Étude statistique des effets de solvant. III. Calcul et interprétation de paramètres empiriques de polarité à partir de propriétés physicochimiques des solvants purs

Abstract

3492 (1985) Using multivariational statistical methods, the calculation and interpretation of empirical parameters of the polarity of solvents has been reexamined. The size of the sample used (57 aprotic solvents and 24 protic solvents) assures that it is representative. For each solvent, the data tabulated include some physical constants (dielectric constants, dipole moments, refractive indices, molar refractions, boiling points, Hildebrand's 6 parameters) or theoretical values (energy levels of frontier orbitals). The methods used are factorial analysis and multiple regression. The results obtained show that, for the aprotic solvents, the parameter ET is a measure of the polarity, of the polarizability, and of the cohesion of the solvent to the extent of 43, 39, and 18% respectively. For the parameter a*, these proportions are respectively 53, 18, and 29%. For the protic solvents, the parameter ET is explained by the same variables except for 5 solvents more acidic than water; this anomaly is explained by the basicity of the oxygen of the betaine used to define ET.[Journal translation] IntroductionDans les approches quantitatives de I'effet des solvants sur les processus chimiques, une propriCtC mesurant cet effet est considCrCe comme une fonction linCaire, soit d'un ou plusieurs paramktres empiriques, soit d'une ou plusieurs grandeurs physicochimiques du solvant, soit de combinaisons des deux types de variable.De nombreuses Cchelles empiriques ont Ct C proposies pour rendre compte: (i) de la polarisabilitC et de la polarit6 des Ces Cchelles ont en commun d'Ctre dCfinies par la variation de propriCtCs spectroscopiques d'une ou plusieurs molCculessondes (ou de propriCtCs thermodynamiques de reactions modkles) quand on passe d'un solvant a un autre. C'est d'ailleurs ce qui limite leur efficacitC quand on veut les utiliser seules dans des conditions trop diffirentes de celles dans lesquelles elles ont Ct C dCfinies (9, 10a). lations a la fois des parametres empiriques et des grandeurs physiques caractkristiques des solvants.Les difficultks rencontries pour attribuer un sens physique prCcis aux paramktres empiriques et pour les utiliser valablement dans des conditions variCes ont conduit a n'utiliser (16) que des grandeurs physicochimiques. De mCme le paramktre r * de Taft et Kamlet a Ct C calculC (17, 18) a partir de fonctions de la constante diklectrique et de l'indice de rCfraction des solvants.A partir de nombreuses donnCes cinktiques, thermodynamiques et spectroscopiques, C. G. Swain et al. (19a)

Panorama of sustainable solvents using the COSMO-RS approach

“…[21][22][23][24] The 138 sustainable solvents have been listed through the review of academic and technical literature (see Table 2). These solvents have been used as supplementary solvents and have been positioned in the classification established with the 153 traditional solvents.…”

“…The base dataset is constituted by the 153 organic solvents proposed by Gramatica et al 20 as an extension of Chastrette's classification. [21][22][23][24] The 138 sustainable solvents have been listed through the review of academic and technical literature (see Table 2). These solvents have been used as supplementary solvents and have been positioned in the classification established with the 153 traditional solvents.…”

Quantitative Measures of Solvent Polarity

“…Another option for treating this type of dimensionality and interrelation questions is the conventional PCA. Chastrette and Carretto applied PCA to analyze 231 and to calculate empirical parameters of solvent polarity starting with the physicochemical properties of the solvents; 232 Chastrette and coworkers 233 used multivariate statistical treatment to classify 83 solvents using eight solvent parameters (K, MR, δ, µ, n D , bp, H , and L ), but their focus was mainly on the grouping of solvents rather than solvent scales. Nevertheless, from the intercorrelation of the solvent parameters they concluded that fewer than eight parameters should be sufficient to describe the whole dimensionality.…”

Grafting of monoglyceride molecules for the design of hydrophilic and stable porous silicon surfaces

“…26 Additionally, besides being more polar, the diol function is less pH-dependant than a carboxylic acid function; the pK a value is 4.76 for acetic acid, whereas it is over 14 for ethylene glycol (14.22). 25 The diol-modified porous silicon surface presented in this work is expected not to be modified when exposed to varying environmental pH conditions. Such hydrophilic and inert-to-pH-change surfaces can be useful in biological and biosensing applications, where hydrophilic stable surfaces are desirable in various buffered conditions.…”

“…This is explained by the higher polarity of a diol function compared to that of a carboxylic acid function, as attested by the values of the dipole moments for ethylene glycol (m = 7.61) compared to acetic acid (m = 5.6). 25 The polarity of solvents is also known to be linked to their dielectric constant, which is 37 and 6.1 for ethylene glycol and acetic acid, respectively. 26 Additionally, besides being more polar, the diol function is less pH-dependant than a carboxylic acid function; the pK a value is 4.76 for acetic acid, whereas it is over 14 for ethylene glycol (14.22).…”