Xylene

1, Nature: xylene molecular weight of 106.16. Colorless, transparent liquid, aromatic scent. There are three isomers: o-xylene (o-Xylene), the relative density (25 ℃ / 4 ℃) 0.87599, freezing point -25.3 ℃, the boiling point 144.4 ℃, refractive index of 1.50295, the flash point (closed ) 17.4 ℃, burning 500 ℃, viscosity (25 ℃) 0.75 mPa • s; inter-xylene (m-xy1ene), the relative density (25 ℃ / 4 ℃) 0.8599, freezing point -47.87 ℃, the boiling point 139.1 ℃, the flash point (opening) 25 ℃, lit 527.8 ℃. Refractive index 1.4946; xylene (p = xy1ene), the relative density (25 ℃ / 4 ℃) 0.8567, Freezing Point 13.26 ℃, the boiling point 138.35 ℃, the flash point (closed) 25 ℃. Refractive index of 1.49325. 
     Xylene is a general mixed xylene. For o-xylene (10% of a 15 per cent), m-xylene (45 to 70 percent), para-xylene (15% -25%) and a small amount of the mixture of ethylbenzene, the relative density (20 ℃ / 4 ℃) is about 0.86, solubility parameter δ = 8.8-9.0. Soluble in ethanol, ethyl ether, insoluble in water. Flammable, explosive vapour and air mixture formation, the explosion limits 1. 09% -6.6% (vol). Poisonous, toxic than benzene and toluene for small, the maximum admissible concentration in the air for 100 mg/m3. 
2.uses: xylene can be used as solvents and thinners. Stored in a cool, ventilated coffers, far away from the fire, heat. 
     According to sources, and xylene divided into the oil-xylene and coking xylene. Xylene is a light petroleum distillate oil to the hydrogenation, catalytic reforming and separation from; coking xylene is Crude Benzol After washing, fractionation proceeds. Mixed xylene is o, the B benzene and xylene mixtures. As the use of chemical raw materials, could be the pre-isomer separation. Mixture mainly used as a solvent for paints and coatings aviation gasoline additive.