Toluene-water

The USP/FCC grade of benzoic acid is usually produced by extraction and crystalliza tion, although distillation has also been used. In the extraction—crystallization process, toluene, water, and methanol have all been used and each is capable of producing a high quaUty benzoic acid product. 

Water Determination. The sample is refluxed with toluene and the resultant toluene—water a2eotrope is distilled iato a gradual water-trap receiver (Dean and Stark apparatus). Here the water and toluene separate iato two distinct layers, permitting the volume of water to be read and its percentage calculated. 

Naphthalene Prttpane Coal gas (town gas) Petroleum Toluene Water gas Hydrogen ... 

Ethanol with acetic acid, acetone, benzene, chloroform, cyclohexane, dioxane, ethyl ether, pentane, toluene, water or xylene. 

Liquid paraffin carbamate and urea herbicides stabilization and enhancement spray solution, 20% in toluene, water investigation [241]... 

Soya oil, 88.6 g, 20.0 g of pentaerythritol, and 0.06 g of lithium hydroxide monohydrate are weighed into a 250-mL three-necked round-bottom flask fitted with a magnetic stirrer, a Dean-Stark separator, and nitrogen inlet and outlet. The reaction mixture is heated to 250°C for 30 min under nitrogen (note a below), then cooled to 200°C. Phthalic anhydride, 34.6 g, 0.70 g of maleic anhydride, and 8.0 g of xylene are added. The reaction mixture is heated to 230°C and the toluene-water azeotrope is removed by distillation. The reaction is stopped when the acid number of reaction medium is lower than 10 (note b below). After cooling to room temperature, 52 g of white spirit is added. 

The Diels-Alder reaction of methyl methacrylate with cyclopentadiene was studied [72] with solutions from three different regions of the pseudophase diagram for toluene, water and 2-propanol, in the absence and in the presence of surfactant [sodium dodecyl sulfate (SDS) and hexadecyltrimethylammonium bromide (HTAB)]. The composition of the three solutions (Table 6.11) corresponds to a W/O-fiE (A), a solution of small aggregates (B) and a normal ternary solution (C). The diastereoselectivity was practically constant in the absence and in the presence of surfactant a slight increase of endo adduct was observed in the C medium in the presence of surfactant. This suggests that the reaction probably occurs in the interphase and that the transition state has a similar environment in all three media. 

In 2001, we developed a simple and quite useful method to manipulate the size of Au nanoparticles by using the heat-treatment of small Au nanoparticles [9,10], which is far from the conventional techniques. The 1-dodecanethiol-protected Au nanoparticles (C12S-AU) of 1.5 0.2 nm in size synthesized by the Brust s two-phase (toluene/water) reaction procedure [3] were heat treated at 150-250 °C at the heating rate of 2°Cmin and held for 30min. This heat treatment of as-synthesized C12S-AU nanoparticles... 

The synthesis of C S-Au nanoparticles as a source for the heat treatment followed the Ernst s two-phase (toluene/water) reaction procedure [3]. The organic (toluene) phase was then separated, evaporated completely in a rotary evaporator at 40 °C, and dried in vacuo at 30 °C for a day. The crude solid obtained was heat treated at 150-250 °C at the heating rate of 2°Cmin, and held for 30 min. The heat-treated product was dissolved in toluene and mixed with methanol to remove excess free C12SH and TOAB. The dark brown precipitate... 

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. 

Br-PADAP showed a significant adsorption at the interface of heptane-water under high-speed stirring conditions (5000 rpm). At the toluene-water interface, the... 

FIG. 8 MD simulation of the adsorption of 5-Br-PADAP at the toluene-water interface after 100 ps. 

TABLE 4 Rotational Relaxation of Octadecylrhodamine B at Toluene-Water Interface... 

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. 

Fig. 1.26 I maging of 129Xe using (a) regular imaging and (b) chemical shift selective imaging sequence along the cross section of three NMR tubes containing toluene, water...

Chen, H., Wagner, J. (1994b) An efficient and reliable gas chromatographic method for measuring liquid-liquid mutual solubihties in alkylbenzene + water mixtures Toluene + water from 303 to 373 K. J. Chem. Eng. Data 39, 474-479. 

Figure 10-12 Toluene water wash process before formal safety review.

A toluene water wash process is shown in Figure 10-12. This process is used to clean water-soluble impurities from contaminated toluene. The separation is achieved with a Podbielniak centrifuge, or Pod, because of a difference in densities. The light phase (contaminated toluene) is fed to the periphery of the centrifuge and travels to the center. The heavy phase (water) is fed to the center and travels countercurrent to the toluene to the periphery of the centrifuge. Both phases are mixed within the centrifuge and separated countercurrently. The extraction is conducted at 190°F. 

When aspirin was partitioned between buffers pH 1-7 and octyl alcohol, partition coefficients ranging from k=17.7 (pH 1) to k=0.025 (pH 7) were obtained.70 Earlier, coefficients of 0.32 in toluene water and 1.81 in chloroformiwater were determined.71... 

Paper chromatography has been used to separate and detect pseudoephedrine hydrochloride from other pharmacologically active amines. Whatman No. 1 paper developed in n-butanol water 95% acetic acid (4 5 1), n-butanol toluene water 95% acetic acid (10 10 5 5), ethyl acetate water 95% acetic acid (3 3 1), or chloroform water 95% acetic acid (10 5 4) gave Rf values of 0.73, 0.35, 0.57, and 0.52 for pseudoephedrine hydrochloride respectively. Visualization of pseudoephedrine hydrochloride was done by spraying the chromatogram with 0.5% bromcresol green in methanol or 0.2% nin-hydrin in acetic acid butanol 5 95.30... 

Ng and Tsakiri—Mo, W, and Ru carbonyl catalysts—kinetics over Mo supported formate mechanism. Ng and Tsakiri127 reported the homogeneous catalysis of water-gas shift using a number of different metal carbonyl complexes (e.g., Mo(CO)6, W(CO)6, and Ru3(CO)12) under basic conditions in toluene-water emulsions (Table 45). The conditions used were PCo = 20.7 atm T = 180 °C 70 ml solution containing 71.4 mmol KOH 2.5 hours 550 revs/min stirring rate. 

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