Table I.
Description of the Process and its Variables to Crystallize and Freeze-Dry the Water/TBA Mixtures
| Step | Temperature (°C) | Length of step (h) | Pressure (mBar) |
|---|---|---|---|
| 1. Freezing | Variable 1 | 1000 | |
| −50 | 2 | 1,000 | |
| 2. Ramping to T c a | Variable 2 | 0.5 | 1,000 |
| 3. Crystallization | Variable 2 | 7 | 1,000 |
| 4. Drying | Variable 2 | 30 | 0.8–1.0 |
| 5. Ramping to T end | 20 | 2 | 0.8–1.0 |
| 20 | 1 | 0.8–1.0 | |
| 6. Emptying | 20 | - | 1000 |
| Process | Variable 1: freezing rate | Variable 2: Tc a | |
| 1. (Slow; −25°C) | From 20 to −50°C at 1°C/min | −25°C | |
| 2. (Slow; −15°C) | From 20 to −50°C at 1°C/min | −15°C | |
| 3. (Fast; −25°C) | Vial on pre-cooled shelf (−50°C); | −25°C | |
| 4. (Fast; −15°C) | Vial on pre-cooled shelf (−50°C) | −15°C | |
a T c crystallization temperature