Mesitylene and derivs

Azid omesitylene or Azido-1,3,5-Trimethyl-benzene. See under Mesitylene and Derivatives... 

Concentrated sulphuric acid. The paraffin hydrocarbons, cych-paraffins, the less readily sulphonated aromatic hydrocarbons (benzene, toluene, xylenes, etc.) and their halogen derivatives, and the diaryl ethers are generally insoluble in cold concentrated sulphuric acid. Unsaturated hydrocarbons, certain polyalkylated aromatic hydrocarbons (such as mesitylene) and most oxygen-containing compounds are soluble in the cold acid. 

A further test of this interpretation is provided by the activation energies of the reactions that occur at the limiting rate. The observed activation energies for the nitration of mesitylene and naphthalene in 67.1% sulphuric acid are 75.3 and 64.8 kJ mol"1 respectively (Coombes et al., 1968). On the interpretation in terms of reaction on encounter the activation energy should be the sum of the AH° term for the formation of the nitronium ion (43 kJ mol"1 in 68.3% sulphuric acid) (Hartshorn et al., 1972), and the term derived from the temperature dependence of the viscosity of the solvent (24 kJ mol"1 see (8) and Table 2). Thus, the expected activation energy is ca. 67 kJ mol-1, a value in reasonable agreement with the experimental results. 

Mesitylene and hexamethylbenzene cyclohexadienyl ruthenium complexes 236 have also been prepared in good yield by reduction of their corresponding bisarene ruthenium dications 235 with sodium borohydride in water (142,143). Cyclohexadienyl derivative 236c can be easily formed by treatment of bisarene ruthenium(O) complex 197 (arene = hexamethylbenzene) with a solution of hydrochloric acid in acetone. The structure of 236c and the presence of the endo C—H bond have been clearly resolved by infrared and 1H-NMR spectra (144,145) [Eq. (28)]. 

Yield of Mesitylenecyclopentadienyliron Derivative from THE Reaction of Mesitylene and Substituted Ferrocene ... 

The meta compound is prepared by other methods (p. 532) in which by starting with a toluene derivative, in which the ortho and para positions are occupied, sulphonation affects the meta position. The ortho and para substituents are then removed. Sulphonic acids of xylene, mesitylene and cymene are also known. 

For mesitylene and durene, the kinetics have been followed by specular reflectance spectroscopy [17]. The results indicated that mesitylene produces a fairly stable radical cation that dimerizes. That of durene, however, is less stable and loses a proton to form a benzyl radical, which subsequently leads to a diphenylmethane. The stability of the radical cation increases with increasing charge delocalization, blocking of reactive sites, and stabilization by specific functional groups (phenyl, alkoxy, and amino) [18]. The complex reaction mechanisms of radical cations and methods of their investigation have been reviewed in detail [19a]. Fast-scan cyclovoltammetry gave kinetic evidence for the reversible dimerization of the radical cations of thianthrene and the tetramethoxy derivative of it. Rate constants and enthalpy values are reported for this dimerization [19b]. 

A number of aromatic nitro compounds, derivatives of benzene, toluene, xylenes, mesitylene and durene have been investigated by proton resonance spectra [37-41]. The nitro group was found to shift the aromatic proton resonance signals to low fields from that of benzene in the order ortho > para > meta. 

The similarity between the absorption spectra of decamethylbiphenyl and hexamethylbenzene7 (Figure 83) may be taken as experimental evidence for very large twists (Type 3). Similarly, the absorption spectra of bimesityl and 2,2, 4,4, 6,6 -hexachlorobiphenyl may be compared with the spectra of mesitylene and m-trichlorobenzene respectively20. The spectra of the two non-planar phenanthmie derivatives, IV and V, are similar to the spectrum of phenanthrene itself21. The naphthalene derivative, VI, exhibits the same... 

The following are some further examples. Acetomesitylene is obtained from mesitylene and glacial acetic acid in the presence of phosphoric oxide and kieselguhr, yields reaching 82.5%.525,566 (o-Nitrobenzoyl)mesitylene is obtained (75%) from mesitylene and a-nitrobenzoic acid in the presence of boron trifluoride and trifluoroacetic anhydride.567 Toluene and benzoic acid in the presence of molybdenum pentafluoride give a 70% yield of 4-methylbenzo-phenone, but with aluminum chloride give a mixture of the 2- and the 4-methyl derivative.568... 

This type of reaction, which results in the formation of diphenylmethane derivatives, is especially characteristic of reactive aromatics such as mesitylene and phenol. 

Petroleum- and coal-derived heavy gasoline fractions with a boiling range of around 160 to 220 °C contain polymethylated benzenes, such as trimethylbenzenes (pseudocumene, mesitylene and hemimellitene), together with the tetramethylated benzenes durene, isodurene and prehnitene. Indane and indene compounds, penta- and hexamethylbenzene and cumene, are also present in these heavy gasoline fraction. (Cumene is predominantly converted to phenol as described in Chapter 5.2). 

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