Slide Thesis Maulidan Firdaus

By: Dr.rer. nat. Maulidan Firdaus, M.Sc.GREEN CHEMISTRYUNSSebelas Maret University

GREEN CHEMISTRY, AN INTRODUCTIONUNSSebelas Maret University

Green Chemistry,

Sustainable Chemistry, Clean Chemistry,

Environmentally Benign Chemistry

GREEN CHEMISTRY, AN INTRODUCTIONUNSSebelas Maret University

CHEMISTRY - PAST, PRESENT, AND FUTURE

An exaggerated but illustrative view of twentieth century chemical manufacturing can be written as a recipe :Start with a petroleum-based feedstock.Dissolve it in a solvent.Add a reagent.React to form an intermediate chemical.Repeat (2)(4) several times until the final product is obtained; discard all waste and spent reagent; recycle solvent.Transport the product worldwide, often for long-term storage.Release the product into the ecosystem without proper evalua- tion of its long-term effects, ex: DDT.

Grashopper Effect Bioaccumulation Biomagnification BiodegradationDDTDDTwindDDTDDTSource: Majewski et al, 1995 UNSSebelas Maret University

DDTACID RAIN ??? UNSSebelas Maret University

Major sources of pollution: Industrial furnaces: SO2, NOx WHAT IS THE EFFECT OF THE INPUT OF ACIDITY ON THE SOIL:This depends on the soil minerals, the input quantity, and time. First the forests react with more growth! Nitrogen and sulfur are macronutrients! Eventually, however, the soil chemistry changes dramatically.

The problem which arises now is the Aluminum from the silicate weathering. At an pH of ~ 5, the Al from the minerals is converted to aluminum hydroxide Al(OH)3. This compound can enter the root cytoplasm, forming complexes and interfere with the cell metabolism like heavy metals.

If, however, the acid input continues further, then the following reaction takes place: Al (OH)3 + 3 H+ Al3+ + 3 H2O

This takes place at an pH of about 4.2 Al3+ binds to the carboxyl groups of the pectin of the cell walls of the root cortex of the forest trees and inhibits the uptake of Ca2+ and Mg2+.

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CHEMISTRY - PAST, PRESENT, AND FUTURE

The recipe for the twenty-first century will be very different:

Design the molecule to have minimal impact on the environment (short residence time, biodegradable).Manufacture from a renewable feedstock (e.g. plant oils, carbohydrate, etc)Use a long-life catalyst.Use no solvent or a totally recyclable benign solvent.Use the smallest possible number of steps in the synthesis.Manufacture the product as required and as close as possible to where it is required.

Reduction of p-Anisaldehyde (3) to 4-Methoxybenzyl alcohol (4) UNSSebelas Maret University

Bromination of 4-Methoxybenzyl alcohol (4)

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Comparison of Synthetic Procedure for the Transformation of p-Anisaldehyde to 4-methoxybenzyl bromide ReactionProcedureGreen MethodologySolution Phase MethodologyReduction of p-anisaldehyde- Solvent-free- Grinding at room temperature- Complete in 10 minutes- Yield 98% (Firdaus, 2008)- Large volume of solvent (~ 50 mL ethanol)- reflux at 80C for 3 hours- Yield 55% (Sardjono, 1999)Bromination of4-methoxybenzyl alcohol- Solvent-free- Stirring at -5C for 1 h to be followed at room temperature for 2 h- Yield 86% (Firdaus, 2008) - Large volume of solvent (~ 40 mL dichloromethane)- reflux at 40C for 4 hours- Yield 83% (Hadanu, 2008)UNSSebelas Maret University

GREEN CHEMISTRY DEFINITION Green chemistry is a form of pollution prevention. It is most simply defined as the use of chemistry techniques and methodologies that reduce or eliminate the use or generation of feedstocks, products, byproducts, solvents, reagents, etc. that are hazardous to human health or the environment

GREEN CHEMISTRY IS ABOUTWaste Minimization at SourceUse of Catalysts in place of ReagentsUsing Non-Toxic ReagentsUse of Renewable ResourcesImproved Atom EfficiencyUse of Solvent Free or Recyclable Environmentally Benign Solvent systems

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10Green Chemistry Is About...ReducingWasteMaterialsHazardEnvironmental ImpactCOSTRisk EnergyUNSSebelas Maret University

11Increasing GreennessPrevention & ReductionRecycling & ReuseTreatmentDisposalPollution Prevention HierarchyUNSSebelas Maret University

12From an economic standpoint, the green chemistry approach has many advantages. The costs associated with regulatory compliance including factors such as waste treatment, disposal costs, and waste control. Environmental compliance budgets of individual chemical companies often rival those funds chosen for research and development. On the other hand, implementation of green procedures could potentially suc- ceed in lowering feedstock costs, increasing conversion rates, decreasing reaction times, improving selectivity, enhancing separations, and lowering the energy required for reactions. As a result, industry could experience significant financial gain if green methods were to be successfully adopted.THE ECONOMICS OF GREEN CHEMISTRYUNSSebelas Maret University

APPLICATIONS IN ACADEMIA

Although the major portion of chemical waste produced comes from industry, significant amounts of hazardous materials are released into the environment by academic laboratories. Out of date procedures employing traditional and hazardous reagents are common, especially in undergraduate laboratories. While the adoption of microscale techniques has substantially improved the environmental position of academic laboratories, a considerable problem still remains. Disposal costs often comprise a large portion of a departments budget. In addition to the financial drain placed on the chemistry department, the use and produc- tion of hazardous waste pose a constant danger for the student. Little progress, however, has been made in transforming the academic labora-tory into a space that is environmentally sound.UNSSebelas Maret University