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Dimethylsulfoxide properties

The powerful solvent properties of dimethylsulfoxide (DMSO), for example, are used to dissolve selectively the polynuclear aromatics found in oils and paraffins. The procedure is shown in Figure 2.5. [Pg.25]

Design Institute for Physical Property Data dimethylformamide dimethylsulfoxide I distribution octane number Economic Commission for Europe j European Economic Community i (Communaute Economique Europeenne)... [Pg.501]

We consider first the Sn2 type of process. (In some important Sn2 reactions the solvent may function as the nucleophile. We will treat solvent nucleophilicity as a separate topic in Chapter 8.) Basicity toward the proton, that is, the pKa of the conjugate acid of the nucleophile, has been found to be less successful as a model property for reactions at saturated carbon than for nucleophilic acyl transfers, although basicity must have some relationship to nucleophilicity. Bordwell et al. have demonstrated very satisfactory Brjinsted-type plots for nucleophilic displacements at saturated carbon when the basicities and reactivities are measured in polar aprotic solvents like dimethylsulfoxide. The problem of establishing such simple correlations in hydroxylic solvents lies in the varying solvation stabilization within a reaction series in H-bond donor solvents. [Pg.358]

Polar solvents have no effect on the rate constant of the reaction R02 + RH [56], This means that the solvation energies of the peroxyl radical R02 and TS R02 HR are very close. A different situation was observed for the reaction of cumylperoxyl radical with benzyl alcohol (see Table 7.10). The rate constant of this reaction is twice in polar dimethylsulfoxide (s = 33.6) than that in cumene (a 2.25). It was observed that the very important property of the solvent is basicity (B), that is, affinity to proton. A linear correlation... [Pg.304]

The recent introduction of non-aqueous media extends the applicability of CE. Different selectivity, enhanced efficiency, reduced analysis time, lower Joule heating, and better solubility or stability of some compounds in organic solvent than in water are the main reasons for the success of non-aqueous capillary electrophoresis (NACE). Several solvent properties must be considered in selecting the appropriate separation medium (see Chapter 2) dielectric constant, viscosity, dissociation constant, polarity, autoprotolysis constant, electrical conductivity, volatility, and solvation ability. Commonly used solvents in NACE separations include acetonitrile (ACN) short-chain alcohols such as methanol (MeOH), ethanol (EtOH), isopropanol (i-PrOH) amides [formamide (FA), N-methylformamide (NMF), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA)] and dimethylsulfoxide (DMSO). Since NACE—UV may present a lack of sensitivity due to the strong UV absorbance of some solvents at low wavelengths (e.g., formamides), the on-line coupling of NACE... [Pg.488]

Polyurethanes 96 containing 1 have been prepared by several research groups, and complex polyurethanes with an elastomeric character and good mechanical properties were described in a few patents. These polymers were obtained from 1 and diisocyanates in the presence of suitable catalysts, e.g., Braun and Bergmann used triethylamine in dimethylsulfoxide [104]. [Pg.169]

Yount et al. (2005) reported the formation of organogels using poly(vinylpyridine) (PVP) and ditopic metallopincer cross-linkers. This study provided particularly pertinent information on the dynamic elements of MSPs and elegantly demonstrated how they control the material s properties. PVP dissolved in dimethylsulfoxide (DMSO) is cross-linked with either bis-Pd - (18a) or Pt -pincer compounds (18b, Fig. 7.13 Yount et al. 2005). Addition of 5% 18a -Pd to a PVP solution results in a viscous material (77 = 6.7 Pa s), whereas the corresponding PVP 18b Pd is a gel (77 = 550 Pa s). Changing R from methyl to ethyl does not affect the thermodynamics of the pyridine/Pd interaction however, the rate of exchange decreases by approximately 2 orders of magnitude. Further studies on these materials and their... [Pg.170]

The coordination properties of this phosphine-alane were further investigated by Fontaine et al. toward the rhodium(III) precursor [RhCp Me2(DMSO)] (Cp =pentamethylcyclopentadienyl, DMSO = dimethylsulfoxide).78 According to the spectroscopic data, the DMSO molecule is retained in the corresponding complex 96, most probably by interaction of its oxygen atom with the pendant alane moiety (Scheme 55). Trimethylaluminium was added to 96 to trap DMSO and generate complex 97 related to 96. But the competition between the external and... [Pg.56]

Persistent interactions are not limited to hydrogen bonds. We mention for example those appearing in solutions of molecules with a terminal C=0 or C=N group dissolved in liquids such as acetone or dimethylsulfoxide. These solvents prefer at short distances an antiparallel orientation which changes at greater distances to a head-to-tail preferred orientation. The local antiparallel orientation is somewhat reinforced by the interaction with the terminal solute group and it is detected by the PCM calculation of nuclear shielding and vibrational properties. Recent experimental correlation studies [25] have confirmed the orientational behaviour of these solvents found in an indirect way from continuum calculations. The physical effect found in this class of solvent-solute pairs seems to be due to dispersion forces. [Pg.14]

Acceptor numbers of various solvents are also listed in Table 3. The values range from zero, for the reference solvent -hexane, to about 130, for trifluoro-methane sulfonic acid. For instance, the acceptor number of aliphatic alcohols varies between 27 and 41 (methanol). Within the group of dipolar aprotic solvents there are considerable differences in acceptor properties. Solvents such as propylenecarbonate, tetramethylene-sulfone, acetonitrile, dimethylsulfoxide, or nitromethane are stronger acceptors than solvents such as acetone, A-methylpyrroli-done, or dimethylacetamide. The acceptor strengths of amine solvents vary considerably with the degree of substitution. For instance, triethylamine has no acceptor properties. [Pg.20]

It should be noted that the different structures of amylose and amylopectin confer distinctive properties to these polysaccharides (Table II). The linear nature of amylose is responsible for its ability to form complexes with fatty acids, low-molecular-weight alcohols, and iodine these complexes are called clathrates or helical inclusion compounds. This property is the basis for the separation of amylose from amylopectin when starch is solubilized with alkali or with dimethylsulfoxide, amylose can be precipitated by adding 1-butanol and amylopectin remains in solution. [Pg.20]

A series of unusual amidinium benzomorphans has been described by Strauss et a/.<53 55) where some members of the series exhibit narcotic antagonist properties. Their synthesis involves a meta bridging process of di- and trinitronaphthalenes (116) with a-phenyl N,N-dimethylacetamidine (117) to produce two isomeric benzazocine amidinium nitronates as their a-phenyl-N,N-dimethylacetamidinium salts (AmH+). The benzomorphan 118 is formed in ethanolic solution, whereas the isomeric benzazocine (119) results from reaction in dimethylsulfoxide. [Pg.173]

HP he study of the behavior of electrolytes in mixed solvents is currently arousing considerable interest because of its practical and fundamental implications (1). Among the simpler binary solvent mixtures, those where water is one component are obviously of primary importance. We have recently compared the effects of small quantities of water on the thermodynamic properties of selected 1 1 electrolytes in sulfolane, acetonitrile, propylene carbonate, and dimethylsulfoxide (DMSO). These four compounds belong to the dipolar aprotic (DPA) class of solvents that has received a great deal of attention (2) because of their wide use as media for physical separations and chemical and electrochemical reactions. We interpreted our vapor pressure, calorimetry, and NMR results in terms of preferential solvation of small cations and anions by water and obtained... [Pg.150]

Weiner, J. H., Macisaac, D. P., Bishop, R. E., and Bilous, P. T., 1988, Purification and properties of Escherichia coli dimethylsulfoxide reductase, an iron-sulfur molybdoenzyme with broad substrate specificity, J. Bacteriol. 270 2505n2520. [Pg.485]


See other pages where Dimethylsulfoxide properties is mentioned: [Pg.203]    [Pg.1]    [Pg.251]    [Pg.155]    [Pg.407]    [Pg.598]    [Pg.962]    [Pg.181]    [Pg.303]    [Pg.177]    [Pg.275]    [Pg.22]    [Pg.176]    [Pg.689]    [Pg.129]    [Pg.385]    [Pg.177]    [Pg.177]    [Pg.360]    [Pg.5]    [Pg.52]    [Pg.372]    [Pg.132]    [Pg.216]    [Pg.406]    [Pg.230]    [Pg.373]    [Pg.383]    [Pg.9]    [Pg.272]    [Pg.381]    [Pg.797]   
See also in sourсe #XX -- [ Pg.7 ]




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