1,4-Dimethylbenzene

Chromic acid oxidation of 4 tert butyl 1 2 dimethylbenzene... 

A similar procedure can be applied to mixtures of 1,2-dimethylbenzene (o-xylene) and 1,4-dimethylbenzene (p-xylene). 

FIGURE 3.21 (a) Degradation of 1,2-dimethylbenzene by dioxygenation and elimination with formation of... 

The iridium complex composed of l/2[ Ir(OMe)(cod)2 ] and 4,4 -di-/ r/-butyl-2,2 -bipyridine (dtbpy) shows a high catalytic activity for aromatic G-H silylation of arenes by l,2-di-/z r/-butyl-l,l,2,2,-tetrafluorodisilane.142 The reaction of 1,2-dimethylbenzene with l,2-di-/< r/-butyl-l,l,2,2,-tetrafluorodisilane in the presence of l/2[ Ir(OMe)(cod)2 ] and dtbpy gives 4-silyl-l,2-dimethylbenzene in 99% yield (Equation (103)), which can be utilized for other functionalizations such as arylation and alkylation. 

Anthraquinone itself is traditionally available from the anthracene of coal tar by oxidation, often with chromic acid or nitric acid a more modern alternative method is that of air oxidation using vanadium(V) oxide as catalyst. Anthraquinone is also produced in the reaction of benzene with benzene-1,2-dicarboxylic anhydride (6.4 phthalic anhydride) using a Lewis acid catalyst, typically aluminium chloride. This Friedel-Crafts acylation gives o-benzoylbenzoic acid (6.5) which undergoes cyclodehydration when heated in concentrated sulphuric acid (Scheme 6.2). Phthalic anhydride is readily available from naphthalene or from 1,2-dimethylbenzene (o-xylene) by catalytic air oxidation. 

Whereas capture of the ipso-cation by acetate in acetic acid solution continues to be one of the best methods of isolating such adducts, its capture by water is, of course, of great importance during normal nitration in aqueous acid. For example, in 60% H2SO4 1,2-dimethylbenzene gives no less than 33% of mono- and di-nitro-3,4-dimethyl phenols15. 

Synonyms AI3-08197 BRN 1815558 CCRIS 905 1,2-Dimethylbenzene o-Dimethylbenzene EINECS 202-422-2 o-Methyltoluene NSC 60920 UN 1307 1,2-Xylene 2-Xylene o-Xylol. 

When flushing a gasoline-contaminated soil in a laboratory column with clean water, Mackay et al. (1996) observed that after 5 pore volumes (i.e., after 5 times replacing the water in the column), the benzene concentration in the effluent decreased from initially 370 to about 75 iig-L, while the 1,2-dimethylbenzene concentration increased from 1200 to 1400 jug-L-1. Try to explain these findings. 

Both anhydrides are prepared in this manner on a large scale for use in the production of ester polymers (Section 29-5A). Phthalic anhydride also is prepared by the oxidation of 1,2-dimethylbenzene ... 

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