Acetone solvent parameters

In polar and H-bonding solvents such as acetone, tetrahydrofuran or methanol CgQ is essentially insoluble. It is sparingly soluble in alkanes, with the solubility increasing with the number of atoms. In aromatic solvents and in carbon disulfide, in general appreciable solubilities are observed. A significant increase of the solubility takes place on going from benzenes to naphthalenes. Although there are trends for the solution behavior of Cjq, there is no direct dependence of the solubility on a certain solvent parameter like the index of refraction n. When the solubility is... 

The chemical shifts have been correlated satisfactorily with the solvent parameters AN (acceptor number (ref. 28)), DN (donor number (ref. 29)) and e (dielectric constant) for a set of nine solvents (acetone, acetonitrile, DMF, DMAc, nitrobenzene, sulfolane, HMPT, benzonitrile, methanol) (ref. 17) (Fig. 4). The predominant weight of AN indicates clearly the basic character of solvated fluorides which, however, is strongly modulated by HF-solvation and can be quantified in that way. Thus, the correlation between the chemical shift and the reactivity of soluble fluoride anions could, in principle, allow to predict their fluorination efficiency in any solvent. 

In most equilibrium-based analytical methods, the success or failure of a determination is not affected by the reaction mechanism, provided that the reaction is either quantitative or the measured parameter at equilibrium is linearly proportional to the initial concentration of the species of interest. This is not the case in reaction-rate methods. Any development of a kinetic method should include, if possible, a complete study of the reaction mechanisms involved in the procedure. (Unfortunately, some reactions, such as catalytic reactions, are so complicated that complete elucidation of the mechanism is impossible.) It should also include a detailed study of the effects of typical sample-matrix components, which can act as catalysts, induce side-reactions, alter the activity of the reactants, and so on. The rates and rate constants for chemical reactions are very sensitive to low concentrations of such spectator species hence, samples containing the same true initial composition of the species of interest but coming from different sources can very often give quite different apparent concentrations. Unless the experimenter is aware of the total reaction mechanism and of all possible factors that can affect either the activation energy or the reaction path, erroneous analytical results can be obtained. A detailed investigation of the simultaneous, in situ, analysis of binary amine mixtures illustrates this point. (Most systems, by the way, are less error-prone than this one.) The rate constants for the reaction of many individual organic amines with methyl iodide in acetone solvent... 

The kinetics of the Menshutkin reaction of pyridine with benzyl bromide in methanol, acetone, and acetonitrile have been studied. " Second-order rate constants for the reactions of ethyl a-haloacetate and triethylamine have been determined in aprotic dipolar ketonic and halogenated solvents, nitrogen-containing solvents, and alcoholic solvents at 30 °C. Simple and multiple regression on various solvent parameters was applied to the results. The same group made a similar study of the reactions of ethyl a-haloacetate with triethylammonium carboxylates in a wide range of protic and aprotic solvents. The kinetics of alkylation of sodium acetate by butyl bromide have been investigated in dipolar non-hydroxylic solvents. Hexamethylphosphoramide is the best solvent for this reaction. 

Abstract Supercritical antisolvent technology can precipitate polyvinylpyrrolidone (PVP) particles and crystallize paracetamol (PCM) crystals first separately and then together in the form of a solid dispersion. Supercritical carbon dioxide (SCCO2) is used as an antisolvent. For PVP particle generation, ethanol, acetone, and mixtures of ethanol and acetone are used as solvents. The initial concentration of PVP in the solution was varied between 0.5 and 5 wt%, the operation pressure between 10 and 30 MPa, and the composition of ethanol/acetone solvent mixtures between 100 and 0 wt% of ethanol at a constant temperature of 313 K. An increase in the content of the poor solvent acetone in the initial solution leads to a significant decrease in mean particle size. Fully amorphous PVP powder always precipitates for all the parameters investigated. 

SAN resins show considerable resistance to solvents and are insoluble in carbon tetrachloride, ethyl alcohol, gasoline, and hydrocarbon solvents. They are swelled by solvents such as ben2ene, ether, and toluene. Polar solvents such as acetone, chloroform, dioxane, methyl ethyl ketone, and pyridine will dissolve SAN (14). The interactions of various solvents and SAN copolymers containing up to 52% acrylonitrile have been studied along with their thermodynamic parameters, ie, the second virial coefficient, free-energy parameter, expansion factor, and intrinsic viscosity (15). 

Solution Properties. Lignin in wood behaves as an insoluble, three-dimensional network. Isolated lignins (milled wood, kraft, or organosolv lignins) exhibit maximum solubiUty in solvents having a Hildebrand s solubiUty parameter, 5, of 20.5 — 22.5(J/cm ) (10 — ll(cal/cm ) > and A// in excess of 0.14 micrometer where A]1 is the infrared shift in the O—D bond when the solvents are mixed with CH OD. Solvents meeting these requirements include dioxane, acetone, methyl ceUosolve, pyridine, and dimethyl sulfoxide. 

The fluids have reasonably good chemical resistance but are attacked by concentrated mineral acids and alkalis. They are soluble in aliphatic, aromatic and chlorinated hydrocarbons, which is to be expected from the low solubility parameter of 14.9 MPa. They are insoluble in solvents of higher solubility parameter such as acetone, ethylene glycol and water. They are themselves very poor solvents. Some physical properties of the dimethylsilicone fluids are summarised in Table 29.2. 

The popularity of this extraction method ebbs and flows as the years go by. SFE is typically used to extract nonpolar to moderately polar analytes from solid samples, especially in the environmental, food safety, and polymer sciences. The sample is placed in a special vessel and a supercritical gas such as CO2 is passed through the sample. The extracted analyte is then collected in solvent or on a sorbent. The advantages of this technique include better diffusivity and low viscosity of supercritical fluids, which allow more selective extractions. One recent application of SFE is the extraction of pesticide residues from honey [27]. In this research, liquid-liquid extraction with hexane/acetone was termed the conventional method. Honey was lyophilized and then mixed with acetone and acetonitrile in the SFE cell. Parameters such as temperature, pressure, and extraction time were optimized. The researchers found that SFE resulted in better precision (less than 6% RSD), less solvent consumption, less sample handling, and a faster extraction than the liquid-liquid method [27]. 

It is necessary to mark, that as difference to work [1] in presented research for description of electrophilicity more preferable Reichardt parameter (value ET) [2] is applied but not electrophilicity E offered by Koppel-Pahn. As analogy with [1] the exclusion from equation (2) the data for one of solvents - acetone or ethylacetate allows to obtain an equation for lg(k) with R > 0.99. 

Here as well as for lg(k), the exclusion of the most deviating data for one of solvents -acetone for AG, heptane or dioxane for E Act and AH, and benzene or heptane for AS allows to receive equations with R > 0.99. For majority of activation descriptors the polarizability as fi(n2) is least meaningful factor exception AS where is 82 also, as and for lg(k). However its exclusion decreases R from 0.95 to 0.93, that undesirable according to [6], The exclusion of other parameters from equation is more noticeable. 

Hydrogen bond donor solvents are simply those containing a hydrogen atom bound to an electronegative atom. These are often referred to as protic solvents, and the class includes water, carboxylic acids, alcohols and amines. For chemical reactions that involve the use of easily hydrolysed or solvolysed compounds, such as AICI3, it is important to avoid protic solvents. Hydrogen bond acceptors are solvents that have a lone pair available for donation, and include acetonitrile, pyridine and acetone. Kamlet-Taft a and ft parameters are solvatochromic measurements of the HBD and HBA properties of solvents, i.e. acidity and basicity, respectively [24], These measurements use the solvatochromic probe molecules V, V-die lliy I -4-n i in tan iline, which acts as a HBA, and 4-nitroaniline, which is a HBA and a HBD (Figure 1.17). 

The procedure chosen for the preparation of lipid complexes of AmB was nanoprecipitation. This procedure has been developed in our laboratory for a number of years and can be applied to the formulation of a number of different colloidal systems liposomes, microemulsions, polymeric nanoparticles (nanospheres and nanocapsules), complexes, and pure drug particles (14-16). Briefly, the substances of interest are dissolved in a solvent A and this solution is poured into a nonsolvent B of the substance that is miscible with the solvent A. As the solvent diffuses, the dissolved material is stranded as small particles, typically 100 to 400 nm in diameter. The solvent is usually an alcohol, acetone, or tetrahydrofuran and the nonsolvent A is usually water or aqueous buffer, with or without a hydrophilic surfactant to improve colloid stability after formation. Solvent A can be removed by evaporation under vacuum, which can also be used to concentrate the suspension. The concentration of the substance of interest in the organic solvent and the proportions of the two solvents are the main parameters influencing the final size of the particles. For liposomes, this method is similar to the ethanol injection technique proposed by Batzii and Korn in 1973 (17), which is however limited to 40 mM of lipids in ethanol and 10% of ethanol in final aqueous suspension. 

FIGURE 3 2 Solvent extraction efficiencies (EF) as functions of dielectric constants (D), solubility parameters (6), and polarity parameters (P and E -). Solvents studied silicon tetrachloride, carbon disulfide, n pentane. Freon 113, cyclopentane, n-hexane, carbon tetradiloride, diethylether, cyclohexane, isooctane, benzene (reference, EF 100), toluene, trichloroethylene, diethylamine, chloroform, triethylamine, methylene, chloride, tetra-hydrofuran, l,4 dioxane, pyridine, 2 propanol, acetone, ethanol, methanol, dimethyl sulfoxide, and water. Reprinted with permission from Grosjean. ... 

The kinetic and activation parameters for the decomposition of dimethylphenylsilyl hydrotrioxide involve large negative activation entropies, a significant substituent effect on the decomposition in ethyl acetate, dependence of the decomposition rate on the solvent polarity (acetone-rfe > methyl acetate > dimethyl ether) and no measurable effect of the radical inhibitor on the rate of decomposition. These features indicate the importance of polar decomposition pathways. Some of the mechanistic possibilities involving solvated dimeric 71 and/or polymeric hydrogen-bonded forms of the hydrotrioxide are shown in Scheme 18. 

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