New Synthetic Routes for a Sustainable Chemistry

1. New Synthetic Routes for a Sustainable Chemistry Michele Aresta

3. Sustainability = Innovation • Raw materials diversification • New production routes • New catalysts • New processes • Process intensification and integration

4. Wise use of technologies • Why to destroy complex structures existing in natural products and then rebuild part of them through long-multistep-complex syntheses? • Cascade of technologies

5. Cascade of technologies • Soft technologies • Do not destroy complex structures that can be recovered and used • Medium strength technologies • Partially modify complex structures • Hard technologies • Destroy complex structures and convert them into simple molecules such as CO, H2 (Syngas) used for building-up new more complex species

6. Innovation • Use of natural resources • Cellulosic materials Glucose units obtained via depolymerization of cellulose

8. Cellulose depolymerization • Use of Ionic Liquids • Cellulose dissolves in ionic liquids • Dissolved cellulose can be precipitated with water • Recovered cellulose (white pulp) can be used for fermentation • Better use of cellulose • Less expensive and polluting processes • Verify the greeness of IL

9. Innovation • Use of natural resources: lignine

10. Better use of lignine • Discover methodologies for a controlled ether-linkage cleavage • Recovery from lignine of aromatic compounds with a complex structure that can be used as such or converted into other more complex compounds • Lignine depolymerization • Lignine partial oxidation • Combination of chemical and biological tools: new biotechnologies.

11. Lower-cost production • Longer fruibility of natural reserves • Better use of energy • Better use of carbon and resources • Safer conditions • Waste reduction at source

12. Energy production • Fraction of extracted carbon really used • The fraction lost in the extraction, distribution, treatment of fossil carbon • Difficult to quantify • 10-40 % • Effficiency in the conversion of chemical energy into electrical, mechanical…. • Electric energy 30-34 % • It is possible to reach 52 % !!! • Mechanical energy 32-35 % • It is possible to improve: fuel consumption in cars • Life of cars vs consumption !!!!

14. Diversify the use of raw materials • Correct use of fossil carbon • Use oil for making chemicals • Use coal for energy • Invent new routes for methane conversion • Use of cellulosic materials and lignine • New chemical conversion • New biotechnological conversion • New hybrid technologies

15. Raw material diversification • Abandon the use of energy intensive compounds • Intensify the use of new processes based on less energy- and carbon-intensive materials • Use of secondary raw materials • Recycling of carbon • Waste conversion and utilisation

16. Raw material diversification • Substitute oil or coal • Use natural products • Use secondary raw materials • Use of methane for chemistry • Use of light hydrocarbons-LH • Light alkanes functionalization • Use of heavy hydrocarbons-HH • Heavy alkanes cutting

17. New reactions Atom economy, innovation, new reactions….. CH4 + H2O CO/H2  CH3OH C6H5CH3  C6H5COOH CH4  CO/H2  CH3OH  CH3COOH CH4 + 1/2O2 CH3OH C6H6 + CO2  C6H5COOH CH4 + CO2  CH3COOH

19. Waste reduction at source • The E-factor

20. Waste reduction at source Synthesis of caprolactame

24. Waste reduction at source • Carboxylation reactions • RCN  RC(O)NH2  RCOOH • C6H5CH3  C6H5COOH • Naphtalene  C6H4(COOH)2 • Milder conditions, non-toxic reagents, more selective reactions

25. Phosgene substitution • COCl2 is made by contact of CO and Cl2 on active-C • Production of ca. 8 Mt/y • No transport  Small plants for in situ utilization • Safe working conditions • Plant in a “dome” • Connection to a waste treatment plant • Banned in several countries • Production moves to East (exception: Tarragona) • Market requires more phosgene or efficient substituents

26. property DMC Phosgene DMS oral toxicity LD 13.8 g/kg LD 440 mg/kg 50 50 toxicity contact LD > 2.5 g/kg per 50 3 toxicity inhalation LC 140 mg/L; LC 16mg/m ; LC 1.5mg/L per 50 50 50 (4h) (75 min) (4h) mutagenic properties none mutagenic irritating prop erties none corrosive (eyes, skin) biodegradability >90% (28 days) rapid hydrolysis rapid hydrolysis TOXICOLOGICAL AND ECOTOXICOLOGICAL PROPERTIES OF DMC, PHOSGENE AND DIMETHYLSULPHATE (DMS)

27. Molecular carbonates Molecular carbamates Isocyanates Ureas Polymeric carbonates (Bis-phenol-A) Polyurethans Co-polymers Uses of Phosgene

28. Pesticides Solvents and reagents Cosmetics Drugs Polymers Additives to gasoline Dialkylcarbonates uses…

29. Synthesis of carbonates from Phosgene 2ROH + COCl2 + 2B  (RO)2CO + 2BHCl B: NaOH Room temperature or close to it Solvent: CH2Cl2

30. Some thermodynamic dataΔGf mol/kcal • CO-26 (H2N)2CO -47.2 COCl2-52.5 KINETICS!!!CO2-96

31. Toxixc compounds substitution • Production of chlorine • New technologies avoiding Hg • Membrane technologies • Chlorine substitution • Substitute chlorinated solvents • Substitute chlorinated monomers

32. Toxic compounds substitution • HCN substitution • Prepared from coal or LNG • Used for the synthesis of: • Nitriles (adiponitrile, acrylonitrile, malonitrile) • Cyanogen-(CN)2 and cyanogenchloride • Oxamide • Polymers • Dyes • Pesticides, steroids • Amides and acids

34. Solvent substitution • Substitution of organic solvents • Chlorinated solvents are already prohibited • Water is often called as the best solvent, with E-Factor=0, but… How easy-difficult is to clean water????!!!!!!! • Substitution of fluorinated derivatives • Chlorofluorocarbons are prohibited as propellents, cleaning agents, washing solvents

35. Use of scfPolarity can be modulated by changing P or adding a co-solvent • Use of sc-CO2 (304 K, 7.3 MPa) in chemical processes • Polymerization solvent • Polymers blowing • Solvent for new materials • Nanoparticles preparation • Hydrogenation reactions • Hydroformilation reactions • Hydrogenation of CO2 to formic acid • CO2 as solvent and reagent

36. Use of scfs Use of sc-water (547 K, 21.8 MPa) Harsh reaction medium Cellulosic material conversion Waste (municipal and agriculture) treatment Industrial waste treatment Production of Syngas (H2-CO) Drawbacks: highly corrosive!!! highly energetic conditions.

38. Outline • Greening the chemical industry • Substitution of toxic compounds • New synthetic methodologies • New raw materials • New catalysts • Direct utilisation of CO2 • As reagent and solvent • Technological uses • Indirect utilisation of CO2 • Nature makes and Chemistry reshapes • The expected benefits • The used and avoided CO2 • Perspectives

39. Greening the chemical industry • Substitution of toxic compounds • Avoiding the use of phosgene, cyanides, halogens • New synthetic methodologies • Avoiding strongly endoergonic reactions (such as those based on Syngas), high temperature processes and multistep syntheses • Direct syntheses • Waste reduction at source • New raw materials • Reducing the carbon dependence, recycling of carbon and other materials • New catalysts • Heterogeneous catalysts • Selective and efficient

40. Utilisation of CO2 • As reagent and solvent 128 Mt/y • Synthesis of molecular chemicals • Co-monomer for polymers • Use as sc-fluid in solventless reactions • Technological uses 18 Mt/y • Additive to beverages, food packaging • Antibacterial (cereals storage-transport) • Extraction of essences, caffeine, chemicals…. • Antiflame • Cleaning solvent (dry-cleaning, electronic and mechanical industry) • Water treatment • Solvent for materials and polymers preparation • Enhanced Oil Recovery

41. O C H2N NH2 ONa /K HO COONa /K O O O O O n O O O ROH C RO OR O2 O O HOOC O COOH Br COOR COOH O O O O R R º RC CR O COOH HOOC O O + RNHC OR’ O C N OH NH2 H3COH A HCOOH RNH2 HCONHR + D CnH2n+2 CnH2n H2 CO2 CO CO 2 COOH COOH H2C=CH2 B C e-, H+ RNH2 + R’X n n

42. Classes of compounds of industrial interest: opportunities and challenges Mt/y scale • Carboxylates: • Formic acid • Long chain acids, lactones, pyrones • Carbonates • Molecular (linear and cyclic) and polymeric • Carbamates • Molecular and polymeric • Acrylic acids and their esters • Energy products

43. CO + H HCOOH 2 2 Ru Rh Leitner et al., J. Chem. Soc. Chem. Commun., 1465-1466, 1993 SC-CO + H HCOOH 2 2 Amines HCOONRR'H2 Jessop et al., Nature, 368, 231-233, 1994 Synthesis of Formic Acid • TOFh ~ 10000 at 80 °C and 1364 at room temperature • High pressure: Laurenczy et al.Appl. Catal. A: Gen., 2003; Chem. Eur. J. 2007

45. Carboxylation of Alcohols2ROH + CO2 ROC(O)OR + H2O • Thermodynamicssays that the reaction is “quasi-neutral”: the equilibrium concentration of the carbonate is reported to be close to 1-2% • Wateris formed that should be eliminated for displacing the equilibrium to right and avoid that catalysts are modified • Thereaction mechanism:in principle an alcohol should undergo an acid-activation (to generate –R) and a base-activation (to generate –OR): bi-functional catalysis

47. Formation of isourea Transition states: DCC + 1 MeOH DCC + 2 MeOH DEa = 34 kcal/mol DEa = 9 kcal/mol

48. Interaction of CH3OH with isourea H-bonded complexes: DE = -6.8 kcal/mol DE = -3.7 DE = -3.4

49. Adduct identification by NMR Equivalent N-H and N...H-O protons Intra-molecular proton exchange DE = 2 kcal/mol

50. § 1H NMR § § * 13C NMR