Synthesis method of 5-bromo-2-chloro benzoic acid
A synthesis method, a technology of chlorobenzoic acid, applied in chemical instruments and methods, preparation of carboxylate, preparation of organic compounds, etc., can solve problems such as low final yield
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[0027] The invention provides a kind of synthetic method of 5-bromo-2 chlorobenzoic acid, comprises the following steps:
[0028] A) under the action of a catalyst, 2-chlorobenzotrichloride is reacted with a brominating reagent to obtain 2-chloro-5-bromobenzotrichloride;
[0029] The bromination reagent includes one or more of bromine, N-bromosuccinimide, dibromohydantoin and hydrobromic acid;
[0030] B) hydrolyzing the 2-chloro-5-bromotrichlorotoluene in the step A) under acidic conditions to obtain 5-bromo-2-chlorobenzoic acid.
[0031] The 5-bromo-2-chlorobenzoic acid prepared by the synthesis method provided by the invention has higher purity and higher yield.
[0032] Under the action of a catalyst, the present invention reacts 2-chlorobenzotrichloride with a bromination reagent to obtain 2-chloro-5-bromobenzotrichloride. In the present invention, preferably, under a protective gas atmosphere, a catalyst is added to 2-chlorobenzotrichloride, and then a bromination reag...
Embodiment 1
[0044] In a 250 ml single-necked bottle, add successively 5 grams (0.017mol) of ferric tribromide, 23 grams (0.10mol) of o-chlorobenzotrichloride, and 100mL (0.88mmol) of hydrobromic acid with a mass concentration of 48%, and stir at room temperature , drop 12.0 g mass concentration of 35% H 2 o 2 (0.12mmol), bromine 10.6g (0.11mol). Heating to 40°C, stirring and reacting for 10 hours; then raising the temperature to 100°C, stirring and reacting for 6 hours, cooling down to room temperature, solids precipitated; filtering, washing 2 times with 200 ml of water to obtain the crude product, the purity of the crude product was 87%, and the yield was 96%. The filter cake was added to a 250 ml single-necked bottle, and 100 ml of water and 100 ml of methanol were added. Stir, reflux for 1 hour, cool naturally, stir and crystallize. Filter, wash with 50 ml of 50% methanol aqueous solution, and dry under vacuum at 60° C. for 5 hours to obtain 19.3 g of yellow solid, yield: 82%, HPL...
Embodiment 2
[0048] 1.2 g (0.006 mol) of iron sulfide and 23 g (0.10 mol) of o-chlorobenzotrichloride were successively added to a 250 ml single-necked bottle, stirred at room temperature, and 17.6 g (0.11 mol) of bromine was added dropwise. Heat to 40°C, stir for 10 hours; cool, filter, and remove iron sulfide. 100 g of 80% concentrated sulfuric acid (0.82 mol) was slowly added dropwise to the reaction solution, stirred, heated to 120° C., and reacted for 4 hours. After cooling down to room temperature, 200 ml of water was added dropwise to dilute the reaction solution, stirred for 0.5 hour, filtered and washed with 100 ml of water to obtain a crude product with a purity of 92% and a yield of 98%. The crude product was transferred to a 250 ml single-necked bottle, and 150 ml of ethanol and 150 ml of water were added. Heating to reflux, stirring for 1 hour, natural cooling and crystallization. Filter, wash with 100 ml of 50% ethanol water, and dry under vacuum at 60° C. for 5 hours to ob...
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