Kinetic Modeling of Solketal Synthesis from Glycerol and Acetone Catalyzed by an Iron(III) Complex

In the last few years, the depletion of the fossil sources and their negative effect on the environment has led to find new alternatives; among these, biodiesel is considered one of the most promising for this purpose. Biodiesel can be produced from the transesterification of vegetable oils or animal fats, obtaining glycerol as a by-product. Glycerol can be used in different processes and one of the most interesting is the condensation with acetone to produce solketal. Among its applications, plasticizers, solvents, and pharmaceutical formulations are the most common. In this work, the attention was focused on the reaction between glycerol and acetone to give solketal promoted by an iron(III) complex. The reaction mechanism was hypothesized, and the kinetics was studied in a batch reactor. Finally, the thermodynamic and kinetic parameters were determined with a reliable model investigating the phenomena that occurred in the reaction network.

Investigation of the thermodynamic and physicochemical properties of lavender oil (Lavandula angustifolia Mill.)-ethanol-water system

The thermodynamic and physicochemical properties of lavender oil (Lavandula angustifolia Mill.)-ethanol-water system were measured. The chemical composition of solutions of the lavender oil in 70%, 75%, 80%, 85%, 90%, and 95% ethanol was determined using GC/MS analysis. The main compounds in the solutions are oxygenated monoterpenes (β-linalool, terpinen-4-ol, α-terpineol, and linalyl acetate), followed by monoterpene hydrocarbons ((Z)-β-ocimene and (E)-β-ocimene), and sesquiterpene hydrocarbons (β-caryophyllene and (E)-β-farnesene). The ternary phase diagrams were constructed. By multiply linear regression model for surface tension prediction was applied. The thermodynamic and kinetic parameters of lavender oil – ethanol - water system were calculated (energy of Gibb’s, enthalpy, entropy, energy of activation, and coefficient of diffusion).

Surface plasmon resonance study for a reliable determination of the affinity constant of multivalent grafted beads

Thermodynamic and kinetic parameters of the multivalent galactose beads are determined via SPR. The results show that the glycoside cluster effect influences the affinity toward the lectin and it is crucial for mimicking the biological samples.

A prudent approach for the removal of copper (II) and cadmium (II) ions from aqueous solutions using indigenous Mactra aequisulcata shells

In this study, the raw seashells of Mactra aequisulcata, of class Bivalvia and phylum Mollusca were employed as an adsorbent to remove copper (II) and cadmium (II) metal ions from aqueous solution. The characterization of shells was performed using FTIR, EDX and SEM, BET isotherm and point of zero charge (pHpzc). Batch experiments were performed to assess various factors on the biosorption efficiency. Maximum adsorption of both metals ions conveniently found at 0.4 g L-1 adsorbent dose, pH 5 and at 303 K. Maximum biosorption capacities for Cu2+ and Cd2+ were 59.57 and 38.12 mg g-1, respectively. The Langmuir isotherm model was found to be the best fit for the acquired equilibrium data. Thermodynamic and kinetic parameters presented that the process was feasible, exothermic and followed pseudo-first order.

DIRECT SCAVENGING ACTIVITY OF 4,7-DIHYDROXYCOUMARIN DERIVATIVE TOWARDS SERIES OF CHLOROMETHYLPEROXY RADICALS

In this study, the mechanisms of antiradical activity of the previously synthesized 4,7- dihydroxycoumarin derivative:(E)-3-(1-((4-hydroxyphenyl)amino)ethylidene)-2,4- dioxochroman-7-yl acetate (A-4OH) according to the series of chloromethylperoxy radicals: OOCH2Cl (chloromethylperoxy), OOCHCl2 (dichloromethylperoxy) and OOCCl3 (trichloromethyl peroxy) were investigated. To assess the mechanisms of antiradical activity of A-4OH against chloromethylperoxy radicals, the following mechanistic pathways were examined: Hydrogen Atom Transfer (HAT), Single-Electron Transfer followed by Proton Transfer (SET-PT), and Radical Adduct Formation (RAF). The investigations were performed in water using sophisticated computational methods. The results of the study show that the activity against selected radicals decreases in series •OOCCl3 > •OOCHCl2 > •OOCH2Cl. The results of thermodynamic and kinetic parameters indicate that A-4OH inactivates selected radicals via the HAT mechanism.

Vacancy diffusion in palladium hydrides

The self-diffusion coefficients of palladium in PdHx (x = 0, 0.25, 0.5, 0.75, 1) were studied using density functional theory to obtain the required thermodynamic and kinetic parameters. The enthalpy...