Method for preparing ortho-nitroaniline by kettle-type continuous operation

A technology of o-nitroaniline and o-nitrobenzene, which is applied in the field of o-nitrochlorobenzene to prepare o-nitrobenzene, can solve the problems of many side reactions, more washing water, and high operating intensity, and achieve product quality and yield Stabilization, reduction of production costs, and reduction of water consumption

Inactive Publication Date: 2009-12-16
JIANGSU YANGNONG CHEM GROUP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the high-pressure pipeline continuous production process has the advantages of simple equipment structure, easy operation, and large production capacity, due to the high temperature and pressure in the production process, there are many side reactions, such as the hydrolysis of o-nitrochlorobenzene, o-nitroaniline molecules Internal dehydration, etc., thereby generating impurities such as o-nitrophenol and benzofurazan, resulting in low product purity and yield, because the molar ratio of o-nitrochlorobenzene and ammonia in this process is high, which also increases the waste water. Handling Difficulty
Although the autoclave batch process is simple, it has the disadvantages of small production capacity and high operating intensity.
In addition, the kettle-type intermittent washing used in the above process cannot completely wash away the ammonium chloride in o-nitroaniline due to the limited number of washings, thus affecting its application in pesticides, medicines, etc., and the washing process requires more washing water , which also produces a large amount of wastewater

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0020] Three 50L high-pressure stainless steel reactors are connected in series, each with an effective volume of 35L, 36L, and 36L, and the total effective volume is 107L. According to the molar ratio of 1:10, o-nitrochlorobenzene (hereinafter referred to as ONCB) and ammonia water are pumped into the first-stage reaction kettle, and the flow rates are V ONCB =6.1L / hr, V NH3 = 11.73 L / hr. The stirring speed is 500rpm, the temperature in the reactor is raised to 170°C-175°C, the pressure is 3MPa-6MPa, and the reaction residence time is 6hr. The reaction liquid overflows sequentially from the first-stage reactor to the next-stage reactor.

[0021] After the reaction, oil-water separation was carried out.

[0022] The water layer is cooled to normal temperature, o-nitroaniline (hereinafter referred to as ONBA) is precipitated in solid form, the filter cake is filtered out and put into the o-nitroaniline tank, and the filtrate is heated to recover ammonia.

[0023] The oil la...

example 2

[0026] Three 50L high-pressure stainless steel reaction kettles are connected in series, and the effective volume of each kettle is 35L, 36L, and 36L respectively, and the total effective volume is 107L. Ortho-nitrochlorobenzene and example 1 recovery preparation concentration are that 42% ammoniacal liquor is squeezed in the first stage reactor by pump, and flow rate is V ONCB =6.1L / hr, V NH3 = 11.73 L / hr. The stirring speed is 500rpm, the temperature is raised and the pressure is increased until the temperature is 160°C-200°C, the pressure is 3MPa-7MPa, and the residence time is 6hr. The reaction liquid overflows sequentially from the top of the first-stage reactor to the next-stage reactor.

[0027] After the reaction, oil-water separation was carried out.

[0028] The water layer is cooled to normal temperature, o-nitroaniline (hereinafter referred to as ONBA) is precipitated in solid form, the filter cake is filtered out and put into the o-nitroaniline tank, and the fi...

example 3

[0033] Three 50L high-pressure stainless steel reaction kettles are connected in series, and the effective volume of each kettle is 35L, 36L, and 36L respectively, and the total effective volume is 107L. The o-nitrochlorobenzene and ammonia water with a concentration of 42% are metered and pumped into the first-stage reaction kettle respectively. The stirring speed is 500rpm, the temperature is raised and the pressure is increased until the temperature is 170°C-175°C, the pressure is 4MPa-5MPa, and the residence time is 6hr. The reaction liquid overflows sequentially from the top of the first-stage reactor to the next-stage reactor.

[0034] After the reaction, oil-water separation was carried out.

[0035] The water layer is cooled to normal temperature, o-nitroaniline (hereinafter referred to as ONBA) is precipitated in solid form, the filter cake is filtered out and put into the o-nitroaniline tank, and the filtrate is heated to recover ammonia.

[0036] The oil layer con...

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PUM

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Abstract

The invention relates to a method for preparing ortho-nitroaniline by kettle-type continuous operation, belonging to the organic chemical engineering field; pressure-resistant reaction kettles are sequentially connected in series, and high-order differences are formed among the reaction kettles, so as to lead the reaction material to overflow to the next-level reaction kettle; 0-nitrophenyl and ammonia water are added in a first-level reaction kettle in the pressure-resistant reaction kettle, and the mixture is reacted under the condition that the temperature in the kettle is 150 DEG C to 250 DEG C, and pressure is 3MPa to 10MPa, and then the reacted products are oil-water laminated; after water is cooled, the ortho-nitroaniline is dissolved out in a solid way and is press-filtered into filter cakes, namely, the ortho-nitroaniline is obtained. The method has simple flow, stable yield coefficient of products and less three wastes, and is easy to realize industrialization.

Description

technical field [0001] The invention belongs to the field of organic chemical industry and relates to a production method for preparing o-nitrochlorobenzene from o-nitrochlorobenzene. Background technique [0002] O-nitroaniline is an important intermediate in organic synthesis. It is an intermediate for many pesticides, medicines and dyes, and it is also widely used in the field of auxiliaries. At present, the synthesis of o-nitroaniline mainly adopts the ammonolysis process of o-nitrochloroaniline, and there are mainly two processes of continuous high-pressure pipeline and intermittent autoclave. About the process of carrying out nitrobenzene aminolysis in high-pressure pipelines, there were US patents published in the 1930s, such as US1877145 and US1884880. From 1937 to 1938, Germany also carried out more detailed research on the ammonolysis process of nitrochlorobenzene in high-pressure pipelines and carried out pilot tests. In the 1970s in my country, Shanghai Dyestuf...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C211/52C07C209/02
Inventor 袁源王秋萍许金来陈林华吴惠戚明甫盛磊
Owner JIANGSU YANGNONG CHEM GROUP
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