Recrystallization of Caffeine Using Supercritical Carbon Dioxide as Antisolvent
| Autor: | Thiago Leandro Souza, Guilherme Sunehiro, Marcos Hiroyuki Kunita, Joel Augusto da Silva Romero, Nanci Pinheiro |
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| Rok vydání: | 2009 |
| Předmět: |
Supercritical water oxidation
Supersaturation Materials science Supercritical carbon dioxide Precipitation (chemistry) General Chemical Engineering Analytical chemistry Supercritical fluid law.invention chemistry.chemical_compound chemistry law Modeling and Simulation Carbon dioxide Particle size Crystallization |
| Zdroj: | Chemical Product and Process Modeling. 4 |
| ISSN: | 1934-2659 |
| DOI: | 10.2202/1934-2659.1396 |
| Popis: | The supercritical antisolvent (SAS) process has been widely used to obtain many types of crystalline and amorphous particles of polymers and drugs. In this process, solute particles precipitate from an organic solution when it is sprayed into a compressed antisolvent continuum. The antisolvent is miscible with the organic solvent, but immiscible with the solute. The objective of this work was to investigate the application of supercritical carbon dioxide as antisolvent for the recrystallization of caffeine; a compound largely employed in pharmaceutical and food industries. The carbon dioxide was pressurized at 100bar and the solution was injected into a precipitation chamber, thereby inducing its supersaturation and particle precipitation. The effect of process parameters such as initial concentration of caffeine in the organic solution (3, 5 and 10mg/mL), organic solution flow rate (3mL/min), concentration of CO2 (96 and 98mol%), drying flow rate (990mL/min) and pressure gradient between the precipitation chamber and the exit of the sprayer tube (110 and 220bar) on the solid state properties of caffeine was investigated. The pressure (100bar) and temperature (60oC) of the precipitation chamber were kept constant. The results showed a great difference between the processed and unprocessed samples. In all experimental conditions a reduction in caffeine mean particle size was observed, with length ranging from 0.6 to 168.3?m and width from 0.1 to 12.7?m, compared to the mean size of unprocessed caffeine particles (16.6 to 214.4?m in length and 7.1 to 131.2?m in width). This fact was confirmed by differential scanning calorimetry (DSC), where the precipitated particles presented lower fusion enthalpy than the unprocessed ones. Smaller crystal needles (0.3?m to 0.4?m) were obtained with crystallization at the lowest caffeine concentration in the presence of 98mol% CO2. |
| Databáze: | OpenAIRE |
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