Standard Enthalpies and Heat Capacities of Solution of Urea and Tetramethylurea in Water

Кустов, А. В.; Smirnova, N. L.

doi:10.1021/je9010689

Cited by 35 publications

(30 citation statements)

References 26 publications

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“…This observation is rather surprising since solubility of a molecular form of porphyrins in organic solvents increases with the temperature. [8,10] However, the situation here is significantly complicated by protonation of amino groups and central nitrogen atoms and also ionion interactions in an aqueous phase. Since porphyrin basicity significantly decreases with the temperature [11] it leads to weaker solute-solvent specific interactions.…”

Section: Resultsmentioning

confidence: 99%

Solubility and Thermodynamics of Dissolution of 13,17-Di-N-(2-aminoethyl)amide of Deuteroporphyrin-IX in Aqueous HCl and Tetraoxalate Buffer at 288-328 K

Кустов¹,

Kruchin²,

Smirnova³

et al. 2016

MHC

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This paper describes the thermodynamic study of aqueous solutions of 13,17-di-N-(2-aminoethyl)amide of deuteroporphyrin-IX (DDA) which is considered as a potential red natural dye and a perspective substrate for creating new water-soluble sensitizers for photodynamic therapy (PDT). Solubility of the macrocycle in highly aqueous solutions of hydrochloric acid and standard tetraoxalate buffer has been determined in the temperature range from T=288 K to T=328 K. Solubility values are found to decrease with the temperature in both cases due to the weakening of porphyrin basicity at elevated temperatures. Free energies, enthalpies and entropies of solution have been computed from solubility data via the Clark and Glue equation. Enthalpies and entropies of solution are negative and constant for both cases in the temperatureSolubility and Thermodynamics of Dissolution of 13,17-Di-N-(2-aminoethyl)amide of Deuteroporphyrin-IX интервале. Отрицательный энтальпийный вклад способствует растворению ДДА, однако, большие отрицатель-ные энтропии процесса приводят к неблагоприятному изменению свободной энергии в целом.Ключевые слова: Дейтеропорфирин IX, водные растворы, кислотно-основные взаимодействия, растворимость, термодинамика растворения. IntroductionNatural porphyrins and related compounds are known to be of great interest for medicine as fluorescence diagnostic labels and drugs for an earlier treatment of different tumors and bacterial infections.[1,2] They also provide an extremely versatile synthetic base for a variety of industrial applications such as the development of non-linear optical materials, natural dyes, different sensors and catalysts etc.[3] Many application fields mentioned above require the information about the macrocycle behavior in a liquid phase at different temperatures and concentrations. Solubility values appear to be one of the most important quantities in this sense. These are, however, scarce and restricted by several organic solvents or their mixtures with water mostly at the standard temperature of 298 K. [4][5][6] During the last several years we have been involved in the intensive and continuing study (see, for example, [7][8][9] and references therein) dealing with the behavior of natural macrocycles in individual and mixed organic solvents modeling their biological environment. Here, we focus on thermodynamics of diamino derivative of deuteroporphyrin-IX in highly aqueous acidic solutions, where protonation of the macrocycle and functional amino groups provides sufficient solubility in water to employ the solute as a natural dye for synthetic or semi-synthetic fabrics. This porphyrin can be also used as perspective substrate to synthesize new hydrophilic water-soluble sensitizers for PDT using a quaternization reaction. Experimental13,17-Di-N-(2-aminoethyl)amide of deuteroporphyrin-IX (1) was synthesized using nucleophilic substitution reaction between previously obtained deuteroporphyrin-IX dimethyl ester (2) and a freshly distilled 70 % aqueous solution of ethylenediamine. 10 ml of an et...

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Section: Resultsmentioning

confidence: 99%

Solubility and Thermodynamics of Dissolution of 13,17-Di-N-(2-aminoethyl)amide of Deuteroporphyrin-IX in Aqueous HCl and Tetraoxalate Buffer at 288-328 K

Кустов¹,

Kruchin²,

Smirnova³

et al. 2016

MHC

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“…1). It may be due to the fact that, unlike the MMTU, the 1,1,3-TMTU molecule does not contain the unsubstituted amino group, whose ability to a strong specific interaction (trough N\H⋯O-bonding) in aqueous solutions of (thio)ureas and amides is well known [13,14,30,[36][37][38][39].…”

Section: Discussionmentioning

confidence: 99%

Volumetric properties of some asymmetrically methyl-N-substituted thioureas in water between (278.15 and 318.15) K at ambient pressure

Ivanov

2014

Journal of Molecular Liquids

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“…The calorimetric measurements were carried out with the isoperibol ampoule calorimeter described in detail elsewhere [4][5][6]. The detection limit of the apparatus was 10 µK.…”

Section: Methodsmentioning

confidence: 99%

Enthalpies and Heat Capacities of Ethyl Acetate Solutions in Water and in Several Organic Solvents at 298–318 K

2012

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The enthalpies of solution of ethylacetate (EtOAc) in water, octane and 1-octanol (OctOH) were measured at 298, 308 and 318 K using a precise isoperibol calorimeter. The standard enthalpies and heat capacities of these non-electrolyte solution were computed and compared with the previously obtained sol H • and C • p values in N,N-dimethylformamide (DMF). Partial molal heat capacities of EtOAc in water and in organic solvents were calculated and compared with the available literature values.

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Standard Enthalpies and Heat Capacities of Solution of Urea and Tetramethylurea in Water

Cited by 35 publications

References 26 publications

Solubility and Thermodynamics of Dissolution of 13,17-Di-N-(2-aminoethyl)amide of Deuteroporphyrin-IX in Aqueous HCl and Tetraoxalate Buffer at 288-328 K

Solubility and Thermodynamics of Dissolution of 13,17-Di-N-(2-aminoethyl)amide of Deuteroporphyrin-IX in Aqueous HCl and Tetraoxalate Buffer at 288-328 K

Volumetric properties of some asymmetrically methyl-N-substituted thioureas in water between (278.15 and 318.15) K at ambient pressure

Enthalpies and Heat Capacities of Ethyl Acetate Solutions in Water and in Several Organic Solvents at 298–318 K

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