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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, (2020/11/26)
The invention relates to a preparation method of 5-bromo-2-chlorobenzoic acid. The preparation method comprises the following steps: taking 2-chlorobenzoic acid as an initial reactant, sequentially carrying out chlorination, acylation and cyclization reactions to obtain a protective group o-chlorobenzoic acid (a compound represented by formula III), and sequentially carrying out bromination and hydrolysis to obtain 5-bromo-2-chlorobenzoic acid. The reaction conditions are mild, and the safety of the preparation process is improved. The yield of the prepared product can reach 75% or above, thepurity can reach 99% or above, and the purity and yield are much higher than those of an existing preparation method. Meanwhile, the preparation method is simple in process step, the product is easy to purify, 5-bromo-2-chlorobenzoic acid can be synthesized on a large scale, and the preparation method has a good industrial development prospect.