Dinitrochlorobenzene synthesis method and microreactor

A technique for the synthesis of dinitrochlorobenzene and its synthesis method, which is applied in the field of synthesizing dinitrochlorobenzene from chlorobenzene, the synthesis method of dinitrochlorobenzene, and the field of microreactors. Consumption, Process Safety Continuity, Effects of Process Safety

Inactive Publication Date: 2009-09-30
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The nitration of aromatic hydrocarbons in microreactors can be found in the US 6861527 of Kal Fabian, the research of Raghunath Halder et al

Method used

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  • Dinitrochlorobenzene synthesis method and microreactor
  • Dinitrochlorobenzene synthesis method and microreactor

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] Use anhydrous nitric acid (≥98%) and concentrated sulfuric acid (≥95%) to prepare a mixed acid with an n / s value of 0.15±0.02 and a water concentration of 4±1%. During the preparation of mixed acid, the temperature is controlled below 35°C. Under normal temperature conditions, the mixed acid and chlorobenzene are continuously pumped into the microreactor (attached figure 1 The reactor shown) and react in the micro reaction channel. The mol ratio of this implementation reaction material nitric acid and chlorobenzene is 2.08, and the liquid hourly space velocity of reactor 1516h -1 . The reaction product flows out of the reactor continuously, and the temperature of the product flowing out of the reactor is 36°C, and it is placed in a separator for stratification, and the acid solution is separated, and the acid solution takes an appropriate amount of water (about 1 / 10 to 1 / 2 of the volume of the spent acid) 20) Dinitrochlorobenzene is reclaimed by dilution and melting ...

Embodiment 2

[0053] The process and mixed acid composition are the same as in Example 1, the temperature of the reactor is controlled at 80°C, the molar ratio of nitric acid to chlorobenzene is 2.22, and the liquid hourly space velocity of the reactor is 1485h -1 , the outlet temperature of the reactor product was 89°C, and only the composition of the organic layer of the product was analyzed.

Embodiment 3

[0055] The process is the same as in Example 1, the mixed acid n / s value is 0.30±0.02, water 4±1%, the reactor is controlled at normal temperature and 80°C respectively, the temperatures at the outlet of the reactor are respectively 31°C and 124°C, and the reaction material nitric acid The molar ratio of p-chlorobenzene is 1.94 and 2.10 respectively under two different temperature conditions, and the liquid hourly space velocity in the reactor is 1695h respectively -1 and 1656h -1 , only analyze the product composition in the product organic layer, table 1 shows.

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Abstract

The invention relates to a one-step method for synthesizing dinitrochlorobenzene from chlorobenzene, and a microchannel reactor. The method comprises the steps of taking chlorobenzene and mixed acid of nitric acid/sulfuric acid (n/s) as initial reaction materials, inputting material flow synchronously into a microreactor through a metering pump and finishing mixed mass transfer and reaction in a reaction channel. The substance ratio of n to s in the reactive mixed acid is 0.1 to 0.5, and the mass ratio of water is less than 10 percent. The microchannel reactor adopts a stainless steel flat-plate structure which comprises fixed pressing-sealing plates, a microchannel plate, a raw-material inlet, a product outlet, as well as a temperature-control pore channel and a thermal-couple measurement-control jack which are positioned on two sealing plates. The method is continuously operated under a technological condition with strong nitrating acid, and is safe in process. The selectivity of the dinitrochlorobenzene in the reactor at an operation temperature between normal temperature and 80 DEG C is more than 99.5 mol percent, wherein the selectivity of 2,4 dinitrochlorobenzene is more than 98 mol percent.

Description

technical field [0001] The present invention relates to aromatic hydrocarbon nitration, specifically a kind of synthetic method of dinitrochlorobenzene and microreactor, is the technique of synthesizing dinitrochlorobenzene (DNCB) from chlorobenzene in one step in microchannel reactor; Its Dinitrochlorobenzene can be safely and continuously synthesized in a microchannel reactor under the conditions of strong nitrifying acid and a reactor at room temperature to 80°C. Background technique [0002] 2,4-Dinitrochlorobenzene (2,4-DNCB) is widely used as an organic synthesis raw material intermediate, mainly used to make dyes (sulfur black), pesticides, medicines, saccharin, dinitrophenol, dinitro Chemical products such as aniline. The conventional preparation process has a one-step method and a step-by-step method: add a certain amount of chlorobenzene into the nitration reaction kettle, and add the pre-prepared mixed acid of nitrifying nitric acid and sulfuric acid in proportio...

Claims

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Application Information

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IPC IPC(8): C07C205/12C07C201/08
Inventor 陈光文焦凤军赵玉潮袁权
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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