Water methanol, 210 Table

From Table 12.3 we find that the polarity index is 10.2 for water and 5.1 for methanol. Using equation 12.30, the polarity index for a 60 40 water-methanol mixture is... 

Isoprene [78-79-5] (2-methyl-1,3-butadiene) is a colorless, volatile Hquid that is soluble in most hydrocarbons but is practically insoluble in water. Isoprene forms binary azeotropes with water, methanol, methylamine, acetonitrile, methyl formate, bromoethane, ethyl alcohol, methyl sulfide, acetone, propylene oxide, ethyl formate, isopropyl nitrate, methyla1 (dimethoxymethane), ethyl ether, and / -pentane. Ternary azeotropes form with water—acetone, water—acetonitrile, and methyl formate—ethyl bromide (8). Typical properties of isoprene are Hsted in Table 1. 

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). 

The difference in retention times between the 920,000 PEO and the 21,000 PEO in Table 17.9 can be used as a measure of the void or pore volume that effectively provides the linear separation range for these columns in water and in a water/methanol mixture. The better separation efficiency of the Shodex columns over the TSK columns is partially related to the larger void volumes of the Shodex columns than the TSK columns. The difference in void volumes for the Shodex, TSK GM-PW, and TSK GM-PWxl columns is partially attributed to the difference in the inner diameters of the three columns, which are 8 (Shodex), 7.8 (TSK GM-PW) and 7.5 (TSK GM-PWxi.) mm. Table 17.9 also... 

TABLE 17.8 Separation Efficiency of Four Linear Columns in Water and Water/Methanol for Polyethylene Oxide Standards... 

Solvent can affect separation in two different ways. Because water is a better solvent for these four columns than water/methanol, based on the swelling or void volume of the columns in Table 17.9, the separation should be better in water than in water/methanol. The relative viscosity of a 0.5% PEO standard from Aldrich (Lot No. 0021kz, MW 100,000) in water and in water/methanol with 0.1 M lithium nitrate is 1.645 and 1.713, respectively. This indicates that the hydrodynamic volume of PEO in water is smaller than in water/methanol. The difference in hydrodynamic volume between two PEO standards should also be larger in water/methanol than in water. Hence, the separation for PEO should be better in water/methanol than in water. The results in Table 17.8 indicate that separation efficiency is better in water than in water/methanol... 

Several factors can contribute to the difference in retention times for PEO in different mobile phases the viscosity of a mobile phase, the hydrodynamic volume of a PEO, and the swelling or void volume of a column. Shodex and TSK columns should swell more in water than in water/methanol, and PEO should therefore come out later in water than in water/methanol. PEO should also elute later in water than in water/methanol because water/methanol is a better solvent for PEO than water. The viscosity of the 50 50 water/methanol mobile phase is higher than the viscosity of water. PEO should therefore elute later in water/methanol than in water due to the difference in viscosity. The results in Table 17.9 indicate that the difference in retention time for PEO in water and in water/methanol depends more on the swelling of columns and the hydrodynamic volumes of PEO than the viscosities of mobile phases. 

PVP K-120 peaks are distorted at the high molecular weight end for tht TSK-PW column in water and in water/methanol. The distortion is more severe in water than in water/methanol. If the distortion is caused by poor separation of the TSK GM-PW column, then the distortion should be more severe in water/methanol than in water, as it was shown earlier that the resolution should be better in water than in water/methanol. The distortion is probably caused by interaction between PVP K-120 and the TSK GM-PW column. There is a high molecular weight shoulder in the PVP K-90 peak for the TSK GM-PW column, especially in water. This may be the reason why M for PVP K 90 determined with the TSK GM-PW column are higher than from the other columns, as shown in Tables 17.3-17.6. 

In contrast with water, methanol, ammonia, and other substances in Table 2.1, carbon dioxide, methane, ethane, and benzene have zero dipole moments. Because of the symmetrical structures of these molecules, the individual bond polarities and lone-pair contributions exactly cancel. 

Dimethylformamide is also a suitable solvent [50], it has, however, the disadvantage of being oxidized at fairly low potentials to A-acyloxy-iV-methyl formamide [51]. The influence of the composition of the ternary system water/methanol/dimethyl-formamide on the material and current yield has been systematically studied in the electrolysis of co-acetoxy or -acetamido substituted carboxylates [32]. Acetonitrile can also be used, when some water is.added [52]. The influence of various solvents on the ratio of Kolbe to non-Kolbe products is shown in Table 1 [53]. 

A rapid technique for the identification of surfactants in consumer products by ESI-MS was proposed by Ogura and co-workers [6], After a simple preparation procedure, infusion of the sample, which was prepared in a water/methanol mixture (50 50) containing 10 mM ammonium acetate, allowed assignment of the [M + NH4]+ ions of Cio- and Ci2-mono- and -diglucoside in the mass spectrum (ion masses as in Table 2.7.1). The approach even permitted quantitative analysis when deuterated internal standards were used. 

Polymer Solubility. The modified polymers were soluble in DMSO, dimethylacetamide, dimethylformamide and formic acid. They were insoluble in water, methanol and xylene. Above about 57% degree of substitution, the polymers were also soluble in butyrolactone and acetic acid. Solubility parameters were determined for each polymer by the titration procedure as described in the literature (65). The polymer was dissolved in DMSO and titrated with xylene for the low end of the solubility parameter and a second DMSO solution was titrated with water for the high end of the solubility parameter range. These solubility parameters and some other solubility data are summarized in Table II. 

Polyphenols were eluted with various mixtures of water-methanol (8 2, 7 3, 6 4 and 5 5 v/v). Further purification was achieved on a cellulose layer, and on an ODS SPE cartridge. The TLC conditions used for the measurements are listed in Table 2.38. The RF values measured on the HPTLC plates are compiled in Table 2.39. 

As for water we can expect the MVIEs for other hydrogen bonded systems in low temperature liquids to have an appreciable inverse librational contribution, and this is the case for those alcohols which have been investigated. The data on the isotopic methanols (Table 12.5) confirm this. As expected from the discussion above, the MVIE for OH/OD substitution is negative. Also the isotope effects seem to be approximately additive, MVIE(CH3/CD3) + MVIE(OH/OD) MVIE(CH3OH/CH3OD) 5.3 x 10-3 - 1.6 x 10-3 - 3.7 x 10-3 (observed = 2.9 x 10 3). 

Also inconclusive are the results of the quenching experiments shown in Table 12. Thus, reaction of the ion with pyridine has been reported to yield nortricyclene, while water and methanol yield mainly 2-exo-norbomyl derivatives. If the ion is classical, the production of alcohols and methyl ethers is regarded as due to condensation of it and water, methanol, or methoxide. The production of nortricyclene would then be regarded as due to a deep seated reaction of pyridine with ion [2] leading to a transition state resembling pyridine, a proton and nortricyclene. 

The complex formation constants presented in Tables 2—4 were measured in water, methanol or ethanol. There is no guarantee, however, that the selectivity sequences thus found will apply in lipid membranes. This being so, it becomes necessary to investigate the stability of a given complex as a function of the embedding medium. 

A regular increase in log K as the methanol portion of water-methanol mixtures is increased is seen in Table 16 for the reaction of either Na+ or K+ with benzo-15-crown-5. The regular increases in log K values through the solvent range are accompanied by nearly compensating changes in the AH° and AS0 values. Also, the total changes in log K... 

In developing the reactivity scale, Nielsen first investigated the transformation rates of 25 PAHs and four derivatives of anthracene in water-methanol-dioxane solutions, taken as a model of wet particles, and containing small amounts of dinitrogen tetroxide and nitric and nitrous acids. The measured half-lives and relative rates are shown in Table 10.29. The range of reactivities in solution for PAHs of different structures is remarkable, from 100,000 (arbitrarily set) for an-thanthrene (XXXII) to <0.2 for the least reactive compounds ... 

Table 1.3 provides rate constants for the decay of selected carbocations and oxocar-bocations in H2O, TFE, and HFIP. As a general comment, water, methanol, and ethanol are highly reactive solvents where many carbocations that are written as free cations in standard textbooks have very short lifetimes. The diphenylmethyl cation, with two conjugating phenyl groups, has a lifetime in water of only 1 ns. Cations such as the benzyl cation, simple tertiary alkyl cations such as tert-butyl, and oxocarbocations derived from aldehydes and simple glycosides, if they exist at all, have aqueous lifetimes in the picosecond range, and do not form and react in water as free ions. This topic is discussed in more detail in Chapter 2 in this volume. 

Stab Sensitivities at Various Densities are given in Table listed on p 202 of Ref 34 Storage, MF is stored under water and trans-ported in a wet condition, because in the dry state it is extremely sensitive to any mechanical action. In winter it i s stored in 50/50—water/methanol or water/ethanol. 

Here, A denotes an add of type HA-, HA or BH+, and z and q denote the charge and the radius, respectively, of species i. The influence of permittivity on p/C, depends on the charges, radii and the charge locations of the add and its conjugate base. Table 3.3 shows the pKa values of some acids and add-base indicators in water, methanol and ethanol [3], The solvent effects on pK l are smaller for BH+-type adds than for HA- or HA-type acids. For the BH+-type acids, zA=l and zB=0 in Eq. (3.16), and the influence of solvent permittivity is expeded to be small. 

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