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Martyn Poliakoff www.nottingham.ac.uk/supercritical
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China Cup
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Paper Cup
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Polystyrene Cup
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Which is best for the Environment? ChinaPaperPolystyene
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Coffee Cups - Manufacture China – most energy to make Polystyrene – made from oil Paper – made from wood, messy process Cost of Energy varies
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Coffee Cups- Use Polystyrene – use once Paper – use once China – multi-use BUT needs washing (hot water, detergent)
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Coffee Cups- Verdict You have to use a china cup 1000 times before it is environmentally better than Polystyrene
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Coffee Cups - Disposal China – landfill Polystyrene – landfill (125 times better) Paper – can be composted – generates CH 4 (greenhouse effect)
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One of the main problems in chemical manufacture is the generation/disposal of (toxic) waste
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Environmental acceptability: the E Factor Industrytons/yr E Oil refining10 6 - 10 8 ca. 0.1 Bulk Chemicals10 4 - 10 6 < 1 - 5 Fine Chemicals10 2 - 10 4 5 - 50 Pharmaceuticals10 - 10 3 25 - 100+ Roger A. Sheldon “Consider the Environmental Quotient” ChemTech, 1994, March, page 38. kgwaste/kgproduct
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Roger Sheldon
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Manufacture of Terephthalic Acid 26 Mtons per year world-wide 500,000 tons per year per plant CH 3 COOH O2O2 Catalyst
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DuPont (former ICI) – Wilton Manufacturing Terephthalic Acid
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Why not make fibres from Sheep?
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Fibre from Sheep 1 Sheep produces 3.5 kg wool/ year 500,000 tons of wool need 10 8 sheep 10 sheep need 1 acre of land 10 8 sheep need 10 7 acres (640 acres = 1 square mile) 10 8 sheep need 15,625 square miles
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Fibre Production Sheep need 15,625 square miles 1 TA plant needs 25 acres
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What is Green Chemistry? Carrying out chemical activities (design, manufacture, use and disposal) such that hazardous substances will not be used or generated
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Assessing Risk Risk = Hazard x Exposure What we do now Limit Exposure Acceptable Risk Green Chemistry if Hazard = 0 Risk = 0
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Areas of Green Chemistry New reactions New catalysts Alternative Feedstocks Safer Solvents
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Most solvents are Volatile Organic Compounds Fire / explosion hazards VOC emissions atmospheric pollution Disposal / recycle environmental pollution Solvents: the problems
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Fork Lift +Toluene ‘Big Bang’
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No solvent Water Ionic Liquids Supercritical Fluids Solvents: Alternatives
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Supercritical Fluids Gases e.g. CO 2, C 2 H 4, H 2 O compressed until they are nearly as dense as liquids SCFs can dissolve solids solubility increases with density (applied pressure)
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Decaffeination in scCO 2 Well established commercially
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Greener Hydrogenation + H2H2 Catalyst Solvent? Use Supercritical CO 2 CO 2 compressed until it is nearly as dense as a liquid ca. 200 atm
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Continuous Supercritical Hydrogenation
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Hydrogenation of Isophorone O Pd Deloxan® 100 bar, scCO 2 40-170°C + H 2 O scCO 2 - quantitative, no by-products The product & by-products have similar boiling points Conventional process requires an expensive downstream separation
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Dr Stephen Ross Thomas Swan & Co Ltd
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HeaterSub-cooler Hydraulic Power Unit CO 2 (liq) from Tank Work Tank Condenser Separator Pump Unit Products Reactor Reactants Flow diagram
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continuous multipurpose 1000 ton p.a. scCO 2 Chemical Plant
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The First Product! OO
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Isophorone Hydrogenation Product of saleable quality without downstream purification Optimized conditions: almost identical for lab (5 mL) and plant (1000 tons p.a.)
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Taking Green Chemistry to Developing Countries
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www.ethiopia.org.uk
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Sugar Cane
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Is it silly to make polymers out of sugar cane? Sugar cane is grown in huge amounts It grows where there is little oil There is a surplus The farmers cannot sell all of it No!!!
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Sugar Cane
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How to do it? “To make a bag from sugar needs new Chemistry” 2 nd July, 2003
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Polymers from Carbohydrate Microorganisms eat carbohydrate They store energy as a polymer Polymer is easily harvested Waste is recycled. Dr Isao Noda, Procter & Gamble
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P & G NODAX TM Polymer from carbohydrate
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Coffee Cups from Waste Carbohydrate Cups for US Navy Can be made on existing machines Composts in 2 days!
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Green Chemistry: What Now? 15 years old – growing fast Spreading all over the world Increasing industrial interest Needs lots of new ideas
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Live on the Web!! http://www.meta- fusion.com/kongress /costday2004/http://www.meta- fusion.com/kongress /costday2004/
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