Industrial o-xylene is used as raw material. First, it is washed with industrial concentrated sulfuric acid until the acid layer is colorless, then it is washed with 10% sodium hydroxide solution and water in turn until it is qualified. After separating the water layer, it is dried with anhydrous calcium chloride, and then it is rectified. After the distillate is clear, the middle fraction is collected, which is the pure product.

Production method:

1. According to the different boiling points of crude benzene components, distillates with boiling range of 135~145℃ are extracted by rectification to obtain xylene.

2. The platinum reforming method uses the light gasoline (initial distillation point is about 138℃) obtained by atmospheric distillation, intercepts the fraction higher than 65℃, first uses molybdenum-containing catalyst to remove harmful impurities, then uses platinum catalyst to reform, extracts with diethylene glycol ether solvent, and then rectifies tower by tower to obtain benzene, toluene, xylene and other products.

3. Toluene disproportionation. In this method, under the action of catalyst, the methyl group of one toluene is transferred to another 166 catalyst (Al-H-deficient mordenite), and reformed toluene (nitration grade) and reformed circulating hydrogen (85%~90%) are used as raw materials, and the reaction temperature is 400 2℃, and the pressure is about 2MPa, etc., to produce benzene and xylene.

4. Xylene is obtained by hydrofining, catalytic reforming and separation of light petroleum fraction mixed benzene. Or the coking crude benzene is washed and fractionated.