ChemicalBook CAS DataBase List 3,4-DIFLUORO-2-METHYLBENZOIC ACID

3,4-DIFLUORO-2-METHYLBENZOIC ACID synthesis

5synthesis methods

Product Name:3,4-DIFLUORO-2-METHYLBENZOIC ACID
CAS Number:157652-31-8
Molecular formula:C8H6F2O2
Molecular Weight:172.13

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3828-49-7 Synthesis

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157652-31-8
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$8.00/250mg

Yield:157652-31-8 82.4%

Reaction Conditions:

with aluminum (III) chloride at 30; for 10 h;Temperature;

Steps:

1; 2 Example 2:
equipped with an electric stirring device,A three-necked flask of a thermometer and an air tube was charged with 8.96 g (0.07 mol) of 2,3-difluorotoluene and 13.1 g (0.1 mol) of anhydrous aluminum trichloride, and carbon dioxide gas was introduced thereto.Turn on the stirring device. Observing temperature changes,When the reaction temperature rises to the highest (about 30 ° C) and then falls back,The three-necked flask was placed in a water bath and the temperature of the water bath was stabilized at 30 °C.After the reaction was carried out for 10 h,Stop the reaction.Slowly pour the mixture from the three-necked flask into ice water.And keep stirring. The resulting white precipitate was suction filtered.After suction filtration, the white solid was dispersed in 50 mL of petroleum ether.Stir and filter.The solid was taken and the filtrate was recovered for use.The above white powder was suspended in 20 mL of methanol.Add 2 mL of concentrated HCl and stir at 45 °C for 30 min.After suction filtration, the filtrate was evaporated to 10 mL of methanol under reduced pressure, and 50 mL of water was slowly added.After stirring for 20 min, suction filtration and drying (80 ° C) to obtain a crude product.This crude product was recrystallized from ethanol/water (1:4) to give 5.6 g of 3,4-difluoro-2-methylbenzoic acid as white crystals with a liquid phase purity of 99.63% (Fig. 3 of the accompanying drawings).The petroleum ether in the petroleum ether filtrate is distilled off under normal pressure.2,3-Difluorotoluene was distilled off under reduced pressure (70-80 ° C / 35 mmHg), and 3.9 g of 2,3-difluorotoluene was recovered.The yield was 82.4%.

References:

Hunan Normal University;Zheng Zijian;Tian Shaixiao;Xu Guangyu CN110204433, 2019, A Location in patent:Paragraph 0007; 0008

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