Faster Greener Chemistry?
Catalyst synthesis and evaluation
A context based case study in Green / Sustainable
Chemistry
What is Context and Problem Based Learning (C/PBL)?
A teaching methodology that aims to increase student
engagement
Uses real-life applications of chemistry principles, techniques
and experiments
Problem scenarios which are ill-defined, and have a number
of satisfactory solutions.
Learners collaborate to solve problems, acquire new
knowledge and present the outcomes or product.
Provides the opportunity to develop valuable transferable
skills (see later).
Academic staff adopt the role of facilitator or guide.
Module Overview
Session 1: Workshop
Module induction
Session 2:
Laboratory
Session 3:
Laboratory
Planning laboratory
work
Synthesis of catalyst
ligand
Preparation of
catalyst
Session 6: Workshop
Cost, performance
and environmental
impact of reactions
Session 5:
Laboratory
Session 4:
Laboratory
Alternative
epoxidation method
Evaluation of catalyst
in epoxidation step
Session 7: Workshop
Session 8: Workshop
Feedback clinic
Group presentations
3
Scientific Skills
The scientific skills developed include:
• Adaptation of an experimental procedure from the literature.
• Effective time planning.
• Accurate record keeping in a laboratory notebook.
• Interpretation of experimental data and relevant scientific
literature.
• Use of chemical databases to find information on raw material
costing and on recent developments to improve the
environmental impact of the process (e.g. alternative conditions
for oxidation).
• Evaluation of the efficiency, relative costs and environmental
impact of the oxidation procedures used.
• Preparation of a scientific report and presentation.
Transferable Skills Developed
Team work:
work in groups to complete the tasks.
Organisation and
planning:
prepare procedures and plan effective use of time in the
laboratory.
Communication:
oral presentation and report writing.
Drawing conclusions
and
recommendations:
Justify decisions, assumptions and conclusions with
reference to results from other groups and supporting
literature.
Numeracy:
apply green chemistry metrics to experimental results.
Professional role &
responsibilities:
adopt role of a professional chemist to consider the
environmental impact & costing
Problem solving:
address the brief in the scenario presented.
Information
technology skills:
use a wiki to collaborate & develop ability to use wordprocessing, spreadsheet, presentation, chemical drawing
and library database software.
Metacognition:
reflect on the case study using the guidelines provided.
You will be asked to summarise your reflections
on the development of these transferable skills at
the end of the case study
Tools to help you
You have or will be provided with a Student Guide for
this project in which you will find:
• An overview of each workshop or laboratory session
and a summary of tasks to be completed during and
after it.
• Appendices containing guidelines for various aspects
of the work involved and literature review supplied by
HugePharma Ltd.
• Details about how the project will be assessed.
Your first task is to read the guide carefully.
Assessment of the Project (see Table 1 in student guide also)
Activity
Group /
individual
% mark
allocation
Contribution to group
(based on participation in lab and workshop
sessions, summaries of meetings and
contribution to group wiki)
Individual
10
OPTIONAL - Peer assessment by other
group members (frequency and quality of
contributions, both online and face-to-face)
Individual
5
Lab notebook and individual work submitted
on a weekly basis
Individual
30
Reflective piece
Individual
10
Final wiki report
(Criteria - content, accuracy, structure,
clarity, references to the literature)
Group
30
Presentation
(assessment by tutor, feedback from tutor
and peers - peer assessment is optional)
Group
15
Faster Greener Chemistry? - Context
You will adopt the role of a chemist employed in a campus
company that specialises in chemical catalysts, Chem Cat
Ltd. The company has been contracted to carry out work
for a large pharmaceutical multinational, HugePharma Ltd.
Your team will report to your laboratory manager according
to the brief outlined in a letter from HugePharma Ltd.
This brief requires that:
• a range of Mn-salen catalysts are prepared and
characterised,
• their performance in a reference reaction (epoxidation of
trans-stilbene) is evaluated and
• the costs and the environmental impact of the process,
and any alternatives suggested are assessed.
Green Chemistry Considerations
The pharmaceutical company have specifically
requested that green chemistry (also known as
sustainable chemistry) principles be implemented to
their full potential in the catalyst synthesis and in the
epoxidation process.
This is essential as they need to maintain their
Integrated Pollution Prevention and Control (IPPC)
licence.
(more information on the relevant European legislation
is available at the following website:
http://ec.europa.eu/environment/air/pollutants/stationary
/ippc/summary.htm )
What you need to do
Your group will need to devise and perform several
laboratory experiments to obtain the results required to
make a recommendation to HugePharma Ltd.
You will also need to analyse the results obtained to
assess the relative costs and the environmental impact
of these processes using suitable metrics.
A report and oral presentation are the means by which
your group will communicate your findings and
recommendations to HugePharma Ltd.
Green Chemistry and Sustainable Development
In 1987, sustainable development was defined by a United
Nations Commission on Environment as “...meeting the
needs of the present without compromising the ability of
future generations to meet their own needs”.[1]
To achieve sustainable development, synthesis should be
optimised to maximise yields, minimise waste and reduce
use of toxic reagents or those in short supply. These
changes are components of the field of green chemistry.
In 1996, IUPAC defined Green Chemistry as “the invention,
design and application of chemical products and processes
to reduce or to eliminate the use and generation of
hazardous substances”.[2]
[1]
[2]
M. Lancaster, Green Chemistry : An Introductory Text Cambridge : Royal Society of Chemistry, 2002.
P. Anastas and P. Tundo, Green Chemistry: Challenging Perspectives, Oxford University Press, 2000.
Twelve Principles of Green Chemistry
The aims of green chemistry are summarised in the
“Twelve Principles of Green Chemistry”*
It is better to prevent waste than to treat or clean up waste after it is
formed.
Synthetic methods should be designed to maximize the incorporation of
all materials used in the process into the final product.
Wherever practicable, synthetic methodologies should be designed to use
and generate substances that possess little or no toxicity to human
health and the environment.
Chemical products should be designed to preserve efficacy of function
while reducing toxicity.
The use of auxiliary substances should be made unnecessary wherever
possible, and innocuous when used.
Energy requirements should be recognised for their environmental and
economic impacts, and should be minimised. Synthetic methods should
be conducted at ambient temperature and pressure.
Twelve Principles of Green Chemistry*
continued
A raw material or feedstock should be renewable rather than
depleting wherever technically and economically practicable.
Unnecessary derivatisation should be avoided whenever
possible.
Catalytic reagents are superior to stoichiometric
reagents.
Chemical products should be designed so that at the end of their
function they do not persist in the environment and break down
into innocuous degradation products.
Analytical methodologies need to be further developed to allow
for real-time, in-process monitoring and control prior to the
formation of hazardous substances.
Substances and the form of a substance used in a chemical
process should be chosen so as to minimise the potential for
chemical accidents.
* P. Anastas and J. Warner, Green Chemistry: Theory and Practice, Oxford University Press, 1998.
Environmental Legislation
The European IPPC Directive requires that industrial and agricultural
activities with a high potential to pollute (e.g. energy industries,
production and processing of metals, mineral industry, chemical industry,
waste management, livestock farming) have a permit.
The conditions for issuing the permit require an organisation to:
• use all appropriate pollution-prevention measures, namely the best
available techniques (which produce the least waste, use less
hazardous substances, enable the substances generated to be
recovered and recycled, etc.);
• prevent all large-scale pollution;
• prevent, recycle or dispose of waste in the least polluting way possible;
• use energy efficiently;
• ensure accident prevention and damage limitation;
• return sites to their original state when the activity is over.
(from Directive 2008/1/EC of the European Parliament 15 January 2008, see
http://europa.eu/legislation_summaries/environment/waste_management/l28045_en.htm )
Environmental Legislation contd.
Guidance information on best available techniques (BAT) is
available in the form of reference documents for particular
activities, e.g. “Reference document on best available
techniques for the manufacture of organic fine chemicals”,
accessible from http://eippcb.jrc.ec.europa.eu/reference/
Most European countries require that organisations that
hold an IPPC licence prepare an Annual Environmental
Report (AER). These reports are made available publicly
(for example, see
http://www.epa.ie/terminalfour/ippc/index.jsp )
The Role of Catalysts
One of the 12 Principles of Green Chemistry is that;
Catalytic reagents are superior to stoichiometric
reagents.
The benefit of incorporating an efficient catalyst into the
process for manufacturing a chemical is very apparent
from the accounts from companies who have won Green
Chemistry awards;
e.g. Development of a catalytic synthesis of a treatment
for type 2 diabetes;
http://www.epa.gov/greenchemistry/pubs/pgcc/winners/g
spa06.html
Manganese-salen Complexes as Catalysts
Salts of Mn(III), particularly those that contain salen type
ligands (salen is bis(salicylaldehyde)ethylene diamine),
have been found to show catalytic activities of significant
interest.
These properties have had two main applications to date;
1. asymmetric epoxidation of alkenes (e.g. Jacobsen’s
catalyst) and oxidation of a range of organic substrates at
commercial scale,
2. development of synthetic enzymes (“synzymes”) which
can act either as catalases or superoxide dismutases.
The focus in this case is on the first application, although
the ability to effect asymmetric reactions will not be
evaluated as chiral substrates will not be employed.
Some Useful Resources
• The URL below links to a video in which Professor Martyn
Poliakoff explains the main principles of Green Chemistry;
http://www.youtube.com/watch?v=_KYiLFkMQ_E&feature=
player_embedded
• The literature review supplied by HugePharma Ltd., which
includes the following;
- Herbert C. Brown Award For Creative Work In Synthetic
Methods, Yarnell, A.; Chemical & Engineering News,
January 21 2008,86 (3), 57
- US Patent No. 6,031,115: Process for Preparing Epoxides
and International Patent No. WO 93/1706, D., Fedouloff,
M., Turner, G.; 2000; SmithKline Beecham plc, see
http://www.everypatent.com/comp/pat6031115.html
Getting Started in Your Group
• Keep an open mind and be prepared to listen.
• Avoid being dismissive or judgemental
• Be aware of your body language – avoid being
negative
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Stages in the Group Process
•
•
•
•
•
•
•
Get to know each other
Establish ground rules
Brainstorm
Agree tasks
Plan your timeline
Keep going
The final product
Guidelines above are based on: Chapter 3 in “Study and
Communication Skills for the Chemical Sciences”; Overton, T.,
Johnson, S., Scott, J.; Oxford University Press (2011)
20
Tools to help you : Using a wiki
• Each group will have their own wiki to allow effective
collaboration. Guidelines on how to use a wiki are
provided in Appendix 1 of your student guide and
should be consulted.
• You will add information to the wiki and your group will
need to meet face to face at least once in the period
between each lab or workshop session.
• At the end of the module, you will publish your final
team report directly from your wiki (i.e. your wiki will
become your final assignment).
• If you have not already been invited to your group
wiki, you need to give your email address to your tutor
by the end of Workshop 1.
Create new
pages and
upload files
Pages created
using project
headings
Introductory text
from tutor
Log of recent activity used to
monitor student contributions
22
Pages can be
edited and linked
to other pages
throughout the
wiki.
Use this space to explain to group members
reasoning for changes made
23
Using Your Wiki
Reminder:
• Create pages in your wiki corresponding with the
sections listed in the Appendix 1 in your student guide.
• You will add information to the wiki during and after
each workshop as you complete tasks.
• The wiki enables your tutor to track your progress and
give you regular feedback .
• The wiki keeps a record of individual contributions to
the group project.
Tools to help you: Oral Presentations
In Session 8, your group will give a presentation.
(see Appendix 6 in your student guide also)
When preparing a presentation, content should:
• Suit your audience (for this presentation, the
audience will be peers and academic staff)
• Be informative and interesting and a suitable length
In all cases, the presentation should be made as simple
and visually engaging as possible.
25
Guidelines
•
•
•
•
Keep slides simple - too much text turns your audience off
A picture speaks a thousand words
Use simple colours, large font where possible
Don’t (over) animate
•
Check that the slide can be read in the environment where you are going to speak
• Credit the source that a diagram or image comes from if
necessary and include references at the end.
• Face your audience and try not to read from cards
26
Structure of Presentation
• Beginning - introduce topic generally, remember
your audience
• Core - longest section containing key findings
• End - briefly summarise results, emphasising
main point and reflecting on theme
“Tell the audience what you're going to say, say it;
then tell them what you've said”.
Dale Carnegie (1888-1955), American writer.
27
Tasks to Complete Before Session 2
• Review the assessment criteria and schedule provided (Tables 1- 3).
• Read the project briefing pack.
• Meet as a group to agree on the list of actions for group. Progress
should then be reported on the wiki by the Recorder for this week by
the day specified.
• Become familiar with how to navigate the group wiki and how to add
and edit pages, add files and add comments. Add a Table of
Contents and a Group Planning and Communication main page (see
Appendix 1).
• Submit a group experimental procedure for the preparation of the
salen ligand using the wiki.
• Individually submit a short chemical safety assessment.
• Add information on the first experiment available in advance
(materials, equipment, literature reference etc.) to your lab
notebooks.
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