Transesterification of leather tanning waste to biodiesel at supercritical condition: Kinetics and thermodynamics studies

Determination of kinetic and thermodynamic parameters of the B100 biodiesel oxidation process in mixtures with natural antioxidants

“…A negative sign indicates that when the species are joined in the transition state there is a decrease in numbers of molecules in the system. On the other hand, as more components are present in the transition state, the system becomes more disordered and the value of ΔS ‡ will be less negative [36,37]. As expected, the control sample showed the most negative value of activation entropy, and treatments containing the ternary mixture (central point) had less negative entropy due to the higher number of species in the transition state, and consequently larger disorder of the reaction system.…”

The mechanism of hydrothermal hydrolysis for glycyrrhizic acid into glycyrrhetinic acid and glycyrrhetinic acid 3- O -mono-β- d -glucuronide in subcritical water

“…The higher activation energy in reaction 2 led a slower clearing rate of the b-1,3 glucosidic bond compared to the b-1,2 glucosidic bond. This phenomenon was due to stronger steric interactions (intra-and intermolecular van der Waals repulsions), which could slow attacks on the carbocation by H + self-dissociated of SW (Ong et al, 2013). Compared with the hydrolysis of cellulose in SW (Sasaki et al, 2002), the activation energy of GL hydrolysis was smaller, which indicated the b-1,4-and b-1,6-glycosidic linkages in cellulose exhibited a much higher stability compared to the b-1,3-and b-1,2 glucosidic bond.…”

<b>Evaluation of the kinetic and thermodynamic parameters of oxidation reaction in biodiesel from a quaternary mixture of raw material

“…According to Ong et al (2013), the negative values for ΔS ‡ may be associated with the formation of activated species in the state in which the reactants combine to form complexes, thereby reducing the number of free species. Thus, the more negative the activation entropy, the more activated complexes species are formed and, finally, the higher the reactivity (Choi, Kim, Jeong, Kim, & Yoo, 2011).…”