CN101774931A

CN101774931A - Method for preparing o-chloroaniline by catalytic hydrogenation

Info

Publication number: CN101774931A
Application number: CN 201010107685
Authority: CN
Inventors: 邱志刚
Original assignee: Jiangsu Kangheng Chemical Co Ltd
Current assignee: Jiangsu Kangheng Chemical Co Ltd
Priority date: 2010-02-10
Filing date: 2010-02-10
Publication date: 2010-07-14

Abstract

The invention discloses a method for preparing o-chloroaniline by catalytic hydrogenation. O-nitrochlorobenzene, ethyl acetate solution, a dechlorination inhibitor and hydrogen are subjected to catalytic hydrogenation synthetic reaction under the effect of a catalyst at the temperature of 25-90 DEG C to obtain the o-chloroaniline. For better technical effects, the o-nitrochlorobenzene, ethyl acetate solution, dechlorination inhibitor are continuously delivered to a fixed bed reactor by a metering pump, inlet amount of hydrogen is controlled by a flow meter, and catalytic hydrogenation synthetic reaction is conducted in the fixed bed reactor. The fixed bed reactor which uses Ni alloy as the catalyst and a neutral carrier as a catalyst carrier is used for controlling the inlet amount of raw materials and hydrogen and the catalyst, thus reducing cost and improving efficiency. In the invention, dechlorination reaction can be effectively inhibited, subsequent processing steps of the principal product are simplified, coupling compounds generated in reaction are little, the selectivity of o-chloroaniline is above 99%, and the dechlorinating amount is below 0.3%. The invention has the advantages of mass industrial production and environment protection.

Description

A kind of shortening prepares the method for Ortho-Chloro aniline

Technical field

The present invention relates to a kind of preparation method of aniline, relate in particular to the method that a kind of shortening prepares Ortho-Chloro aniline, belong to the preparation field of Ortho-Chloro aniline.

Background technology

Ortho-Chloro aniline is a kind of important in dyestuff intermediate, medicine intermediate, solvent, mould inhibitor and reagent etc., is widely used in the production of fine chemicals such as agricultural chemicals, dyestuff, medicine.Traditional nitroreduction mainly contains iron powder reducing method, sodium sulfide reducing method, catalytic hydrogenating reduction method, electrochemical reducing.The iron powder reducing method produces a large amount of iron mud, serious environment pollution; Shortcomings such as there is reduction route complexity in the sodium sulfide reducing method, and product yield is low, and waste liquid amount is big; The electrochemical reducing energy consumption is too high; The shortening method route that responds is short, and energy consumption is low, advantages such as environmental protection.But, prepare in the process of Ortho-Chloro aniline in catalytic hydrogenation of o-nitro-chlorobenzene, the side reaction that the dechlorination of C-Cl key hydrogenolysis generates amino condensation formation azo on aniline and the phenyl ring also may take place, thereby make the subsequent processing steps of principal product increase links such as filtration, and in reaction, can produce a large amount of coupling compounds, this coupling compound can be attached on the rectifying tower wall, can bring very big difficulty when rectifying tower carries out periodic cleaning.Simultaneously, the hydrogenchloride of dechlorination generation causes corrosion to equipment.In addition, traditional shortening generally all is to adopt intermittent reaction.

Summary of the invention

Technical problem to be solved by this invention is to overcome the deficiencies in the prior art, but provides the simple serialization of a kind of major product subsequent disposal to produce and reduce the preparation method of the Ortho-Chloro aniline of coupling compound in the reaction;

Technical problem to be solved by this invention is achieved through the following technical solutions:

A kind of shortening prepares the method for Ortho-Chloro aniline, comprise: with o-Nitrochlorobenzene, ethyl acetate solution, dechlorination inhibitor and hydrogen are under 25 ℃-90 ℃ the condition in temperature of reaction, under the effect of catalyzer, carry out the shortening building-up reactions, promptly get Ortho-Chloro aniline, obtain Ortho-Chloro aniline elaboration 99.9% again after the rectifying;

In order to reach better technique effect, adopt volume pump with o-Nitrochlorobenzene, ethyl acetate solution and dechlorination inhibitor are transported in the fixed-bed reactor continuously, with the input of under meter control hydrogen, be under 25 ℃-90 ℃ the condition, to carry out the shortening building-up reactions in temperature of reaction; Wherein, described fixed-bed reactor are to be catalyzer with the Ni alloy, are formed by support of the catalyst with neutral carrier (quartz sand).

Preferably, the temperature of described shortening building-up reactions is 55 ℃-65 ℃; Further preferred, described shortening building-up reactions is to carry out under the condition of 1.0Mpa at pressure;

Wherein, described Ni alloy catalyst consumption is preferably the 5%-20wt% of o-Nitrochlorobenzene, and the consumption of dechlorination inhibitor is preferably the 10%-60wt% of Ni alloy catalyst consumption.

Described solvent is preferably ethyl acetate, its consumption is 1-10 a times of raw material, the present invention selects for use ethyl acetate as solvent, and can simplify the processing after hydrogenation finishes: directly the water that catalyzer, reaction are generated separates with reaction solution, and water can directly be taken away many unknown impurities.Loss when having reduced solvent recuperation simultaneously and energy consumption.

Catalyst n i alloy of the present invention can be Ni/C, Ni/SiO ₂, in the Ni alloys such as Ni/Mo, Ni/Al, Ni/Mo/Al any one to be to replace price comparatively expensive noble metal catalyst such as Pd/C, Pt/C, Po etc.; In addition, the present invention adopts neutral carrier (for example: quartz sand) replace the carrier of traditional basic supports as catalyzer, these have not only reduced production cost, also significantly improved catalytic performance, generated azo-compound when having reduced aniline simultaneously and being the compounds hydrogenation, azo-compound finally becomes the residue behind the last rectifying product, this residue aborning, be attached on the wall, intractable when regularly handling rectifying tower, and increase energy consumption.

Described dechlorination inhibitor is preferably organic amine, for example can be organic amines such as aniline, Monoethanolamine MEA BASF, diethanolamine, trolamine, diethylamine, triethylamine, pyridine and pyridines low molecular compound, piperidines and piperidines, Dyhard RU 100, more preferably Dyhard RU 100.

The inventive method can effectively suppress dechlorination reaction, wherein, adopt the inlet amount of fixed-bed reactor may command raw material, hydrogen, the temperature and the catalyst consumption of reaction, reduce cost and improved usefulness, and effectively reduced the subsequent treatment process of major product, and made the coupling compound in the impurity significantly reduce, helped the periodic cleaning of rectifying tower.The selectivity of the inventive method Ortho-Chloro aniline is greater than 99%, and the dechlorination amount has significant volume increase, puies forward effects such as effect less than 0.3%, can realize large-scale industrial production.

Description of drawings

Fig. 1 shortening of the present invention prepares the synthetic route chart of Ortho-Chloro aniline.

Embodiment

Further describe the present invention below in conjunction with specific embodiment, advantage of the present invention and characteristics will be more clear along with description.But these embodiment only are exemplary, scope of the present invention are not constituted any restriction.It will be understood by those skilled in the art that and down can make amendment or replace without departing from the spirit and scope of the present invention, but these modifications and replacing all fall within the scope of protection of the present invention the details of technical solution of the present invention and form.

The comparative example:

Embodiment a

Prior art: with o-Nitrochlorobenzene 150g, methyl alcohol 300ml joins in the autoclave, adds Raney-Ni catalyzer (Ni/Al) 7.5g simultaneously, triethylamine 1.50g, airtight autoclave is opened the hydrogen valve, in autoclave, feed hydrogen, take a breath 3 times, regulate still and be depressed into 1.0MPa, stir and be warming up to 55-65 ℃ of reaction, cause pressure and do not changing (about 3h), sampling, through the gas chromatographic analysis result, Ortho-Chloro aniline content 97.50%.The major product Ortho-Chloro aniline and the impurity that obtain mix, filter out catalyzer and part insolubles after, reclaim after solvent and the distillation water outlet rectifying obtain Ortho-Chloro aniline elaboration 102g (yield 85%, GC99.9%).Residue is about 20.0g, wherein contains the coupling compound of 1-3/100 in the residue, in rectifying tower, when the periodic cleaning rectifying tower, is difficult to cleaning.

Embodiment b

The technology of the present invention: with o-Nitrochlorobenzene 150g, ethyl acetate 300ml joins in the autoclave, adds Raney-Ni catalyzer (Ni/C) 7.5g simultaneously, triethylamine 1.50g, airtight autoclave is opened the hydrogen valve, in autoclave, feed hydrogen, take a breath 3 times, regulate still and be depressed into 1.0MPa, stir and be warming up to 55-65 ℃ of reaction, cause pressure and do not changing (about 3h), sampling, through the gas chromatographic analysis result, Ortho-Chloro aniline content 98.50%.Separatory obtains the ethyl acetate phase, reclaim behind the solvent rectifying obtain Ortho-Chloro aniline elaboration 110g (yield 90%, GC99.9%).Residue is about 10.0g, and owing to used ethyl acetate solvent and neutral catalyst, need not to filter, as long as simple separatory, and in reaction coupling compound only be prior art 1/2 in addition still less, when the periodic cleaning rectifying tower, reduced the cleaning difficulty.

Embodiment 1

With o-Nitrochlorobenzene 50g, ethyl acetate 200ml joins in the autoclave, adds Raney-Ni catalyzer (Ni/C) 2.5g simultaneously, Dyhard RU 100 1.0g, airtight autoclave is opened the hydrogen valve, in autoclave, feed hydrogen, take a breath 3 times, regulate still and be depressed into 1.0MPa, stir and be warming up to 55-65 ℃ of reaction (mending hydrogen repeatedly), causing pressure is not changing, sampling, through the gas chromatographic analysis result, Ortho-Chloro aniline content 97.80%.Separatory obtains the ethyl acetate phase, and rectifying obtains Ortho-Chloro aniline elaboration 36.5g and impurity behind the recovery solvent, (yield 90%, GC99.9%).Impurity is stayed in the still, and after testing, the coupling compound in the impurity is less than 1/100.

Embodiment 2

With o-Nitrochlorobenzene 1Kg, ethyl acetate 2kg, Dyhard RU 100 10g goes in fixed-bed reactor with the metering pump delivery, and fixed-bed reactor are that the Kunlun, Beijing Yongtai Science and Technology Ltd. produces model KLGC.Filling Ni/C in the fixed bed is catalyzer, with quartz sand is carrier, control the input of hydrogen simultaneously with under meter, pressure is to the 1.0MPa in the variable valve controlling reactor, control fixed bed outside temperature 55-65 ℃ of reaction, reaction solution is through gas chromatographic analysis Ortho-Chloro aniline content 99.60% (aniline 0.1%) as a result.Separatory obtains the ethyl acetate phase, reclaims behind the solvent rectifying and obtains Ortho-Chloro aniline elaboration 738g all the other are impurity.(yield 92%, GC99.9%).Impurity is stayed in the still, and after testing, the coupling compound in the impurity is less than 1/100.

Embodiment 3

With o-Nitrochlorobenzene 5Kg, ethyl acetate 10kg, Dyhard RU 100 50g after mixing, goes in fixed-bed reactor with the metering pump delivery, and fixed-bed reactor are that the Kunlun, Beijing Yongtai Science and Technology Ltd. produces model KLGC; Filling Ni/C in the fixed bed is catalyzer, is carrier with quartz sand, controls the input of hydrogen simultaneously with under meter, and pressure is to the 1.0MPa in the variable valve controlling reactor, 55-65 ℃ of reaction of the extraneous Heating temperature of control fixed bed, continuously feeding, about 2h reaction finishes.Reaction solution through gas chromatographic analysis as a result Ortho-Chloro aniline content be 99.80% (aniline 0.1%).Separatory obtains the ethyl acetate phase, reclaim behind the solvent rectifying obtain Ortho-Chloro aniline elaboration 3.8Kg all the other for impurity (yield 93.5%, GC99.9%).Impurity is stayed in the still, and after testing, the coupling compound in the impurity is less than 1/100.

Claims

1. a shortening prepares the method for Ortho-Chloro aniline, comprise: with o-Nitrochlorobenzene, ethyl acetate solution, dechlorination inhibitor and hydrogen are under 25 ℃-90 ℃ the condition in temperature of reaction, under catalyst action, carry out the shortening building-up reactions, promptly get Ortho-Chloro aniline.

2. in accordance with the method for claim 1, it is characterized in that: adopt volume pump with o-Nitrochlorobenzene, ethyl acetate solution and dechlorination inhibitor are transported in the fixed-bed reactor continuously, with the input of under meter control hydrogen, carry out the shortening building-up reactions; Wherein, described fixed-bed reactor are to be catalyzer with the Ni alloy, are support of the catalyst with neutral carrier quartz sand.

3. according to claim 1 or 2 described methods, it is characterized in that: the temperature of described shortening building-up reactions is 55 ℃-65 ℃.

4. according to claim 1 or 2 described methods, it is characterized in that: described shortening building-up reactions is to carry out under the condition of 1.0Mpa at pressure;

5. according to claim 1 or 2 described methods, it is characterized in that: described Ni alloy catalyst consumption is the 5%-20wt% of o-Nitrochlorobenzene, and the consumption of dechlorination inhibitor is the 10%-60wt% of Ni alloy catalyst consumption.

6. it is characterized in that in accordance with the method for claim 1: the consumption of described ethyl acetate solution is a 1-10 times of weight of o-Nitrochlorobenzene.

7. it is characterized in that in accordance with the method for claim 1: described Ni alloy is selected from Ni/C, Ni/SiO ₂, among Ni/Mo, Ni/Al or the Ni/Mo/Al any one.

8. it is characterized in that in accordance with the method for claim 1: described dechlorination inhibitor is an organic amine.

9. it is characterized in that in accordance with the method for claim 8: described organic amine comprises aniline, Monoethanolamine MEA BASF, diethanolamine, trolamine, diethylamine, triethylamine, pyridine, pyridines low molecular compound, piperidines, piperidines or Dyhard RU 100.