Victoria V. Krupskaya

Natural Mg-Fe clinochlores: Enthalpies of formation and dehydroxylation derived from calorimetric study

Abstract This paper presents the results of the first experimental thermochemical investigation of two natural trioctahedral chlorites (clinochlores). The study was performed with the help of a high-temperature heat-flux Tian-Calvet microcalorimeter. The samples were characterized by X ray spectroscopy analysis, X ray powder diffraction, thermal analysis, and FTIR spectroscopy. The enthalpies of formation of clinochlores were found using the melt solution calorimetry method to be: –8806 ± 16 kJ/mol for composition (Mg4.9Fe0.32+

Synthesis of octahydro-2H-chromen-4-ol from vanillin and isopulegol over acid modified montmorillonite clays: Effect of acidity on the Prins cyclization

{\text{Fe}}_{0.3}^{2 + }

Effect of nitric acid modification of montmorillonite clay on synthesis of solketal from glycerol and acetone

Al0.8)[Si3.2Al0.8O10](OH)8 and –8748 ± 24 kJ/mol for composition (Mg4.2Fe0.62+

Synthetic and natural materials with the brucite-like layers as high active catalyst for synthesis of 1-methoxy-2-propanol from methanol and propylene oxide

{\text{Fe}}_{0.6}^{2 + }

Effect of acid modification of kaolin and metakaolin on Brønsted acidity and catalytic properties in the synthesis of octahydro-2H-chromen-4-ol from vanillin and isopulegol

Al1.2)[Si2.8Al1.2O10](OH)8. The experimental data for natural samples allowed calculating the enthalpies of formation for end-members and intermediate members of the clinochlore (Mg5Al)[Si3AlO10](OH)8 and chamosite (Fe5Al)[Si3AlO10](OH)8 series. An important feature of the clinochlore structure is the presence of two distinct hydroxyl-containing octahedral layers: the interlayer octahedral sheet and octahedral 2:1 layer; the enthalpies of water removal from these positions in clinochlore structure were determined as: 53 ± 20 kJ/(mol·H2O) and 131 ± 10 kJ/(mol·H2O), respectively. These obtained first thermodynamic characteristics of Mg-Fe clinochlores can be used for quantitative thermodynamic modeling of geological and industrial processes including clinochlores of different composition.