Correlations between kinetic and thermodynamic parameters of the extraction of tobacco leaves

Abstract

The correlations between thermodynamic and kinetic parameters in the extraction of tobacco leaves (solid – liquid system) were determined. The values of the parameters internal molecular diffusion coefficient, activation energy and entropy were used in the calculation procedure presented in the study, with regard to the extraction process of leaves of three types of tobacco (Virginia, Burley and Oriental), carried out with 50% ethanol as a solvent at different temperatures (20, 30, 40, 50, 60 and 70°C) and duration (10, 20, 30, 40, 50 and 60 min). On the basis of the Arrhenius law the effective diffusion coefficient in solid – liquid system and the reaction rate constant of the three types of tobacco were computed.

Optimization of methanol extraction parameters for total flavonoids from onion processing waste

“…Therefore, heat input is required for the extraction process. These are in accordance with another published research [18,20].…”

“…The decreasing values of entropy (S) with increasing extraction time (t) at the same temperature could be explained by the associative mechanism, the degrees of freedom due to the activation complex, and more precisely the mechanism of the reaction that occurs in the process itself. Similar results have been reported by others [19,21,28,29].…”

“…Sampling was accomplished at regular intervals (Table 4) and after filtering the obtained extracts were used for TFC determination. Kinetic modelling and calculations of the kinetic and thermodynamic parameters were conducted according to the equations presented in the literature [16][17][18][19][20][21][22].…”

“…The extraction from plant raw materials obeys the laws of diffusion and one of the main parameters is the diffusion coefficient. The diffusion coefficient was determined by the equations of Minosyan (D1), Wilke-Chang (D2) and Stoke's-Einstein (D3) and the effective diffusion coefficient (De) was also determined according to the Arrhenius equation [19,23].…”