Supercritical CO2 recovery of caffeine from green coffee oil: new experimental solubility data and modeling

• Main Authors: Álvaro Bandeira Antunes de Azevedo, Theo Guenter Kieckbusch, Alexandre Keiji Tashima, Rahoma Sadeg Mohamed, Paulo Mazzafera, Silvio Alexandre Beisl Vieira de Melo
• Format: Article
• Language: English
• Published: Sociedade Brasileira de Química 2008-01-01
• Series: Química Nova
• Subjects: caffeine solubility; coffee oil; supercritical carbon dioxide
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422008000600009

The caffeine solubility in supercritical CO2 was studied by assessing the effects of pressure and temperature on the extraction of green coffee oil (GCO). The Peng-Robinson¹ equation of state was used to correlate the solubility of caffeine with a thermodynamic model and two mixing rules were evaluated: the classical mixing rule of van der Waals with two adjustable parameters (PR-VDW) and a density dependent one, proposed by Mohamed and Holder² with two (PR-MH, two parameters adjusted to the attractive term) and three (PR-MH3 two parameters adjusted to the attractive and one to the repulsive term) adjustable parameters. The best results were obtained with the mixing rule of Mohamed and Holder² with three parameters.