scholarly journals The enthalpy and entropy of formation of thallium(I) chloride complex (TlCl) in aqueous solution at 25°

1969 ◽  
Vol 22 (2) ◽  
pp. 469 ◽  
Author(s):  
MH Panckhurst
Keyword(s):  
Aqueous Solution ◽  
Chloride Complex ◽  
Entropy Of Formation ◽  
Enthalpy And Entropy

scholarly journals Kinetics and Mechanism of the Redox Reaction Between Pt(IV) Chloride Complex Ions and Sodium Thiosulfate in Aqueous Solution. Part I: Acidic Solution/ Kinetyka I Mechanizm Reakcji Redox Pomiędzy Chlorkowymi Jonami Kompleksowymi Pt(Iv) I Tiosiarczanem Sodu W Roztworach Wodnych. Część I: Roztwór Kwaśny

2014 ◽  
Vol 59 (4) ◽  
pp. 1413-1420 ◽  
Author(s):  
K. Pacławski ◽  
J. Piwowonska
Keyword(s):  
Acidic Solution ◽  
Solid Phase ◽  
Sodium Thiosulfate ◽  
Chloride Complex ◽  
Elementary Step ◽  
Kinetics And Mechanism ◽  
Complex Ions ◽  
Mechanism Of Reaction ◽  
Entropy Of Activation ◽  
Enthalpy And Entropy

Abstract In this work, spectrophotometric studies of the kinetics and mechanism of reaction between [PtCl6]2- complex ions and sodium thiosulfate, were carried out. The influence of different conditions, such as: initial concentrations of reductant and platinum(IV) complex ions, ionic strength, pH and temperature on the rate constant, was experimentally determined. From the obtained results, the molecularity of the first elementary step, value of the enthalpy and entropy of activation in Eyring equation as well as corresponding rate equation, were experimentally determined. It was found that the reaction is relatively slow and leads to the S, Pt and PtS colloids formation. The best conditions for solid phase formation containing Pt are at pH = 5.

scholarly journals Inclusion complexes of pesticides in aqueous solutions of methylated-β-cyclodextrin

2013 ◽  
Vol 67 (2) ◽  
pp. 231-237 ◽  
Author(s):  
Goran Petrovic ◽  
Gordana Stojanovic ◽  
Olga Jovanovic ◽  
Aleksandra Djordjevic ◽  
Ivan Palic ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Water Solubility ◽  
Inclusion Complexation ◽  
Solubility In Water ◽  
Other Substances ◽  
Poorly Soluble ◽  
Enthalpy And Entropy ◽  
Methylated Cyclodextrin ◽  
Organic Pesticides ◽  
Hplc Data

Disadvantage of some organic pesticides is their low water solubility. Among other substances, cyclodextrins and modified cyclodextrins were considered as agents for improving pesticides water solubility. The solubility of poorly soluble pesticides, dimethoate, simazine, linuron and thiram, was determined in aqueous solution of methylated-?-cyclodextrin (mbCD) by ultraviolet spectrophotometry. Methylated-?-cyclodextrin was obtained by the modified Hawort method and characterized by 1H NMR and HPLC data. The average degree of substitution was 13.8. Methylation was done either on C-2, C-3, and C-6 atoms of glucopyranose unit therefore obtained product can be assort as randomly m?CD. Solubility of the studied pesticides in aqueous solution of m?CD increases in relation to their solubility in water for dimethoate 506, for simazine167, for thiram 44, and for linuron 20 times. Reactions of dimethoate and simazine with m?CD were entropy-driven while the inclusion complexation of m?CD with the linuron and thiram were driven by both, enthalpy and entropy, as determined by calorimetric measurements. The observed solubility increment of the investigated pesticides in aqueous solution of m?CD, suggests that it can be efficiently used in pesticide solutions formulations and increase their bioavailability, and biodegradability.

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