Application
The 2,4,6-Trifluorobenzoic acid is crucial and an important raw material for preparing the photosensitizers, medicines and pesticides, and also finds applications in pharmaceutical and agrochemical industries.
Synthesis
Add 90 grams of 2,4,6-trifluoro-3,5-dichlorobenzoic acid, 540 grams of water, 33 grams of magnesium oxide, and 0.9 grams of 10% wet palladium-carbon to a 1-liter pressure-resistant reactor. Replace the gas with nitrogen 3 times, and then replace the gas with hydrogen 5 times. Use hydrogen to control the internal pressure of the kettle to 0.8-0.9 MPa, turn on the stirring, increase the temperature to 80-85°C for 10 hours, and stop the reaction. The reaction system is lowered to room temperature, the pressure in the kettle is removed, the reaction liquid is filtered, and the filtrate is adjusted to pH 1-2 with 20% hydrobromic acid solution, filtered, and the filter cake is rinsed and dried to obtain 2,4,6-Trifluorobenzoic acid 62.95 grams, the yield is 97.3%, and the purity is 99.1%.
Structure and conformation
In the title compound, C7H3F3O2, the C—C—C angles in the ring are greater than 120° for F-bonded C atoms [123.69 (13), 123.88 (12) and 123.66 (12)°]. In the crystal, inter-molecular O—H—O hydrogen bonds between carboxyl groups give rise to the formation of a centrosymmetric dimer, while dispersive F—O contacts [2.8849 (16) Å] connect the dimers into infinite strands along the a axis.
