2-nitrotoluene

CAS accession No.: 88-72-2

Chinese Name: 2-nitrotoluene; O-Nitrotoluene

English Name: 2-nitrotoluene

English alias: 2-methyl-1-nitrobenzene; 2-Methylnitrobenzene; o-Nitrophenylmethane; 2-Nitrotoluol; alpha-Methylnitrobenzene 

Molecular formula: C7H7NO2

Molecular weight: 137.14

EINECS login No.: 201-853-3

Physicochemical properties

Melting point: - 9 ℃

Boiling point: 222 ℃

Water solubility: 0.44g/l (20 ℃)

Refractive index: 1.5445-1.5465

Flash point: 95 ℃

Density: 1.163

Property description

Yellow flammable liquid. Melting point: - 9.5 ℃, boiling point 221.7 ℃, relative density 1.163 (20 / 4 ℃), refractive index 1.5474, flash point 106 ℃, ignition point 420 ℃. Insoluble in water, soluble in chloroform and benzene, and miscible with ethanol and ether. It can volatilize with water vapor.  

Product application

Used in the synthesis of various dyes.  

Other information

Toluene is nitrated with mixed acid to produce mixed nitrotoluene, which is mainly o-Nitrotoluene (about two-thirds) and p-nitrotoluene (about one-third). The pure product is obtained after separation. Add toluene into the reactor, cool it to below 25 ℃, add the prepared mixed acid (i.e. nitric acid 25-30, sulfuric acid 55-58 and water 20-21), and adjust the temperature not to exceed 50 ℃. Continuous stirring for 1-2h, and then standing for 6h, the generated nitrotoluene is separated, washed with water and alkali to remove unreacted toluene and aliphatic compounds. The composition of the crude nitrotoluene product is o-Nitrotoluene 55-60; The interval is 2-5 and the contraposition is 35-40. The yield is 90-95. Using the difference between boiling point and melting point for crude distillation and crystallization, different structures can be separated. That is, the crude nitrotoluene is first vacuum distilled to separate most of the o-Nitrotoluene, and the residual fraction containing more p-nitrotoluene is then separated by vacuum distillation, cooled, crystallized and separated to obtain the finished product. The tar like substance with high boiling point remains in the distillation kettle. The m-nitrotoluene is contained in the mother liquor after separation of para isomers, and is obtained by repeated accumulation and rectification. The purity of ortho and para nitrotoluene can reach 98 and 99 respectively. The domestic process is two pots connected in series, and the reaction temperature of the main pot is 40-45 ℃, and the secondary pot is 50-55 ℃. The preparation of mixed acid is roughly the same: nitric acid 26-28, sulfuric acid 56-57, water 16-18. Raw material consumption quota: toluene (98) 800kg / T, nitric acid (98) 470kg / T, sulfuric acid (92.5) 450kg / T, caustic soda (42) 100kg / T.