4,5-Difluoro-2-nitrobenzoic acid Chemical Properties

Melting point:

165-167 °C (lit.)

Boiling point:

349.7±42.0 °C(Predicted)

Density 

1.661±0.06 g/cm3(Predicted)

storage temp. 

Sealed in dry,Room Temperature

form 

powder to crystal

pka

1.85±0.25(Predicted)

color 

White to Light yellow

CAS DataBase Reference

20372-63-8(CAS DataBase Reference)

Safety Information

Hazard Codes 

Xi

Risk Statements 

36/37/38

Safety Statements 

26

WGK Germany 

3

HazardClass 

IRRITANT

HS Code 

29163990

MSDS

• Language:English Provider:SigmaAldrich

4,5-Difluoro-2-nitrobenzoic acid Usage And Synthesis

Chemical Properties

Solid

General Description

4,5-Difluoro-2-nitrobenzoic acid can be obtained from the nitration of 4,5-difluorobenzoic acid or 3,4-difluorobenzoic acid.

Synthesis

Step 1: 3,4-difluorobenzoic acid (120.0 g, 0.7589 mol) and concentrated sulfuric acid (96.4%, 1.0 L) were added to a 2 L three-necked round-bottom flask. The mixture was mechanically stirred at room temperature for 1.0 hour and then cooled to 0°C. Fuming nitric acid (>90% HNO3 content, 57.30 mL, 1.273 mmol, 1.677 eq.) was added dropwise over 30 minutes. After addition, the reaction mixture was stirred at room temperature for 16 hours. Subsequently, the reaction mixture was slowly poured into crushed ice (5 Kg) under stirring. 4,5-difluoro-2-nitrobenzoic acid precipitated as a yellow solid. The slurry was continued to be stirred at 0 °C for 0.5 h. The solid product was then collected by filtration through a Brinell funnel. The yellowish solid was washed with cold water and air dried; 120 g of product was obtained in 79% yield.

References

[1] Journal of Heterocyclic Chemistry, 2001, vol. 38, # 1, p. 61 - 67
[2] Farmaco, 2001, vol. 56, # 9, p. 664 - 676
[3] Patent: WO2008/36843, 2008, A2. Location in patent: Page/Page column 31-33
[4] Patent: US4994606, 1991, A
[5] Patent: US5003103, 1991, A

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