How much would this process cost?
. What types of preparations and skills would future operators need?
Imagine how difficult it would be to answer these and other questions if the chemist
doesn’t work closely with a chemical engineer. How efficient would the final process be? To
truly understand the impacts of this novel chemistry in the real-world manufacturing
environment, the chemist will need to involve engineers beginning at the earliest stages
of development.
Similarly, a chemical engineer working on transforming a laboratory synthesis into a
scalable, effective production process will need to collaborate closely with a chemist to
understand how the chemical synthesis might be changed. A myriad of chemically related
questions must be answered to design and scale-up a good manufacturing process:
. What function is the solvent performing in the reaction?
. Are there alternative reaction pathways that can be used to:
Avoid uncontrollable exotherms?
Substitute reactant A for B to avoid safety issues?
Eliminate hazardous reagents?
. If we recirculate part or all of the reaction mother liquors, howmuch of material X can
be tolerated by the reaction system before we are not able to do this?
. Are there any reactivity issues by introducing solvent Y as a mass separating agent?
. What are the potential side reactions?
. Are there any alternative catalytic methods that we might be able to use?
The decisions that are made in the design of synthetic chemistry pathways affect and
either enableor restrict the engineeringopportunities, andviceversa.Chemists and chemical
engineers should operate in an integrated fashion if the goal is to design an efficient process,
in the widest sense of the term and in the context of green chemistry and engineering.
Hopefully, we have made a good case for integrating green chemistry and green
engineering, but our effort to integrate disciplines is not over. Carrying on with our
original scenario, the chemist and engineer have successfully identified a chemical they
want to make and the synthetic route or pathway to be used to make it, and have some idea
of the critical process parameters that they need to focus on if they are to optimize the
process from a green chemistry and green engineering perspective. So, is anythingmissing?
What about knowledge of how the various reactants, reagents, catalysts, solvents,
by-products, and so on, used in the process affect living organisms and the environment?
One might be tempted to ask who really cares about such things, since most of the materials
may be consumed in the process and the product we are making is a valuable material that
others need or want.
14 GREEN CHEMISTRYAND ENGINEERING IN THE CONTEXT OF SUSTAINABILITY