Symmetrical trimethylbenzene

I Synonyms/Trade Names Mesitylene, Symmetrical trimethylbenzene, sym-Trimethylbenzene ... 

Ladenburg, partly in collaboration with Friedel, published researches on inorganic (silicon chloroform, silicon-oxalic acid Si2H204, silicon oxychloride, etc.), and organic (aliphatic and aromatic) compounds of silicon. He established the formula Su2(C2H5)g for tin triethyP discovered by Cahours (see p. 511), and prepared other organic tin compounds. He proved that mesity-lene is symmetrical trimethylbenzene. His work on the structure of benzene is considered elsewhere (p. 802). 

The procedure has been extended to symmetric methylbenzenes, namely p-xylene, 1,3,5-trimethylbenzene (mesitylene) and 1,2,4,5-tetramethylbenzene (durene) [52]. The steric hindrance causes no major limitation to the reaction and a dean monoarylation rather than a polysubstitution is obtained. For instance, a variety of ArX under irradiation in the presence of mesitylene affords the bulky biaryl compounds in satisfactory yields (>50%) (Scheme 10.36) [52],... 

In their studies of conductance of the methylbenzenes in anhydrous hydrofluoric acid, Kilpatrick and Luborsky (96) found that the specific conductance of solutions of prehnitene and durene changed with time, and additional experiments indicated this was due to rearrangement toward isodurene. It should be noted that the symmetrical configuration 1,2,4,5- is the strongest base of the three tetramethylbenzenes. The concentration and stability of the ArH+ ions are the important factors in the isomerization. With the xylenes and trimethylbenzenes in anhydrous hydrofluoric acid, no reaction was observed at 20°, but isomerization did take place upon addition of boron trifluoride. This is interpreted to be due to an increase in the concentration of ArH+ by the reaction... 

Moreover, since this compound had been formed by the convergence of three molecules of acetone, it was very likely that the hydrocarbon had a symmetrical molecular structure, namely, that it was 1,3,5-trimethylbenzene, the oxidized molecule being benzene 1,3,5-tricarboxylic acid. This assignment was also supported by the fact that only one isomer of any further substitution of mesitylene was known.If one accepts this argument, and then removes any one of... 

Restricted Internal Rotation of Several Symmetric Tops. The tables of thermodynamic functions for an internal rotation of a single symmetric top may be used for several symmetric tops [with moments of inertia calculated from equation (20)] provided both potential energy and kinetic energy cross-terms between the tops can be neglected. Both assumptions have been generally made in calculations for molecules with several tops. Where there are reliable calorimetric data at one or more temperatures, the tables have been used to calculate appropriate potential barriers. Using this procedure thermodynamic contributions have been calculated for propane, 2-methylpropane, 2,2-dimethylpropane, cis-but-2-ene, rm a -but-2-ene, isobutene, o-xylene, > m-xylene, p-xylene, 1,2,3-trimethylbenzene, > 1,2,4-trimethylbenzene, dimethyl sulphide,2-chloro-2-methylpropane, and dimethyl-amine. In several cases thermodynamic contributions have been calculated using potential barriers estimated from those of related molecules. Examples of this procedure are found in calculations for 2-fluoro-2-methylpropane, 2-chloropropane, 2-bromopropane, 2-iodopro-pane, 2,2-dichloropropane, 2-bromo-2-methylpropane, 2-iodo-2-methylpropane, 1,3,5-trimethylbenzene, 1,2,3,5-tetramethylbenzene, 1,2,4,5-tetramethylbenzene, 1,2,3,4-tetramethylbenzene, pentamethyl-benzene, and hexamethylbenzene. ... 

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