《绿色化学教材课件Ch2》由会员分享，可在线阅读，更多相关《绿色化学教材课件Ch2（26页珍藏版）》请在金锄头文库上搜索。
1、Chapter 2: Atom Economy- Avoiding Waste0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng100 % atom economy 0403809 Green Chemistry Chapter 2: Atom Economy Z. WengOutline 2.1 Environmental Factor: EEnvironmental Factor: E 2.2 Where Does Chemical Waste Come From 2.3 Atom EconomyAtom Economy 2.4
2、Examples of Atom EconomyExamples of Atom Economy 2.52.5 Design Atom-Economic Reactions2.12.1 Environmental Factor: E Environmental Factor: ERoger 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 targ
3、et product are considered to be WASTEWASTE.0403809 Green Chemistry Chapter 2: Atom Economy Z. WengEnvironmental Environmental Factor:Factor:If the atom Utilization = 100%E = 0The more waste formed, the higher of E and the more serious of the pollution0403809 Green Chemistry Chapter 2: Atom Economy Z
4、. WengThe Environmental FactorIndustriesProduct tonnageEPetrol106 108 0.1Bulk Chemicals104 10 61 5Fine Chemicals102 1 045 50Pharmacy10 10325 1000403809 Green Chemistry Chapter 2: Atom Economy Z. WengSheldon, R. A. Green Chem., 2007, 9, 1273. Is the actual amount of waste formed in the process, inclu
5、ding 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 o
6、f the waste problem.The Environmental Factor0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng2.2 Where does chemical waste come from? 1.Stoichiometric Bronsted acid and bases 2. - Aromatic nitrations with H2SO4 / HNO3 - Acid promoted rearrangements, e.g. Beckmann (H2SO4) - Base promoted conden
7、sations, 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/HCl4. Halogenation and halogen replacement - Nucleophilic substitutions5. Solvent losses - Air emiss
8、ions & aqueous effluent0403809 Green Chemistry Chapter 2: Atom Economy Z. WengBarry Trost, Professor of Stanford UniversityCommodity chemical producers typically practice good atom economy0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng2.3 Atom Economy Fine chemical and pharmaceutical produce
9、rs 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 twice0403809 Green Chemistry Chapter 2: Atom Economy Z. WengThe two main characteristic
10、s 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 minimized0403809 Green Chemistry Chapter 2: Atom Economy
11、 Z. Weng0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng0403809 Green Chemistry Chapter 2: Atom Economy Z. WengExample 1: Methyl MethacrylateFor the manufacture of polymethyl methacrylate acrylic plastics (PMMA) and PVC. Calculate the ato
12、m economy of the following ACH process: 0403809 Green Chemistry Chapter 2: Atom Economy Z. Weng2.4 Examples of Atom Economy0403809 Green Chemistry Chapter 2: Atom Economy Z. WengExample 2: Ibuprofen布洛芬 0403809 Green Chemistry Chapter 2: Atom Economy Z. WengThe Original Boots Synthesis of Ibuprofen04
13、03809 Green Chemistry Chapter 2: Atom Economy Z. WengSumme: -7 C, 24 H, N, 8 O, Cl, NaAtom Economy of the Boots synthesis of ibuprofen 0403809 Green Chemistry Chapter 2: Atom Economy Z. WengReagentsformulaReagentsFWUtilizedatomsWeight of utilized atomsUnutilized atomsWeight of unutilized atomsC10H14
14、13410C, 13H133H1C4H6O31022C, 3H272C, 3H, 3O75C4H7ClO2122.5C, H133C, 6H, Cl, 2O109.5C2H5ONa68-02C, 5H, O, Na68H3O19-03H, O19NH3O33-03H, N, O33H4O236H, 2O333H3Total:20C, 42H, N, 10O, Cl, Na514.5Ibuprofen13C, 18H, 2OIbuprofen206Waste products: 7C, 24H, N, 8O, Cl, NaWaste products:308.5% Atom Economy =
15、(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. WengAtom Economy of the BASF Improved Synthesis of Ibuprofen 0403809 Green Chemistry Chapter 2: Atom Econo
16、my Z. WengReagentsformulaReagentsFWUtilizedatomsWeight of utilized atomsUnutilized atomsWeight of unutilized atomsC10H1413410C, 13H133H1C4H6O31022C, 3H, O432C, 3H, 2O59H222H2-0CO28C, O28-0Total:15C, 22H, 4O266Ibuprofen13C, 18H, 2OIbuprofen206Waste products: 2C, 4H, 2OWaste products:60% Atom Economy
17、= (206 / 266) 100% = 77% 2.5 Design Atom-Economic Reactions0403809 Green Chemistry Chapter 2: Atom Economy Z. WengTo address the atom economy, the by-product D would vanish if the desired product is C.0403809 Green Chemistry Chapter 2: Atom Economy Z. WengSynthesis of ,-Unsaturated Carbonyl Compound
18、s 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 Alternative0
19、403809 Green Chemistry Chapter 2: Atom Economy Z. WengRedox IsomerizationA 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. Weng1,4-Dienes Formation from Alkene-Alkyne CouplingTotal synthesis of the a
20、nticancer agent Amphidinolide P isolated from a marine organism.Although there are 4 double bonds, only one, the monosubstituted double bond reacted. Furthermore, a very labile -lactone as well as unprotected hydroxyl groups remain totally unaffected.Trost, B. M. et al. J. Am. Chem. Soc. 2005, 127,1
21、7921.0403809 Green Chemistry Chapter 2: Atom Economy Z. WengPalladium Catalyzed Alkyne-Alkyne CouplingTrost, B. M. et al. J. Am. Chem. Soc. 1997, 119, 698.0403809 Green Chemistry Chapter 2: Atom Economy Z. WengTrost, B. M. et al. Nature 2008, 456, 485.Total Synthesis of Bryostatin 16 Using Atom-Economical Approaches Bryostatins were first isolated from coral-like sea creatures called bryozoans, and have been shown to have potent action against various types of cancer.
