Method for preparing nitro compound from aromatic hydrocarbon compound through isothermic tubular reaction

A technology for aromatic hydrocarbon compounds and nitro compounds, which is applied in the field of preparing nitro compounds by a warm-tube reaction, can solve the problems of uneven heating, no zoned temperature control, and increased reaction by-products, etc., and achieves stable and controllable reaction temperature and avoids side effects Product generation, the effect of improving quality stability

Active Publication Date: 2018-07-03
CHINA PETROLEUM & CHEM CORP +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The reactor can improve the fluidity of the reaction fluid in the tubes and reduce the pressure drop, but there are also problems of uneven heating in different tube areas and high reaction by-products
[0008] Existing tubular reactors adopt a single heat transfer medium inlet and outlet for both tube-side heat transfer and shell-side heat transfer, and there is no targeted temperature control in the reactor; in fact, for tubular reactions, especially It is the laminar flow phenomenon that industrialized high-viscosity materials will inevitably appear in the shell side of the large-diameter tubular reactor. In different areas perpendicular to the axis, especially the flow rate of the material at the axis and the tube wall is different. Effective control may lead to a large temperature difference between the axis and the tube wall, resulting in an increase in reaction by-products

Method used

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  • Method for preparing nitro compound from aromatic hydrocarbon compound through isothermic tubular reaction
  • Method for preparing nitro compound from aromatic hydrocarbon compound through isothermic tubular reaction

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Experimental program
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Effect test

Embodiment 1

[0029] According to the above specific implementation method, the aromatic hydrocarbon compound is benzene, and HNO in benzene and mixed acid 3 The molar ratio is 1.01:1, and the nitrification reaction is carried out in the tubular reactor. There are 4 coolant inlets connecting the tubular reactor and the coolant distribution pipe (that is, the tubular reactor is divided into 4 diameter areas in the axial direction. temperature control), the nitration control temperature is 60°C, and the nitration reaction product is separated by nitration, washed with alkali, washed with water, and refined to obtain nitro compounds.

[0030] Implementation effect: the actual highest temperature in the axial direction of the tubular reactor with different pipe diameters is 60.2°C, and the lowest temperature is 59.9°C; after the reaction in the tubular reactor, the selectivity of nitrobenzene is 100%; the yield of nitrobenzene product is refined 99.5%.

Embodiment 2

[0032] According to the above specific implementation method, the difference is that the aromatic compound is toluene, and HNO in toluene and mixed acid 3 The molar ratio is 1.10:1, and the nitration reaction is carried out in the tubular reactor. There are 8 coolant inlets connected to the tubular reactor and the coolant distribution pipe (that is, the tubular reactor is divided into 8 diameter areas in the axial direction. temperature control), the nitration control temperature is 40°C, and the nitration reaction products are separated by nitration, washed with alkali, washed with water, and refined to obtain nitro compounds.

[0033] Implementation effect: the actual highest temperature in the axial direction of the tubular reactor with different pipe diameters is 40.1°C, and the lowest temperature is 40.0°C; after the reaction in the tubular reactor, the total selectivity of nitrotoluene (three isomers) is 99.93%; The total yield of refined nitrotoluene (three isomers) is ...

Embodiment 3

[0035] According to the above specific implementation method, embodiment 3 is basically the same as embodiment 1, the difference is that HNO in benzene and mixed acid 3 The molar ratio is 1.03:1, and the nitration reaction is carried out in the tubular reactor. There are 2 coolant inlets connecting the tubular reactor and the coolant distribution pipe (that is, the tubular reactor is divided into 2 diameter areas in the axial direction. temperature control), the nitration control temperature is 58°C, and the nitration reaction products are separated by nitration, washed with alkali, washed with water, and refined to obtain nitro compounds.

[0036] Implementation effect: the actual highest temperature in the tube reactor with different pipe diameters in the axial direction is 58.4°C, and the lowest temperature is 57.8°C; after the reaction in the tubular reactor, the selectivity of nitrobenzene is 99.95%; the yield of nitrobenzene product is refined 99.2%.

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Abstract

The invention belongs to the technical field of organic chemistry and particularly relates to a method for preparing a nitro compound from an aromatic hydrocarbon compound through isothermic tubular reaction. The method is characterized by comprising the following steps: adequately mixing two phases, namely a nitration raw material and mixed acid by virtue of a static mixer in a tubular reactor soas to realize simultaneous flow, reaction and heat exchange in a shell of the tubular reactor, and carrying out nitration separation, alkali washing, washing and refining, so as to obtain the nitro compound, wherein row tubes which can be controlled in different regions are arranged in the tubular reactor and are used for removing reaction heat. The method for preparing the nitro compound has thebeneficial effects that the flow is simple, the continuous production is realized, the reaction process is easy to control, the heat transfer efficiency is high, the situation that byproducts are increased due to the overheat in the reaction can be effectively avoided, the energy consumption and the raw material consumption are low, and the production process is safe and reliable.

Description

technical field [0001] The patent of the invention belongs to the technical field of organic chemical industry, and relates to a method for continuous liquid-liquid two-phase reaction using a tubular reactor, in particular to a method for preparing nitro compounds by isothermal tubular reaction of aromatic compounds. Background technique [0002] Usually, the nitration reaction of aromatic compounds is carried out by mixing aromatic compounds with mixed acids, such as nitrobenzene by nitration of benzene, nitrochlorobenzene by nitration of chlorobenzene, and dinitrotoluene by nitration of toluene. [0003] Isothermal nitrification has the characteristics of relatively low temperature and equipment material requirements, good investment and operation stability, and is widely used. The traditional nitration process is that the aromatic compound and the mixed acid are mixed in a certain proportion and then enter the reactor to flow, react and exchange heat; the nitration mixtur...

Claims

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Application Information

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IPC IPC(8): C07C201/08C07C205/06C07C205/12B01J19/24B01J14/00
CPCB01J14/00B01J19/2415B01J2219/00051C07C201/08C07C205/06C07C205/12
Inventor 杨忠林金汉强丁红霞孙盛凯赵思远季峰崎
Owner CHINA PETROLEUM & CHEM CORP
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