CN114315635A - 2, 2' -dichloroazobenzene synthesis process - Google Patents
2, 2' -dichloroazobenzene synthesis process Download PDFInfo
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- CN114315635A CN114315635A CN202111607378.4A CN202111607378A CN114315635A CN 114315635 A CN114315635 A CN 114315635A CN 202111607378 A CN202111607378 A CN 202111607378A CN 114315635 A CN114315635 A CN 114315635A
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- dichloroazobenzene
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Abstract
The invention relates to a synthesis process of 2, 2' -dichloroazobenzene, which is characterized by comprising the following steps: the specific synthesis process is as follows: s1: preparing raw materials; s2: preparing 2, 2' -dichloroazobenzene; s3: carrying out reduced pressure distillation; s4: cooling and crystallizing; 2, 2' -dichloroazobenzene is continuously synthesized in a fixed bed reactor, and step-by-step molding is not needed in equipment; the catalyst is used for catalytic synthesis through the alumina-supported ruthenium catalyst, and the production rate is improved by using the catalyst; in the production process, 2-chloronitrobenzene and hydrogen are directly used as raw materials to directly synthesize 2, 2' -dichloroazobenzene under the action of the ruthenium catalyst loaded on alumina, so that the production efficiency is high, the synthesis process is simple, and the production efficiency is improved; the yield of the 2,2 '-dichloroazobenzene is 91%, and the content of the 2, 2' -dichloroazobenzene is more than 99% by liquid phase detection.
Description
Technical Field
The invention relates to the field of 2,2 '-dichloroazobenzene, in particular to a synthesis process of 2, 2' -dichloroazobenzene.
Background
2,2 ' -dichloroazobenzene is an important intermediate for synthesizing DCB (3, 3 ' -dichlorobenzidine), and the pigment synthesized by DCB accounts for more than 27 percent of the total pigment, so the method has important significance for the synthesis research of 2,2 ' -dichloroazobenzene;
at present, the synthesis method mainly comprises an electrolytic reduction method, a catalytic hydrogenation method and a chemical reduction method, but the chemical reduction method is still mainly used at home. The chemical reduction method comprises the following steps: 1. the traditional zinc powder reduction method has the disadvantages of laggard process, large zinc powder consumption, high cost, difficult three-waste treatment and substantial elimination; 2. the glucose-zinc powder reduction method is improved, but still has the problems of high cost, complex post-treatment and serious pollution; 3. the formaldehyde-hydrazine hydrate reduction method is a main domestic industrial production method at present, the method has the advantages of easily available raw materials and high yield, but a large amount of wastewater is generated in the production process, the intermediate product needs to be separated and purified, the operation is complex, the labor intensity is high, the price of hydrazine hydrate is high, the toxicity is high, and the environmental pollution is serious.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a high-yield 2, 2' -dichloroazobenzene synthesis process.
In order to solve the technical problems, the technical scheme of the invention is as follows: the 2, 2' -dichloroazobenzene synthesis process has the innovation points that: the specific synthesis process is as follows:
s1: preparation of raw materials: mixing 2-chloronitrobenzene and isopropanol solution to form a mixed solution by taking the 2-chloronitrobenzene and raw materials, wherein the content of the 2-chloronitrobenzene in the mixed solution is 25-35 percent; taking alumina as an adsorbent, and adsorbing a ruthenium catalyst by the alumina;
s2: preparation of 2, 2' -dichloroazobenzene: putting the ruthenium catalyst adsorbed by the alumina into a fixed bed reactor, continuously introducing a mixed solution of 2-chloronitrobenzene with the 2-chloronitrobenzene content of 25-35 percent and isopropanol into the fixed bed reactor through a booster pump, simultaneously introducing hydrogen into the solution in the fixed bed reactor, and heating the fixed bed reactor to 125-160 ℃;
s3: and (3) reduced pressure distillation: opening a pressure relief valve of the fixed bed reactor, performing pressure relief on the fixed bed reactor, and then distilling a product after reaction to distill out an isopropanol solvent;
s4: cooling and crystallizing: and cooling and crystallizing the product after the isopropanol solvent distillation is finished to obtain 2, 2' -dichloroazobenzene crystal.
Further, the mass ratio of the ruthenium catalyst adsorbed by the alumina to the mixed solution with the content of the 2-chloronitrobenzene being 25% -35% is 1: 20.
Further, in the S2, the flow rate of the mixed solution of 2-chloronitrobenzene and isopropanol is 10 ml/min.
The invention has the advantages that:
1) according to the invention, 2' -dichloroazobenzene is continuously synthesized in a fixed bed reactor, and step-by-step and equipment-by-equipment molding is not needed; the catalyst is used for catalytic synthesis through the alumina-supported ruthenium catalyst, and the production rate is improved by using the catalyst; in the production process, 2-chloronitrobenzene and hydrogen are directly used as raw materials to directly synthesize 2, 2' -dichloroazobenzene under the action of the ruthenium catalyst loaded on alumina, so that the production efficiency is high, the synthesis process is simple, and the production efficiency is improved; the yield of the 2,2 '-dichloroazobenzene is 91%, and the content of the 2, 2' -dichloroazobenzene is more than 99% by liquid phase detection.
Drawings
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
FIG. 1 is a flow chart of a process for synthesizing 2, 2' -dichloroazobenzene of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention.
Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
A synthesis process of 2, 2' -dichloroazobenzene comprises the following specific synthesis processes:
s1: preparation of raw materials: mixing 2-chloronitrobenzene and isopropanol solution to form a mixed solution by taking the 2-chloronitrobenzene and the isopropanol solution as raw materials, wherein the content of the 2-chloronitrobenzene in the mixed solution is 25 percent; taking alumina as an adsorbent, and adsorbing a ruthenium catalyst by the alumina;
s2: preparation of 2, 2' -dichloroazobenzene: putting 5kg of ruthenium catalyst adsorbed by alumina into a fixed bed reactor, and continuously introducing 100kg of mixed solution with the 2-chloronitrobenzene content of 25 percent into the fixed bed reactor through a booster pump at the flow rate of 10 ml/min; simultaneously introducing hydrogen into the solution in the fixed bed reactor, and heating the fixed bed reactor to 125 ℃;
s3: and (3) reduced pressure distillation: opening a pressure relief valve of the fixed bed reactor, performing pressure relief on the fixed bed reactor, and then distilling a product after reaction to distill out an isopropanol solvent;
s4: cooling and crystallizing: and cooling and crystallizing the product after the isopropanol solvent distillation is finished to obtain 2, 2' -dichloroazobenzene crystal.
Example 2:
a synthesis process of 2, 2' -dichloroazobenzene comprises the following specific synthesis processes:
s1: preparation of raw materials: mixing 2-chloronitrobenzene and isopropanol solution to form a mixed solution by taking the 2-chloronitrobenzene and the isopropanol solution as raw materials, wherein the content of the 2-chloronitrobenzene in the mixed solution is 25 percent; taking alumina as an adsorbent, and adsorbing a ruthenium catalyst by the alumina;
s2: preparation of 2, 2' -dichloroazobenzene: putting 5kg of ruthenium catalyst adsorbed by alumina into a fixed bed reactor, and continuously introducing 100kg of mixed solution with the 2-chloronitrobenzene content of 30 percent into the fixed bed reactor through a booster pump at the flow rate of 10 ml/min; simultaneously introducing hydrogen into the solution in the fixed bed reactor, and heating the fixed bed reactor to 125 ℃;
s3: and (3) reduced pressure distillation: opening a pressure relief valve of the fixed bed reactor, performing pressure relief on the fixed bed reactor, and then distilling a product after reaction to distill out an isopropanol solvent;
s4: cooling and crystallizing: and cooling and crystallizing the product after the isopropanol solvent distillation is finished to obtain 2, 2' -dichloroazobenzene crystal.
Example 3:
a synthesis process of 2, 2' -dichloroazobenzene comprises the following specific synthesis processes:
s1: preparation of raw materials: mixing 2-chloronitrobenzene and isopropanol solution to form a mixed solution by taking the 2-chloronitrobenzene and the isopropanol solution as raw materials, wherein the content of the 2-chloronitrobenzene in the mixed solution is 25 percent; taking alumina as an adsorbent, and adsorbing a ruthenium catalyst by the alumina;
s2: preparation of 2, 2' -dichloroazobenzene: putting 5kg of ruthenium catalyst adsorbed by alumina into a fixed bed reactor, and continuously introducing 100kg of mixed solution with the 2-chloronitrobenzene content of 35 percent into the fixed bed reactor through a booster pump at the flow rate of 10 ml/min; simultaneously introducing hydrogen into the solution in the fixed bed reactor, and heating the fixed bed reactor to 125 ℃;
s3: and (3) reduced pressure distillation: opening a pressure relief valve of the fixed bed reactor, performing pressure relief on the fixed bed reactor, and then distilling a product after reaction to distill out an isopropanol solvent;
s4: cooling and crystallizing: and cooling and crystallizing the product after the isopropanol solvent distillation is finished to obtain 2, 2' -dichloroazobenzene crystal.
Example 4:
the fixed bed reactor in S2 alone was heated to 140 ℃ under the same conditions as in example 1;
example 5:
the same conditions as in example 2 were followed, except that the fixed bed reactor in S2 was heated to 140 ℃.
Example 6:
the same conditions as in example 3 were followed, except that the fixed bed reactor in S2 was heated to 140 ℃.
Example 7:
the fixed bed reactor in S2 was heated to 160 ℃ alone, as in the rest of the conditions in example 1.
Example 8:
the fixed bed reactor in S2 was heated to 160 ℃ alone, as in the rest of the conditions in example 2.
Example 9:
the fixed bed reactor in S2 was heated to 160 ℃ alone, as in the rest of the conditions in example 3.
As can be observed from the above table, the yield of 2, 2' -dichloroazobenzene is the highest at the reaction temperature of 140 ℃ in the case that the contents of 2-chloronitrobenzene in the mixed solution are the same; under the condition of the same reaction temperature, the yield of the 2, 2' -dichloroazobenzene prepared from the mixed solution with the 2-chloronitrobenzene content of 30 percent is the highest; in conclusion; the 2-chloronitrobenzene content is 30 percent and the production is carried out under the reaction of 140 ℃ as the optimal production process.
It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (3)
1. A synthesis process of 2, 2' -dichloroazobenzene is characterized in that: the specific synthesis process is as follows:
s1: preparation of raw materials: mixing 2-chloronitrobenzene and isopropanol solution to form a mixed solution by taking the 2-chloronitrobenzene and raw materials, wherein the content of the 2-chloronitrobenzene in the mixed solution is 25-35 percent; taking alumina as an adsorbent, and adsorbing a ruthenium catalyst by the alumina;
s2: preparation of 2, 2' -dichloroazobenzene: putting the ruthenium catalyst adsorbed by the alumina into a fixed bed reactor, continuously introducing a mixed solution of 2-chloronitrobenzene with the 2-chloronitrobenzene content of 25-35 percent and isopropanol into the fixed bed reactor through a booster pump, simultaneously introducing hydrogen into the solution in the fixed bed reactor, and heating the fixed bed reactor to 125-160 ℃;
s3: and (3) reduced pressure distillation: opening a pressure relief valve of the fixed bed reactor, performing pressure relief on the fixed bed reactor, and then distilling a product after reaction to distill out an isopropanol solvent;
s4: cooling and crystallizing: and cooling and crystallizing the product after the isopropanol solvent distillation is finished to obtain 2, 2' -dichloroazobenzene crystal.
2. The process for synthesizing 2, 2' -dichloroazobenzene according to claim 1, wherein: the mass ratio of the ruthenium catalyst adsorbed by the alumina to the mixed solution with the content of the 2-chloronitrobenzene being 25-35% is 1: 20.
3. The process for synthesizing 2, 2' -dichloroazobenzene according to claim 1, wherein: and in the S2, the flow rate of the mixed solution of the 2-chloronitrobenzene and the isopropanol which is introduced into the fixed bed reactor is 10 ml/min.
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- 2021-12-27 CN CN202111607378.4A patent/CN114315635A/en active Pending
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| GB1176337A (en) * | 1965-12-23 | 1970-01-01 | Du Pont | Producing Amines by Catalytic Hydrogenation over supported Ruthenium Catalyst |
| CN101342487A (en) * | 2008-07-11 | 2009-01-14 | 南开大学 | Support catalysts for p-chloronitrobenzene selective hydrogenation and preparation method thereof |
| CN101643428A (en) * | 2008-08-08 | 2010-02-10 | 夏恩将 | Method for preparing 3,3'-dimethoxybenzidine hydrochloride |
| CN101691332A (en) * | 2009-09-28 | 2010-04-07 | 江苏扬农化工集团有限公司 | Method for preparing 4-amino diphenylamine by catalytic hydrogenation |
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| CN104496844A (en) * | 2014-11-25 | 2015-04-08 | 江南大学 | Preparation method of alkyloxy azobenzene photosensitive foam control agent |
| US20180282258A1 (en) * | 2015-10-01 | 2018-10-04 | Monsanto Technology Llc | Process for catalytic hydrogenation of halonitroaromatics |
| CN106496063A (en) * | 2016-10-21 | 2017-03-15 | 福州大学 | A kind of method for preparing hydrodiazo benzene-like compounds |
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