- Method for co-production 2-methyl-6-nitrobenzoic acid and 3-nitro-2-methylbenzoic acid
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The invention discloses a method for co-production of 2-methyl-6-nitrobenzoic acid and 3-nitro-2-methylbenzoic acid. The method is characterized by comprising the following steps: (1) feeding 3-nitro-o-xylene and dilute nitric acid into an oxidation reaction kettle, carrying out heating, and conducting reacting under certain pressure by using oxygen as an oxidant; (2) after the reaction is finished, discharging an oxidation reaction solution to obtain a crude product; (3) washing the crude product with water, conducting esterifying, and performing distilling to recover a solvent after the reaction is finished, thereby obtaining an esterified concentrated solution; (4) adding alkali into the esterification concentrated solution to adjust a pH value, carrying out layering, and distilling anorganic layer under reduced pressure to recover 3-nitro-2-nitrobenzoic acid; and (5) extracting a water layer with an organic solvent, adjusting an pH value with an acid, and performing filtering anddrying to obtain the 2-methyl-6-nitrobenzoic acid. In a low-concentration nitric acid environment, 3-nitro-2-nitrobenzoic acid is produced and 2-methyl-6-nitrobenzoic acid is co-produced with oxygen used as an oxidizing agent, so the problems of low selectivity of 3-nitro-o-xylene in an oxidation process and high risks in a concentrated nitric acid oxidation process are solved.
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Paragraph 0022; 0025; 0028; 0033
(2020/10/14)
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- CO-production method 3 - nitro -2 - methyl benzoic acid and 3 -nitrophthalic acid (by machine translation)
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The method comprises the following steps: (3 -) in nitric acid, oxidizing -2 - nitro-3 - methylbenzoic acid to 1 nitro 3 - methylbenzoic acid under the presence of a catalyst and an initiator; and (3 -) filtering to obtain the -2 -nitro 2 methylbenzoic acid crude product after the reaction is completed by heating while carrying out the reaction to complete the reaction and completing a 3 - nitro -2 -2 - methylbenzoic acid crude product after the reaction is completed, and the obtained crude 3 - product -2 - is obtained by recrystallizing the 4 mother liquor in the mother 3 - 1 liquor step (3) after the reaction is complete and the reaction is complete and the 3 - process is completed by carrying out the reaction on the 3 - mother liquor in the presence of a 3 - catalyst and an initiator to obtain the 3 -nitrobenzoic acid crude product. The method solves the problems of large waste water waste salt amount, difficult aftertreatment and serious environmental pollution in the prior art. (by machine translation)
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Paragraph 0019; 0023; 0027; 0031; 0035; 0041; 0045-0047
(2020/07/15)
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- Metal-Free Aerobic Oxidation of Nitro-Substituted Alkylarenes to Carboxylic Acids or Benzyl Alcohols Promoted by NaOH
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Efficient and selective aerobic oxidation of nitro-substituted alkylarenes to functional compounds is a fundamental process that remains a challenge. Here, we report a metal-free, efficient, and practical approach for the direct and selective aerobic oxidation of nitro-substituted alkylarenes to carboxylic acids or benzyl alcohols. This sustainable system uses O2 as clean oxidant in a cheap and green NaOH/EtOH mixture. The position and type of substituent critically affect the products. In addition, this sustainable protocol enabled gram-scale preparation of carboxylic acid and benzyl alcohol derivatives with high chemoselectivities. Finally, the reactions can be conducted in a pressure reactor, which can conserve oxygen and prevent solvent loss. The approach was conducive to environmental protection and potential industrial application.
- Fang, Kun,Li, Guijie,She, Yuanbin
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p. 8092 - 8103
(2018/06/25)
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- Method for preparing nitro aromatic acid/nitro alpha-aryl alcohol through oxidizing substituted alkyl nitrobenzene by oxygen
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A method for preparing nitro aromatic acid/nitro alpha-aryl alcohol through oxidizing substituted alkyl nitrobenzene by oxygen comprises the following steps: taking substituted alkyl nitrobenzene shown as the formula (1) as a raw material, oxygen as an oxidizing agent and sodium hydroxide as an alkaline substance, mixing in a solvent uniformly, reacting for 3 to 24h at the temperature of 25 to 65 DEG C, and treating obtained reaction liquid to obtain the nitro aromatic acid or nitro alpha-aryl alcohol; the mass ratio of the substituted alkyl nitrobenzene to the sodium hydroxide is 1 to (2 to 10) and the oxygen pressure is 0.1 to 2.0 MPa. The method provided by the invention has the advantages that a catalyst is not needed, the raw material is low in price and easy to recycle, the reaction temperature is moderate, the production and control are easy; the raw material transformation rate is high; the target product selectivity is high, the yield is up to 91%, and the application prospect is wide. The formula (1) is shown in the description.
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Paragraph 0121; 0122; 0123
(2017/09/01)
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