Process and system for continuous preparation of phenylenediamine

A preparation process, the technology of phenylenediamine, which is applied in the field of catalytic hydrogenation to synthesize aniline compounds, can solve the problems such as the danger of dinitrobenzene, and achieve low operating costs, less three wastes, and economically reasonable effects

Active Publication Date: 2019-10-25
江苏方圆芳纶研究院有限公司
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

Storage of dinitrob

Method used

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  • Process and system for continuous preparation of phenylenediamine

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Example Embodiment

[0047] figure 1 It is a schematic diagram of the system configuration of an embodiment of the preparation system of the present application. Refer to figure 1 The continuous preparation process and system of phenylenediamine of the present application will be described.

[0048] figure 1 The preparation system can be effectively applied to, for example, a continuous preparation process of phenylenediamine using benzene as a raw material, and includes a nitrification unit, a washing unit, and a hydrogenation reduction unit that are sequentially connected through a pipeline, and the nitration unit includes a pipe connected in series. Type reactor I1, phase separation device I7, tubular reactor II2, and phase separation device II8, the washing unit includes a water washing tower I9, an alkali washing tower 10 and a water washing tower II20 connected in sequence, and the hydrogenation reduction unit includes The vertical tube reactor III3, the first gas-liquid separator 11, the fra...

Example Embodiment

[0052] Example 1

[0053] A continuous preparation process of phenylenediamine includes the following steps:

[0054] 1) Mix nitric acid and sulfuric acid to form mixed acid I. The mass percentage of the mixed acid I is: 15% sulfuric acid, 75% nitric acid, and 10% water; benzene and mixed acid I are continuously fed into a solid filled with 7g MCM-41 molecular sieve The reaction is carried out in the tubular reactor I of the acid catalyst, the feed rate of benzene is 39 g / min, the feed rate of mixed acid is 44.1 g / min, the temperature of the tubular reactor I is controlled to 35°C, and the materials are reacted in the tube Discharge after staying in vessel I for 1.3 hours;

[0055] 2) The discharging obtained in step 1) is subjected to continuous phase separation to obtain acid phase I and organic phase I, respectively, and the organic phase I and mixed acid II are continuously fed into a tubular reactor filled with 10g MCM-41 molecular sieve solid acid catalyst Ⅱ. The mass percent...

Example Embodiment

[0064] Example 2

[0065] A continuous preparation process of phenylenediamine includes the following steps:

[0066] 1) Mix nitric acid and sulfuric acid to form mixed acid I. The mass percentage composition of the mixed acid I is: sulfuric acid 20%, nitric acid 60%, and water 20%; benzene and mixed acid I are continuously fed and filled with 6g HZSM-5 solid The reaction is carried out in tubular reactor I with acid catalyst. The feed rate of benzene is 46.8 g / min, the feed rate of mixed acid I is 63 g / min, and the temperature of tubular reactor I is controlled to 75°C. Discharge after staying in reactor I for 0.2 hours;

[0067] 2) The discharging obtained in step 1) is continuously phase separated to obtain acid phase I and organic phase I respectively. The organic phase I and mixed acid II are continuously fed into a tubular reactor filled with 10g HZSM-5 solid acid catalyst Ⅱ. The mass percentage composition of the mixed acid II is: sulfuric acid 35%, nitric acid 60%, water 5%...

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Abstract

The invention discloses a process and a system for continuous preparation of phenylenediamine. With the process provided by the invention, benzene is used as a raw material; a solid acid catalyst is adopted; meanwhile, mixed acid is added; two-stage continuous nitration is performed; obtained mixed dinitrobenzene is directly subjected to two-stage continuous hydrogenation reduction without being separated; thus, the phenylenediamine is obtained. According to a scheme of the invention, a large amount of nitrobenzene and dinitrobenzene is not needed to be stored in the process; meanwhile, by adoption of a continuous pipeline reaction, a material is not accumulated, so possibility of sudden explosion is fundamentally eliminated; and the process is an intrinsically-safe preparation process forthe phenylenediamine.

Description

technical field [0001] The invention relates to a method for synthesizing aniline compounds by catalytic hydrogenation, in particular to a continuous preparation process and system of phenylenediamine. Background technique [0002] Nitrobenzene compounds are important fine chemical intermediates and can be widely used in dyes, medicines, pesticides and explosives. At present, the industry still adopts the traditional process of nitration under certain reaction conditions with benzene and nitric acid as raw materials and sulfuric acid as a catalyst. The disadvantage of this process is that a large amount of waste acid and waste water will be produced and need to be treated; in addition, for every 1 mole of nitrification reaction, the heat released is more than 100kJ, and the specific heat capacity of sulfuric acid is very small, and the temperature raised by heating sulfuric acid with the same heat is often It is three times higher than the temperature raised by heating wate...

Claims

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Application Information

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IPC IPC(8): C07C209/36C07C211/51C07C201/08C07C205/06
CPCC07C201/08C07C209/36C07C211/51C07C205/06
Inventor 王农跃赵全忠闻国强沙艳松许坚章冬霞韩杰李斌
Owner 江苏方圆芳纶研究院有限公司
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