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Method of preparing dihalogen nitrobenzoate using dihalogen methyl nitrobenzene oxidation

A technology of dihalogenated nitrobenzoic acid and dihalogenated nitrotoluene, which is applied in the field of preparation of organic compounds, can solve problems such as high equipment requirements, large equipment investment, and potential safety hazards, and achieve safe operation, low equipment investment, and low pollution small effect

Inactive Publication Date: 2007-07-18
YANCHENG SHIHONG CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Compared with the traditional nitric acid oxidation process, the yield is high, and it is particularly safe and economical; yet, because it is to nitrotoluenes, nitrobenzyl alcohols, its esters and / or ethers (chemical general formula II compound) is added to the heating mixture of nitric acid and water, therefore, on the one hand, the requirements for equipment are relatively high, and the equipment investment is relatively large; Security risks

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] In a corrosion-resistant 5-liter reactor equipped with a stirrer, add 3000 milliliters of 68% nitric acid and 300 grams of 4,6-dichloro-2-nitrotoluene with a purity of 99%. Close the reaction kettle, raise the temperature to about 140°C with stirring, control the pressure below 0.5MPa, and react for 20 hours; then raise the temperature to 180°C, and react for 2 hours at a pressure of about 0.7MPa. HPLC follow-up analysis showed that the raw material disappeared, and the purity of 4,6-dichloro-2-nitrobenzoic acid was greater than 99.0%. After cooling to below 40°C, the material was suction-filtered, washed with 100 ml of water, and the filter cake was dried at 110°C to obtain 320 g of 4,6-dichloro-2-nitrobenzoic acid with a yield of 93.1%. At the same time, 2700 milliliters of nitric acid and 100 milliliters of washing liquid were recovered for reuse.

Embodiment 2

[0015] In the corrosion-resistant 5 liters of reactors that stirrer is housed, add the 65% nitric acid 2700 milliliters that reclaims among the embodiment 1, 130 milliliters of 98% nitric acid, 100 milliliters of filter cake washing water, purity 99% 4,6 -Dichloro-2-nitrotoluene 300 g, V 2 o 5 1 g. Close the reaction kettle, heat up to about 140°C with stirring, control the pressure below 0.5MPa, and react for 16 hours; then raise the temperature to 180°C, keep the pressure below 0.7MPa, and react for 2 hours. HPLC follow-up analysis showed that the raw material disappeared, and the purity of 4,6-dichloro-2-nitrobenzoic acid was greater than 99.0%. After cooling to below 40°C, the material was suction-filtered, washed with 60 ml of water, and the filter cake was dried at 110°C to obtain 325 g of 4,6-dichloro-2-nitrobenzoic acid with a yield of 94.5%. Recover 2800 milliliters of nitric acid and 60 milliliters of washing water.

Embodiment 3

[0017] In the corrosion-resistant 5 liters of reactors that stirrer is equipped with, add the nitric acid 2700 milliliters that reclaims among the embodiment 1, the 4 of 300 milliliters of 65% nitric acid purity 99%, 300 grams of 6-dichloro-2-nitrotoluene , 1 g of tetrabutylammonium bromide. Close the reaction kettle, raise the temperature to about 140°C with stirring, control the pressure below 0.5MPa, and react for 16 hours; then raise the temperature to 180°C, and react for 2 hours under the pressure of 0.7MPa. HPLC follow-up analysis showed that the raw material disappeared, and the purity of 4,6-dichloro-2-nitrobenzoic acid was greater than 99.0%. After cooling to below 40°C, the material was filtered with suction, washed with 60 ml of water, and the filter cake was dried at 110°C to obtain 323 grams of 4,6-dihalo-2-nitrobenzoic acid, with a yield of 94%. Nitric acid was recovered 2720ml, 60ml of washing water.

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Abstract

This invention provides a method of using dipl-halogena nitrotoluene to prepare dipl-halogena nitrobenzoic acid. Mix dipl-halogena nitrotoluene with nitric acid under normal temperature, and then take reaction at 110 to 300 deg C and 0 to 10MPa, to gain dipl-halogena nitrobenzoic acid. The mixture ratio (mol / mol) of nitric acid and dipl-halogena nitrotoluene is 1:21 to 100; the nitric acid concentration of 4% to 70%. Since the invention at room temperature and atmospheric pressure directly mix the materials, so operating temperature is low than the start temperature many, thus making operation simple and safe, the low production costs and high-yield, the reaction residue can be reused, little pollution, and good economic and social benefits.

Description

Technical field [0001] The invention relates to a method for preparing organic compounds, in particular to a method for preparing dihalonitrobenzoic acid by oxidation of dihalonitrotoluene. Background technique [0002] Dihalonitrobenzoic acid is an important intermediate for the synthesis of dyes, pharmaceuticals and other chemical products. There are many methods for its preparation. There are also many methods for preparing dihalogennitrobenzoic acid by oxidation of dihalogennitrotoluene, such as: in sulfuric acid medium Oxidation with manganese dioxide or dichromate, catalytic oxidation with air, oxidation with potassium permanganate, oxidation with nitric acid, etc. In the above-mentioned methods, there are one or several deficiencies in the defects of low yield, long cycle, high cost, heavy pollution, and high potential safety hazards. For this reason, people are constantly improving and proposing new processes. For example: Chinese Patent No. 01807893.1, named as a m...

Claims

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Application Information

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IPC IPC(8): C07C51/215C07C63/70
Inventor 李松跃朱立家
Owner YANCHENG SHIHONG CHEM
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