Post on 25-Feb-2016
description
Dr. Ed Marshall
Room: M220, RCS 1
e.marshall@imperial.ac.uk
www.ch.ic.ac.uk/marshall/4I10http://webct1.imperial.ac.uk
4.I10 Green Chemistry Lecture 1 Slide 1
Module 4I10: Green Chemistry
Lecture 1: An Introduction to Green Chemistry
Imperial CollegeLondon
Lecture 1: Learning Objectives
By the end of today's lecture you should:
(i) be able to define what is meant by the term Green Chemistry;
(ii) appreciate how Green Chemistry may be beneficial to industry;
(iii)understand that Green Chemistry is not an easy subject.
"We can't solve problems by using the same kind of thinking we used to create them."
4.I10-1-2
Albert Einstein (1879-1955)
Imperial CollegeLondon
So what is Green Chemistry?
Imagine you are at a party and you have to explain what Green Chemistry is to someone who isn't a chemist.
What would words are you going to use to tell them?
Scenario:
Imperial CollegeLondon
4.I10-1-3
Imperial CollegeLondonBrown Chemistry
Is this the public perception of the chemical industry?
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Brown Chemistry Imperial CollegeLondon
Cuyahoga River 1952 and 1969…
…major fires also happened in 1868 and 1936.
4.I10-1-5
Brown Chemistry – the UK’s worst chemical accident
Flixborough 1974
Imperial CollegeLondon
28 fatalities
40 tonnes cyclohexane released in 1 minute (225 °C, 10 atm)
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Brown Chemistry – the world’s worst chemical accident
Bhopal 1984
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Imperial CollegeLondon
Brown Chemistry
Is this reputation deserved?
Imperial CollegeLondon
4.I10-1-8
Imperial CollegeLondonWhy does the chemical industry need Green Chemistry?
The Chemical Industry has responsibilities:
to the environment
to the public
to shareholders
As legislation becomes stricter and as petrochemical feedstocks are depleted, so green chemical processes will become more cost effective.
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Imperial CollegeLondonClass exercise: Which is greener - Disposable or Cotton Nappies?
In groups of 4, discuss whether it is better to use disposable nappies (diapers) or reusable cotton nappies.
Results of Vote:
In favour of disposable:
In favour of cotton:
Far more importantly......what factors did you consider in your answer?
4.I10-1-10
Imperial CollegeLondonThe answer
In 2004 the UK Environment Agency concluded that there is…
"no significant difference between the environmental impactsof either nappy system, although the life cycle stages are different"
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Disposable Nappies - Simplified System Outline DiagramEnvironmental Resources
Ener
gy S
uppl
y
Environment (air, land and water)
Other Production Inputs
timber polymers acrylic acid NaOH packaging
pulp and bleaching
plastic components
super absorbantpolymer
disposablenappy
landfill
electricitygeneration
retail
recycle
domestic use landfillincineration
Home Laundered Cotton Nappies - again, simplifiedEnvironmental Resources
Ener
gy S
uppl
y
Environment (air, land and water)
Other Production Inputs
fertiliser
pesticide
cottoncultivation
cottonginning
cottonspinning
cotton productionand wet processing
cotton nappyother nappyconstruction
materialspackaging
retail
domestic usesewage treatment
packagingdisposal
electricitygeneration
water
detergentmanufacture
linermanufacture
Imperial CollegeLondonSo what factors do we need to consider?
4.I10 1 - 12
transportation(fuels, emissions)
waste and theenvironment
energy
Green Chemistry: a cradle to grave approach
productionprocess
i.e. conditions, risks, hazards
raw materials
solvents
other chemicalse.g. additives
Imperial CollegeLondonGreen Chemistry: A reductionary approach
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Materialsincluding
plant
Energy Waste
Risk andHazards
Toxicity
Impact onenvironment
Green Chemistry reduces…
Cost
Green Chemistry is not anti-industry
Imperial CollegeLondonDefinitions of Green Chemistry
“The reduction or elimination of the use or generation of hazardous substances in the design, manufacture and application of chemical products”
Green Chemistry theory and Practice - Anastas and Warner
“Green Chemistry underlies our commitment to potentially harmful technologies by developing alternative syntheses to prevent environmental pollution.”
Green Chemistry is not anti-industry
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Imperial CollegeLondonSummary of Lecture 1
By the end of today's lecture you should:
• be able to define what is meant by the term Green Chemistry:
• appreciate how Green Chemistry may be beneficial to industry:
• understand that Green Chemistry is not an easy subject:
Green Chemistry ultimately reduces cost and increases responsibility to the environment, the public and shareholders
The reduction or elimination of the use or generation of hazardous substances in the design, manufacture and
application of chemical products
Green Chemistry is a cradle to grave approach
4.I6 1 - 15
Imperial CollegeLondonWhat we will cover in lectures 2-8
Lecture 2: Metrics
Lecture 3: Catalysis
Lecture 4: Green Solvents
Lecture 5: Biofuels
Lecture 6: Biomass
Lecture 7: Biotechnology
Lecture 8: Hazards
4.I6 1 - 16
Imperial CollegeLondonFinally, here is one part of last year’s exam question
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Green Chemistry is often said to be a 'cradle to grave' approach. Explain what this term means with specific reference to the industrial production of polyethylene.
5 marks