Toluene-water systems

The heptane water and toluene water interfaces were simulated by the use of the DREIDING force field on the software of Cerius2 Dynamics and Minimizer modules (MSI, San Diego) [6]. The two-phase systems were constructed from 62 heptane molecules and 500 water molecules or 100 toluene molecules and 500 water molecules in a quadratic prism cell. Each bulk phase was optimized for 500 ps at 300 K under NET ensemble in advance. The periodic boundary conditions were applied along all three directions. The calculations of the two-phase system were run under NVT ensemble. The dimensions of the cells in the final calculations were 23.5 A x 22.6 Ax 52.4 A for the heptane-water system and 24.5 A x 24.3 A x 55.2 A for the toluene-water system. The timestep was 1 fs in all cases and the simulation almost reached equilibrium after 50 ps. The density vs. distance profile showed a clear interface with a thickness of ca. 10 A in both systems. The result in the heptane-water system is shown in Fig. 3. Interfacial adsorption of an extractant can be simulated by a similar procedure after the introduction of the extractant molecule at the position from where the dynamics will be started. 

In batch, this catalyst system (1 mol%) will convert cyclooctene in a two-phase toluene-water system at 60°C to the epoxide in 87% yield after 90 minutes and in 99% yield after 160 min (Scheme 4.2). The nature of the PTC is extremely important best results were obtained with MeN0ct3HS04. 

Most studies of biocatalysis in ionic liquids have been concerned with the use of isolated enzymes. It should not be overlooked, however, that the first report on biocatalysis and ionic liquids involved a whole-cell preparation Rhodococcus R312 in a biphasic [BMIm][PF(s]-water system [7]. It was shown, using a nitrile hydrolysis test reaction, that the microorganism maintained its activity better in ionic liquid than in a biphasic toluene-water system. 

Adachi K, Watarai H (2005) Interfacial aggregation of thioether-substituted phthalocyaninatomagnesium(II)-palladium(II) complexes in the toluene/water system. J Mater Chem 15(44) 4701 1710... 

Separation factors for HDEHP-HC1 and HDEHP-HCIO4, toluene-water systems at 25°C [10]. 

TABLE 10.3. Kinetic parameters for the interfacial complexation of Ni(II) and Zn(II) with 5-Br-PADAP in heptane/water and toluene/water systems. 

Figure 9. Effect of feed concentration on the RO performance for the toluene-water system. The operating conditions are identical to those of Figure 2 except that the operating pressure = 3450 kPa. Curve a (O) 8.7 ppm Curve b (%) 12.4 ppm Curve c CQ 20.8 ppm.

Figure 11. Correlation of In Ki and ni of Equation 1 with membrane pore size (In C nad) for separation of the toluene-water system...

Bromobenzene was carbonylated in a biphasic toluene/water system in the presence of Pd(tppts)3 giving the expected benzoic acid exclusively with high conversion [79]. 

Although the telomerization of dienes in a two-phase system has been intensively investigated with compounds containing active hydrogen such as alcohols, amines, phenols, acids, etc., the selective and productive telomerization of butadiene continues to be a challenge. It is only recently that primary octadi-enylamines have been obtained with selectivity up to 88% in the telomerization of butadiene with ammonia using a two-phase toluene/water system and Pd(OAc)2/tppts as the catalyst [Eq. (23)] [125]. 

It was found that the reproducibility and activity of pre-formed cationic [Ir(COD)ferrocenyl diphosphine] complexes were superior to those of the neutral systems. A series of hydrogenations was carried out in a bi-phasic toluene/water system (see below). As anticipated, the activity and selectivity of the catalysts is strongly influenced by the nature of the phosphorous substituents of the ferroce-nyl diphosphine. These effects are summarized in Tab. 5. The final level of 89% enantioselectivity was achieved with the tert- butyl /4-methoxy-3,5 -di meth ylphenyl derivative. 

The variation of the desorption energy with the contact angle is displayed in Fig. 3. Binks and Lumsdon investigated a toluene-water system with constant interfacial tension of 36mN/m by using silica nanoparticles of constant radius of lOnm and various wettabilities [4]. At a contact angle of 90°, a maximum in desorption... 

The catalytic reaction mixtures were refluxed at 353 K in a round bottom flask. They included 10 ml of solvent (methanol or water), 0.5 g catalyst, 0.1 mole substrate and Oxidant/Substrate = 0.2. The monophasic (phencH methanol) or biphasic (toluene + water) system was stirred vigourously at 1000 rpm with a magnetic stirrer. 

BMIM][BF4]/toluene/water system [103]. The activity of the catalyst followed the trend PBD>NBR>SBR, which corresponds to the order of polymer solubility in the ionic liquid. The degree of hydrogenation (as a percent of total hydrogenation) was 94% for PBD (4 h reaction time), 43% for NBR (4 h reaction time), and 19% for SBR (3 h reaction time). 

Polymeric sulfones obtained by radical copolymerization of monomeric sulfones with styrene are active interfacial catalysts. Their activity was studied in the reaction of n-CgH]7Br with MI (M = Li, Na, K) in a toluene-water system [191]. Reaction of n-CgHiyBr with Nal at 100 °C for 48 hours produced only traces of n-CigH]7l when catalysts, including such low-molecular weight catalysts as DMSO, methyl phenyl sulfoxide and methyl benzyl sulfoxide, were absent. When this reaction was catalyzed by polymeric sulfone, the yield of n-CigH,7l was 43%. However, in the presence of polymeric catalyst an 82% yield was obtained after a reaction time of 160h. 

It has been demonstrated that yeast cells and other microorganisms are active in the presence of ILs [6, 37]. In the very first report on biocatalysis in ILs, Lye and coworkers showed that a toluene-water system has a more detrimental effect on the microorganism Rhodococcus R312 than a system of [BMIM][PF6] and water, which is well tolerated [24]. Consequently, a better yield for the hydration of 1,3-dicyanobenzene [Eq. (7)] to 3-cyanobenzamide was obtained with the microorganism in the two-phase IL/water system than in the toluene system. 

In 1982, Slegeir et al. [24] also reported tungsten-based catalysts for homogeneous WGS reaction. In 1992 Ng and Tsakiri [25] reported Mo(CO)6 catalysts for homogeneous WGS reaction. They investigated methanol-water system and toluene-water systems by using KOH as a base. Table 7.13 shows the effect of Mo(CO)6 and KOH concentrations on the WGS activity of Mo(CO)6 for methanol-water system. 

Mo(CO)6 was also used as a catalyst for the reaction in a toluene-water emulsion (toluene water=3 l by volume). The amoxmt of H2 production increases almost linearly with increasing Mo(CO)6 concentration up to 2.84 mmol (0.04 M) and then decreases with further increase in catalyst concentration for toluene-water system. Also increasing KOH concentration increases the WGS activity. The catalytic results show that for CO loading... 

They also investigated other hydrocarbon water solvents for the homogeneous WGS reaction. The results are presented inTable 7.14. Under the reaction conditions used, methanol is found to be the most effective solvent. Water is found to be three times less effective than methanol even though the dipole moment of water is higher than methanol. However, the toluene-water system (toluene water = 1 1 by volume) exhibits similar activity to that of pure water and is more effective than the toluene-water system with toluene water = 3 1 by... 

Evaporation in a pot still requires only the sensible heat to raise the solvent to its boiling point plus the latent heat of evaporation. Although in steam distillation the sensible heat is lower because the boiling point is lower (84.1 °C in steam vs. 110.7°C in the case of toluene), steam is used as a carrier gas and then wasted in the condenser. Further, all the steam used is too contaminated to return to the boiler as hot condensate and its heat is therefore lost. To reduce the amoimt of steam used, the operation can be rim at a reduced pressure (Fig. 5.3). Since the lowest temperature at 360mmHg for the toluene/ water system would be 65 °C, there would be no serious problem in condensing at this pressure and the steam saving would be appreciable. 

Generally, all palladium- and nickel-based catalysts of the first generation are usually loaded in amounts of 1-5 mol% [1-6], rarely under 1 mol% and sometimes 5-10 mol%. The palladium-based SM reactions can be performed in the presence of water, moreover in two-phase toluene / water system as the original procedure. 

The investigation of volume fraction of dispersed phase in the microchannel is not trivial. Equating volume fraction (e ,) to volumetric flow fraction (Pjy = Vjy/iVjy + Vq), a new group, Rej df le ), is introduced to characterize the flow pattern of liquid-liquid systems in capillaries [40]. The following criteria were obtained for the toluene/water system ... 

Assume that 1-butanol and water are immiscible and that the system is dilute (constant total flow rates). Find the acetic acid wt. fractions in the extract, y, and the raffinate, x, products. Note There are multiple solution paths for this problem D32. For the toluene-water system in Example 13-5 we found that toluene is the dispersed phase if Qsolvent/Qfeed Which phase is dispersed if... 

Oxidation of alkyl aromatics in a biphasic toluene-water system can give the acid.186 After optimization (reagent concentrations, pH, additional mechanical stirring), toluene is transformed to benzoic acid in 60% yield within 3 h. Xylenes were submitted to the same treatment and gave interesting yields unfortunately the nature of the acid(s) obtained is not mentioned. Nitrotoluenes are also oxidized, in lower yields, only to the acids without dimer formation. 

KOT Koetz, J., Gunther, C., Kosmella, S., Kleinpeter, E., and Wolf, G., Polyelectrolyte-induced structural changes in the isotropic phase of sulfobetaine/pentanol/toluene/ water system, Progr. Colloid Polym. Sci., 122, 27, 2003. 

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