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Rakennuspalikoita luonnostaihmisen hyvinvointiin ja terveyteen

vihreän kemian keinoinKristiina WähäläKestävä kemia –

mahdollisuuksia vihreään kasvuun24. 5. 2016 Helsinki, Finland

14.6.2016Matemaattis-luonnontieteellinen tiedekunta 1

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Rakennuspalikoita luonnostaihmisen hyvinvointiin ja terveyteen

vihreän kemian keinoinKristiina Wähälä

Kemian laitosHelsingin yliopisto

14.6.2016Matemaattis-luonnontieteellinen tiedekunta /Henkilön nimi / Esityksen nimi 2

Green Chemistry is the use of chemistry for pollutionprevention.

More specifically, Green Chemistry is the design of chemicalproducts and processes that are more environmentally benign.

Green Chemistry is a philosophy that seeks to reduce theenvironmental impact of chemical processes and products.

It can be considered as chemists aspiring to the principles ofSustainable Development – people, planet, profit.

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12 Principles of Green Chemistry1. Prevention of waste2. Atom economy3. Less Hazardous Chemical Syntheses4. Designing Safer Chemicals5. Safer Solvents and auxiliaries6. Energy Efficiency7. Renewable Feedstocks8. Reduce Derivatisation9. Catalysis10. Design for Degradation11. Real-time analysis for Pollution Prevention12. Inherently Safer Chemistry for Accident Prevention

14.6.2016 5Matemaattis-luonnontieteellinen tiedekunta /Henkilön nimi / Esityksen nimi

THE IDEAL SYNTHESIS

Atom economy

Simple

100 % yield

Availablematerials

Environmentallyacceptable

No wastedreagents

One step

Safe

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Solvent

• The compound present in greatest quantity is the solvent• Liquid at room temperature

• Choosing solvent• The effect that the solvent has on the chemical reaction’s

products, mechanism, rate of equilibrium• Stability of substrates, products and catalysts, transition

states, intermediates, in the solvent• Suitable liquid temperature range for useful reaction rates• Sufficient solvent volatility for removal from the product by

evaporation or distillation• Cost, which is a particularly important consideration when

scaling up for industrial applications

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Reactions in water

• Excellent solvent dissolving ionic compounds• Ability to form H-bonds• High boiling point, melting point, critical temperature 374

°C (CO2 311 °C)• Polar and therefore easy to separate from apolar solvents• Nonflammable and incombustible• Cheap and widely available• Odourless and colourless• Density is sufficiently different from most organic

substances to allow convenient separation

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Multiphasic Solvent Systems

• The poor solubility of organic compounds in water‒ 1. Addition of co-solvent‒ 2. Rapid stirring, ultrasound, mw, heating‒ 3. Use of detergents and surfactants‒ 4. Phase Transfer Catalysts

• Aqueous-organic biphasic catalysis is the mostextensively studied biphasic method: hydrogenations,hydroformylations, oxidations, C-C coupling, olefinmetathesis and polymerizations

• Although out of fashion for many years, stoichiometricorganic reactions are also becoming increasinglycommon in water

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Supercritical fluids

• Carbon dioxide• Chemically inert, nonflammable, nonprotic, inert to

radical and oxidizing conditions, non toxic, althoughgreenhouse gas, can be obtained in large quantities asa by-product of fermentation and is easily exacted fromthe atmosphere

• Facile separation of products• Pharmaceutical industry, cosmetics, food and

electronics• Steel reactors

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Key Features of Ionic Liquids

• Liquid range of 300 °C (-96 - +200 °C)• Excellent solvents for organic, inorganic and polymeric

materials• Catalysts as well as solvents• Highly solvating - low volumes used• No measurable vapour pressure• Non-flammable• Thermally stable under conditions up to 200 °C• Display Brønsted, Lewis and ‘super’ acidity• Electric conductivity• Biphasic systems possible• Liquid crystalline structures

Ionic Liquids: “Designer” Solvents for Green Synthesis by Kenneth R. Seddon ,ChemFiles, Enabling Technologies, Ionic Liquids, Vol. 5, 2005

www.helsinki.fi/yliopisto 14.6.2016 11

C-HCATLAB

K. Chernichenko, Timo Repo, et al. JACS, 2016, 4060 - 4068.

Ansa-aminoboranes

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Organic chemistry synthesis

• Friedel-Crafts alkylationand acylation

• Heck ja Suzuki coupling• Oxidation and reduction

reactions• Asymmetric

hydrogenation• Oligomerization and

polymerization

• Cracking• Arom. sulfonation, nitration,

halogenation• Diazonisation• Diels-Alder-reactions• N-ja O-alkylations• Aldol- condensation

Enzymes

chemical catalysis

Jussi Sipilä, Annele Hatakka, Kristiina Hilden, Ronald de Vries, Paula NousiainenUniversity of Helsinki

Lignin valorization

14.6.2016 14

Wood harvesting waste

Stilbenes and lignans from roots of Norway spruce

LuKe

Latva-Mäenpää H., Laakso T., Sarjala T., Wähälä K. & Saranpää P. Trees 2013; Holzforschung 2013

14.6.2016 15Matemaattis-luonnontieteellinen tiedekunta /Henkilön nimi / Esityksen nimi

Latva-Mäenpää H., Laakso T., Sarjala T.,Wähälä K. & Saranpää P. Trees 2013;Holzforschung 2013

LuKe

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Cancer drugsSemisyntheticderivatives

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Betulin from the white outer barkof birch (up to 30% of dry weight)

Green Chem., 2016, 18, 516-523

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• In the laboratory or large scale synthesis of complex natural products,there are two major hurdles:• 1) first, the large number of reaction steps often needed, and• 2) the need for efficient stereocontrol in those steps.

• Consider a 20-step synthetic sequence, each proceeding in 50% yield. Theoverall yield is then 0.520 = 0,00009 %. For example then, 1000 moles ofthe starting material would give 0,09 moles of the product.

• Another problem is the stereochemistry consideration. Very often,laboratory reactions giving good enantiomeric purity are• 1) expensive and• 2) wasteful, whereas the compounds isolated from Nature are quite often the

pure enantiomers.

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Synthetic drugs versus naturalproduct