21739-92-4Relevant articles and documents
An efficient chromium(iii)-catalyzed aerobic oxidation of methylarenes in water for the green preparation of corresponding acids
Jiang, Feng,Liu, Shanshan,Wei, Yongge,Yan, Likai,Yu, Han,Zhao, Wenshu
supporting information, p. 12413 - 12418 (2021/09/28)
A highly efficient method to oxidize methylarenes to their corresponding acids with a reusable Cr catalyst was developed. The reaction can be carried out in water with 1 atm oxygen and K2S2O8as cooxidants, proceeds under green and mild conditions, and is suitable for the oxidation of both electron-deficient and electron-rich methylarenes, including heteroaryl methylarenes, even at the gram level. The excellent result, together with its simplicity of operation and the ability to continuously reuse the catalyst, makes this new methodology environmentally benign and cost-effective. The generality of this methodology gives it the potential for use on an industrial scale. Differing from the accepted oxidation mechanism of toluene, GC-MS studies and DFT calculations have revealed that the key benzyl alcohol intermediate is formed under the synergetic effect of the chromium and molybdenum in the Cr catalyst, which can be further oxidized to afford benzaldehyde and finally benzoic acid.
Preparation method 5 - bromo -2 -chlorobenzoic acid
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Paragraph 0040-0041; 0044-0045; 0049; 0052-0054; 0057-0058, (2021/09/01)
The invention provides a preparation method of 5 -bromo -2 -chlorobenzoic acid, which comprises (1) contacting 2 - chlorobenzonitrile with a bromination reagent for bromination reaction to obtain 5 - bromo -2 - chlorobenzonitrile. (2) Hydrolysis of 5 - bromo -2 - chlorobenzonitrile in the presence of a base to give 5 - bromo -2 -chlorobenzoate. The 5 - bromo -2 -chlorobenzoate is then contacted with a protic acid to give 5 - bromo -2 -chlorobenzoic acid. The preparation method has the advantages of simple process, high safety, cheap and accessible raw materials, low cost and 5 - bromo -2 - chlorobenzoic acid yield, high purity and the like.
Preparation method of 5-bromo-2-chlorobenzoic acid
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Paragraph 0029-0051, (2020/09/16)
The invention relates to a preparation method of 5-bromo-2-chlorobenzoic acid, which is characterized by comprising the following steps: reacting 2-chlorobenzotrichloride used as a raw material with abromination reagent under the catalytic action of a first catalyst to generate 2-chloro-5-bromobenzotrichloride, adding water and a hydrolysis catalyst into the 2-chloro-5-bromobenzotrichloride, andcarrying out after-treatment and purification to obtain 5-bromo-2-chlorobenzoic acid, wherein the first catalyst is prepared by compounding iron bromide, ferrous bromide, copper bromide, (ferrocene methyl) trimethyl ammonium bromide and brominated ferrocene. The invention further discloses the 5-bromine-2-chlorobenzoic acid prepared according to the preparation method of the 5-bromine-2-chlorobenzoic acid. According to the preparation method of 5-bromine-2-chlorobenzoic acid disclosed by the invention, the traditional preparation process conditions are optimized and innovated, so that the product purity, the reaction conversion rate and the production efficiency are effectively improved, the preparation cost is low, the environmental pressure is low, the synthesis route is short, the operation is simple and feasible, the emission of three wastes is reduced, and the reaction yield is high.