Benzoic acid preparation toluene oxidation method

benzoic acid

[Structural formula]

[Physical and chemical properties] Also known as benzoic acid

[Preparation method] The production methods of benzoic acid mainly include toluene oxidation method, benzaldehyde oxidation method, benzyl alcohol oxidation method and so on

(1) Toluene oxidation method

①The commonly used catalyst for toluene liquid phase air oxidation is soluble cobalt salt or manganese salt, with acetic acid as the solvent

The reaction mechanism is a free radical reaction, the reaction temperature is about 165°C, the pressure is 0.

②Toluene chlorination hydrolysis method: Toluene is photochlorinated at 100～150℃ to obtain trichlorobenzylbenzene, in the presence of ZnCl ₂ (or with lime milk and iron powder), it reacts with water to obtain benzoic acid

Because this method consumes chlorine, the heating and corrosion of HCI aqueous solution is extremely serious.

③Potassium permanganate oxidation method

a.

b.

Weigh 8.

The reaction mixture was filtered under reduced pressure while hot, and the filter cake was washed with a small amount of hot water; then the filtrate was placed in a 200 mL beaker and cooled in an ice-water bath

c.

Related links: Hydroquinone (HQ) technical indicators and applications