| ¹H NMR reaction monitoring (400 or 600 MHz, acetonitrile, 30 °C, target pressure ±2 bar, excitation-sculpting solvent suppression) | Product signal: δ 6.9; ionic-liquid signal used as the internal standard: δ 8.7; seven samples from t₀ to 3 h at 30 min intervals |
|---|---|
| Second-order rate constants (varying CO₂ pressure) | Trend with pressure: increase followed by decrease; the dimerization trend was similar but less distinct, with larger uncertainties because that product could not be followed directly |
| Second-order rate constant (varying ionic-liquid mole fraction) | Maximum at an ionic-liquid mole fraction between 0.5 and 0.6 |
| ¹H NMR reaction-rate series (30 °C; varying CO₂ pressure or N₂ at 20, 60, 100 and 140 bar) | Image data were not transcribed; uncertainties were shown as half the range of duplicate experiments |
Adrian Jowett, Stuart Prescott, Raffaella Mammucari, Jason Harper. “Carbon dioxide expanded ionic liquid mixtures for changing reaction outcomes and efficient separation.” ChemRxiv (). https://doi.org/10.26434/chemrxiv.15007576/v2
| ¹H NMR extraction monitoring (acetonitrile, 25 or 50 °C, CO₂ at 50, 100 or 150 bar, sampled after every 30 g CO₂) | Dicyclopentadiene signal: δ 5.5; dimethyl bicyclo[2.2.1]hepta-2,5-diene-2,3-dicarboxylate signal: δ 6.94; ionic-liquid signal used as the internal standard: δ 8.8; changes represented relative amounts, not absolute concentrations; no loss of ionic liquid was observed; the first sample was taken after stable conditions were reached, and subsequent samples were compared with the first sample |
|---|---|
| ¹H NMR initial composition (ionic-liquid signal at δ 8.8 as internal standard) | Dimer 4: 5.8 mol %; product 3: 3.8 mol % |
| ¹H NMR extraction series (25 or 50 °C, CO₂ at 50, 100 or 150 bar) | Replicate results were averaged; uncertainties were based on NMR signal-to-noise and exceeded variation between replicate experiments; image data were not transcribed |