Preparation toluene

Figure 5. Typical Guinier and Debye plots observed for PBLG-138,000/toluene prepared by quenching to various temperatures a) T = 28.2. Continued on next page.

Measured airborne and blood concentrations of ethylbenzene in several occupational settings are presented in Tables 3 and 4, respectively. Most occupational exposures to ethylbenzene result from use of products containing technical grades of mixed xylenes. No ethylbenzene was found from off-gassing of cured paint in a hyperbaric pressure chamber under normal atmospheric pressure, but under higher pressures, levels of 0.4-4.5 ppm [1.7-19.5 mg/m ] were measured (Lillo et al., 1990). Silk screen operations were found to entail exposure levels of less than 4 mg/m (Verhoeff et al., 1988). Ethylbenzene may also be present in low-grade toluene preparations (Inoue et al, 1995). 

Figure 4. Primary dispersions of Ti02 with S30B TGA in toluene prepared at 100°C and at room temperature, respectively...

Figure 5. Primary dispersions of Ti02 in toluene prepared at room temperature with SX%B TGA block copolymers of various compositions (see Table IV)...

Recently Kobe Mid Lakemeyer [17] drew attention to the fact that nitrating mixtures used for mononitration of toluene prepared spent acid from trinitration contain 14-17 wt. % of nitrosylsulphuric acid. They investigated the influence of nitrosylsulphuric acid, S02(OH)ONO, on the rate of mononitration of toluene. The rate at 35°C is at a maximum at ca. 4.0 mole % of nitrosylsulphuric acid. 

Benzene and toluene form ideal solutions. Consider a solution of benzene and toluene prepared at 25°C. Assuming that the mole fractions of benzene and toluene in the vapor phase are equal, calculate the composition of the solution. At 25°C the vapor pressures of benzene and toluene are 95 and 28 torr, respectively. 

A further example of the regiospecific synthetic utility of phenoxy magnesiumbromide is illustrated by the foltowing reaction. Phenoxymagnesium bromide in toluene, prepared in the usual way from phenol and ethylmagnesium bromide in toluene, treated dropwise with oxalyl chloride in toluene over 20 mins, and then reacted at ambient temperature for 7 hours, gave, after work-up by acidification, 2-hydroxyphenylglyoxylic acid in 44% yield (ref.57). 

For reference, silane-based monolayers prepared on flat wafers and other non-porous substrates have been reported to have a population density of 4.8 silanes/nm [14]. Thus, the toluene preparation of thiols SAMMS seems to provide reasonably good surface coverage of the internal pore surfaces of the mesoporous silica, but there are certainly defects (e.g. pinhole defects and dangling hydroxyls) in the monolayer structure, leaving the question, Is the level of coverage limited by the pore curvature, or is it due to the procedure employed . As we shall see, it is due to the procedure. 

EXAMPLE 11.6-1. Enthalpy-Concentration Plot for Benzene-Toluene Prepare an enthalpy-concentration plot for benzene-toluene at 1 atm pressure. Equilibrium data are given in Table 11.1-1 and Figs. 11.1-1 and 11.1-2. Physical property data are given in Table 11.6-1. 

The potential reaction of the reducing agent 2 with hydrocarbon solvents like toluene and xylenes that contain benzylic hydrogens was investigated. When a solution of 2 in toluene (prepared in situ by sonication for 13 h) was quenched with methyl iodide or dimethyl sulfate, very small amounts (<6%) of ethyl benzene or xylenes were observed. When a solution of 2 in benzene (prepared in situ by sonication for 13 h) was quenched with methyl iodide or dimethyl sulfate, negligible amounts (<1.5%) of toluene were seen. Since the sonication conditions (42 C bath temperature, hot-spot peak temperature and pressure of about 3000K and 300atm, respectively, have been measured [81] ... 

A flame dried round-bottom flask was charged with triazolium salt 46 (0.2 equiv) and toluene (5 mL). To this solution was added KHMDS (0.5 M in toluene prepared prior to use from 0.05 g of KHMDS in 0.5 mL of toluene) (0.2 equiv) via syringe, and the solution was stirred at ambient temperature for 5 min. A solution of 43 (1 equiv, 0.12 mmol) in toluene (2 mL) was added. The resulting solution was allowed to stir at ambient temperature and monitored by TLC. The reaction mixture was placed directly onto a silica gel column. The desired product was purified by flash column chromatography, eluted with a suitable solution of hexane and ethyl acetate (typically 4 1). Evaporation of solvent afforded analytically pure product 44. 

Similarly prepare four additional standards to cover the concentration range of interest. For example, for benzene, prepare 0.1, 0.5, 1.0, 1.5, 3.0 weight % standards for toluene, prepare 1.0, LO, 5.0, 10.0, 15.0 mass % equivalent standards. 

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