Thermodynamic and Kinetic Considerations in the Copolymerization
of Ethylene and Carbon Dioxide
Craig J. Price
B. Jesse E. Reich
Stephen A. Miller
10.1021/ma052697k.s001
https://acs.figshare.com/articles/journal_contribution/Thermodynamic_and_Kinetic_Considerations_in_the_Copolymerization_of_Ethylene_and_Carbon_Dioxide/3226771
The thermodynamics of ethylene and carbon dioxide copolymerization are assessed with average
bond dissociation energies, the Benson additivity method, and density functional theory (DFT) calculations (B3LYP
6-31G<sup>†</sup>). The DFT results suggest that formation of the alternating copolymer is exothermic (Δ<i>H</i> = −4.31 kcal/mol per repeat unit), but endergonic at most temperatures (>−159 °C, the ceiling temperature), and therefore it
is practically inaccessible because of entropic factors. However, these thermodynamic calculations show that the
polymerization is favorable (exergonic) at room temperature (25 °C) when the molar quotient of ethylene/carbon
dioxide exceeds 2.37 (29.7 mol % CO<sub>2</sub> or less). Various copolymerization conditions with catalytic amounts of
late transition metal complexes (Fe, Co, Ni, Cu) in combination with MAO (methylaluminoxane) produced
oligomers or polymers containing only ethylene. The lack of ester functionality, as confirmed by mass spectrometry
and <sup>13</sup>C NMR, attests to the dubious nature of previous reports claiming up to 30 mol % incorporation of carbon
dioxide.
2006-04-18 00:00:00
molar quotient
ester functionality
Benson additivity method
carbon dioxide
mass spectrometry
calculations show
MAO
Various copolymerization conditions
carbon dioxide copolymerization
3LYP
bond dissociation energies
CO
DFT results
entropic factors
ethylene
13 C NMR
Carbon Dioxide
Kinetic Considerations
transition metal complexes