Carbon disulfide constant

Arsenic tribromide (arsenic(III) bromide), AsBr, is similar to the trichloride. The dielectric constant at 35°C is 8.33. The compound is usually made by treating arsenic with a solution of bromine in carbon disulfide. 

Pure carbon disulfide is a clear, colorless Hquid with a deHcate etherHke odor. A faint yellow color slowly develops upon exposure to sunlight. Low-grade commercial carbon disulfide may display some color and may have a strong, foul odor because of sulfurous impurities. Carbon disulfide is slightly miscible with water, but it is a good solvent for many organic compounds. Thermodynamic constants (1), vapor pressure (1,2), spectral transmission (3,4), and other properties (1,2,5—7) of carbon disulfide have been deterrnined. Principal properties are Hsted in Table 1. 

Thermodynamic calculations for reactions forming carbon disulfide from the elements are compHcated by the existence of several known molecular species of sulfur vapor (23,24). Thermochemical data have been reported (12). Although carbon disulfide is thermodynamically unstable at room temperature, the equiHbtium constant of formation increases with temperature and reaches a maximum corresponding to 91% conversion to carbon disulfide at about 700°C. Carbon disulfide decomposes extremely slowly at room temperature in the absence of oxidizing agents. 

Sulfur vapor is an equiUbrium mixture of several molecular species, including Sg, S, and S2. The equiUbrium shifts toward S2 at higher temperatures and lower pressures. The overall reaction is endothermic and theoretically consumes 1950 kj/kg (466 kcal/kg) of carbon disulfide when the reactants are at 25°C and the products are at 750°C. Most of the heat input goes into dissociation of sulfur vapor to the reactive species, S2. Equation 25 is slightly exothermic when the reactants are at a constant temperature of 750°C. 

Extensive research has been conducted on catalysts that promote the methane—sulfur reaction to carbon disulfide. Data are pubhshed for sihca gel (49), alurnina-based materials (50—59), magnesia (60,61), charcoal (62), various metal compounds (63,64), and metal salts, oxides, or sulfides (65—71). Eor a sihca gel catalyst the rate constant for temperatures of 500—700°C and various space velocities is (72)... 

It has been proposed that aromatic solvents, carbon disulfide, and sulfur dioxide form a complex with atomic chlorine and that this substantially modifies both its overall reactivity and the specificity of its reactions.126 For example, in reactions of Cl with aliphatic hydrocarbons, there is a dramatic increase in Ihe specificity for abstraction of tertiary or secondary over primary hydrogens in benzene as opposed to aliphatic solvents. At the same time, the overall rate constant for abstraction is reduced by up to two orders of magnitude in the aromatic solvent.1"6 The exact nature of the complex responsible for this effect, whether a ji-coinplex (24) or a chlorocyclohexadienyl radical (25), is not yet resolved.126- 22... 

The molecule S12, like Se, is of Dsd symmetry but in the soHd state it occupies sites of the much lower C211 symmetry [163]. Due to the low solubihty and the thermal decomposition on melting only solid state vibrational spectra have been recorded [2,79]. However, from carbon disulfide the compound Si2-CS2 crystallizes in which the S12 molecules occupy sites of the high Sg symmetry which is close to 03a [163]. The spectroscopic investigation of this adduct has resulted in a revision [79] of the earher vibrational assignment [2] and therefore also of the earlier force constants calculation [164]. In Fig. 24 the low-temperature Raman spectra of S12 and Si2-CS2 are shown. 

The dispersion interaction is nicely isolated from other factors by examining the solutes in mixtures of heptane and carbon disulfide nonpolar solvents of similar dielectric constant, but quite different refractive index. Under these conditions there is a better than 0.95 correlation between VM-h and the McRae term as illustrated for 27ii9Sn H in Fig. 7. 

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. ... 

Figure 18. Correlations between the solubility of cmchonidme and the reported empirical polarity (A) and dielectric constants (B) of 48 solvents [66]. Those solvents are indicated by the numbers in the figures 1 cyclohexane 2 n-pentane 3 n-hexane 4 triethylamine 5 carbon tetrachloride 6 carbon disulfide 7 toluene 8 benzene 9 ethyl ether 10 trichloroethylene 11 1,4-dioxane 12 chlorobenzene 13 tetrahydrofuran 14 ethyl acetate 15 chloroform 16 cyclohexanone 17 dichloromethane 18 ethyl formate 19 nitrobenzene 20 acetone 21 N,N-drmethyl formamide 22 dimethyl sulfoxide 23 acetonitrile 24 propylene carbonate 25 dioxane (90 wt%)-water 26 2-butanol 27 2-propanol 28 acetone (90 wt%)-water 29 1-butanol 30 dioxane (70 wt%)-water 31 ethyl lactate 32 acetic acid 33 ethanol 34 acetone (70 wt%)-water 35 dioxane (50 wt%)-water 36 N-methylformamide 37 acetone (50 wt%)-water 38 ethanol (50 wt%)-water 39 methanol 40 ethanol (40 wt%-water) 41 formamide 42 dioxane (30 wt%)-water 43 ethanol (30 wt%)-water 44 acetone (30 wt%)-water 45 methanol (50 wt%)-water 46 ethanol (20 wt%)-water 47 ethanol (10 wt%)-water 48 water. [Reproduced by permission of the American Chemical Society from Ma, Z. Zaera, F. J. Phys. Chem. B 2005, 109, 406-414.]...

The C NMR chemical shifts and one-bond coupling constants J( C—H) have been obtained for 2,1,3-benzothiadiazole, 2,1,3-benzoselenadiazole, and 2,1,3-benzooxadiazole in carbon disulfide <74OMR(6)430>. 

Water freezes to ice at 0°C expands by about 10% on freezing boils at 100°C vapor pressure at 0°, 20°, 50°, and 100°C are 4.6, 17.5, 92.5, and 760 torr, respectively dielectric constant 80.2 at 20°C and 76.6 at 30°C dipole moment in benzene at 25°C 1.76 critical temperature 373.99°C critical pressure 217.8 atm critical density 0.322 g/cm viscosity 0.01002 poise at 20°C surface tension 73 dynes/cm at 20°C dissolves ionic substances miscible with mineral acids, alkalies low molecular weight alcohols, aldehydes and ketones forms an azeotrope with several solvents immiscible with nonpolar solvents such as carbon tetrachloride, hexane, chloroform, benzene, toluene, and carbon disulfide. 

Table VII shows the rate constants and other data observed and calculated for some anthracenes in different solvents. Some values of ao2 and j8 for anthracenes in different solvents are listed in Table VIII, taken from Livingston s article.3 There are discrepancies in some j8 values reported, and the Ao2 values are not always comparable, since, for example, they may or may not depend on the oxygen concentrations applied (e.g., anthracene in benzene or carbon disulfide, respectively). Furthermore, one may suspect that A0s values greater than unity are either in error (see, however, p. 34) or indicate a secondary oxidation...

In general, solvency of beeswax is better correlated with nematocidal efficacy than is solvency of cholesterol. All outstanding nematocides dissolve or emulsify beeswax at 25 C. in proportions of 1 5 to 1 10. However, the action is not identical, though the minimum amoimt of solvent may be the same. Thus 1,3-dichloropropene, allyl bromide, and chloropicrin are emulsifiers, while carbon disulfide dissolves, forming a clear solution and ethylene bromide clears the beeswax as it dissolves. Herein may be the answer to divergent actions of compounds with similar constants. A small change in temperature causes 1,3-dichloropropene and allyl bromide to form clear solutions, which again become cloudy when the temperature is reduced. 

The kinetics of the carbon disulfide elimination reaction were studied using PMR and visible spectroscopy (16). This spontaneous reaction was found to be first order in the M(RSXant)2 complexes (M = Ni, R = Et, r-Bu, Bz M = Pd, R =/ -Bu), both in the disappearance of the starting material and in the formation of the mercaptide-bridged species in CHC13 and THF. The pseudo-first-order kinetics observed in CS2 are attributed to an equilibrium between the M(RSXant)2 complexes and this solvent. Rate constants for the reaction are of the order of 10 3 to 10"1 min"1 depending on solvent, temperature, alkyl... 

Liquid viscosity data are available for cthanethiol at 25rC,11 for dimethyl sulfide from OV to 36 C.1 and for carbon disulfide from - I3 C to - M C l The constants for... 

In the mitigated case, in which the spilled carbon disulfide is retained by the dike installed around the tank, there is a large reduction in the vaporization rates of carbon disulfide for both sets of meteorological conditions. The primary reason for the differences is that the available surface area for vaporization is significantly reduced. Second, the vaporization rate remains essentially constant for the duration of the incident because the surface area for vaporization is constant. The small variations that do show in these curves are due to small effects of heat transfer into the diked carbon disulfide, as discussed in Chapter 5. 

Here, T is the observed line width (Av << F), 7d is the peak-to-valley intensity in the difference spectrum, and To is the peak height of the Raman line. Although this equation is for Lorentzian-shaped bands, the results are approximately the same for Gaussian-shaped bands (the constant 0.385 becomes 0.350). In the case of carbon disulfide-benzene mixtures, the smallest shift observed was -0.06 cm-1, and the associated error was 0.02 cm-1 (77). A convenient rotating system that can be used for (1) difference spectroscopy, (2) normal rotating sample techniques (solid and solution), and (3) automatic scanning of the depolarization ratios as a function of the wave number has been designed (45). 

For simplicity, one can desorb the sample charcoal in a vial containing 0.5 milliliters of carbon disulfide and prepare all standard mixtures in 0.5 milliliters of carbon disulfide and inject a constant volume of 1 microliter of desorbed sample and standard into the gas chromatograph. Calibration curves are prepared by plotting concentration of solvent in ul/ml carbon disulfide versus peak area. 

The 13C NMR chemical shifts and one-bond coupling constants 7(13C-H) have been obtained for (1), (2) and (5) in carbon disulfide (Table 8) (74OMR(6)430) (see also Section 4.01.3.4). The chemical shifts for the 3a-position in the title compounds are the reverse of what would be expected on the basis of a purely inductive effect of the Group VIA heteroatoms. If the chemical shifts are controlled by through-bond effects, then mesomeric interaction of (2) is of considerable importance in these systems. Thus, the 13C NMR... 

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