CN1187314C - Synthesis of arylamine compound - Google Patents

Abstract

A method for synthesizing aromatic amine compounds is prepared by reacting aromatic nitro compounds in an organic solvent in the presence of carbon monoxide and water, selenium as a catalyst, and alkali as a cocatalyst. Wherein: there may be no substituents or substituents on the aromatic nitro compound phenyl, and the substituent X may be one or more electron-donating and/or electron-withdrawing groups; the molar ratio of aromatic nitro compounds to water 1:1 to 1:1000; the molar dosage of selenium is 0.1 to 100% of the aromatic nitro compound; the molar dosage of the base is 0 to 400% of the aromatic nitro compound; the weight ratio of the aromatic nitro compound to the solvent is 1 : 2 to 1: 1000; the reaction time is 1 to 36 hours; the reaction temperature is 20 to 120°C. The invention is simple and safe to operate, easy to obtain raw materials, less pollution, high selectivity, sensitive groups such as halogens and acyl groups on the aromatic ring are not affected, the yield is moderate to excellent, and the catalyst is easy to separate, recover and recycle after the reaction.

Description

A kind of method of synthesizing arylamine compound

technical field

The invention relates to a method for synthesizing aromatic amine compounds, in particular to a method for synthesizing aromatic amine compounds through selenium catalytic reduction of aromatic nitro compounds by using carbon monoxide and water under normal pressure.

Background technique

Aromatic amines, as a large class of important organic synthesis intermediates and raw materials, are widely used in medicine, pesticides, dyes and other fields. At present, the vast majority of aromatic amines are produced through the reduction of aromatic nitro compounds, and the number of relevant documents is huge. The reduction methods of nitro compounds used in industrialization mainly include the following: iron filings reduction, alkali sulfide reduction, Electrolytic reduction and catalytic hydrogenation reduction. Although the iron filings method and the soda sulfide method have wide adaptability, simple process, and reasonable technical economy, they are seriously polluted to the environment and have been gradually eliminated; the electrolysis method has high yield, easy operation, and environmental friendliness, but it consumes a lot of energy and is now widely used. It is used in laboratory synthesis and semi-industrial production; the catalytic hydrogenation method has large output and high product quality, and has obvious advantages in solving environmental pollution problems. Therefore, this method has become the mainstream in industry, but this method requires the use of excellent catalysts. The cost is high and the selectivity is poor. It is difficult to prepare from this method for many aromatic amines containing sensitive groups such as halogens and carbonyls. In addition, there are hydrazine reduction methods and metal hydride reduction methods under the action of catalysts, but they are only suitable for the reduction of special aromatic nitro compounds, and the cost is high, so they are not universal. In recent years, a reaction using carbon monoxide as a reducing agent to reduce aromatic nitro compounds has attracted people's interest due to its high selectivity to nitro (Tafesh A M, Weiguny J.A Review of the Selecivity Catalytic Reduction of Aromatic Nitro Compounds into Aromatic Amines Isocyanates, Carbamates and Ureas Using CO.J Chem Rev, 1996, 96: 2035-2052), but the reaction noble metal catalyst systems involved are somewhat complicated, and some are costly, and are not the most favorable industrialized methods. At a lower reaction temperature (80°C), the selenium/carbon monoxide/water system has been reported for the reduction of aromatic nitro compounds to aromatic amines (T Miyata, K Kondo, S Murai, THirashima and N Sonoda. Selenium-Catalyzed Reduction of Aromatic NitroCompounds to Amines by CO/H2O in the Presence of Triethylamine. AngewChem Int Ed Engl, 1980, 19(12): 1008), the yield is moderate to good, but triethylamine must be used as a cocatalyst. We reported the reaction of selenium/carbon monoxide/water system for the reduction of aromatic nitro compounds to efficiently produce aromatic amines under the conditions of inorganic alkali and no alkali (Peng Aidong, Lu Shiwei, CN02107742.8, 2002). Most of the above carbon monoxide/water reduction systems need to be completed under high pressure.

Contents of the invention

The object of the present invention is to provide a kind of method of synthesizing aromatic amine compound. The method has mild reaction conditions, simple and safe operation under normal pressure, easy to obtain raw materials, less pollution, high selectivity, sensitive groups such as halogens and acyl groups on the aromatic ring are not affected, the yield is moderate to excellent, and the catalyst is easy to obtain after the reaction. Separate recovery and recycling.

In order to achieve the above object, the technical scheme adopted in the present invention is as follows: in the presence of carbon monoxide and water, using aromatic nitro compounds as raw materials, selenium as a catalyst, and alkali as a promoter, or without adding any promoter, often in an organic solvent The reaction is carried out under pressure, and the nitro part is reduced to an amino group to prepare the corresponding arylamine compound; the reaction formula is as follows:

in:

There may be no substituents or substituents on the phenyl of the aromatic nitro compound, and the substituent X may be one or more electron-donating groups and/or electron-withdrawing groups; the molar ratio of aromatic nitro compounds to water 1:1 to 1:1000; the molar dosage of selenium is 0.1-100% of the reactant aromatic nitro compound; the molar dosage of alkali is 0-400% of the reactant aromatic nitro compound; the reaction time is 1-36 hours ; The reaction temperature is 20-120° C.; the weight ratio of the aromatic nitro compound to the solvent is 1:2 to 1:1000.

In the present invention:

The electron-donating substituents in the aromatic nitro compound of the reactant are alkyl groups, alkoxy groups, amino groups, etc., and the electron-withdrawing substituents are fluorine, chlorine, bromine, iodine, cyano, aldehyde groups, Keto, trifluoromethyl or carboxyl, etc.;

The base is an inorganic base or an organic base; the inorganic base is one or more of sodium hydroxide, potassium hydroxide, potassium carbonate, sodium carbonate and sodium acetate; the organic base is pyridine, triethylamine, Aniline, triphenylphosphine, 1,5-diazabicyclo[5.4.0]-5-undecene (DBU), 1,5-diazabicyclo[5.3.0]-5-nonene ( One or more of DBN), N-methylpyrrolidine and 1,4-diazabicyclo[2.2.2]octane (DABCO).

Said not adding any co-catalyst means only using selenium as a catalyst without adding a co-catalyst to react;

The carbon monoxide can use industrial carbon monoxide tail gas containing air, hydrogen, nitrogen, carbon dioxide and/or water vapor, wherein the sum of nitrogen, carbon dioxide and/or water vapor is less than or equal to 95% of the total volume, and the air content is less than or equal to the total volume 30% of;

The organic solvent is one or more polar and/or non-polar inert solvents. The polar solvent is tetrahydrofuran (THF), N,N-dimethylformamide (DMF), dimethyl sulfoxide ( DMSO), diethylene glycol, N-formylpiperidine (FP), ethylene glycol diethyl ether, dioxane, crown ether or acetone; non-polar solvents are toluene, n-hexane, xylene or benzene.

The present invention has the following advantages:

1, the present invention is normal pressure reaction. The equipment investment is small, and the operation is simple and safe.

2. Low cost. The raw material of the invention is simple and easy to obtain, and only non-metal selenium with low price is used as the catalyst.

3. Friendly to the environment. The invention has little reaction corrosion, significantly reduces the burden of three wastes treatment, meets the requirement of clean production, and is beneficial to large-scale industrial production.

4. The difficulty of the reaction process is low. The invention is simple and convenient to operate, and the subsequent separation of the product and the catalyst is easy, and can be separated by simple phase separation.

5. Good economy. The invention has high reaction selectivity, adopts non-metallic selenium as a catalyst, and has good reduction selectivity to nitro groups, sensitive groups such as halogen and cyano groups on the aromatic ring are not affected, and the yield is moderate to high; in addition, the invention has atom-economical reaction s efficiency.

6. With phase transfer function. In the catalytic reaction of the present invention, the solid selenium powder catalyst is insoluble in the reaction system before the reaction starts, and the selenium in the solid phase is converted into an active species dissolved in the reaction system in the reaction process to carry out an efficient homogeneous catalytic reaction. After the end, the catalyst is precipitated as solid-phase selenium powder, which is easy to separate and recover from the product, and can be recycled. Therefore, the present invention combines the advantages of homogeneous catalysis and heterogeneous catalysis.

Detailed ways

The present invention is described in detail below by way of examples, however, the present invention is not limited to the following examples.

Example 1

Add nitrobenzene (10mmol), Se (0.2mmol), H ₂ O (0.5mol), sodium acetate (20mmol) and solvent DMF (40ml) into a 100ml three-necked flask with a condenser and stirring, and continuously feed Carbon monoxide, heated to 88°C and stirred for 4 hours, cooled to room temperature, switched from carbon monoxide to oxygen or air and stirred for 0.5-1 hour, then filtered out the selenium powder, concentrated the filtrate obtained from the filtration, and carried out content determination by gas chromatography to obtain The chromatographic yield of aniline was 100% (calculated as nitrobenzene). The content determination adopts HP-4890D gas chromatography system, including FID detector, SE-54 capillary column (30mm) 0.32mm×1.5, vaporization chamber temperature: 280°C, column temperature: 150°C, external standard method for quantification.

Example 2

The aromatic nitro substance is o-chloronitrobenzene, and other experimental methods and conditions are the same as in Example 1. The yield of o-chloroaniline determined by gas chromatography is 89% (calculated in o-chloronitrobenzene).

Example 3

The aromatic nitro substance is p-ethylnitrobenzene, and other experimental methods and conditions are the same as in Example 1. The yield of p-ethylaniline as determined by gas chromatography is 99% (calculated as p-ethylnitrobenzene).

Example 4

The aromatic nitro substance is p-acetylnitrobenzene, and other experimental methods and conditions are the same as in Example 1. The yield of p-acetylaniline as determined by gas chromatography is 99% (calculated as p-acetylnitrobenzene).

Example 5

The aromatic nitro substance is p-ethoxynitrobenzene, and other experimental methods and conditions are the same as in Example 1. The yield of p-ethoxyaniline measured by gas chromatography is 67% (calculated as p-ethoxynitrobenzene).

Example 6

The aromatic nitro substance is o-methylnitrobenzene, and other experimental methods and conditions are the same as in Example 1. The yield of o-methylnitroaniline as determined by gas chromatography is 99% (calculated as o-methylnitrobenzene).

Example 7

The aromatic nitro substance is p-bromonitrobenzene, the reaction temperature is 100° C., other experimental methods and conditions are the same as in Example 1, and the yield of p-bromoaniline measured by gas chromatography is 56% (calculated as p-bromonitrobenzene).

Example 8

The aromatic nitro substance is p-fluoronitrobenzene, other experimental methods and conditions are the same as in Example 7, and the yield of p-fluoroaniline as determined by gas chromatography is 45% (calculated as p-fluoronitrobenzene).

Example 9

The consumption of triethylamine was 10 mmol, and the reaction time was 9 hours. Other experimental methods and conditions were the same as in Example 1. The yield of aniline determined by gas chromatography was 100% (in terms of nitrobenzene).

Example 10

Nitrobenzene (20mmol), selenium (0.1mmol), water (20mmol), triethylamine (20mmol), oil bath temperature 150°C, carbon monoxide reaction initial gauge pressure 1Mpa, reaction for 2 hours, other experimental methods and conditions are the same implementation Example 1, the yield of aniline measured by gas chromatography is 63% (in terms of nitrobenzene).

Example 11

No sodium acetate was added, the reaction temperature was 50° C., and the reaction time was 20 hours. Other experimental methods and conditions were the same as in Example 1. The yield of aniline measured by gas chromatography was 98% (calculated as nitrobenzene).

Example 12

The amount of water was 1 mol, and other experimental methods and conditions were the same as in Example 11. The yield of aniline determined by gas chromatography was 87% (calculated as nitrobenzene).

Example 13

The solvent is acetone, and other experimental methods and conditions are the same as in Example 11. The yield of aniline determined by gas chromatography is 21% (calculated as nitrobenzene).

Example 14

The solvent is formylpiperidine and the reaction time is 10 hours. Other experimental methods and conditions are the same as in Example 11. The yield of aniline determined by gas chromatography is 98% (calculated as nitrobenzene).

Example 15

The solvent was toluene, and the reaction time was 20 hours. Other experimental methods and conditions were the same as in Example 1. The yield of aniline measured by gas chromatography was 87% (in terms of nitrobenzene).

Example 16

Sodium carbonate 10mmol, other experimental methods and conditions are the same as in Example 1, and the yield of aniline measured by gas chromatography is 90% (in terms of nitrobenzene).

Example 17

Aromatic nitro is p-methylnitrobenzene, sodium hydroxide 10mmol, other experimental methods and conditions are the same as embodiment 1, and the p-methylaniline yield measured by gas chromatography is 93% (in p-methylnitrobenzene) .

Example 18

The aromatic nitro substance is m-trifluoromethylnitrobenzene, potassium hydroxide 20mmol, and the reaction time is 5 hours. Other experimental methods and conditions are the same as in Example 1. The yield of m-trifluoromethylaniline measured by gas chromatography is 98%. (calculated as m-trifluoromethylnitrobenzene).

Claims (6)

1, a kind of method of synthesizing arylamine compound in the presence of carbon monoxide and water, is a raw material with the aromatic nitro compound, and selenium is catalyzer, and alkali is promotor, reacts under normal pressure in organic solvent, and its reaction is shown below:

Wherein:

The molar ratio of material of aromatic nitro compound and water is 1: 1～1: 50;

The mole dosage of selenium is 0.1～2% of an aromatic nitro compound;

The mole dosage of alkali is 200～400% of an aromatic nitro compound;

The weight ratio of aromatic nitro compound and solvent is 1: 2～1: 1000;

X is one or more electron-donating groups and/or electron-withdrawing group, and wherein electron-donating group is alkyl, alkoxyl group or amido; Electron-withdrawing group is fluorine, chlorine, bromine, iodine, cyano group, aldehyde radical, ketone group, trifluoromethyl or the carboxyl that directly links to each other with aromatic ring;

Reaction times is 1～36 hour;

Temperature of reaction is 20～120 ℃.

2, the method for synthesizing arylamine compound as claimed in claim 1 is characterized in that, described alkali is mineral alkali or organic bases.

3, method as claimed in claim 2 is characterized in that, described mineral alkali is one or more in sodium hydroxide, potassium hydroxide, salt of wormwood, yellow soda ash and the sodium acetate; Described organic bases is pyridine, sodium alkoxide, triethylamine, aniline, triphenylphosphine, 1,5-diaza-bicyclo [5.4.0]-5-undecylene, 1,5-diaza-bicyclo [5.3.0]-5-nonene, N-crassitude and 1, one or more of 4-diaza-bicyclo [2.2.2] octane.

4. the method for claim 1, it is characterized in that, described carbon monoxide is the industrial carbon monoxide tail gas that contains air, hydrogen, nitrogen, carbonic acid gas and/or water vapour, wherein the content sum of nitrogen, carbonic acid gas and/or water vapour is smaller or equal to 95% of cumulative volume, and air content is less than 30%.

5, the method for claim 1 is characterized in that, described organic solvent is one or more polarity and/or nonpolar inert solvent.

6, method as claimed in claim 5, it is characterized in that, described polar solvent is ethanol, tetrahydrofuran (THF), N, dinethylformamide, dimethyl sulfoxide (DMSO), glycol ether, N-formyl piperidine, ethylene glycol diethyl ether, dioxane, crown ether or acetone; Non-polar solvent is normal hexane, toluene, dimethylbenzene or benzene.