Oxidation preparation method of fluorobenzene formaldehyde

A technology of fluorobenzaldehyde and fluorotoluene, which is applied in the field of preparation of fluorobenzaldehyde, can solve the problems of affecting development and large power consumption, and achieve the effects of low production cost, elimination of environmental hazards, and high yield

Inactive Publication Date: 2010-06-16
NANJING UNIV OF SCI & TECH
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Problems solved by technology

Yu Chengguang et al. (Yu Chengguang, Bu Linghai, Mao Zhen et al. Synthesis of fluorobenzaldehyde by indirect electrooxidation [J]. Fine Chemical Intermediates, 2007, 37(1): 52~54.) introduced in detail the organic electrosynthesis Fluorobenzaldehyde has the characteristics of good selectivity, high yield, easy separation of products, mild conditions, and low environmental pollution, but it consumes a lot of electric energy, and there are still problems to be solved in electrodes, electrolyzers, and diaphragm materials, which affect its performance. development of

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[0011] In conjunction with the accompanying drawings, the oxidation preparation method of fluorobenzaldehyde of the present invention mainly utilizes Mn 2 o 3 Realize the oxidation of p-fluorotoluene in sulfuric acid medium to synthesize fluorobenzaldehyde. For the by-product heavy metal salt manganese sulfate, it is converted into manganese carbonate by adding ammonium bicarbonate, and then converted into Mn by burning. 2 o 3 , Realize the recycling of solid oxidant, no waste residue is generated, and it will not cause harm to the environment. Include the following steps:

[0012] In the first step, add Mn to the reaction device 2 o 3 and fluorotoluene. Wherein fluorotoluene refers to p-fluorotoluene, o-fluorotoluene or m-fluorotoluene. Fluorotoluene and Mn 2 o 3 The molar ratio is 1:2~3.

[0013] In the second step, the reaction device is heated, and sulfuric acid is started to be added dropwise. The heating temperature is 40-80 DEG C, and the mass concentration of...

Embodiment 1

[0022] mn 2 o 3 Oxidative synthesis of m-fluorobenzaldehyde

[0023] 20g of m-fluorotoluene and 60g of Mn 2 o 3 Place in a 500mL four-necked flask, and install a thermometer, a mechanical stirrer, and a condenser. Heat with a water bath to adjust the reaction temperature to 50°C. 70% (wt) 200mL sulfuric acid was dropped into the flask, and the drop was completed within 1 hour, and the reaction was maintained at 50° C., and the reaction was detected by GC control for about 8 hours.

[0024] After the reaction is finished, cool and filter the product directly, the filtrate is mainly a mixed solution of sulfuric acid and manganese sulfate, and extract the product in the filtrate with 50mL dichloromethane; Extract the product in the filtrate, after separation, the water phase is manganese sulfate solution, the oil phase is mixed with the former, and the product at 66-68°C / 20mmHg is collected by vacuum distillation to obtain 21.3g, the purity of GC analysis is 99.6%, and the y...

Embodiment 2

[0026] mn 2 o 3 of recycling

[0027] The manganese sulfate solution of embodiment 1 (concentration is 150g L -1 ) to adjust the reaction temperature to 30°C. Under the condition of stirring, adjust its pH to 6.0 by adding ammonia solution dropwise, slowly add ammonium bicarbonate (concentration is 150g·L -1 ), to pH=6.8 as the end point, placed for aging, filtered, washed with deionized water, washed with Ba 2+ Detected to no SO 4 2+ . Place the filter cake in a muffle furnace, adjust the temperature to 370°C, and burn for 6h. Ignite at 650°C for 1 hour, take it out and cool to obtain 49.3g of manganese trioxide.

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Abstract

The invention discloses an oxidation preparation method of fluorobenzene formaldehyde, comprising the following steps: adding Mn2O3 and fluorotoluene in a reaction device; heating the reaction device, and beginning to dropwise add sulfuric acid; and after the reaction, purifying the product fluorobenzene formaldehyde through processing. The invention has high synthetic product yield which can reach 90%; the generated heavy metallic salt can be effectively converted into Mn2O3, thus eliminating the harm to the environment; the invention has easily obtained reaction raw materials, simple process flow and low production cost; the waste acid generated by oxidation can be recycled, thus improving the utilization rate of the device, realizing continuous operation and satisfying the requirement of industrialization.

Description

technical field [0001] The invention belongs to the preparation technology of fluorobenzaldehyde, in particular to an oxidation preparation method of fluorobenzaldehyde. Background technique [0002] Fluorobenzaldehyde is an important intermediate in organic synthesis, which can be widely used in the synthesis of fine chemicals such as medicine, pesticide, and plastic additives. At present, the main synthesis methods of fluorobenzaldehyde reported include halogenation hydrolysis, direct chemical oxidation, electrochemical oxidation, oxygen oxidation and so on. Dong Chengguo et al. (Dong Chengguo, Zuo Shizhi, Ni Jiabao. Synthesis of p-fluorobenzaldehyde [J]. Dyestuff Industry, 2001, 38(3): 32-34.) Synthesized using p-fluorotoluene as raw material by chlorination and hydrolysis p-Fluorobenzaldehyde, the total yield reached 86.23%. Although the yield of the product obtained by the chlorination hydrolysis method is high, the product contains a small amount of chlorine, which i...

Claims

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Application Information

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IPC IPC(8): C07C47/55C07C45/28
Inventor 李斌栋吕春绪许昕
Owner NANJING UNIV OF SCI & TECH
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