The preparation and use of 1,2-Dimethylbenzene

1,2-Dimethylbenzene, also known o-Xylene, is colourless, flammable liquid with aromatic smell. It is an aromatic hydrocarbon, based on benzene with two methyl substituents bonded to adjacent carbon atoms in the aromatic ring (the ortho configuration). What's more, 1,2-Dimethylbenzene is miscible with ethanol, ether, acetone and benzene, insoluble in water.
1,2-Dimethylbenzene was mainly obtained from coal tar originally, but now the majority of domestic and overseas extract this product from oil catalytic reforming and aromatics thermal cracking. As the structure of 1,2-Dimethylbenzene, p-xylene, m-xylene is very similar, their physical parameters vary little. In industry, the separation of 1,2-Dimethylbenzene uses superfractionation. The rectification requires about 150 tower plates and reflux ratio 5-8 and consumes more energy.
1,2-Dimethylbenzene is mainly used as chemical raw material and solvent. It can be used in the production of phthalic anhydride, phthalic nitrile, dimethyl phenol, dimethylaniline, dyes, pesticide, drug (such as vitamin) and so on. It is also used as aviation gasoline additive. In addition, 1,2-Dimethylbenzene is used in organic synthesis. For example: it can react with benzoyl chloride to get 3,4-dimethyl-benzophenone.