绿色化学教材课件Ch.ppt

Chapter 2:Chapter 2: Atom EconomyAtom Economy - Avoiding Waste 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng 100 % atom economy 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng OutlineOutline 2.1 Environmental Factor: EEnvironmental Factor: E 2.2 Where Does Chemical Waste Come From 2.3 Atom EconomyAtom Economy 2.4 Examples of Atom EconomyExamples of Atom Economy 2.52.5 Design Atom-Economic Reactions 2.12.1 Environmental Factor: E Environmental Factor: E Roger A.Sheldon in 1992 It is used to quantifyquantify the effects of production process to the environment Idea: All other compounds formed other than the target product are considered to be WASTEWASTE. 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng Environmental Environmental Factor:Factor: If the atom Utilization = 100% E = 0 The more waste formed, the higher of E and the more serious of the pollution 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng The Environmental FactorThe Environmental Factor IndustriesProduct tonnageE Petrol106 108 0.1 Bulk Chemicals 104 10 61 5 Fine Chemicals 102 1 045 50 Pharmacy10 10325 100 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng Sheldon, R. A. Green Chem., 2007, 9, 1273. Is the actual amount of waste formed in the process, including solvent losses, acids and bases used in work- up, process aids, and, in principle, waste from energy production. Can be derived from amount of raw materials purchased /amount of product sold, i.e., from the mass balance: E= raw materials-product/product. A good way to quickly show the enormity of the waste problem. The Environmental FactorThe Environmental Factor 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng 2.2 Where does chemical waste come from? 1. Stoichiometric Bronsted acid and bases - Aromatic nitrations with H2SO4 / HNO3 - Acid promoted rearrangements, e.g. Beckmann (H2SO4) - Base promoted condensations, e.g. Aldol (NaOH, NaOMe) 2. Stoichiometric Lewis acids - Friedel-Crafts acylation (AlCl3, ZnCl2, BF3) 3. Stoichiometric oxidants and reductants - Na2Cr2O7, KMnO4, MnO2; - LiAlH4, NaBH4, Zn, Fe/HCl 4. Halogenation and halogen replacement - Nucleophilic substitutions 5. Solvent losses - Air emissions & aqueous effluent 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng Barry Trost, Professor of Stanford University Commodity chemical producers typically practice good atom economy 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng 2.32.3 Atom Economy Atom Economy Fine chemical and pharmaceutical producers typically do not practice good atom economy Relatively low percentage of starting material atoms end up in final product Many atoms are wasted (form waste stream) Unconverted or unused raw material is paid for twice 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng The two main characteristics of chemical reaction with 100% The two main characteristics of chemical reaction with 100% atom utilization:atom utilization: The reactants could be fully utilized, and the resource could be most possibly used economically The waste could be minimized 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng Example 1: Methyl Methacrylate For the manufacture of polymethyl methacrylate acrylic plastics (PMMA) and PVC. Calculate the atom economy of the following ACH process: 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng 2.4 Examples of Atom Economy 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng Example 2: Ibuprofen 布洛芬 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng The Original Boots Synthesis of Ibuprofen 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng Summe: -7 C, 24 H, N, 8 O, Cl, Na Atom Economy of the Boots synthesis of ibuprofen 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng Reagents formula Reagents FW Utilized atoms Weight of utilized atoms Unutilized atomsWeight of unutilized atoms C10H1413410C, 13H133H1 C4H6O31022C, 3H272C, 3H, 3O75 C4H7ClO2122.5C, H133C, 6H, Cl, 2O109.5 C2H5ONa68-02C, 5H, O, Na68 H3O19-03H, O19 NH3O33-03H, N, O33 H4O236H, 2O333H3 Total: 20C, 42H, N, 10O, Cl, Na 514.5Ibuprofen 13C, 18H, 2O Ibuprofen 206 Waste products: 7C, 24H, N, 8O, Cl, Na Waste products: 308.5 % Atom Economy = (206 / 514.5) 100% = 40% An improved synthesis by BASF won the Presidential Green Chemistry Challenge Greener Synthetic Pathways Award in 1997 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng Atom Economy of the BASF Improved Synthesis of Ibuprofen 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng Reagents formula Reagents FW Utilized atoms Weight of utilized atoms Unutilized atomsWeight of unutilized atoms C10H1413410C, 13H133H1 C4H6O31022C, 3H, O432C, 3H, 2O59 H222H2-0 CO28C, O28-0 Total: 15C, 22H, 4O 266Ibuprofen 13C, 18H, 2O Ibuprofen 206 Waste products: 2C, 4H, 2O Waste products: 60 % Atom Economy = (206 / 266) 100% = 77% 2.5 Design Atom-Economic Reactions 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng To address the atom economy, the by-product D would vanish if the desired product is C. 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng Synthesis of ,-Unsaturated Carbonyl Compounds Through Redox Isomerization The synthesis of ,-unsaturated carbonyl compounds frequently involves the use of olefination protocols including but not limited to Wittig, Horner-Emmons-Wadsworth, Julia-Kocienski, etc., protocols. All of these suffer from low atom economy. An Atom Economic Alternative 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng Redox Isomerization A key step in the synthesis of Leukotriene B4 Trost, B. M. et al. J. Am. Chem. Soc. 2008, 130,11970. 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng 1,4-Dienes Formation from Alkene-Alkyne Coupling Total synthesis of the anticancer agent Amphidinolide P isolated from a marine organism. Although there are 4 double bonds, only one, th