Benzene molar concentrations

Nitration in the presence of strong acids or Lewis acids Solutions of dinitrogen pentoxide in sulphuric acid nitrate 1,3-dimethyl-benzene-4,6-disulphonic acid twice as fast as a solution of the same molar concentration of nitric acid. This is consistent with Raman spectroscopic and cryoscopic data, which establish the following ionisation ... 

Fig. 6. Dependence of relative molar concentrations Wj/nA0 of reaction components on reciprocal space velocity W/F (hr kg mole-1) in the consecutive demethylation of m-xylene. Temperature 330°C, catalyst Ni-AljOs (55% wt. AljOs), initial molar ratio of reactants 0 = 5. The curves were calculated (1—xylene, 2—toluene, 3—benzene) the points are experimental values.

Chromatography by ion exchange on a sulfonated poly(styrene-co-divinyl benzene) phase has been proposed as a replacement for titrimetry.57 Eluted by a dilute solution of a neutral salt such as sodium ethanesulfonate, the conductance of the protons can be measured in the absence of a suppressor from sub-millimolar to molar concentration. The response factors of mono-, di-, and trichloroacetic acid and of o-phthalic acid were large and essentially equivalent to ethanesulfonic acid, while the response factor of acetic acid was far smaller. A syringe pump has generated pressures as high as 72,000 psi (5000 bar) in a capillary column packed with 1 p particles, generating a fraction capacity of 300 peaks in 30 minutes.58... 

You live in a town where air pollution caused primarily by traffic is quite substantial. From a recent article in the local newspaper you have learned that the benzene concentration in the air in your area may reach up to 10 parts per billion on a volume base (i.e., 10 ppbv). You wonder to what extent the olive oil that you use for your salad, and that you have left in an open bottle on the table on your balcony, is contaminated with this rather toxic compound. Calculate the maximum concentration of benzene in the olive oil assuming an average temperature of 25°C and a total pressure of 1 bar. Use the ideal gas law to convert ppbv to molar concentrations. 

Fig. 28. Rate of nitration of benzene to dinitrobenzene as a function of the molar concentration of sulphuric acid. (Various curves correspond to various molar concentrations of H2S04, when [HN03] = 1.) (Hetherington and Masson [9]).

The distribution coefficient of benzene, K2, between the pore and the fluid phases is defined as the ratio of the molar concentration of benzene in the pore phase, P2,p> to that in the fluid phase, p2,f, at infinite dilution in both phases. 

The effects of the reaction temperature, T, the air flow rate Fa (reported at 20°C and 1 atm), the depth of the catalyst bed, H f, and the molar concentration of benzene, c, on the conversion, selectivity and production were reported by Kizer et al (14). The experiments were performed according to a factorial plan of 2 experiments within the following limits ... 

A small molecule mimic of polystyrene (cumene) was dissolved in benzene at a concentration of 1 M available benzylic H-atoms. When /er/-butoxy radicals were introduced, the ratio of acetone to /er/-butanol was 11. However, when /er/-butoxy radicals were introduced into benzene solutions containing polystyrenes of various molecular weights at the same molar concentration of benzylic H-atoms, the acetone /er/-butanol ratio dropped precipitously as the molecular weight of the polystyrene increased (Figure 24.2). 

Fig. 12. Apparent kp (1 mole see ) for the propagation step of polystyryllithium in benzene as a function of the molar concentration of added ( ) tetrahydrofuran (o) dioxane (A) lithium-fert.-butoxide 30°C. Concentration of active chains 1 X lO M [74, 75, 77].

The X max of 242, 247, 252, 258, 26k, and 267 nm are typical of fine structure due to isolated benzene chromophore. Using the spectrum and the molar concentration of propoxyphene hydrochloride (1.94 x 10"3 moles/liter), the following table can be constructed. 

Fig. 4.19 Dependence of the complex coalescence behavior of aqueous solutions of benzene and its derivatives upon their molar concentration. Own, not yet published data from the 197O s.

If this is true, then at otherwise identical conditions toluene should demonstrate greater pore blocking and higher separation than benzene. Curve c in Figure 9 for toluene and curve a in Figure 4 for benzene are at the same pressure and approximately the same molar concentration. In all cases, the expected result is found. For example, for membrane 2, the separations are 41% and 9% and the pore blocking factors are 0.30 and 0.08 for toluene and benzene, respectively. Thus, the modified Small s... 

Concentration of droplets (mg C/volume Molar concentration of benzene Initial molar concentration of benzene Hydrogen molecule... 

Benzene content in water and in oil product may be determined from its partial pressure, which is calculated from its molar concentration (See example 2.15) ... 

Fig. 12. Infrared spectra of the salts AH" AljBrf recalculated to one molar concentration of the absorbent (c = 2.9 M, 1 = 5.7 10 mm) where A = benzene 1), toluene 2), mesitylene 3), anthracene 4), as well as the infrared spectrum of diphenylmethane 5)...

As shown by Gileadi et al. [123-125], it is possible to form solutions based on aromatic hydrocarbons such as ethyl benzene, toluene, benzene, and mesity-lene. The electrolyte comprises ATBr and KBr [126]. By using a nearly molar concentration of these species, it is possible to obtain specific conductivity of the same order of magnitude as that measured in polar aprotic solutions (around 5 mQ Cm" ) at ambient temperatures. It was found that these electrolytes do not dissolve in the above solvents to form ions or ion pairs, but rather form clusters which are charged aggregates of ALBrv K. The conductivity mechanism is thus... 

The rate expression for toluene is determined in a similar manner as that for benzene. The concentration of toluene in the system is a function of two competing reactions one where toluene is a product, and the other where toluene is a reactant. A one-to-one molar relation exists between the consumption of benzene and the production of toluene in reaction 1, and in general, the reaction rates for all species that participate in reaction 1 may be determined simply by stoichiometry, where the rate of formation for toluene must be equal to the rate of reaction for benzene by mass balance. ... 

Thus, the molar evaporation rate is higher when the total pressure is decreased. This is solely due to the increase in the mole fraction of benzene at the liquid interface (from 0.13 in the last example to 0.33 in this example). The increase in the molecular diffusivity as the total pressure increases is exactly compensated by the decrease in the total molar concentration. 

Figure 9.8 Log k vs. log Pow (a) and k vs. log (b) relationships predicted by eqs. 9.23 and 9.24 (solid lines), and experimental values (symbols) for a series of monosubstituted benzenes acetanilide, acetophenone, benzaldehyde, benzene, benzonitrile, benzyl alcohol, benzylamine, bromobenzene, butyrophenone, he phenone, methyl benzoate, methyl phenyl ether, nitrobenzene, propiophenone, toluene, and valerophenone. Molar concentrations of SDS in mobile phase (1,a) 0, (2, ) 0.016, (3,0) 0.05, (4,°) 0.1, and (5) 0.15. Reprinted from Ref 21 with permission of Elsevier.

The multiple linear equations given in TABLE 3 indicate a significant relationship of the observed toxicities with several physico-chemical characteristics of these compounds. However, only some 60% of the total variation is explained by equation 3d and the corresponding standard error of the estimate, s = 0.60 is quite large. This means that for a number of compounds the predicted toxic concentrations differ by more than one order of magnitude from those observed experimentally. As there is a spread of close to five orders of magnitude between the molar concentrations of the least and most toxic compounds, the predictive capacity of equation 3d is still of value, though somewhat limited in applicability. This fact stimulates the desire for a closer inspection of the data with a view to delineate more precise relationships for smaller, more easily defined subsets of mono-substituted benzene derivatives. 

A second Mobil process is the Mobil s Vapor Phase Isomerization Process (MVPI) (125,126). This process was introduced in 1973. Based on information in the patent Hterature (125), the catalyst used in this process is beHeved to be composed of NiHZSM-5 with an alumina binder. The primary mechanism of EB conversion is the disproportionation of two molecules of EB to one molecule of benzene and one molecule of diethylbenzene. EB conversion is about 25—40%, with xylene losses of 2.5—4%. PX is produced at concentration levels of 102—104% of equiHbrium. Temperatures are in the range of 315—370°C, pressure is generally 1480 kPa, the H2/hydrocatbon molar ratio is about 6 1, and WHSV is dependent on temperature, but is in the range of 2—50, although normally it is 5—10. 

Mobil s High Temperature Isomerization (MHTI) process, which was introduced in 1981, uses Pt on an acidic ZSM-5 zeoHte catalyst to isomerize the xylenes and hydrodealkylate EB to benzene and ethane (126). This process is particularly suited for unextracted feeds containing Cg aHphatics, because this catalyst is capable of cracking them to light paraffins. Reaction occurs in the vapor phase to produce a PX concentration slightly higher than equiHbrium, ie, 102—104% of equiHbrium. EB conversion is about 40—65%, with xylene losses of about 2%. Reaction conditions ate temperature of 427—460°C, pressure of 1480—1825 kPa, WHSV of 10—12, and a H2/hydtocatbon molar ratio of 1.5—2 1. Compared to the MVPI process, the MHTI process has lower xylene losses and lower formation of heavy aromatics. 

N-Acetyl-(R)-phanylalanlna (6). The rhodium catalyst was obtained by adding (-) dlop 5 (from diethyl tartrate) to a benzene solution of [RhCi(cyclooctene)2]2 under Ar, and stirring for tS mn A solution of the Rh catalyst (1 mM in EtOH PhH 4 1) was introduced under Hj to a solution of a-N acetylamino- phenytacrylic acid 4 (molar ratio Rh 4 1.540) The solvent was evaporated, the residue dissolved In 0 5 N NaOH, the catalyst was filtered and the solution acidified and concentrated to dryness to give 6 (81% ee) in 90 95% yield... 

Conversion of coal to benzene or hexane soluble form has been shown to consist of a series of very fast reactions followed by slower reactions (2 3). The fast initial reactions have been proposed to involve only the thermal disruption of the coal structure to produce free radical fragments. Solvents which are present interact with these fragments to stabilize them through hydrogen donation. In fact, Wiser showed that there exists a strong similarity between coal pyrolysis and liquefaction (5). Recent studies by Petrakis have shown that suspensions of coals in various solvents when heated to 450°C produce large quantities of free radicals (. 1 molar solutions ) even when subsequently measured at room temperature. The radical concentration was significantly lower in H-donor solvents (Tetralin) then in non-donor solvents (naphthalene) (6). 

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