Lecture 9 - Carbon Dioxide Notes PDF

Lecture 9 – Carbon Dioxide Jim Avik Ghoshdastidar Chemistry and Chemical Biology McMaster University CHEM 3I03 – Industrial Chemistry 1  Discovery of Carbon Dioxide Joseph Black (1728– 1799)...

Lecture 9 – Carbon Dioxide Jim Avik Ghoshdastidar Chemistry and Chemical Biology McMaster University CHEM 3I03 – Industrial Chemistry 1  Discovery of Carbon Dioxide Joseph Black (1728– 1799) 2 more electronegative atom. o electrons left. However, the The carbon atom now has 6 valenc arbon atom has only 4 electrons 2 The CO Molecule n its valence shell in this structure. Linear molecule, no permanent dipole (Lewis structure!) O C O It is omnipresent!  Essential link in the Carbon Cycle!  If it was not a gas, life would be really slow! Repeat this process on the left. (compare to SiO2)  By-product of fossil fuel or biomass burning The carbon atom now has an octet. (coal, oil, gas, etc.)  Greenhouse gas (IR active), pollutant Lewis structure of CO2. (argument made since 1990’s)  Refrigerant in A/C (µJT ≈ 11 K/bar @ 293.15 K, 1 atm)  Dry ice (refrigeration to -78°C, sublimes, see phase diagram) 3 more electronegative atom. o electrons left. However, the The carbon atom now has 6 valenc The CO Molecule arbon atom has only 4 electrons 2 n its valence shell in this structure. O C O  CO2 snow cleaning (µJT, phase diagram) Repeat this process on the left.  Fire extinguishers (inert, MW = 44 g/mol, i.e. heavier than air) The carbon atom now has an octet.  Shielding gas for welding (only Lewis structure alternative is Ar) of CO. 2  Inert environment (preservation of fruit, vegetables, cereals, coffee,...)  Carbonated beverages (equilibrium with bicarbonate)  Feedstock (e.g. Bosch-Meiser process)  Solvent (scCO2; switchable solvents) 4  “Carbon is the foundation for all life on Earth” “Carbon is the chemical backbone of all life on Earth” Ref: https://oceanservice.noaa.gov/facts/carbon- cycle.html#:~:text=The%20carbon%20cycle%20describes%2 0the,this%20system%20does%20not%20change. Ref: https://en.wikipedia.org/wiki/Carbon_ cycle#/media/File:Carbon_cycle.jpg 5  Infrared Spectrum of CO2  asymmetric stretch at 2369 cm-1 ,  doubly degenerate bend at 667 cm-1 6  Phase Diagram of CO2 Triple Point 5.11 bar, 217 K  above 1 atm → CO2 sublimes at normal atmospheric pressure and quite a low temperature. Critical Point 72.3 bar, 304 K → the supercritical fluid is easily observed in a closed system. Ref: http://en.wikipedia.org/wiki/File:Carbon_dioxide_pressure-temperature_phase_diagram.svg 7  Industrial CO2 Sources HELSINKI UNIVERSITY OF TECHNOLOGY ENE-47.153  Fossil fuel combustion The enhanced greenhouse effect: sources for energy  Haber-Bosch process, hydrogen production, etc.  Cement industry: CaCO3 ⇌ CaO + CO2 Sources of the enhanced greenhouse effect: R. Zevenhoven, P. Kilpinen “Control of pollutants in flue gases and fuel gases” http://www.hut.fi/~rzevenho/gasbook 8  In-Class Activity: CO2 as a Feedstock How many metric tons of urea could be manufactured via the Bosch-Meiser (CO2/NH3) process using all the CO2 emitted by Canada in 2022?  Bosch-Meiser process  direct reaction to ammonium carbamate intermediate  2 NH3 + CO2 ⇌ H2N-COONH4 (∆H = −117 kJ/mol, 110 atm, 160°C)  H2N-COONH4 ⇌ OC(NH2)2 + H2O (∆H = +15.5 kJ/mol, 160-180°C)  assume that the reactions go to completion (100% yield)  Hint: find the EDGAR database online (Emissions Database for Global Atmospheric Research) 9  In-Class Activity: Solution  Find the mass of CO2 for Canada in 2022:  Convert to moles using molecular weight of CO2:  Using the CO2/NH3 process of urea production stoichiometry, determine the mass of urea:  Determine the mass in metric tons: 10  Water Gas Shift Reaction H2O(g) + CO ⇌ H2 + CO2 + 41.19 kJ  Exothermic, i.e. favoured at lower temperatures  Uses mixed metal-oxide catalysts  Typically, High T stage followed by Low T stage  High T: Fe/Cr-based catalysts, 310-450°C  Low T: Cu-based catalysts, 200-250°C  1780 Felice Fontana (industrial value later...)  Important as a follow-up to steam reforming  Remove CO from feed for Haber-Bosch process Felice Fontana or fuel cells (catalyst poison) (1730 – 1805)  Balance H2 : CO ratio for Fischer-Tropsch process 11  CO2 as a Feedstock Derivative Pathway Target Product  50% of recovered CO2 gas Methanol Conversion to ethylene/propene and subsequent polyethylene, polypropylene is used at point of polymerization of olefin production as a feedstock, Conversion to ethylene/propene and further to vinyl poly(vinyl chloride), polystyrene, mainly for urea and chloride, styrene, acrylic acid, methacrylic acid, acrylonitrile acrylonitrile–butadiene– styrene (ABS), polyacrylates, poly(methyl methanol - remainder methacrylate), polyacrylonitrile distributed as liquid or solid, or vented Conversion to ethylene oxide (EO), ethylene glycol, polyesters (PET), polyurethanes propylene oxide (PO), EO- or PO-based polyols  Reactions with H2 to yield formic acid, formaldehyde, Conversion to propene, oxidation to acetone and further conversion to bisphenol A aromatic polycarbonates, epoxy resins methanol, methane, etc. Urea & Conversion of urea to melamine and conversion of urea–formaldehyde resins, urea–  Polymers from CO2 Methanol methanol to formaldehyde and subsequent polycondensation melamine resins, polyoxymethylene (POM) derivatives: DMC Dimethylcarbonate (DMC) replaces COCl2 polycarbonates, polyurethanes Ref: Ullmann’s: “Carbon Dioxide” by S. Topham et al.; DOI: 10.1002/14356007.a05_165.pub2 12  but in the traditional ‘‘salting out’’ method). H owever, the addition of a salt d, tetrabu- to water is usually avoided because the resulting salty solution s miscible cannot be disposed of or recycled without expensive treatment to s the ionic e carboxyl- e aqueous bbling N 2 Switchable Solvents (Green Centre Canada) remove the salt. I f there were a salt that could be either easily removed (if the water is to be discarded) or neutralized (if the e again be ure for an midine and N ile Red is a single er content water and Scheme 4 Three switchable hydrophilicity solvents. The hydrophobic form is shown in yellow and the hydrophilic form in blue. In the first two cases, CO2 triggers the change to a hydrophilic solvent. In the third case, CO2 triggers the reverse change.21,36,37 Energy Environ. Sci., 2012, 5, 7240–7253 | 7245 13 Ref: P. G. Jessop, S. M. Mercer, and D. J. Heldebrant, CO2-triggered switchable solvents, surfactants, and other materials. Energy Environ. Sci., 2012, 5, 7240–7253; http://faculty.chem.queensu.ca/people/faculty/Jessop/switchable.html Lecture 10 – Emission Control Jim Avik Ghoshdastidar Chemistry and Chemical Biology McMaster University CHEM 3I03 – Industrial Chemistry 14