XYLENE

XYLENE, dimethylbenzenes. Colourless liquids, well mixed with ethyl alcohol, diethyl ether, acetone, benzene; poorly soluble in water. The construction of unit No.35/1 was launched in Bashkortostan at the Industrial Complex No.18 (ref. Gazprom Neftekhim Salavat for production of toluene‑xylene fraction in 1954; the production of xylene started in 1960, after the reconstruction of unit No.35/3. Unit 35‑9/2 was installed at the Chernikovsky Oil Refinery, in 1960, for xylene extraction from 3511/300 unit catalyzate; between 1982—83, a complex for the production of aromatic hydrocarbons (designed capacity in para‑xylene and orto‑xylene of 165 thous. t each). The complex comprises the blocks of secondary distillation of a wide gasoline fraction (85–140°С) and its reforming, aromatic hydrocarbons extraction from reformate, followed by separation of benzene and orto‑xylene by means of rectification, adsorption of para‑xylene at molecular sieves (Parex process), isomerization of meta‑xylene (Isomar process). The production of orto‑xylene was launched at OAO Salavatnefteorgsintez in 2005. Oxidation of orto‑xylene produces phthalic anhydride (Gazprom Neftekhim Salavat), para‑xylene — terephthalic acid (OAO Polief), chlorination of para‑xylene — hexachlorine‑para‑xylene (Bashkir Soda Company). Xylene is a solvent for varnishes, paints, mastics, a high‑octane additive to motor fuels.