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Solid Acid Catalysts ZEOLITE-CATALYZED FRIEDEL-CRAFTS ACYLATION O AlCl3 O + CH3COCl O solvent MeO + HCl MeO O O MeO H-beta + (CH3CO)2O O MeO + CH3CO2H ZEOLITE-CATALYZED FRIEDEL-CRAFTS ACYLATION Homogeneous AlCl3 >1 equivalent Solvent (recycle) Hydrolysis of products 85-95% yield 4.5 kg aqueous effluent per kg 12 unit operations Heterogeneous H-beta, catalytic & regenerable No solvent No water necessary >95% yield /higher purity 0.035 kg aqueous effluent per kg 3 unit operations S. Ratton, Chem. Today (Chim. Oggi), March/April, 1998, 33 SALT-FREE ESTERIFICATION OF AMINO ACIDS CONVENTIONAL: NH3+ NH3+ Cl O- HCl (1 eq.) OH R MeOH/HCl (cat.) O R + NH3 Cl - OMe + H2O R O O SALT-FREE ESTERIFICATION OF AMINO ACIDS ZEOLITE-CATALYZED: + NH2 NH3 O- OMe MeOH, H-USY, 100 C R + H2O O R O R = PhCH2 (aspartame intermediate); S/C = 20 (w/w), 83% yield (TON = 180) Naphtha cracking catalyst (H-USY) Opt. Active amino acids (partially) racemized M.Wegman, J.M.Elzinga, E.Neeleman, F.van Rantwijk and R.A.Sheldon, Green Chem., 3,61,2001 Catalytic Oxidations TS-1 CATALYZED OXIDATIONS WITH H2O2 Hydrophobic molecular sieve (5.6 x 5.3Å) / HI (Xoctane / XH2O) TS-1=3.4 ; Ti / SiO2=0.1 NOH O O NH3 R2CHOH R2C O TS - 1 + 30% H2O2 PhOH OH OH + OH OH Enichem B.Notari, Stud. Surf. Sci. Catal., 37 , 431 (1988) Cyclohexanone Oxime Manufacturing Process Current Process Ammoximation Process (NH4)2SO4 NOH O Oximation NOH Oximation O NH3 (NH3OH)2SO4 H2 H2O2 dil H2SO4 NO Air O2 NH3 H2 NH3 GREEN CHEMISTRY DEFINITION Green Chemistry is the utilisation of a set of principles that reduces or eliminates the use or generation of hazardous substances in the design, manufacture and application of chemical products . GREEN CHEMISTRY IS ABOUT • • • • • • Waste Minimisation at Source Use of Catalysts in place of Reagents Using Non-Toxic Reagents Use of Renewable Resources Improved Atom Efficiency Use of Solvent Free or Recyclable Environmentally Benign Solvent systems Green Chemistry Is About... Waste Materials Hazard Risk Energy Cost Why do we need Green Chemistry ? • Chemistry is undeniably a very prominent part of our daily lives. • Chemical developments also bring new environmental problems and harmful unexpected side effects, which result in the need for ‘greener’ chemical products. • A famous example is the pesticide DDT. • Green chemistry looks at pollution prevention on the molecular scale and is an extremely important area of Chemistry due to the importance of Chemistry in our world today and the implications it can show on our environment. • The Green Chemistry program supports the invention of more environmentally friendly chemical processes which reduce or even eliminate the generation of hazardous substances. • This program works very closely with the twelve principles of Green Chemistry. “It is better to prevent waste than to treat or clean up waste after it is formed” Chemical Process Human society is constantly facing such environmental issues and problems, air pollution, global climate change, soil and water pollution, acid rain, depletion of natural resources and accumulation of natural hazardous waste Green chemistry preventing pollution and sustaining the earth In this presentation the synthesis of ibuprofen by Friedel-crafts alkylation of isobutyl benzene with lactic acid and its derivatives was attmpted using various acid catalysts like Zn-Zeolite-Y, AlCl3/MCM-41, AlCl3/SiO2 Classic Route to Ibuprofen H C l, AcO H , Al W aste Ac 2 O Ac O H HCl H 2 O / H+ C lC H 2 C O 2 Et AlC l 3 Na O Et C OC H 3 EtO 2 C O HC O N H2 O H H 2 O / H+ N H O2C OHN Hoechst Route To Ibuprofen AcOH HF H2 / Ni CO, Pd Ac2O O HO HO2C IBUPROFEN OH Is this possible and if so how to effect this reaction catalytic? CH3 + COOH CH3 Lactic acid CH3 CH3 COOH CH3 First synthezised By the Boots company in Nottingham England in 1960s IBUPROFEN “The use of auxiliary substances (e.g. solvents, separation agents, etc.) should be made unnecessary wherever possible, and innocuous when used” “Energy requirements should be recognized for their environmental impacts and should be minimized. Synthetic methods should be conducted at ambient pressure and temperature” Heating Cooling Stirring Distillation Compression Pumping Separation Energy Requirement (electricity) GLOBAL WARMING Burn fossil fuel CO2 to atmosphere “A raw material of feedstock should be renewable rather than depleting wherever technically and economically practical” Non-renewable Renewable Resource Depletion • Renewable resources can be made increasingly viable technologically and economically through green chemistry. Biomass, Carbon dioxide, Nanoscience, Solar, Waste utilization Poly lactic acid (PLA) for plastics production Polyhydroxyalkanoates (PHA’s) The major uses of GREEN CHEMISTRY • • • • • Energy Global Change Resource Depletion Food Supply Toxics in the Environment ENERGY The vast majority of the energy generated in the world today is from non-renewable sources that damage the environment. Carbon dioxide Depletion of Ozone layer Effects of mining, drilling, etc Toxics ENERGY Green Chemistry will be essential in developing the alternatives for energy generation (photo-voltaics, hydrogen, fuel cells, bio-based fuels, etc.) as well as continue the path toward energy efficiency with catalysis and product design at the forefront. GLOBAL CHANGE • Concerns for climate change, oceanic temperature, stratospheric chemistry and global distillation can be addressed through the development and implementation of green chemistry technologies RESOURE DEPLETION Due to the over utilization of nonrenewable resources, natural resources are being depleted at an unsustainable rate. Fossil fuels are a central issue. RESOURCE DEPLETION Renewable resources can be made increasingly viable technologically and economically through green chemistry. Biomass Nanoscience & technology Solar Carbon dioxide Chitin Waste utilization FOOD SUPPLY While current food levels are sufficient, distribution is inadequate Agricultural methods are unsustainable Future food production intensity is needed. Green chemistry can address many food supply issues FOOD SUPPLY Green chemistry is developing: Pesticides which only affect target organisms and degrade to innocuous byproducts. Fertilizers and fertilizer adjuvants that are designed to minimize usage while maximizing effectiveness. Methods of using agricultural wastes for beneficial and profitable uses. TOXICS IN THE ENVIRONMENT Substances that are toxic to humans, the biosphere and all that sustains it, are currently still being released at a cost of life, health and sustainability. One of green chemistry’s greatest strengths is the ability to design for reduced hazard. Pollution Prevention Hierarchy Prevention & Reduction Recycling & Reuse Treatment Disposal DDT • However, DDT is soluble in organic solvents…. and thus in animal fat. DDT and or DDE have been detected in fat deposits of all birds and fish that have been analyzed including from those from desert regions or ocean depths. • In North America the average person has 3 ppm concentration of DDT/DDE in their body fat. DDT • Concerns regarding its possible long term health effects and its demonstrated damage to the life cycle of birds lead to the ban in most of western countries. • (U S 1973) CONCLUSION • Green chemistry Not a solution to all environmental problems But the most fundamental approach to preventing pollution