Nitration of benzene

Benzene and nitric acid can produce nitrobenzene under the catalysis of concentrated sulfuric acid;

Nitrification is a strong exothermic reaction, which is easy to produce substitutes, but the further reaction speed is slow. Among them, concentrated sulfuric acid is used as a catalyst, which reacts when heated to 50~60 degrees Celsius, and benzene reacts with sulfuric acid when heated to 70 ~ 80 degrees Celsius.

Therefore, the water bath heating method is generally used to control the temperature. After a nitro group is attached to the benzene ring, the further nitration of benzene can be inhibited, and the nitro group is a passivation group.

Extended data:

Physical properties:

Benzene is a colorless, sweet and transparent liquid at room temperature. Its density is less than that of water, and it has a strong aromatic smell. The boiling point of benzene is 80. 1℃ and the melting point is 5.5℃. The density of benzene is lower than that of water, with a density of 0.88g/cm3, but its molecular weight is heavier than that of water.

Benzene is insoluble in water, and 1.7g benzene can be dissolved in 1 liter of water at most; Benzene is a good organic solvent, which has strong solubility for organic molecules and some nonpolar inorganic molecules. It can be miscible with most organic solvents except polyols such as glycerol and ethylene glycol. Inorganic substances are insoluble in benzene except iodine and sulfur.

Benzene can react with water to form azeotrope with boiling point of 69.25℃ and benzene content of 9 1.2%. Therefore, benzene distillation is often added in the reaction of generating water to take it out.

The molar mass is 78. 1 1g/mol.

Minimum ignition energy: 0.20mJ

Upper explosion limit (volume fraction): 8.0%.

Lower explosion limit (volume fraction): 1.2%.

Combustion heat: 3303.08kJ/mol(25℃, gas).

Solubility: insoluble in water, soluble in most organic solvents such as ethanol, ether and acetone.

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