
Green Chemistry Milan Sanader Author, Nelson Chemistry
GREEN CHEMISTRY INVOLVES… • Reducing or eliminating the use or production of hazardous substances in the manufacture of chemical products • Considering the hazards of reagents as well as their properties
A GREEN CHEMICAL PROCESS IS “benign by design”
Principles of Green Chemistry • Preventing pollution makes more sense that treating it • Less toxic reagents are safer • Use less solvents • Design for energy efficiency
Use Renewable Feedstocks • Design Safer Chemicals • Use catalysis rather than stoichiometric reagents • Improve atom economy % of atoms in raw materials than make it into the final product
Less Hazardous Chemical Syntheses • Reduce Derivatives • Design for Degradation • Real-time analysis for Pollution Prevention
EXAMPLES OFGREEN CHEMISTRY Safer dry cleaning Replace chlorinated solvents like perchloroethylene (perc) with liquid carbon dioxide (CO2)
VIAGRA SYNTHESIS • Reduction in solvent from 1300 L/kg to 7 L/kg • Elimination of the solvent dichloromethane, CH2Cl2
Ibuprofen Synthesis Boot’s synthesis BHC synthesis 3 steps Catalysts Atom economy >90% • 6 steps • Atom economy: 40% • (40% of atoms in raw materials end up in product)
Battery Recycling Tonolli Canada
Flash Smelting Features: • Smelting occurs in an enriched oxygen atmosphere • Exothermic reactions fuel the smelter
Flash Smelting • Reduced fuel consumption • Energy released fuels the reaction • High yield of sulfur oxides – enough to make the conversion to sulfuric acid economically feasible • Use of scrubbing is minimized or eliminated
Green Chemistry Is About... Waste Materials Hazard Reducing Risk Energy Environmental Impact COST
Some Aspects of Green Chemistry Safer Reactions & Reagents Catalysis Solvent Replacement Separation Processes Green Chemistry Use of Renewable Feedstocks Energy Efficiency Waste Minimisation Process Intensification
IN SUMMARY,GREEN CHEMISTRY IS… • Based on proven chemistry • Cost effective • More sustainable = A “win-win” for business and the environment