S-Trimethylbenzene

Manufacture. The only current U.S. manufacturer of trimesic acid is Amoco Chemical Co. It is produced by oxidation of mesitylene (1,3,5-trimethylbenzene) via the Hquid-phase oxidation in acetic acid using the cobalt— manganese—bromine catalyst system (138). This is a variant of the system used to produce terephthaUc and isophthaUc acids as well as trimellitic anhydride. American Bio-Synthetics Corp. did produce it by batch oxidation of mesitylene with potassium permanganate. 

All the PMBs are Hsted on the U.S. EPA s Toxic Substances Control Act NonConfidential Chemical Substances Inventory (Table 8). In the early to mid-1980s, pseudocumene, mesitylene, hemimellitene, and trimethylbenzene were coveted by TSCA Section 8(a) Preliminary Assessment Information Rule (PAIR) reporting requirements (22) and by TSCA Section 8(d) for health and safety data (23). Mesitylene is the subject of a test rule subacute oral toxicity and subchtonic oral toxicity in tats were underway in 1994 (24). The Safe Drinking Water Act (SDWA) allows monitoring for pseudocumene and mesitylene at the discretion of the State (25). Of the PMBs, only pseudocumene is subject to SARA Tide III section 313 annual release reporting (26). 

Reported aqueous solubilities and Henry s law constants of 1,2,3-trimethylbenzene at various temperatures... 

FIGURE 3.1.1.7.1 Logarithm of mole fraction solubility and Henry s law constant versus reciprocal temperature for 1,2,3-trimethylbenzene. 

Thomas and Delfino (1991) equilibrated contarninant-free groundwater collected from Gainesville, FL with individual fractions of three individual petroleum products at 24-25 °C for 24 h. The aqueous phase was analyzed for organic compounds via U.S. EPA approved test method 602. Average 1,2,3-trimethylbenzene concentrations detected in water-soluble fractions of unleaded gasoline, kerosene, and diesel fuel were 1.219, 0.405, and 0.118 mg/L, respectively. 

Figure 5 Plots of log versus AG°et for fluorescence quenching of RAcrH" (2.0 x 10 " M) by various electron donors (a) in MeCN and (b) in benzene at 298 K. Numbers refer to electron donors benzene (1), toluene (2), ethylbenzene (3), cumene (4), ra-xylene (5), o-xylene (6), 1, 3, S-ttimethylbenzene (7),/ -xylene (8), 1,3-trimethylbenzene (9), 1, 2,3,4-tetramethylbenzene (11), 1,2,3,5-tetramethylbenzene (12), 1,2,4,5-tetramethylben-zene (13), pentamethylbenzene (14), hexamethylbenzene (15), triphenylamine (16), N,N-dimethylaniline (17), ferrocene (18), and decamethylferrocene (19). (From Ref. 79.)...

Pio. 22. Eluotropic strength of water-acetonitrile on pyrocaibon. The eluites used are ( ) 2,3.4.S-tetramethylbenzene. (O) 1.3.4-trimethylbenzene, and ( ) 3,4,S-trimethylphenol. Reprinted with permission Horn Colin et at. (Ml). 

In most cases Selectivity is not affected strongly by changing temperature in RPC. Co et al. (142) found a small decrease in selectivity with increasing temperature on pyrocarbon columns. The relative retention of the pair octylbehsene-3,4,S-trimethylphenol decreased from -1.08 to 1.05 over the range 20 to 70°C whereas the relative retention of 1,2,3- and 1,2,4-trimethylbenzenes decreased from 1.24 to 1.2 over the same range. 

Kramp, F., and S. E. Paulson, On the Uncertainties in the Rate Coefficients for OH Reactions with Hydrocarbons, and the Rate Coefficients of the 1,3,5-Trimethylbenzene and m-Xylene Reactions with OH Radicals in the Gas Phase, J. Phys. Chem. A., 102, 2685-2690 (1998). 

The bis-urea thin filaments can be very long in non-polar solvents such as 1,3,5-trimethylbenzene. Consequently, these solutions show a high viscosity r]/r]Q = 8 at a concentration C = 0.04 molL and at T = 20 °C) and a high concentration dependence of the viscosity (ri/rio C ) [43]. As in the case of UPy based supramolecular polymers, the value of this exponent is in agreement with Cates s model for reversibly breakable polymers [26,27]. However, the solutions are not viscoelastic, even at concentrations well above the overlap concentration [43]. Consequently, the relaxation of entanglements, probably by chain scission, must be fast (r < 0.01 s). 

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