Crystallization purification method of 3,5-di-tert-butyl-4-hydroxybenzoic acid
A technology of hydroxybenzoic acid and di-tert-butyl, which is applied in the field of crystallization and purification of 3,5-di-tert-butyl-4-hydroxybenzoic acid, and can solve problems such as increased ash content
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Embodiment 1
[0016] Example 1; 1. Add 50 g of crude 3,5-di-tert-butyl-4-hydroxybenzoic acid obtained by Kolbe-Schmitt reaction into 83 ml of tetrahydrofuran, stir and dissolve at 60°C, A clear solution was obtained with a solution concentration of 0.6 g / ml.
[0017] 2. Add 2.5 g of activated carbon to the solution, raise the temperature to 65°C for decolorization reaction for 2 hours, and cool down the reaction solution to 60°C after decolorization and filtration.
[0018] 3. Add petroleum ether at 60°C dropwise to the reaction solution until the solution becomes turbid, stop adding petroleum ether, raise the temperature to make the reaction solution from cloudy to clear, and slowly cool down at 5°C / h, and cool the reaction solution to 15°C After that, the crystal growth was continued for 10 h to crystallize 3,5-di-tert-butyl-4-hydroxybenzoic acid from the solvent. Then the crystal slurry was filtered, the filter cake was washed with 15 g of methanol, and dried to obtain 46.51 g of a whit...
Embodiment 2
[0019] Example 2; 1. Add 50 g of crude 3,5-di-tert-butyl-4-hydroxybenzoic acid obtained by Kolbe-Schmitt reaction into 166 ml of toluene, stir and dissolve at 80°C, A clear solution was obtained with a solution concentration of 0.3 g / ml.
[0020] 2. Add 5 g of activated carbon to the solution, raise the temperature to 110°C for decolorization reaction for 2 hours, and cool down the reaction solution to 80°C after decolorization and filtration.
[0021] 3. Add petroleum ether at 80°C dropwise to the reaction solution until the solution becomes turbid, stop the dropwise addition, raise the temperature to make the reaction solution from turbid to clear, slowly cool down at 5°C / h, cool the reaction solution to 15°C and continue to raise Crystal 10h to crystallize 3,5-di-tert-butyl-4-hydroxybenzoic acid from the solvent. Then the crystal slurry was filtered, the filter cake was washed with 15 g of ethanol, and dried to obtain 47.05 g of a white product, that is, 47.05 g of crystal...
Embodiment 3
[0022] Example 3; 1. Add 50 g of the crude 3,5-di-tert-butyl-4-hydroxybenzoic acid obtained by the Kolbe-Schmitt reaction into 166 ml of xylene, stir and dissolve at 80°C , to obtain a clear solution with a solution concentration of 0.3 g / ml.
[0023] 2. Add 2.5 g of activated carbon to the solution, raise the temperature to 110°C for decolorization reaction for 2 hours, and cool down the reaction solution to 80°C after decolorization and filtration.
[0024] 3. Add petroleum ether at 80°C dropwise to the reaction solution until the solution becomes turbid, stop the dropwise addition, raise the temperature to make the reaction solution from turbid to clear, and slowly cool down at 10°C / h, cool the reaction solution to 15°C and continue to raise Crystal 10h to crystallize 3,5-di-tert-butyl-4-hydroxybenzoic acid from the solvent. Then the crystal slurry was filtered, the filter cake was washed with 20 g of ethanol, and dried to obtain 45.8 g of a white product, that is, 45.8 g ...
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