Sulfolane dielectric constant

Electronic and Electrical Applications. Sulfolane has been tested quite extensively as the solvent in batteries (qv), particularly for lithium batteries. This is because of its high dielectric constant, low volatUity, exceUent solubilizing characteristics, and aprotic nature. These batteries usuaUy consist of anode, cathode polymeric material, aprotic solvent (sulfolane), and ionizable salt (145—156). Sulfolane has also been patented for use in a wide variety of other electronic and electrical appHcations, eg, as a coil-insulating component, solvent in electronic display devices, as capacitor impregnants, and as a solvent in electroplating baths (157—161). 

The dissociation is much more favoured in DMSO than in sulfolane, in spite of the magnitude of their dielectric constants which are almost identical, i.e. 46.68 and 43.3, respectively. The favourable dissociation,could be ascribed to extraordinarily strong solvation by DMSO around the cations... 

On the basis of the results in acetonitrile, it might be reasonable to assume that the values for A//het(R-R ) and AG°het(R-R ) are apparently close to each other also in sulfolane, since the dielectric constant (43.3) and the donor number (14.8) of this solvent are close to those of acetonitrile (37.5 and 14.1, respectively). On the basis of this assumption, Arnett s equation (28) was examined for reactions of type (23). For these reactions, except for [3-2], only the AGhet(R-R ) values are avtiilable. As shown in Fig. 3, the values for this system are about 10 kcal moP less than predicted from (28). The negative deviation can also be ascribed to steric congestion in these hydrocarbon molecules. The large negative deviations, similar to those observed in sulfolane, are also seen in Fig. 3 for the values of AGSet(R-R ) in DMSO. 

Another method of reducing ion pairing is to use a solvent having a high dielectric constant, such as sulfolane ... 

This material has a dielectric constant of 43.3 at 30UC it has very low proton basicity (pA, = — 12.9) and is a weak Lewis base (117). Indeed, sulfolane is an excellent solvent for the rhodium catalytic system, giving good rates... 

The changes in the o-Ps lifetimes should be explainable on the basis of eq. (10) and its connection with the free volume. It is interesting to note that in sulfolan, the latter does not change at the liquid/plastic phase transition. The changes in I3 cannot yet be quantified. Changes in the dielectric constant (in the Onsager radius) should be one of the main factors to consider. 

Conductometric and spectrophotometric behavior of several electrolytes in binary mixtures of sulfolane with water, methanol, ethanol, and tert-butanol was studied. In water-sulfolane, ionic Walden products are discussed in terms of solvent structural effects and ion-solvent interactions. In these mixtures alkali chlorides and hydrochloric acid show ionic association despite the high value of dielectric constants. Association of LiCl, very high in sulfolane, decreases when methanol is added although the dielectric constant decreases. Picric acid in ethanol-sulfolane and tert-butanol-sulfolane behaves similarly. These findings were interpreted by assuming that ionic association is mainly affected by solute-solvent interactions rather than by electrostatics. Hydrochloric and picric acids in sulfolane form complex species HCl and Pi(HPi). ... 

Useful solvents must themselves resist oxidation or reduction, should dissolve suitable ionic solutes and nonelectrolytes, and in addition should be inexpensive and obtainable in high purity. Kratochvil indicated that the most potentially useful solvents are those that have a dielectric constant greater than about 25 and have Lewis-base properties. Some solvents meeting these criteria are acetonitrile, dimethyl-sulfoxide, dimethylformamide, dimethylacetamide, propylene carbonate, ethylene carbonate, formamide, sulfolane, and y-butyrolactone. Solvents of the Lewis-base type show specific solvation effects with many metal cations (Lewis acids). Thus acetonitrile functions as a Lewis base toward the silver ion. At the same time it reacts but little with the hydrogen ion. 

Figure 2 The fraction of carbon monoxide as a function of the dielectric constant of the solvent used. The results were obtained by irradiation of the naked CdS ( ) and Q-TiOj/SiOj photocatalyst ( ). Solvents used were (a) carbon tetrachloride, (b) dichloromethane, (c) 2-propanol, (d) propionitrile, (e) ethylene glycol monoethyl ether, (f) acetonitrile, (g) sulfolane, (h) propylene carbonate, and (i) water.

Both DMSO and sulfolane are extensively used in the chemical, pharmaceutical, polymer, and electronics industries as polar aprotic solvents, with unique properties such as a high dielectric constant, high polarity, and high miscibility with organic and aqueous materials. For example, sulfolane finds use in the refining industry for the separation of benzene, toluene, and xylene (BTX) fractions from paraffins. 

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. 

There is always a certain amount of ring-chlorinated by-product formed in the nitrations. Reactions carried out either by using an excess of aromatics as solvent (TiCU is miscible with many aromatics) or in carbon tetrachloride solution, always contain chlorinated by-products. The amount of chlorinated by-products can be decreased by using solvents with higher dielectric constants. Tetramethyiene sulfone (sulfolane) was found to be a suitable solvent for the TiCL and also for most of the other Lewis-acid-catalyzed nitrations. It has excellent solvent properties for aromatics and the catalysts as well as for nitryl halides. It is superior to other solvents that can be used, such as nitromethane. As it is completely miscible with water, the work-up of the reaction mixtures after the reactions are completed is very easy. 

Boron nitride Hexafluoroethane Sulfur hexafluoride Tributyl phosphate dielectric ceramics Ytterbium oxide dielectric chemical Chlorotrifluoromethane dielectric constant enhancer, condensers N-Nitrosodimethylamine dielectric elec, equipment Sulfolane... 

Polyoxyalkylene-modified silane (SiHX) is combined with non-aqueous solvent and electrolyte salt to form non-aqueous solution. Preferred SiHX is 0.001 to 0.1% by volume of solution. Light metals such as Li, Na, K, Mg, Ca, and A1 are used as electrolyte salts in concentration of 0.5 to 2 M. Suitable solvents include aprotic dielectric constant compounds such as ethylene carbonate, y-butyrolactone, and aprotic low viscosity solvents such as dimethylcarbonate, sulfolane, and acetic acid esters. 

Alcohol Homologation Solvent and promoter effects on the cobalt carbonyl catalysed methanol homologation have been studied under synthesis gas pressure.The main product in a methanol/hydrocarbon two-phase system is 1,1-dimethoxyethane (ca. 70 selectivity).Using similar iodide promoted cobalt catalysts, R2C 0Me)2 and dimethylcarbonate are converted to acetaldehyde with up to 87 selectivity.Ruthenium in the presence of Co, 12 and dppe improves the ethanol selectivity in the homologation of dimethylether. Best results are achieved in inert solvents with high dielectric constants, e.g. sulfolane (e = 44), and with BF3 as activator. 

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