Production principle and technical formula of 1,4-dihydroxyanthraquinone

1,4 -dihydroxyanthraquinone (1,4-dihydroxyanthraquinone), also known as quinizarin, has a molecular formula of C ₁₄ H ₈ O ₄ , a molecular weight of 240.
2, and a structural formula of

1.

Orange crystals are precipitated from acetic acid and ether , and dark red needle-like crystals are precipitated from alcohol, benzene, and toluene
.

2.
Production principle

In the presence of boric acid and sulfuric acid , phthalic anhydride (phthalic anhydride) and hydroquinone undergo a thermal condensation reaction, and then the finished product is obtained by dilution, neutralization, oxidation, and pressure filtration
.

3.

4.

5.

Condensation reactor, beating tank, filter press, liquid storage tank
.

6.
Production process

Add 836 kg of 95% sulfuric acid, 121 kg of hydroquinone, 330 kg of phthalic anhydride, and 109 kg of boric acid into the condensation reaction kettle , and heat to 150-155°C for 12 hours
.

7.
Laboratory method

In a 250 mL round bottom flask, place 11.
5 g of p-chlorophenol, 30 g of phthalic anhydride, 5 g of crystalline boric acid and 109 mL of 96% sulfuric acid, and mix them evenly
.