Acetone-water-methanol mixture

Physical properties of the acid and its anhydride are summarized in Table 1. Other references for more data on specific physical properties of succinic acid are as follows solubiUty in water at 278.15—338.15 K (12) water-enhanced solubiUty in organic solvents (13) dissociation constants in water—acetone (10 vol %) at 30—60°C (14), water—methanol mixtures (10—50 vol %) at 25°C (15,16), water—dioxane mixtures (10—50 vol %) at 25°C (15), and water—dioxane—methanol mixtures at 25°C (17) nucleation and crystal growth (18—20) calculation of the enthalpy of formation using semiempitical methods (21) enthalpy of solution (22,23) and enthalpy of dilution (23). For succinic anhydride, the enthalpies of combustion and sublimation have been reported (24). 

Selectivity for the methylene group has been mostly the focus of interest and was determined by a host of investigators. Data obtained by Karger et al. (148) we shown in Fig. 26. It is seen that the selectivity is a linear ftinction of the solvent composition, when water-methanol mixtures are used as the mobile phase, and decreases with the water content of the eluent. The linearity characteristic of methanol mixtures is absent in the data for water-acetonitrile and water-acetone mixtures but again... 

A more recent study using dry acetone and acetone-water mixtures was reported by Nilsson and Beronius (22). For acetone containing 0.005% by weight they found Ao, KA, and a to be 195.0 fi-1 cm2 eq-1, 4202, and 9.3 A, respectively. All three of these parameters were found to decrease as the concentration of water was increased. They suggest that the change in these parameters is a result of the strong solvation of the salt by the water. Nilsson (23) conducted similar studies on acetone and methanol mixtures and noted similar results. 

Complexes of Me [14]-4,1 l-dieneN4 are, however, more conveniently prepared by reaction of the dianiono salt of the free organic ligand with metal carbonates or acetates in methanol or water-methanol mixtures. The isolation of the free organic ligand salt is achieved by the reaction of the monoperchlorate, or similar salt of ethylenediamine, with acetone or mesityl oxide (4-methyl-3-penten-2-one). The material can also be isolated from the reaction mixture produced by tris(ethylenediamine)iron(lI) perchlorate and acetone. The preparations described here involve the reaction of the ciperchlorate or bis(trifluoromethanesulfonate) salt of Me [14]-4,1 l-dieneN4 with the appropriate metal ion. 

These binary interaction parameters were obtained using the program WS.EXE described in Appendix. D.5, and the data files am200.dat, mw250.dat, and aw250.dat for acetone-methanol, methanol-water, and acetone-water binary mixtures, respectively.)... 

If a compound is poorly soluble in water, the pKa may be difficult to measure. One way around this problem is to measure the apparent pKa of the compound in solvent and water mixtures and then extrapolate the data back to a purely aqueous medium using a Yasuda-Shedlovsky plot. The organic solvents most frequently used are methanol, ethanol, propanol, dimethylsulphoxide (DMSO), dimethyl formamide (DMFA), acetone and tetrahydrofuran (THF). However, methanol is by far the most popular because its properties are closest to water. A validation study in water-methanol mixtures has been reported by Takacs-Novdk et al. (1997) and the determination of the pfCas of ibuprofen and quinine in a range of organic solvent-water mixtures has been reported by Avdeef et al. (1999). 

Polar lipids are only sparingly soluble in hydrocarbon solvents but most polar lipids dissolve in more polar solvents such as methanol, ethanol, or chloroform. Chloroform-methanol mixtures dissolve most polar lipids but polyphosphoinositides or lyso-phospholipids are poorly soluble in this solvent mixture. Water-methanol mixtures may dissolve significant amounts of the most polar lipids such as gangliosides. Acetone is a poor solvent for phospholipids but glycolipids are more soluble in this solvent. 

Step 1 Start-up. In this step, the acetone and methanol mixture is placed in the bottom of the column together with some entrainer. Heat is added in the reboiler and vapor boil-up moves up the column. At the same time, entrainer water is fed continuously into the middle of the column at a flowrate (to be specified). The column is run under total reflux conditions until the acetone of the top product reaches its purity specification of 95 mol%. 

Many investigators have studied substitution at iron(II)-diimine complexes in binary aqueous mixed solvents and other investigators in aqueous salt solutions. Some years ago the results of addition of salts and a cosolvent were assessed, for [Fe(5N02phen)3] in water, t-butyl alcohol, acetone, dimethyl sulfoxide, and acetonitrile mixtures containing added potassium bromide or tetra-n-butylammonium bromide. " Now the effects of added chloride, thiocyanate, and perchlorate on dissociation and racemization rates of [Fe(phen)3] in water-methanol mixtures have been established. The main explanation is in terms of increasing formation of ion pairs as the methanol content of the medium increases, but it is somewhat spoiled by the (unnecessary) assumption of a mechanism involving interchange within the ion pairs. Kip values (molar scale) of 11,18, and 25 were estimated for perchlorate, chloride, and thiocyanate in 80% (volume) methanol at 298.2 K. These values may be compared with values of 20, 7, and 4 for association between [Fe(phen)3] and iodide, " [Fe(bipy)3] and iodide, " and [Fe(phen)3] and cyanide " " in aqueous solution (at 298.2,... 

An important publication by Kost et al. (63JGU525) on thin-layer chromatography (TLC) of pyrazoles contains a large collection of Rf values for 1 1 mixtures of petroleum ether-chloroform or benzene-chloroform as eluents and alumina as stationary phase. 1,3- and 1,5-disubstituted pyrazoles can be separated and identified by TLC (Rf l,3>i y 1,5). For another publication by the same authors on the chromatographic separation of the aminopyrazoles, see (63JGU2519). A-Unsubstituted pyrazoles move with difficulty and it is necessary to add acetone or methanol to the eluent mixture. Other convenient conditions for AH pyrazoles utilize silica gel and ethyl acetate saturated with water (a pentacyanoamine ferroate ammonium disodium salt solution can be used to visualize the pyrazoles). 

The general reaction procedure and apparatus used are exactly as described in Procedure 2. Ammonia (465 ml) is distilled into a 2-liter reaction flask and to this is added 165mlofisopropylalcoholandasolutionof30g(0.195 mole) of 17/ -estradiol 3-methyl ether (mp 118.5-120°) in 180 ml of tetrahydrofuran. The steroid is only partially soluble in the mixture. A 5 g portion of sodium (26 g, 1.13 g-atoms total) is added to the stirred mixture and the solid dissolves in the light blue solution within several min. As additional metal is added, the mixture becomes dark blue and a solid (matted needles) separates. Stirring is inefficient for a few minutes until the mass of crystals breaks down. All of the sodium is consumed after 1 hr and 120 ml of methanol is then added to the mixture with care. The product is isolated as in Procedure 4h 2. After being air-dried, the solid weighs 32.5 g (ca. 100% for a monohydrate). A sample of the material is dried for analysis and analyzed as described in Procedure 2 enol ether, 91% unreduced aromatics, 0.3%. The crude product may be crystallized from acetone-water or preferably from hexane. 

Following the completion of the polymerization process, the beaded polymer is recovered from the suspension mixture and freed from the stabilizer, diluents, and traces of monomers and initiators. For laboratory and small-scale preparation, repeated washings with water, methanol, or acetone are appropriate. Complete removal of the monomer diluent, solvents, and initiator, especially from macroporous resin, may require a long equilibration time with warm methanol or acetone. In industry, this is usually accomplished by stream stripping. 

A mixture consisting of 22.7 g potassium o-bromobenzoate, 16.6 g 2,6-dichloro-3-methvlani-line, 12 ml N-ethylmorpholine, 60 ml diethylene glycol dimethyl ether, and 1.0 g anhydrous cupric bromide is heated in a nitrogen atmosphere at 145 C to 155°C for 2 hours. The reaction mixture is diluted with 60 ml diethylene glycol dimethyl ether and acidified with 25 ml concentrated hydrochloric acid. The acidic mixture is diluted with 100 ml of water and the liquid phase decanted from the insoluble oil. The insoluble oil is stirred with methanol and the crystalline N-(2,6-dichloro-3-methylphenyl)anthranilic acid which separates is collected and washed with methanol. The product, after recrystallization from acetone-water mixture melts at 248 C to 250°C. 

To obtain anthocyanins closer to their natural state, a number of researchers have used neutral solvents for initial extraction such as 60% methanol, n-butanol, cold acetone, mixtures of acetone, methanol, and water, or simply water. Methanol is the most common solvent used for anthocyanin extraction. Metivier et al. (1980) compared the efficiency of extraction with three different solvents (methanol, ethanol, and water) and different acids, and found that methanol extraction was 20% more effective than ethanol and 73% more effective than water when used for anthocyanin recovery from grape pomace. 

The most critical decision to be made is the choice of the best solvent to facilitate extraction of the drug residue while minimizing interference. A review of available solubility, logP, and pK /pKb data for the marker residue can become an important first step in the selection of the best extraction solvents to try. A selected list of solvents from the literature methods include individual solvents (n-hexane, " dichloromethane, ethyl acetate, acetone, acetonitrile, methanol, and water ) mixtures of solvents (dichloromethane-methanol-acetic acid, isooctane-ethyl acetate, methanol-water, and acetonitrile-water ), and aqueous buffer solutions (phosphate and sodium sulfate ). Hexane is a very nonpolar solvent and could be chosen as an extraction solvent if the analyte is also very nonpolar. For example, Serrano et al used n-hexane to extract the very nonpolar polychlorinated biphenyls (PCBs) from fat, liver, and kidney of whale. One advantage of using n-hexane as an extraction solvent for fat tissue is that the fat itself will be completely dissolved, but this will necessitate an additional cleanup step to remove the substantial fat matrix. The choice of chlorinated hydrocarbons such as methylene chloride, chloroform, and carbon tetrachloride should be avoided owing to safety and environmental concerns with these solvents. Diethyl ether and ethyl acetate are other relatively nonpolar solvents that are appropriate for extraction of nonpolar analytes. Diethyl ether or ethyl acetate may also be combined with hexane (or other hydrocarbon solvent) to create an extraction solvent that has a polarity intermediate between the two solvents. For example, Gerhardt et a/. used a combination of isooctane and ethyl acetate for the extraction of several ionophores from various animal tissues. 

Solubilities of LaCl3-7H20 and of NdCl3-6H20 in acetone/water mixtures have been reported, and compared with those for chlorides of barium and of the alkali metals (323). For these trichlorides, the solubility increases as acetone is added to water up to about 15% acetone, then decreases (LaCl3 and NdCl3 are effectively insoluble in acetone itself). There is also some information, presented only in graphical form, on solubilities of praseodymium trichloride in water-rich methanol, ethanol, and ether mixtures (314), and one fact on yttrium trichloride in a water/ether mixture (264). 

The sequence of the selectivities towards cations is also solvent dependent for dibenzo-18-crown-6 [11] the sequence is K+ > Na+ > Rb+ > Cs+ in water, methanol, dimethylformamide and dimethyl sulfoxide (Dechter and Zink, 1976 Srivanavit et al., 1977), whereas it is Na+ > K+ > Rb+ > Cs+ in acetonitrile (Hofmanova et al., 1978). A reversal of the K+/Na+ selectivity on going to apolar aprotic solvents was also observed for fluorenyl salts (Wong et al., 1970). Whereas for alkali cations the sequence of binding constants and enthalpies are the same in water (Izatt et al., 1976a), they differ considerably in methanol/water mixtures (Izatt et al., 1976b), dimethyl sulfoxide and acetone (Arnett and Moriarity, 1971). 

Silica plates were activated at 120°C for 30 min then cooled in a desiccator. Separations were performed with dichloromethane-methanol mixed in various volume ratios. C18 plates were not pretreated and separation was carried out with mixtures of acetone-water. It was established that both adsortion and RP-TLC can be applied for the separation of tetraphenylporphyrin pigments. Topological indexes may help the better understanding the physicochemical procedures underlying the separation [309],... 

Ellingboe, J. L. and Runnels, J.H. Solubilities of sodium carbonate and sodinm bicarbonate in acetone-water and methanol-water mixtures. J. Chem. Eng. Data, 11 (3) 323-324,1966. 

The construction and preparation of these electrodes were described in chapter 3.1. The modern version of this electrode, produced by Radelkis, Budapest, is a compromise between the original construction described by Pungor etal. [310,311, 313] and a system with a compact membrane. Electrodes with silver chloride, bromide and iodide are manufactured. According to the manufacturer these electrodes should be soaked before use for 1-2 hours in a dilute solution of the corresponding silver halide. They can be used in a pH region from 2 to 12 and the dFisE/d log [X ] value is approximately 56mV. These electrodes can be employed for various automatic analytical methods (see chapter 5). They can readily be used in mixtures of alcohol with water, for example up to 90% ethanol and methanol and up to 4% n-propanol and isopropanol [196]. In mixtures of acetone-water and dimethylformamide-water, they work reliably only in the presence of a large excess of water [197]. 

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