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Production method of 2,5-dichloroaniline

A technology of dichloroaniline and its production method, which is applied in the field of hydrogenation of 2,5-dichloronitrobenzene to prepare 2,5-dichloroaniline, which can solve the difficulty of increasing post-processing equipment investment, recovering energy consumption, and increasing operation and safety hazards, reducing production safety and cleanliness, etc., to achieve the effects of increasing production capacity and equipment utilization, improving stability and safety, and reducing production costs and equipment investment

Inactive Publication Date: 2013-10-02
JIANGSU YANGNONG CHEM GROUP +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The processes described in the above documents have their own characteristics, but there are also some shortcomings: 1. The intermittent hydrogenation process requires repeated heating and cooling and gas replacement, which not only increases the difficulty of operation and potential safety hazards, but also increases the consumption of nitrogen and hydrogen ; 2, the use of alcohol organic solvents as hydrogenation solvents increases the investment in post-processing equipment and recycles energy consumption, while alcohols also reduce the safety and cleanliness of production when they are used as solvents

Method used

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  • Production method of 2,5-dichloroaniline

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Three stainless steel autoclaves are connected in series. The volumes of the three reactors are 100L, 50L, and 50L respectively. The effective volume of the entire hydrogenation system is 140L (including the catalyst filtration circulation system).

[0024] Add 60L, 30L, and 30L of 2,5-dichloronitrobenzene into the three-stage reactor respectively, and at the same time add 3.8kg, 1.9kg, and 1.9kg of 1wt% platinum / carbon catalyst wet base respectively, and feed the system after replacement Hydrogen to the reaction pressure of 0.8MPa, raise the temperature and control the reaction temperature at 80-90°C, carry out the hydrogenation reduction reaction under this condition for 5h, until the conversion of 2,5-dichloronitrobenzene is complete.

[0025] Turn on the metering pump to continuously feed 2,5-dichloronitrobenzene and ammonia water into the primary kettle, the feed flow rate of 2,5-dichloronitrobenzene is 24L / h, and the feed flow rate of ammonia water is 20mL / h. Keep...

Embodiment 2

[0028] Three stainless steel autoclaves are connected in series. The volumes of the three reactors are 100L, 50L, and 50L respectively. The effective volume of the entire hydrogenation system is 140L (including the catalyst filtration circulation system). React according to the continuous process of embodiment 1, in order to investigate the stability of process, run continuously 240h with above-mentioned method, in the process, product yield and reaction conversion rate, selectivity are measured every 48h of running, test result is as follows.

[0029]

[0030] It can be seen from the above table that under the conditions of 80-90°C and 0.8 MPa, the hydrogenation conversion rate of 2,5-dichloronitrobenzene basically reaches 100%, and the selectivity reaches more than 99.8%. The content is more than 99.5%, and the yield is more than 97%.

Embodiment 3

[0032] Four stainless steel autoclaves are connected in series. The volumes of the four reactors are 100L, 100L, 50L, and 50L respectively. The effective volume of the entire hydrogenation system is 200L (including the catalyst filtration circulation system).

[0033]Add 60L, 60L, 30L, and 30L of 2,5-dichloronitrobenzene into the three-stage reactor respectively, and simultaneously add 1wt% platinum / carbon catalyst wet base 3.8kg, 3.8kg, 1.9kg, 1.9kg, After the system is replaced, hydrogen gas is introduced to the reaction pressure of 0.8MPa, the temperature is raised and the reaction temperature is controlled at 80-90°C, and the hydrogenation reduction reaction is carried out under this condition for 4.5 hours until the conversion of 2,5-dichloronitrobenzene is complete.

[0034] Turn on the metering pump to continuously feed 2,5-dichloronitrobenzene and ammonia water into the primary kettle, the feed flow rate of 2,5-dichloronitrobenzene is 40L / h, and the feed flow rate of am...

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Abstract

The invention discloses a production method of 2,5-dichloroaniline, which comprises the steps that solvent-free hydrogenation is performed taking 2,5-dichloronitrobenzene as a raw material; a hydrogenation reactor is formed by connecting in series multiple stages of high pressure reactors; 2,5-dichloronitrobenzene, hydrogen, a catalyst and an assistant ammonia water are mixed and perform continuous hydrogenation reaction; hydrogenation liquid flowing out of the final-stage reactor is subjected to membrane filtration and solid-liquid separation; the separated catalyst is not required to be regenerated, and directly returns to the first-stage reactor; and clear liquid is rectified to obtain a finish product of 2,5-dichloroaniline. Compared with the existing hydrogenation process, the method is easy and simple to operate; a solvent is not required to be added; the raw material cost and energy consumption are saved; the product yield and quality are stable; and the automatic continuous production of 2,5-dichloroaniline can be achieved.

Description

technical field [0001] The present invention relates to a kind of production method of 2,5-dichloroaniline, more specifically, the present invention relates to a kind of method of preparing 2,5-dichloroaniline by hydrogenation of 2,5-dichloronitrobenzene. Background technique [0002] 2,5-Dichloroaniline is an important intermediate of a variety of pesticides, dyes and pigments. In the pesticide industry, it is mainly used to synthesize the herbicide dicamba. In the dye industry, it is used to synthesize ice-dyeing dye scarlet base GG, and to print and dye scarlet cloth. Chromogenic agent; also used in the manufacture of nitrogen fertilizer synergists, such as the synthesis of N-2,5-dichlorophenyl succinamic acid. [0003] At present, the industrial production of 2,5-dichloroaniline at home and abroad mainly includes iron powder reduction method, alkali sulfide reduction method and catalytic hydrogenation method. The iron powder reduction method uses 2,5-dichloronitrobenzen...

Claims

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Application Information

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IPC IPC(8): C07C211/52C07C209/36
Inventor 袁源徐林顾志强丁克鸿戚明甫汪洋唐日光高俊萍
Owner JIANGSU YANGNONG CHEM GROUP
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